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In this work, copper sulfide particles are synthesized with different Co doping concentrations such as 0, 1 and 5% at 80 °C by optimizing synthesis times from 1 to 3 h. Copper sulfide particles possess two structural phases of covellite CuS and digenite Cu9S5. The increase in synthesis time from 1 to 3 h increases the Cu9S5 phase growth and changes the morphology from flower to microsphere. The CuS synthesized with 0, 1 and 5% Co dopant concentrations demonstrate flower consisting of agglomerated nanosheets, microsphere and flower like microsphere. The elemental investigation substantiates Co ions presence in CuS microspheres. The A1g (LO) mode intensity is decreased with increase in Co dopant concentration confirming Co incorporation into CuS microsphere. The CuS synthesized with 0, 1, 5% Co dopants exhibit 322 mV, 305 mV and 289 mV to attain 100 mA/cm2 in 1 M KOH seawater. The CuS synthesized with 5% Co dopant demonstrates higher double layer capacitance (Cdl) of 173.9 mFcm−2 and lower charge transfer resistance (Rct) of 6.07 Ω with 78.84% retention after 10 h continuous stability than that of the other pristine (118.3 mFcm−2, 13.72 Ω) and 1% Co doped CuS microsphere (165.7 mFcm−2, 8.55 Ω) indicating more surface active site and rapid charge carrier transport, respectively.

When valuable digenite is heavily oxidized, it may not respond to the flotation process and remain largely in the tailing with the pyrite. This is problematic because the recovery of digenite from heavily oxidized Cu-S ore is of great significance. In this study, the effect of sodium sulfide on the selective flotation separation of heavily oxidized digenite and pyrite was investigated. The micro-flotation results showed that the floatability of digenite could be effectively restored with the addition of sodium sulfide and sodium butyl xanthate (SBX). However, pyrite showed a poor floatability under the same conditions. Based on this, the flotation separation of artificially mixed minerals was carried out, and a satisfactory result with 51.4% Cu grade and 93.1% Cu recovery could be obtained in the optimized flotation conditions. Then, the sulfidization mechanism of heavily oxidized digenite was discussed in detail through an examination of zeta potential measurements, adsorption measurements, contact angle measurements, and X-ray photoelectron spectroscopy (XPS) analyses. The results indicated that the negatively charged SH− could adsorb on the surface of digenite through chemisorption, and lower the quantity of hydrophilic copper sulfate and oxides/hydroxides on the digenite surface in the presence of SBX, thus significantly increasing the surface contact angle, decreasing the amount of SBX adsorbed to the value observed for unoxidized digenite, and promoting the flotation of heavily oxidized digenite.

The Lar porphyry Cu-Mo deposit is located 20 km northeast of Zahedan in the Sistan Suture Zone (SSZ), in the southeastern part of Iran. Lar is a sub-economic porphyry Cu-Mo deposit with average grades of 0.16% Cu, 0.01% Mo, and 0.66 ppb Au. The Cu-Mo mineralization developed in post-collisional shoshonitic syenitic to monzonitic intrusions in an Oligocene igneous complex known as the Lar Igneous Complex (LIC). The host and country rocks have undergone variable degrees of supergene and hypogene alteration including silicic, potassic, propylitic, phyllic, and argillic alteration. The Cu-Mo mineralization is mainly controlled by NNW striking faults and fractures, and occurs as quartz veins and veinlets, disseminated sulfides, and stockworks. The mineralization can be divided into two types: hypogene and supergene. Hypogene mineralization is characterized by chalcopyrite, pyrite, bornite, molybdenite and magnetite, whereas supergene mineralization is characterized by enargite, covellite, chalcocite, digenite, malachite, azurite, and iron hydroxides. Sulfur isotope values for hypogene sulfides range from 0.28 to −1.76‰ and suggest an igneous source/or mantle-derived origin for sulfur. The δ18O values for quartz in mineralized quartz veins range from 9.6 to 11.5‰. These values would be in equilibrium with waters having calculated δ18OH2O values of 9.3–11.2‰, suggesting magmatic water. Re-Os dating of two molybdenite samples from two different drill holes yields dates of 29.72 ± 0.11 and 31.95 ± 0.11, suggesting that the system was active for at least 2.0 m.y.

Ethyl isobutyl xanthogenic acetate (EIBXAC) was used as a novel collector in the flotation of secondary copper sulfide minerals owing to its ability to separate copper and sulfur. The collectivity and selectivity mechanisms of this novel collector were investigated using single-mineral and artificial mixed-mineral tests, combined with adsorption tests, fourier transform infrared spectroscopy (FTIR) tests, and density functional theory (DFT) calculations. The results of the flotation indicated that EIBXAC had a better collecting effect than ammonium dibutyl dithiophosphate (ADD) on covellite and digenite, which had an insignificant effect on pyrite. The artificial mixed-mineral experiment indicated that EIBXAC could improve the grade of the copper concentrate while maintaining the same recovery, it had higher efficiency and selectivity. Based on the results of the adsorption and FTIR tests, the adsorption capacities of EIBXAC on the surfaces of covellite, digenite, and pyrite were quite different: Cu-S bonds were formed on covellite and digenite, and Fe-O bonds were formed on pyrite, which was also verified that EIBXAC was chemically adsorbed on the mineral surface. DFT calculations indicated that the adsorption capacity of EIBXAC for covellite and digenite was stronger than that of ADD, which had a weaker adsorption capacity for pyrite. This study can provide theoretical guidance for the application of EIBXAC.

Digenite (Cu1.8S) has attracted extensive attention as candidate for use in thermoelectric applications due to its low-cost, low-toxicity characteristics, but the thermoelectric (TE) property is still not good. In this work, PbS was used for improving TE properties of polycrystalline Cu1.8S bulk. Cu1.8S+ x wt% PbS (x = 0, 0.5, 1, 2, 3) bulk samples were fabricated via mechanical alloying (MA) and spark plasma sintering (SPS) techniques. The effects of adding PbS on the TE performance of Cu1.8S were investigated in detail at the temperature between 323 K and 773 K. According to the results, introducing PbS is an efficient approach for optimizing the TE properties of Cu1.8S, which is mainly due to the maintained electrical transport properties by the regulated hole carrier concentration and the modified band structure, as well as the reduced the thermal conductivity by the generated point defect and additional interfaces. An optimum thermoelectric figure of merit (ZT) value of 1.1 was obtained at 773 K for the Cu1.8S sample with 2 wt% PbS, which is 2.2 times higher than that of the pristine Cu1.8S (0.49 at 773 K).

In the present study, the mechanochemically prepared covellite, CuS and chalcocite, Cu2S nanocrystals are compared in detail. Concretely, the SEM, EDS, N2 adsorption, UV–Vis, PL, FTIR, ZP measurement, PCCS, XPS and DTA/TG were used. SEM, EDS and elemental mapping have shown that the agglomerates containing nanoparticles of the corresponding phases were formed as a result of milling. The nitrogen adsorption method has documented richer surface properties in the case of CuS sample. The specific surface area values were 2.7 m2 g−1 and 1.4 m2 g−1 for CuS and Cu2S, respectively. UV–Vis and PL measurements have shown that these materials might be suitable for optoelectronic applications, as the optical bandgaps were 1.92 eV and 3 eV for CuS and Cu2S, respectively. FTIR spectrum of CuS exhibited a peak at 621 cm−1, which is characteristic for this material. ZP values were more negative in the case of CuS and PCCS has confirmed the finer character of this sample (x50 values were 680 nm and 617 nm for Cu2S and CuS, respectively). XPS method documented the surface oxidation of the prepared Cu2S. The thermal stability measurement up to 550 °C has shown that Cu2S does not undergo significant changes (only 1.4% weight loss was observed), whereas CuS is losing sulfur and is transformed into digenite and chalcocite (14.3% weight loss was observed). The mechanochemically synthesized copper sulfides show high activities in photodecolorization of Methyl Orange dye under visible light irradiation, as Cu2S was able to completely decompose the dye in 150 min and CuS caused 80% decomposition after the same time of treatment.

The source of metal and sulphur in porphyry and related epithermal deposits is a long debated issue. The role of mantle-derived magmas in providing the metals has proved particularly problematic. Here we report new He and Ar isotope determinations from ore fluids from the Zijinshan high sulfidation-epithermal Cu-Au deposit and Wuziqilong transitional Cu deposit from the giant Zijinshan porphyry-epithermal Cu-Au-Mo-Ag ore system (from 105 to 91 Ma), to decipher the contribution of mantle-derived volatiles and heat. Hydrothermal fluids in pyrite and digenite have 3He/4He up to 5.7 Ra, among the highest measured in ancient ore-forming fluids. A linear correlation between He and Ar isotopes indicate that the ore fluids were, to a first order, a mixture between a shallow crustal fluid, with low 3He/4He, and a dominantly mantle-derived fluid with high 3He/4He. The mantle 3He/4He is close to values typical of the upper mantle indicating the initial magmas that provided the heat for hydrothermal systems did not assimilate large volumes of continental crust. The ore-forming fluids have 3He/heat ratios that are 10 to 80 times higher than that of mid-oceanic ridge hydrothermal fluids, indicating that the metal-bearing fluids acquired heat and volatiles in a convective, rather than conductive, hydrothermal regime. It appears that mantle-derived volatiles, heat and probably metals have made a major contribution to the Cu-Au-Mo-Ag mineralization in the Zijinshan orefield.

The ease or complexity of the selective separation of copper sulphur minerals during sulphide flotation is always dominated by the level of surface oxidation. The interaction between oxidized pyrite and other base metal sulphides is important for the flotation process. In this study, the effects of fine digenite particles on the flotation of heavily oxidized pyrite in the presence of sodium butyl xanthate were investigated. The micro-flotation results showed that the floatability of pyrite declined sharply once it was over-oxidized. However, the addition of fine digenite significantly restored the floatability and flotation rate of pyrite, even in strong alkaline solutions. Scanning electron microscopy (SEM) and energy dispersive spectrometry (EDS) of the flotation products indicated no copper ions on the pyrite surface. This restoration can be attributed to fine digenite particles adsorbing on the surface of coarse pyrite particles and removing a large number of fine pyrite particles covering the pyrite surface in the presence of sodium butyl xanthate. The extended Derjaguin–Landau–Verwey–Overbeek theory based on zeta potential measurements and contact angle measurements was used to calculate the interaction energy between mineral particles. The calculation results showed good agreement with the flotation and SEM-EDS analysis results and explained the mechanism of particle interaction.

The growing demand of copper metal in the world continues to push the limit of utilization of complex copper resources, among which the iron oxide associated with copper–gold-uranium ore deposits (IOCG-U) contain economic copper and abundant gangues including uranium-bearing minerals that carry naturally occurring radionuclides and pose a challenge for public health and environment. To support the removal of radionuclides from copper flotation concentrate, the particle size fractionation method is integrated into the H2SO4 leach process to illustrate the deportment of long-life radionuclides (238U, 230Th, 226Ra, 210Pb, 210Po) and other non-copper elements during the process. H2SO4 leach treatment largely dissolved non-copper elements (Fe, Ca, Mg, Al, K, F, U, Th, etc) from the gangue minerals and promoting the further copper phase transformation from the primary chalcopyrite and bornite towards covellite and copper sulphates. In the leach process, over 98% of 238U and 230Th were dissolved into H2SO4 leach solution due to the decomposition of uranium-bearing minerals, while the released 226Ra, 210Pb and 210Po from uranium-bearing minerals were largely remobilized, precipitated as insoluble sulphate salts, and accumulated in the small particle size fractions of the H2SO4 leach residue. The underlying mechanism of this deportment is attributed to the mineralogical changes as an increased amount of covellite, digenite and copper sulphate are associated with the small particle size fractions, and serve as preferential hosts for 226Ra, 210Pb and 210Po. Therefore, a conceptual flowsheet which facilitates further removal of 226Ra, 210Pb and 210Po from the H2SO4 leach residue is discussed based on particle size fractionation of the copper concentrate leach residue where radionuclides have been selectively leached or re-distributed.

The Kekura gold deposit in Western Chukotka, Russia is spatially related to the granitic rocks of the Early Cretaceous Gvardeisky Complex. The deposit was formed during five mineralization stages: (1) cassiterite-scheelite-chalcopyrite-bornite-arsenopyrite, (2) molybdenite, (3) chalcopyrite-gold-bismuth tellurides, (4) arsenopyrite-gold-scheelite, and (5) stibnite-gold-silver. The tetrahedrite group minerals (Ttgs) were identified in stages 2, 4, and 5. In the molybdenite stage Ttgs are associated with digenite, bornite, chalcopyrite, molybdenite, and arsenopyrite. Ttgs from the arsenopyrite-gold-scheelite stage are associated with scheelite, chalcopyrite, sphalerite, galena, and native gold with fineness of 800–850. Along with tetrahedrite, stibnite-gold-silver mineralization includes Ag-Au and Au-Ag-Hg alloys, native silver, sphalerite, stibnite, boulangerite. The molybdenite stage Ttgs display a wide range of the Sb/(Sb + As + Bi) ratio (sb) 0.06–0.85 and a narrow range of the Fe/(Fe + Zn) ratio (fe) 0.78–1.00, and are enriched in Cu (up to 5.767 apfu Cu at the M(1) site); the Ag content does not exceed 0.080 apfu. Ttgs of the arsenopyrite-gold-scheelite stage have the Cu-free at M(1) site, but are highly variable in the sb and fe values, ranging from 0.24 to 1.00, and from 0.14 to 1.00, respectively; the Ag concentration is higher than that in the molybdenite stage Ttgs, reaching 0.365 apfu. The stibnite-gold-silver tetrahedrite has high Ag (up to 3.442 apfu) and sb and fe ranging from 0.68 to 1.00 and from 0.10 to 0.84, respectively. Some Ttgs compositions of the molybdenite and stibnite-gold-silver stages are Bi-bearing that is caused by the replacement of previous Bi-minerals.

The Lavra Velha deposit is a poorly understood gold deposit hosted by the 2.1 Ga Ibitiara Granitoid, within the Sao Francisco Craton (Brazil). Although not consensually agreed, Lavra Velha has been inserted into the Iron Oxide-Copper-Gold (IOCG) class. The major alteration footprint of the deposit involves an upward mineralogical zoning from widespread chlorite-epidote-calcite (propylitic) to white mica-hematite-quartz association with an intervening magnetite-tourmaline-quartz-white mica realm. The ore occurs mostly as massive lenses composed of magnetite, hematite, pyrite, tennantite, bismuthinite, digenite and native gold. Gold is present as inclusion within hematite, pyrite, quartz and cassiterite, in association with white mica, but also with supergene jarosite-goethite. The proximal footwall and hanging walls of the mineralization are commonly anomalous in Cr-Ni-Co and, where weathered, a talc-nontronite association is documented. Such features are considered to represent ultramafic rocks closely associated with mineralization. Reflectance spectroscopy results show that white mica, hematite and Fe-tourmaline are closely and spatially associated with gold mineralization, thus representing a proximal alteration mineralogy. Notably, white mica becomes progressively more phengitic (>2210 nm) as higher Au grades are laterally approached, whereas it has muscovitic composition (

Digenite (Cu1.8S) as a low-cost, low-toxicity thermoelectric material attracts more and more attention due to its excellent electrical transport. In this paper, the Bi2S3 and Bi2S3@Bi core-shell were introduced to Cu1.8S bulk prepared by mechanical alloying (MA) and spark plasma sintering (SPS) technique. The core-shell structural nanorods were synthesized by a hydrothermal method using Bi2S3 nanorods as the template. The effects of adding Bi2S3 on the thermoelectric properties of Cu1.8S were investigated in detail at the temperature between 323 K and 723 K. The power factor of Cu1.8S was enhanced by introducing Bi2S3@Bi core-shell nanorods due to improved Seebeck coefficient. A maximum thermoelectric figure of merit (ZT) value of 0.77 was attained at 723 K due to optimized thermal transport properties and to the maintained electrical transport properties, which is 2.4 times higher than that of the pristine Cu1.8S (0.32 at 723 K).

The fluid-driven transformation of chalcopyrite (CuFeS2) into Cu-rich sulfides (e.g., digenite, Cu1.8S; covellite, CuS; and chalcocite, Cu2S) is a complex mineral replacement reaction where the reaction pathway is controlled by the interplay between evolving mineral make-up, texture/porosity, and solution chemistry. This transformation was investigated in CuCl2 + H2SO4 solutions under mild hydrothermal conditions (180 to 300 °C); the reaction kinetics, nature of minerals formed, and oxidation states of aqueous Fe and Cu were followed in-situ in real-time using synchrotron powder X-ray diffraction (PXRD) and X-ray absorption spectroscopy (XAS). These results are corroborated by an analysis of the textures of reaction products from comparative ex-situ quench experiments. The in-situ and ex-situ experiments revealed that: (i) aqueous Cu2+ quickly reduced to Cu+ during chalcopyrite replacement in all experiments, and Fe dissolved as Fe2+; (ii) covellite was the first mineral to form, followed by digenite-high with delayed nucleation; and (iii) a non-quenchable hydrated Fe sulfate mineral (szomolnokite, FeSO4.H2O) formed at 240 °C at relatively low concentrations of added CuCl2, which supressed the formation of digenite-high. The quantitative mineral phase evolution retrieved using in-situ PXRD was modelled using a novel dual power law (dual Avrami approach). Avrami exponents revealed that chalcopyrite replacement proceeded initially via a 3-dimensional growth mechanism, followed by diffusion-controlled growth. This is consistent with initial formation of a porous covellite rim around chalcopyrite, confirmed by the observation of the ex-situ reaction products, followed by a second reaction stage where the transport properties of aqueous Fe (released from the chalcopyrite) and aqueous Cu (added from the initial solution) to and from the reaction front become the rate-limiting step; and these two kinetic stages exist even where covellite was the only replacement product. The activation energies calculated for these two kinetic stages were 42.9 ± 7.4 kJ mol−1 and 39.3 ± 13.1 kJ mol−1, respectively. We conclude that (i) the replacement of chalcopyrite by covellite and digenite proceeds via an interface coupled dissolution and reprecipitation mechanism; (ii) availabilities of aqueous Cu+ and of Fe2+ play a critical role in covellite nucleation and on the sequence of mineral precipitation during chalcopyrite replacement; the Cu+ to Cu2+ ratio is controlled by the kinetics of Cu2+ to Cu+ reduction, which increases with increasing temperature, and by the transport of Cu2+ through the daughter mineral to the reaction front, while Fe2+ availability is limited at high temperature by the formation of insoluble ferrous sulfate; and (iii) this reaction evolves from a bulk fluid-chemistry controlled reaction (initial formation of covellite) to an interface-controlled reaction (digenite-high or further transformation to covellite). The current findings highlight the complex feedback between Cu2+/Cu+ aqueous redox, mineral nucleation, and ion transport properties during replacement reactions, and the applicability of combined in-situ PXRD and XAS techniques in deciphering complex fluid-driven mineral replacement reactions.

Secondary copper sulfide mineral fine particles are easily oxidized, and their effective recovery by froth flotation is extremely challenging. This study investigated the roles of sodium sulfide (Na2S) and sodium butyl xanthate (SBX) in the hydrophobic agglomeration flotation of oxidized digenite fine particles. The microflotation experiments of the study showed that the simultaneous addition of Na2S and SBX is beneficial for improving the floatability of heavily oxidized digenite fine particles. In addition, the recovery at pH 7.0 was apparently higher than that of the unoxidized digenite fine particles, indicating that hydrophobic agglomeration of digenite fine particles may occur. The results of the zeta potential measurements, X-ray photoelectron spectroscopy analyses, and contact angle measurements suggested that negatively charged hydrogen sulfide ion and xanthate ion respectively hydrolyzed from Na2S and SBX adsorbed on the surface of digenite. Moreover, they significantly decrease the amount of hydrophilic copper sulfate and oxides/hydroxides on the surface, thus improving the surface hydrophobic degree of digenite. The results of the optical microscopy analysis, particle size analysis, and extended Derjaguin–Landau–Verwey–Overbeek theory calculations provided strong evidence for the roles of Na2S and SBX in promoting the hydrophobic agglomeration of the digenite fine particles. After treatment with Na2S and SBX, the total interaction energies between the digenite fine particles were negative, indicating that the strong hydrophobic attractive forces promote the formation of large-sized agglomerates, enabling the digenite fine particles to be more easily captured by bubbles than those without the treatment. Therefore, effective recovery of heavily oxidized digenite fine particles can be realized by the hydrophobic agglomeration flotation technology induced by Na2S and SBX.

Bis( O -isobutyldithiocarbonato)copper(II) complex [Cu(SCSOCH 2 CH(CH 3 ) 2 ) 2 ] was used as a single source precursor to synthesize both copper sulfide thin films and nanoparticles. The copper sulfide thin films were deposited by the aerosol assisted chemical vapor deposition method, whereas the nanoparticles were synthesized by the hot injection route. The deposited copper sulfide thin films showed different morphologies based on spherical to flower or flakes-like crystallites depending on the temperature of deposition. Powder X-ray diffraction studies of the deposited films revealed formation of pure Covellite-hexagonal phase of copper sulfide, with high crystallinity at elevated temperature. The diffraction pattern of nanoparticles synthesized in dodecanthiol, and 1-octadecene at 150 °C, 190 °C and 230 °C showed the formation of monodispersed nanoparticles of Cu 1.78 S Roxbyite phase with an average size of ca . 12 ± 1 nm. Interestingly, when oleylamine was used as a capping solvent, the formation of Covellite and Digenite phases were obtained at temperatures of 110 °C and 190 °C respectively. Electron microscopic studies showed formation of rod shaped particles at 110 and 150 °C, whereas at higher temperatures formation of fairly spherical nanoparticles were observed.

The several-hundred-m-thick Eocene-Oligocene volcanic units in the Urmia-Dokhtar magmatic arc in northwestern Central Iran host stratabound and fault-controlled copper mineralization. The Kuh-Pang deposit (2.8 Mt at 1.65 wt% Cu, 0.52 g/t Au, 34 g/t Ag) has vein-style copper mineralization, with primary Cu-sulfides of chalcopyrite, bornite, chalcocite and digenite, and supergene Cu-sulfides of chalcocite, covellite, malachite and azurite, in a tectonic–hydrothermal breccia zone within rhyodacite and andesite flows. The mineralization is accompanied by a variety of alterations including silicic, carbonate, argillic and advanced argillic within a broad-scale propylitic halo. The main ore formation is related to hydrothermal breccias, and has a close association with silicic and argillic alterations. Sulfides formed during hydrothermal alteration, as indicated by: 1) the occurrence of disseminated sulfides in the groundmass of hydrothermally altered rocks, 2) the co-precipitation of sulfides and alteration minerals (e.g., kaolinite, alunite) in the cement of hydrothermal breccias, and 3) the occurrence of sulfides filling fissures and voids of hydrothermally altered rocks (vuggy quartz). The main mineralization stages include: (i) pre-ore stage with pyrite and arsenopyrite, (ii) main ore-stage with chalcopyrite, bornite, chalcocite I and digenite, and (iii) late-ore and supergene enrichment stage with chalcocite II and covellite. Electron microprobe analyses of pyrite show that As, Cu and Co are the most abundant minor elements. Back-scatter electron imaging of pyrite shows zoning features that closely reflect variations in the As/S ratio. High Cu concentration in pyrite is probably related to the presence of sub-micrometer particles and aggregates of chalcopyrite or other Cu-bearing sulfide minerals. Silver is preferentially enriched in supergene chalcocite and covellite. The mineral assemblage indicates a trend from intermediate to high sulfidation state, and arsenopyrite geothermometry defines temperatures for the pre-ore sulfides ranging from 250 to 370°C. The sulfur isotope composition of pre-ore pyrite and arsenopyrite shows a δ34S range of −1 to 3‰, indicating a magmatic sulfur-source. The copper sulfides have lower δ34S values (−9 to −3‰), indicating that the ore-forming fluids gradually became SO42−-enriched and relatively oxidized during Cu mineralization. The tectono-magmatic setting, mineral assemblage and hydrothermal alteration, including advanced argillic and silicic zones, suggest that the Kuh-Pang copper deposit is a high sulfidation epithermal deposit in a volcanic arc terrain.

The basalt-hosted Wocan Hydrothermal Field (WHF), located on the NW slope of an axial volcanic ridge at a depth of ∼3000 m at 6°22′N on the slow-spreading Carlsberg Ridge, northwest Indian Ocean, was discovered in 2013 during Chinese DY28th cruise. Preliminary investigations show that the field consists of two hydrothermal sites: Wocan-1, which shows indications for recent high-temperature hydrothermal activity, is located near the peak of the axial volcanic ridge at a water depth of 2970–2990 m, and Wocan-2 site, located at a water depth of 3100 m, ∼1.7 km to the northwest of Wocan-1. The recovered hydrothermal precipitates can be classified into four groups: (i) Cu-rich chimneys; (ii) Cu-rich massive sulfides; (iii) Fe-rich massive sulfides; and (iv) silicified massive sulfides. We conducted mineral texture and assemblage observation and Laser-ablation ICP-MS analyses of the hydrothermal precipitates to study the mineralization processes. Our results show that there are distinct systematic trace element distributions throughout the different minerals in the four sample groups. In general, chalcopyrite from the group (i) is enriched in Pb, As, Mo, Ga, Ge, V, and Sb, metals that are commonly referred to as medium- to low-temperature elements. In contrast these elements are present in low contents in the chalcopyrite grains from other sample groups. Selenium, a typical high-temperature metal, is enriched in chalcopyrite from groups (ii) and (iv), whereas Ag and Sn are enriched only in some silicified massive sulfides. As with chalcopyrite, pyrite also shows distinct trace element associations in grains with different habitus. The low-temperature association of elements (Pb, Mo, Mn, U, Mg, Ag, and Tl) is typically present in colloform/framboidal pyrite, whereas the high-temperature association (Se, Co, and Bi) is enriched in euhedral pyrite. Sphalerite in the groups (i) and (iii) at Wocan-1 is characterized by high concentrations of Ga, Ge, Pb, Cd, As, and Sb, indicating that sphalerite in these sample groups likely precipitated at intermediate temperatures. Early bornite, which mainly occurs in the central part of the Cu-rich chimney, is typically enriched in Sn and In compared to the other minerals. In contrast, late bornite that likely formed during increasing interaction of hydrothermal fluids with cold, oxygenated seawater has low Sn and In, but significantly higher concentrations of Ag, Au, Mo and U. Digenite, also forming in the exterior parts of the samples during the late stages of hydrothermal fluid venting, is poor in most trace elements, except Ag and U. The notable Ag enrichment in the late-stage mineral assemblages at both Wocan-1 and Wocan-2 may therefore be related to lower temperatures and elevated pH. Our results indicate that Wocan-1 has experienced a cycle of heating with Cu-rich chimney growth and subsequent cooling, followed by late seafloor weathering, while Wocan-2 has seen intermediate- to high-temperature mineralization followed by intense silicification of sulfides. Seafloor weathering processes or mixing of hydrothermal fluids with seawater during the waning stages of hydrothermal fluid flow result in significant redistributions of trace elements in sulfide minerals.

The Zijinshan high-sulfidation epithermal Cu–Au deposit is located in the Zijinshan ore field of South China, comprising porphyry–epithermal Cu–Au–Mo–Ag ore systems. The Cu ore body is more than 1000 m thick and is characterized by an assemblage of digenite–covellite–enargite–alunite. Digenite is the dominant Cu-bearing mineral, which makes this deposit unique, although the mechanisms of digenite formation remain controversial. To elucidate the genesis of digenite, this paper presents the Cu isotopic compositions of Cu-sulfides in the Zijinshan high-sulfidation Cu–Au deposit. The Cu isotopic values (65Cu relative to NIST 976) of all samples range from −2.97‰ to +0.34‰, and most values fall in a narrow range from −0.49‰ to +0.34‰, which is similar to the Cu isotopic signature of typical porphyry systems. Copper isotope ratios of each mineral decrease with increasing depth, a trend that is also typical of porphyry deposits. The variation tendency of δ65Cu values between sulfides is consistent with the sequence of mineral formation. These observations suggest that the Cu-sulfides in the Zijinshan Cu–Au deposit have a hypogene origin.

The Ca–Cr–Cu–Fe–Mg–Mn–S system has been thermodynamically assessed using all available experimental data. The thermodynamic description of the high-temperature phase Chromium and Iron Pyrrhotite is described using a two-sublattice model which allows the description of the stability range of this phase in the binary Fe–S and Cr–S systems and also the solubility of such elements as Cu, Mg and Mn in the binary systems. Particular attention was given also to the phases Oldhamite and Digenite, which exhibit very wide solubility with respect to the metal elements. In this part of the report binary and quasi-binary subsystems are presented.

Cu-Fe-sulphide mineral assemblages from the Olympic Dam (OD) Fe-oxide Cu-U-Au-Ag deposit, South Australia, are studied down to the nanoscale to explore the potential these minerals have for understanding genetic processes such as primary deposit zonation. Cu-Fe-sulphide pairs: ‘brown’ bornite associated with chalcopyrite (bornite-chalcopyrite zone); and symplectites of ‘purple’ bornite with species from the chalcocite group, Cu2 − xS (bornite-chalcocite zone), co-define an upwards and inwards deposit-scale zonation at OD. In the bornite-chalcocite zone, there is also an increase in the proportion of chalcocite relative to bornite within the symplectites towards upper levels. In this case, two-phase Cu2 − xS assemblages are also present, as anisotropic, hexagonal chalcocite (CcH) with lamellar exsolutions of digenite, distinguishable at the μm-scale. Using compositional data (electron microprobe) combined with Transmission Electron Microscopy (TEM) study of foils prepared in–situ via Focused Ion Beam (FIB)-SEM, we show that Cu-Fe-sulphides from different ore zones feature nanoscale intergrowths, lattice defects, superstructure domains (na) and antiphase boundary domains (APBs) that can be interpreted as due to exsolution, coarsening and phase transformation during cooling from high-T solid solutions in the system Cu-Fe-S and sub-systems according to published phase diagrams. ‘Brown’ bornite [(Cu + Fe)/S > 5] contains pervasive lamellae of chalcopyrite which extend down to the nanoscale; such specimens appear homogeneous at the μm-scale. ‘Purple bornite’ [(Cu + Fe)/S 300 °C (high-T phases, Cu-poor digenite), followed by cooling along distinct paths down to

Zijinshan is the largest high-sulfidation epithermal Cu–Au deposit on mainland China. The primary mineralization at the deposit is characterized by pyrite, digenite and covellite. Although some Rb Sr isochron ages of the fluid inclusions in quartz and the apparent K-Ar age of the Cu-bearing alunite alteration zone have been previously interpreted as the ore-forming age, the Rb-Sr and K-Ar dating systems are usually readily reset due to their closure temperature, and thus document the latest thermal event. In order to precisely determine the age of the Cu mineralization, eight-pyrite separates were Re-Os dated, and seven yielded an isochron age of 103 ± 4 Ma with an initial 187 Os/ 188 Os ratio of 0.45 ± 0.14. This date is interpreted as the age of Cu mineralization, which is in agreement with geochronological data from molybdenite and the porphyritic granodiorite that hosts Cu-Mo mineralization at Luoboling (located 2 km NE of Zijinshan), suggesting that these two deposits were formed during the same metallogenic event. The relatively low initial 187 Os/ 188 Os ratio indicates that the source of the Cu at Zijinshan is predominantly the crust with input from the mantle.

Digenite (Cu1.8S) is a subject of increasing interest as a potential p-type thermoelectric material because of its element abundance, low cost and environmental friendliness. However, its thermoelectric properties are limited by high thermal conductivity. In this work, the Cu1.8S with x wt% Bi2Te3 (x = 0, 0.5, 1, 3, 5) samples were prepared by combining mechanical alloying (MA) and spark plasma sintering (SPS) technology. The results reveal that Bi2Te3 addition can effectively optimize the thermoelectric properties of Cu1.8S materials by tuning the carrier concentration and introducing nanoprecipitates. As a result, the optimal Cu1.8S +1 wt% Bi2Te3 sample presents an excellent performance, with relatively high ZT value of 1.1 (at 773 K), which is approximately 2.4 times that of pure Cu1.8S.

We report the synthesis and crystal structures of bis(dibenzyl dithiocarbamato) copper(II) and silver(I) complexes and their use as precursors to prepare Cu1.8S and Ag2S nanoparticles. Single crystal analysis of bis(dibenzyl dithiocarbamato)Cu(II) complex consist of a monomeric entity where the two dibenzyl dithiocarbamate ligands form a distorted square planar geometry around the Cu(II) ion. The bis(dibenzyl dithiocarbamato)Ag(I) formed hexameric coordination complex consisting of two distorted hexagonal Ag3S3 rings. The complexes were thermolysed at 220 °C to prepare copper sulphide and silver sulphide nanoparticles. Powder X-ray diffraction (p-XRD) patterns of the copper sulphide nanoparticles were indexed to digenite Cu1.8S, while silver sulphide nanoparticles were confirmed to be acathinite Ag2S. High-resolution transmission electron microscopy (HRTEM) images showed Ag2S nanoparticles with particle size in the range 11.4–27.4 nm while Cu1.8S nanoparticles are semi-spherical in shape with slightly agglomerated particles in the range 6.9–24.0 nm. The as-prepared nanoparticles were used as nano-photocatalysts for the degradation of methylene blue dye (MB) under UV light irradiation with degradation efficiency of 42.52% and 48.39% for Cu1.8S and Ag2S nanoparticles respectively.

Bis( O -alkylxanthato)copper(II) (alkyl = Et ( 1 ), Hex ( 2 ) and Oct ( 3 )) complexes were synthesized and used as single source precursors for the synthesis of copper sulfide nanoparticles by thermolyses in oleylamine, solid state deposition and doctor’s blade method at different temperatures and reaction times. The p-XRD pattern of the copper sulfide nanoparticles obtained from complex ( 1 ) by colloidal thermolysis in oleylamine show pure Digenite phase (Cu 9 S 5 ) under all reaction conditions. TEM images show significant changes in size and shape of crystallites by variation of the growth temperature or time. Thermolysis of complex ( 2 ) in oleylamine gave pure phase Digenite (Cu 9 S 5 ) at higher temperature (250 °C) with disks and rectangular cuboidal morphologies whereas at lower temperature (200 °C) traces of Covellite (CuS) were also observed. The p-XRD analysis of the nanoparticles produced from the thermolysis of complex ( 3 ) in oleylamine show Digenite (Cu 9 S 5 ) as the predominant phase with some impurity of Djurleite (Cu 31 S 16 ) phase. The melt method produced Digenite and Covellite phases from complex ( 1 ) and pure Digenite phase from complex ( 2 ). Complex ( 3 ) gave the Digenite and Chalcocite phases. Nanoparticles from all three complexes by the melt method show spherical and cuboid morphology. p-XRD of thin films by the doctor blade method show Digenite as the major phase and Djurleite as the minor phase. These results showed that the phase of copper sulfide were directly dependent on the type of precursor (alkyl chain length), growth temperature and the method used.

The Zijinshan orefield is a Cu–Au–Mo–Ag porphyry–epithermal mineralization system of Cretaceous age in southeastern China, comprising the Zijinshan high-sulfidation (HS) Au–Cu deposit, Luoboling porphyry Cu–Mo deposits, Yueyang low-sulfidation Au–Ag–Cu deposit, and Wuziqilong and Longjiangting intermediate-sulfidation (IS) Cu deposit. A number of Sn-(W)-sulfides occur in the Zijinshan orefield, including kiddcreekite, hemusite, colusite, vinciennite, stannoidite, mawsonite and kesterite. The occurrence represents the first report of hemusite, colusite and vinciennite in China. The relative abundance and diversity of Sn-(W)-sulfide-bearing assemblages make the Zijinshan orefield possibly unique in the world, and carries implications for the evolution of the mineralizing environment. Detailed electron probe studies of the Sn-minerals reveal that kiddcreekite, hemusite, mawsonite, stannoidite and kesterite have compositions close to ideal formulae. In contrast, colusite displays grain-scale zoning expressed by W, Sn and As. Vinciennite displays compositional variation depending on mineralization style: an average composition of Cu 10.74 Fe 3.88 Sn(As 0.85 ,Sb 0.08 )S 15.4 in the Zijinshan HS deposit, Cu 10.71 Fe 3.9 SnAs 0.85 S 15.34 in the Wuziqilong Cu deposit and Cu 10.76 Fe 3.7 Sn 1.02 (As 0.5 ,Sb 0.45 )S 15.54 with higher Sb contents (3.32%) in the adjacent Longjiangting Cu deposit. In the Zijinshan HS Au–Cu deposit, the main Cu-mineral assemblage varies from bornite-rich to digenite- to covellite-rich with increasing depth. Correspondingly, tin mineralogy varies from kesterite at upper levels to stannoidite-dominant at mid-to-upper levels of the copper orebody, to vinciennite- and mawsonite-dominant at depth, implying an increase in sulfidation and oxidation state downwards. Moreover, kiddcreekite is always partially replaced by wolframite and (hypogene) covellite at depth, also indicating overprinting by high- f O 2 and - f S 2 fluids in the covellite stage of mineralization. Kiddcreekite, along with a primary chalcopyrite–pyrite mineral association, occurs widely in the Zijinshan orefield (Zijinshan, Yueyang, Luoboling, Wuziqilong, Longjiangting and Dayanli), and is likely indicative of the early IS stage of epithermal system. Analogous with published data, kiddcreekite most commonly occurs in porphyry-style mineralization, implying the presence of the mineral has potential as an indicator of porphyry systems. Vinciennite-bearing Cu–Sn–As mineral associations occur in a specific position in the Zijinshan HS Au–Cu, Wuziqilong and Longjiangting Cu deposits, indicative of a transitional zone between porphyry and HS epithermal-style mineralization. The occurrence of the identified Sn-(W)-sulfide-bearing assemblages has considerable potential implications for understanding the architecture of a complex porphyry–epithermal environment and for exploration for underlying porphyry copper deposits. There is potential for discovery of a subjacent porphyry Cu deposit within the Zijinshan orefield.

Photothermal ablation (PTA) therapy has a great potential to revolutionize conventional therapeutic approaches for cancers, and a prerequisite is to obtain efficient photothermal nanoagents. For the preparation of hydrophilic copper sulfide-based photothermal nanoagents, we have developed a simple solvothermal route with the mixture of water/ethanol/polyethylene glycol (molecular weight 400, abbreviated as PEG-400) as the solvent. By adjusting Cu/S precursor ratio from 1/5 to 1/1, we have realized the simultaneous control of morphology (from octahedral-like particles, nanoplates to nanoparticles), phase (from digenite Cu9S5 to covellite CuS) and optical absorption (from no NIR absorption to strong NIR absorption). When Cu/S precursor ratio is 1/1, the resulting sample has the smallest size (∼40 nm), excellent hydrophilicity and the highest photoabsorption in NIR region. The aqueous dispersion containing CuS nanoparticles exhibits excellent photothermal conversion performance under the irradiation of 980 nm laser, for example, the temperature of the aqueous dispersion of CuS nanoparticles (0.20 g/L) can increase by 18.0 °C at 360 s under the irradiation of 980 nm laser with power density of 1.50 W cm−2. Therefore, this kind of CuS nanoparticles has great potential as the photothermal nanoagents for PTA of cancer cells.

Pure, Co, and Ho-doped digenite (Cu9S5 or Cu 1.8 S) nanostructures were synthesized through simple solvothermal approaches. The effect of surfactant) Tween 20, polyethylene glycol, and oleic acid) on the morphology and optical properties of nanostructures was investigated in detail. The plasmonic band of samples synthesized in the presence of Tween 20 and oleic acid was reduced because of trapping of Cu vacancies by the carboxylate groups of surfactants. In addition, the surfactants adsorbed on the nanostructure surface have a negative impact on catalytic activity of particles, while the Fenton-like activity of doped catalysts yielded good performance in terms of methylene blue (MB) decolorization (98% and 90% for Ho and Co doping Cu 1.8 S, respectively). Ho improves redox cycling of Cu 2 + to Cu + and Co improves reactivity with H 2 O2 accelerate MB decolorization.

Uncapped nanocrystalline cuprous nitride (Cu3N) decomposes spontaneously to CuO at room temperature due to the presence of water and oxygen in the atmosphere. Long-chain capping molecules have been successfully used to cap and protect the core nanocrystals from complete oxidation. Moreover, the use of co-surfactants has been shown to alter the morphologies and properties of nanocrystals due to preferential binding. In an attempt to cap Cu3N nanocrystals and alter their morphology, hexadecylamine (HDA) and 1-dodecanethiol (DDT) were used as surfactant and co-surfactant respectively. Contrary to common belief, herein we show that DDT does not only act as a co-surfactant however it also results in the complete substitution of nitrogen ions in Cu3N with sulfur ions thereby resulting in the formation of a mixture of Cu3N and Cu2S after 2.5 min of DDT addition. Longer reaction times result in the formation of pure Cu2S (chalcocite) and ultimately Cu9S5 (digenite). The substitution is consistent with the HSAB theory. XRD, EDX, TEM, and XPS confirmed the transitioning of Cu3N nanocrystals to chalcocite and digenite nanocrystals. The resultant morphologies were spherical particles for Cu3N, hexagonal particles for Cu2S and small spherical particles for Cu9S5 nanocrystals. 1HNMR and FTIR spectroscopies elucidated the capping of the nanocrystals by HDA and DDT. The optical properties showed the transitioning of the band-gap. The photoluminescence spectra of both Cu2S and Cu9S5 showed blue-shifted emission energy from the band gap energy due to surface traps and defects.

Understanding mineral transformations of composite copper sulphide ores and the associated reaction mechanism at low to medium temperatures in acidic solutions with oxidant restriction is important for in situ recovery operations because natural ore bodies typically comprise multiple sulphide species and their dissolution is oxidant consuming. Here we present experimental observations on mineral replacement reactions of coarse-grained natural bornite (Cu5FeS4)–chalcocite (Cu2S) samples in acidic solutions at 90 °C and in the absence of oxidant. Transformations were found to follow a three-stage reaction sequence for bornite and one stage for chalcocite. Bornite replacement commenced with the formation of digenite (Cu1.8S) along fractures and surfaces. Bornite–digenite interfaces are sharp and digenite rims contain nanochannels that connect to the original bornite. When copper dissolution exceeded 30%, copper-deficient lamellae exsolved from the bornite by solid-state diffusion; this texture appeared only in stronger acidic solutions with extended times and did not occur in the heating experiments without fluid. Chalcocite that was present together with bornite in the unreacted samples transformed into digenite characterized by laminar replacement textures. Finally, all phases were replaced by covellite (CuS) accompanied by the formation of porosity. These replacements showed the concomitant operation of fluid-induced solid-state diffusion and fluid-mediated mineral replacement by coupled dissolution–precipitation reactions. The textures found in the resulting covellite showed a promising increase in porosity that could be beneficial for hard-rock in situ recovery and suggests a pathway for refractory sulfide processing by acid pre-treatment.

The existing technologies for porphyry copper ores beneficiation, located in deposits in the Urals of Russia, allow the production of chalcopyrite concentrates with a copper content of 19 to 30%. Subsequent technology for the concentrates processing includes autogenous smelting, matte desulfurization, and blister copper refining operations. The current work presents a new hydrometallurgical approach for the copper concentrate enrichment up to a higher grade of 50–55% Cu, which could significantly increase the production capacity and efficiency of smelting and with a process simultaneously avoiding the matte desulphurization operation. The suggested method consists of oxidative pressure leaching followed by hydrothermal pretreatment of chalcopyrite concentrates with copper sulfate solutions. The pressure oxidative leaching of the chalcopyrite concentrates allows Cu extractions up to 99% and produces Cu-rich solution for the hydrothermal pretreatment stage. Optimization of the hydrothermal pretreatment stage was carried out within the following limits: T = 150–230 °C, CuCuSO4/CuCuFeS2 = 1.2–3.3, H2SO4 = 20–120 g/L. Recommended parameters were established as T = 230 °C, CuCuSO4/CuCuFeS2 = 1.8–1.9, H2SO4 = 20–40 g/L, t = 60–100 min since this allows concentrate to be obtained with Cu content of 51–52% and residual Cu concentrations of as low as 0.08–0.13 g/L in the final solution. A parametric model of the hydrothermal pretreatment stage was obtained. The solutions and residues after hydrothermal pretreatment of the material were analyzed for their chemical and phase composition. A technological flowsheet, as well as strategies for by-product processing, were also suggested.

The Zijinshan Cu-Au deposit, located in Fujian Province, is the largest high-sulfidation epithermal (HSE) deposit in Southeastern China and is usually regarded as a major part of the porphyry Cu system in the Zijinshan ore field. Molybdenite samples collected from the Cu mineralization zone yield a first weighted mean Re-Os age of 111.31 ± 0.70 Ma, which is explained as the time of dickite-alunite alteration. Combining the newly reported muscovite 40Ar-39Ar and zircon U-Pb ages (~113 Ma), the mineralization of Zijinshan is likely to initiate before ca. 110 Ma. This result is obviously older than the Re-Os age of the adjacent Luoboling porphyry Cu-Mo deposit (~105 Ma). Pyrite, chalcopyrite, bornite, digenite, and covellite collected from the deep potassic, middle phyllic and upper epithermal zones are used to conduct LA-ICP-MS trace element analysis. The spatial zonings of mineralization and alteration and the regular variations of trace elements in sulfides at vertical direction imply a potentially complete transition from porphyry to epithermal mineralization and the deep origin of ore-forming fluids. Mineralogical and trace element characteristics indicate that the chalcopyrite formed in both stages, whereas bornite is the product of epithermal mineralization, rather than a porphyry stage residue. The majority of digenite and covellite has hypogene genesis. Pyrite and digenite in the epithermal zone are major carriers of primary Au. Au in pyrite is Te-Bi related and exists as solid solutions or different-sized telluride and Bi-sulfosalt inclusions. Compared to As, Te and Bi played more important roles to scavenge Au and Ag and achieve the primary Au enrichment. Differently, Au in digenite is independently locked in digenite lattice. Bornite and digenite are good carriers of primary Ag, which mainly exists as solid solutions. The high sulfidation state stage is the major period for concentrations of primary Au and Ag. The upward increase of Au in primary sulfides of HSE Cu zone implies that the distribution pattern of upper Au enrichment and lower Cu enrichment is not only caused by supergene process, but is also controlled by hypogene trend. Based on the mineralization and alteration zonings, the spatial variation of trace elements and the presented Re-Os age, the ore-forming fluids of the Zijinshan Cu-Au deposit most likely originate from deep region, rather than from the adjacent Luoboling porphyry deposit. The Zijinshan and the Luoboling deposits should belong to two independent hydrothermal systems.

The copper mineralization at the southeastern fringe of the Khetri copper belt in western India is primarily hosted within the metapelites and dolomite units of the Mesoproterozoic Ajabgarh Group of rocks. The copper mineralization is well exposed along a NE-SW trending basinal part around Nim ka Thana area where a few of the prospects namely Dokan, Baniwala-ki-Dhani, Dariba, and Nanagwas primarily consist of abundant bornite, chalcopyrite, covellite, digenite, and chalcocite as disseminated phases hosted within a wide-ranging litho units and along quartz-calcite-barite veins. An integrated approach has been adopted to understand the metallogenetic evolution of this bornite dominated copper mineralization. δ13CV-PDB and δ18OV-SMOW results of the carbonate veins ranging from 0.57‰ to -3.75‰ and δ18O range from 15.01‰ to 20.74‰ respectively suggest the influx of hydrothermal fluid in shaping up the deposit. δ13C (CO2) of the ore-bearing fluid ranges from -1.67‰ to 2.65‰ and δ18O (H2O) from 7.11‰ to 12.84‰ respectively also suggest the input of hydrothermal source. The S-isotopic values of Cu-mineralized barite samples range between 16‰ and 20‰, which are lower than that of seawater (δ34S‰= 20–22‰). This provides the evidence that the barite mineralization could have formed from the hydrothermal fluid that is cogenetic with the late-stage mineralization in a phase-wise separation as an associated mineral assemblage in the system progressively enriching the bornite-rich copper deposit. Based on the field data and evidences, petrographic characteristics, mineral chemistry, fluid inclusion, and stable isotopic signatures, a three-stage mineralization event is proposed as 1) syngenetic precipitation of dispersed bornite-pyrite in a euxinic environment; 2) hydrothermal vein-type mineralization dominated by chalcopyrite-bornite phase, and 3) supergene enrichment of the vein filled mineralization with the development of wide-scale chalcocite-digenetite-covellite mineral phases. Fluid inclusion microthermometry suggests a temperature range from 225o-320°C with moderate salinity fluid representing epithermal mineralization which is coherent with the stable isotope data (C, O and S isotopes) of the mineralized carbonate and barite veins suggesting the involvement of large scale hydrothermal fluid influx. Te content of various Cu-bearing sulfide phases shows a gradual change in the concentration from chalcopyrite (2.21% to 2.31%), bornite (2.31% to 4.50%), chalcocite (2.77% to 2.87%), digenite (2.57% to 3.70%) and covellite (2.53% to 3.13%) suggesting their evolution from hydrothermal to supergene process. The studied area has experienced wide-scale alterations and Na-metasomatism with the development of associated minerals such as scapolite, tremolite, and sericite. Occurrence of primary and secondary copper sulfides in the metasedimentary sequence, alteration assemblages affected by Na-metasomatism, association of magnetite and specularite in the study area is affiliated to the hydrothermal system akin to IOCG clan as noted from the adjoining Khetri Copper Deposit.

The Ouansimi copper deposit, located South of the Kerdous inlier in Morocco, is an example of vein-type mineralization hosted in the Adoudou Formation limestone of the Lower Cambrian Taroudant Group. The copper-bearing veins are mainly controlled by Variscan NNW-trending faults and are subdivided here into Eastern, Western, and Central structures. On the basis of mineralogical, metallographic, and fluid inclusion studies, two mineralizing processes are proposed. A primary process is interpreted for the chalcopyrite, digenite, galena, sphalerite, carrollite, and pyrite with quartz and dolomite as gangue minerals. A secondary process is proposed for chalcocite, bornite, covellite, native copper, copper carbonate and oxide. Microthermometric analysis of fluid inclusions was carried out on quartz and dolomite gangues. Primary fluid inclusions trapped in quartz show the existence of fluids with temperatures of 175°C–275 °C and salinities of 10–15 wt % NaCl eq. However, fluid inclusions in dolomite indicate fluids with temperatures of 200°C–250 °C and salinities of 20–25 wt % NaCl equiv. Combining ore mineralogy and fluid inclusion microthermometry, two main hypogene sulphide mineralization stages can be distinguished in the Ouansimi copper deposit. The first Cu–Fe stage, with quartz as a gangue mineral, was related to hydrothermal fluids with moderate temperature and low salinity. The second Cu–Zn–Pb–Co–Ni–Fe stage was associated with dolomite as a gangue mineral and infilled cavities and fractures cutting quartz. This second phase was related to hydrothermal fluids with moderate temperature and high salinity. The tectonic evolution of the Ouansimi deposit was characterized by thrusting of the south limb over the north limb and by dextral and sinistral offsets of the mineralized structures along late-stage ENE-WSW-trending faults.

The Inkaya Cu–Pb–Zn–(Ag) prospect is a typical example of the hydrothermal mineralization occurring in the Menderes Massif, which crop out in Western Anatolia. The prospect located approximately 20 km west of Simav (Kutahya-Turkey) in northern part of the Menderes Massif have been characterized through the detailed examinations involving geological, mineralogical, whole-rock geochemistry, fluid inclusion, stable isotope and lead isotope. The Inkaya Cu–Pb–Zn–(Ag) prospect is located along an E–W-trending fault in the Cambrian Simav Metamorphics, which consist of quartz–muscovite schist, quartz–biotite schist, muscovite schist, biotite schist and the Arikayasi Formation, which is composed of marbles. Galena, sphalerite, chalcopyrite, pyrite and fahlore are the main minerals, and they are accompanied by small amounts of cerussite, anglesite, digenite, enargite, chalcocite, covellite, bornite, and Fe-oxides with gangue quartz. In addition to Pb, Zn, Cu, Ag, the ore samples contain substantial quantities of As, Cd and Bi and small amount of Au. Average contents of Cu, Pb, Zn and Ag are 77,400 ppm, 102,600 ppm, 6843 ppm and 203 ppm, respectively. The δ34S values for galena, chalcopyrite and pyrite formed in the same stage vary in the range from − 1.7 to − 2.1‰ (average − 2.0), 0.1 to 0.3‰ (average 0.2) and − 1.5 to 2.6‰ (average + 1.5), respectively. δ34S values for H2S, representing the composition of the fluids responsible for the sulfide mineral formations and calculated from the δ34S value are between − 2.77 and 1.33‰; it is consistent with the sulfur in sulfide minerals. δ18Oquartz values range from 11.3 to 16.4‰ and estimated δ18Ofluid values range from 5.4 to 10.6‰. Pyrite–galena and pyrite–chalcopyrite pairs calculated to determine equilibrium isotope temperatures based on δ34S values are between 254.6 and 277.4 °C for pyrite–galena and 274.7 °C for pyrite–chalcopyrite. Sulfur and oxygen isotope values similar to the values for fluid equilibrated with an felsic magmatic source. Fluid inclusion studies on quartz of the same silicification stage coexisting with galena, sphalerite and chalcopyrite collected from the mineralized vein indicate that the temperature range of the fluids is 235 °C to 340 °C and that the salinities are 0.7 to 4.49 wt.% NaCl equivalent. The wide range of homogenization temperatures and relatively lower salinities of the fluid inclusions indicate that at least two different fluid generations were trapped in the quartz from only one fluid type. Also, lower salinities of fluid inclusion probably indicate mixing of meteoric water and magmatic fluid. The galena has 206Pb/204Pb values of 18.862–18.865, 207Pb/204Pb values of 15.707–15.711, and 208Pb/204Pb values of 39.033–39.042. The lead isotope values show a similarity with upper crustal values.

A copper sulfide (digenite phase, Cu 9 S 5 ) film composed of hierarchical microprotrusions was fabricated for corrosion protection of the underlying Cu substrate. The copper sulfide microprotrusions follow a heterogeneous nucleation, growth and aggregation mechanism. After hydrophobization with stearic acid, the film exhibits a water contact angle of 163° and a sliding angle of ~ 2°, and shows enhanced corrosion resistance. The mechanism of corrosion protection is clarified according to the proposed equivalent circuits, which show that the superhydrophobic film behaves as an effective barrier and largely separates the Cu substrate from the corrosive solution. The film exhibits good chemical stability against acidic or basic solutions due to the chemical inertness of copper sulfide. It shows good adhesion to the substrate and maintains its hydrophobic property after abrasion test.

Copper concentrates with elevated enargite content are not apt to be treated by the current technology of smelting/converting because of the high risk of pollution with toxic arsenic compounds. Therefore, these copper–high arsenic concentrates must be pretreated to remove the arsenic before smelting and the traditional method of pretreatment is roasting. In this work, an alternative hydrometallurgical method for selective removal of arsenic from enargite is presented. The process consists of alkaline digestion with a concentrated Na 2 S–NaOH solution followed by water leaching. The experimental results obtained using high grade enargite showed that the alkaline digestion is very effective for rapid and selective removal of arsenic from enargite. The copper in the solid residues remains as digenite (Cu 9 S 5 ). More than 97% of the arsenic was removed in 12 min of digestion at 80 °C, 100% excess of Na 2 S and 2 M of NaOH. The kinetics of the digestion reaction was analyzed by a shrinking particle kinetic model and the determined activation energy was 22.1 kJ/mol for the temperature range of 70–90 °C. This activation energy is consistent with a mass transfer kinetic control.

Cu x S thin films were deposited on glass substrates at room temperature by photochemical deposition after 1 h photo irradiation using the precursor solution containing copper sulphate pentahydrate (CuSO 4 ·5H 2 O), sodium thiosulphate (Na 2 S 2 O 3 ) as a source material for Copper and Sulphur respectively and Di Sodium salt of EDTA as a chelating agent in acidic medium (pH~3.0). The as deposited and annealed Cu x S thin films were investigated using XRD, UV–vis, AFM, SEM and Hall measurements. The deposited thin films were annealed at temperature up to 400 °C for 1 h. Above 200 °C the deposited film of Cu x S changes from anilite phase (Cu 1.75 S) to digenite (Cu 1.8 S) phase. The reduction in sulphur content of the films is evident in the EDX analysis. From the Hall Effect results as deposited and annealed films show p-type conductivity with increasing bulk concentration. Analyses of the optical bandgap of the films indicate an indirect bandgap between 1.75 and 2.35 eV.

The Kairei hydrothermal field was the first confirmed active submarine hydrothermal system on the Central Indian Ridge. It has been suggested to be related to mafic as well as ultramafic host rocks based on vent fluid composition and the presence of ultramafic rocks in its vicinity. In this study, detailed geochemical and mineralogical analyses have been carried out on the hydrothermal precipitates from the Kairei vent field in order to investigate the possible presence of indications for an ultramafic substrate at this vent site. The studied samples included fragments of sulfide chimneys, massive sulfides and talc-bearing and silicified breccias. Three mineralization stages were identified: (1) a high-temperature stage consisting largely of chalcopyrite, isocubanite, and pyrite; (2) a medium to low temperature stage characterized by the mineral assemblages of sphalerite and pyrite; and (3) a weathering stage characterized by secondary Cu-sulfides (bornite, digenite, covellite and idaite), Fe-oxihydroxides, Opal-A, and Cu-chloride (paratacamite and atacamite). The sulfide geochemistry is characterized by high concentrations of Cu and Zn (Cu + Zn up to 29.3 wt.%, n = 17) and Au (mean 5.28 ppm, n = 17), which is comparable to results from seafloor massive sulfides collected from ultramafic-hosted sites in the Atlantic Ocean, but differs from those of typical mafic-hosted deposits. The high concentrations of Cu and Au at the Kairei hydrothermal field could be an indication for the involvement of ultramafic rocks in the subseafloor. Ultramafic-hosted, Au-rich sulfide deposits may not be restricted to the Atlantic Ocean and may be common along all slow- and intermediate-spreading ridges.

Copper and gold mineralization in the Maher-Abad deposit, eastern Iran, is closely related to the multiple emplacement episodes of Upper Eocene granodiorite porphyries within andesitic volcaniclastic and coeval quartz monzonite stocks. The magmatic hydrothermal fluids thereafter hydrofracturing provided appropriate conduits, formed a stockwork of quartz and quartz–sulfide veinlets within the porphyritic host rocks which were extensively altered into potassic, propylitic, phyllic, and argillic assemblages. Four main vein/veinlet groups have been identified: (A) quartz ± K-feldspar ± biotite ± anhydrite with pyrite, chalcopyrite, sporadic magnetite and pyrrhotite; (B) quartz, pyrite and minor chalcopyrite; (C) chalcopyrite, quartz and/or minor bornite, pyrite, digenite and sporadic pyrrhotite; and (D) quartz, calcite and/or clay minerals ± pyrite ± hematite ± galena. The Cu–Au mineralization is mainly associated with the early potassic (biotite) alteration zone in the deep central part of the Madanha stock. Based on the phase contents at room temperature, three types of fluid inclusions are recognized at Maher-Abad: (1) liquid-rich two-phase (LV), (2) vapor-rich (VL ± H) and (3) halite-bearing multiphase (LVH). Homogenization experiments revealed a temperature range of 150–488 °C for the studied inclusions. Ice-melting of aqueous two-phase inclusions and melting of halite in the aqueous multiphase inclusions provide salinity of 9.5 to 47.9 wt.% NaCl equivalent. Fluid-inclusion studies reveal that the single-phase low-salinity magmatic fluid, exsolved from a granodioritic magma, was separated into vapor and hypersaline brine (~ 45 wt.% NaCl eq.) phases. The coexisting phases were trapped at temperature 460 °C and lithostatic pressure of ~ 350 bars (corresponding to a depth of 1.3 km) as VL ± H and LVH fluid inclusions, respectively. Such magmatic-derived fluids underwent phase separation episodically under lithostatic pressure conditions and formed the early copper sulfide-bearing quartz veinlets intimately related to the potassic alteration zone. Copper–iron sulfide precipitation and phase separation concomitant of boiling in this zone led to rapid depletion of the fluid in reduced sulfur. As a result, Au(HS) 2 − complexes are destabilized forcing most of the gold to precipitate above 400 °C. A positive trend of the homogenization temperature and salinity during the formation of the phyllic alteration zone is attributed to the cooling of a moderately saline fluid (produced dominantly by magmatic-vapor condensation) and its subsequent boiling and mixing with meteoric waters at a hydrostatic pressure of ~ 100–125 bars corresponding to a depth of ~ 1–1.2 km. The argillic alteration zone formed at temperature of 210–230 °C from fluids with salinity of 16–18 NaCl wt.% eq. at a hydrostatic pressure of ~ 80 bars and a depth of 800 m from paleo-surface. The fluid density is typically lower ( 3 ) than that of the potassic zone (> 1 g/cm 3 ), indicating that the late trapped fluid was more dilute.

The Mumbwa mineralized district is located approximately 200 km west of Lusaka, at the north-eastern margin of the Pan-African granitic Hook batholith . Polymetallic sulphide occurrences in the area have been known for hundreds of years, but more recent geophysical and geochemical investigations led to the discovery of a copper-rich hydrothermal system , mostly associated with late-stage syenite intrusions of the Hook batholith. The extent of the hydrothermal system is not known, but to date two main centres have been identified, the Sugar Loaf and Mutoya. Sulphide mineralization occurs along regional-scale lineaments , following a 25 km-long NNW-trending corridor. Mineralized host rocks are characterized by brecciation, often pervasively replaced by magnetite-hematite, and by strong metasomatism with multiple - and often superimposed - alteration cycles, from potassic, to carbonate, sericite-chlorite and amphibole-apatite-carbonate. Sulphur isotopes suggest that a mixture of magmatic and sedimentary-derived evaporitic fluids were critical in providing sulphur and metals. Late syenitic intrusions triggered the relevant hydrothermal circulation and favoured the mineralization processes. Diagrams plotting key element geochemistry and alteration indexes highlight vectors to alteration and mineralization and suggest that the sulphides preferably concentrated in rocks affected by hydrothermal iron oxides in association with sericite-chlorite alteration. At the Kitumba prospect (in the Sugar Loaf mineralized centre), granitic to syenitic bodies host a hypogene copper mineralization (mostly chalcopyrite), that was subsequently overprinted by pervasive and deep supergene mineralization (malachite, chalcocite, chalcosiderite, cuprite, digenite, chrysocolla, bornite , native copper). Supergene mineralization has been identified in boreholes to depths exceeding 700 m. Reserves at Kitumba are estimated at 27.9 Mt with an average grade of 2.2% copper at a 1.0% copper cut-off grade. Gold is present, although generally at low grades. In the Mutoya centre, metasedimentary rocks alternate with felsic intrusions. Two prospects have been identified, characterized by large areas of magnetite-hematite breccias hosting sulphide mineralization with predominantly pyrite and minor chalcopyrite . An affiliation to the iron oxide copper gold (IOCG) category is discussed. Many, but not all of the distinctive IOCG features, are present in the studied area.

Digenite (Cu1.8S) has attracted extensive attention as a candidate for use in thermoelectric applications owing to its low cost and low toxicity, but its thermoelectric (TE) properties are still poor. In this study, Pb doping was used to improve the TE properties of Cu1.8S polycrystalline materials. Pb-doped Cu1.8S was fabricated using mechanical alloying (MA) and the spark plasma sintering (SPS) technique. The effects of Pb doping on the TE properties of Cu1.8S were investigated in detail. The power factor of Cu1.8S was maintained upon the introduction of Pb owing to an improved Seebeck coefficient and slightly reduced electrical conductivity. A maximum TE figure of merit (ZT) value of 0.77 was attained at 773 K for a Pb0.01Cu1.79S sample, which was 1.57 times higher than that of a pristine Cu1.8S sample.

The Gercus Basalt is a recently discovered body within the Gercus Formation, which is exposed on both limbs of the large, double-plunging, NW/SE-trending Bekhair Anticline to the north of Duhok city, northern Iraq. The basalt is mostly basanitic and alkaline in nature, greenish to grayish black in color, and very fine-grained, vesicular, amygdaloidal and microscopically porphyritic in texture. It consists of anorthoclase, diopside, forsterite and accessory titaniferous magnetite, ilmenite and apatite as well as their alteration products. The primary minerals are pervasively altered by calcitization, zeolitization, serpentinization, chloritization, silicification, iddingsitization, martitization, and possibly anorthoclasization. Copper mineralization has taken place as veins and fracture/joint-filling which is mostly observed near the northwestern plunge of the anticline where the basalt attains its maximum thickness of about 16 m. Twelve copper minerals were found within veins and fractures, including primary minerals (bornite, chalcopyrite and an unidentified sulfide – Cu2.3FeS3) and their secondary alteration and replacement products represented by sulfides (covellite, digenite, and chalcocite), native copper, cuprite, carbonates (malachite and azurite), silicate (chrysocolla) and possibly sulfates. The copper minerals are in many cases zonally arranged as spherules where the primary minerals acted as cores, surrounded outward by secondary minerals. Primary copper mineralization is of late magmatic hydrothermal origin, postdating the emplacement, consolidation, deuteric alterations, and fracturing/jointing of the Gercus Basalt; followed by the formation of secondary supergene copper minerals as a result of alteration and replacement of the primary copper sulfides along mineralized veins and fractures/joints due to chemical weathering by meteoric and/or groundwater during Eocene time.

An ambient pressure solution chemical process using tetraethylene glycol as solvent, copper(II) chloride and thioacetamide as precursors, polyvinylpyrrolidone as capping agent synthesized Cu x S ( x = 1 or 1.8) nanocrystals by injecting Cu(II) precursor solution into thioacetamide precursor solution at 200–280 °C. Influence of the synthesized temperature and refluxing time on the formed phases and growing morphologies of Cu x S nanocrystals was investigated based on XRD, TEM, HRTEM and EDX. Optical properties of the synthesized Cu x S nanocrystals were characterized. The results showed that single-phase, snowflake-like shaped covellite CuS nanocrystals were formed at injection temperature of 220 °C and below. And single-phase, well-dispersed, polyhedral-shaped digenite Cu 1.8 S nanoparticles were grown at injection temperature of 260 °C and above. The formation mechanism of the CuS and Cu 1.8 S nanocrystals in this phase-selective solution synthesis was discussed.

The hydrothermal treatment of Chilean Codelco-type copper concentrates with copper sulfate solutions was investigated as a mean of removal of impurities and subsequent increase of the copper assay. The behavior of the mineral phases (digenite, chalcopyrite, covellite, bornite, pyrite and sphalerite) was similar to those obtained in previous works from pure mineral samples. An almost complete transformation of bornite, chalcopirite, covellite and sphalerite into Cu 2 − x S phases was obtained at 225 °C–240 °C. The highest degree of elimination (around 80%) of impurities was in Zn, Cd, Tl and Bi. An intermediate elimination (40–70%) was achieved for Pb and Te, with only moderate elimination (20–40%) of Mo, Hg, Sb and As. Temperature was the variable having the greatest influence on the elimination of the impurities. A concentrate containing 33% Cu, 33% S, 22% Fe and 2% Zn was converted to a highly enriched concentrate containing 70% Cu, 19% S and 3% Fe. The advantages of a concentrate of this type would include: (1) raising by more than twice the smelting capacity due to the high copper content, (2) generation of a minimum amount of slag, (3) reduction by almost 50% in sulfur emissions, (4) substantial reduction of wastes containing hazardous metals and, finally (5), retention of the option to hydrometallurgical copper recovery since the neo-formed Cu 2 − x S phases are more reactive than chalcopyrite to the chemical or biochemical leaching.

The nature and basic kinetics of the hydrothermal reactions of bornite, covellite and pyrite with copper sulfate solutions were investigated, as a previous study on the behavior of the bulk Chilean copper concentrates. The reaction of bornite produced digenite at 2+ ] (aq) , and the activation energy was ∼ 100 kJ/mol. Covellite was transformed to digenite at 200 °C. The reaction was characterized for an irregular nucleation and growth of the products, which were non-protective. The order with respect the [Cu 2+ ] (aq) was 0.6 and the activation energy ∼ 110 kJ/mol. The pyrite reaction was significant at > 200 °C and extensive at 240 °C. It produced a mixture of digenite/chalcocite-Q, with small amounts of djurleite. The transformation has a high Philling–Betworth ratio (∼ 1.6), causing the break of the product layers. The reaction order and the activation energy were also 0.6 and ∼ 110 kJ/mol, respectively. The rate of the bornite reaction should be controlled by solid-state ionic diffusion, whereas for covellite and pyrite the rates should be limited by electrochemical processes. Towards the hydrothermal transformation, the reactivity of the main phases present in Chuquicamata-type concentrates was: bornite > chalcopyrite > covellite > sphalerite > pyrite.

The Lufilian foreland is a triangular-shaped area located in the SE of the Democratic Republic of Congo and to the NE of the Lufilian arc, which hosts the well-known Central African Copperbelt. The Lufilian foreland recently became an interesting area with several vein-type (e.g., Dikulushi) and stratiform (e.g., Lufukwe and Mwitapile) copper occurrences. The Lufilian foreland stratiform Cu mineralization is, to date, observed in sandstone rock units belonging to the Nguba and Kundelungu Groups (Katanga Supergroup). The Mwitapile sandstone-hosted stratiform Cu prospect is located in the north eastern part of the Lufilian foreland. The host rock for the Cu mineralization is the Sonta Sandstone of the Ngule Subgroup (Kundelungu Group). A combined remote sensing, petrographic and fluid inclusion microthermometric analysis was performed at Mwitapile and compared with similar analysis previously carried out at Lufukwe to present a metallogenic model for the Mwitapile- and Lufukwe-type stratiform copper deposits. Interpretation of ETM+ satellite images for the Mwitapile prospect and the surrounding areas indicate the absence of NE–SW or ENE–WSW faults, similar to those observed controlling the mineralization at Lufukwe. Faults with these orientations are, however, present to the NW, W, SW and E of the Mwitapile prospect. At Mwitapile, the Sonta Sandstone host rock is intensely compacted, arkosic to calcareous with high silica cementation (first generation of authigenic quartz overgrowths). In the Sonta Sandstone, feldspar and calcite are present in disseminated, banded and nodular forms. Intense dissolution of these minerals caused the presence of disseminated rectangular, pipe-like and nodular dissolution cavities. Sulfide mineralization is mainly concentrated in these cavities. The hypogene sulfide minerals consist of two generations of pyrite, chalcopyrite, bornite and chalcocite, separated by a second generation of authigenic quartz overgrowth. The hypogene sulfide minerals are replaced by supergene digenite and covellite. Fluid inclusion microthermometry on the first authigenic quartz phase indicates silica precipitation from an H 2 O–NaCl–CaCl 2 fluid with a minimum temperature between 111 and 182 °C and a salinity between 22.0 and 25.5 wt.% CaCl 2 equiv. Microthermometry on the second authigenic quartz overgrowths and in secondary trails related to the mineralization indicate that the mineralizing fluid is characterized by variable temperatures (Th = 120 to 280 °C) and salinities (2.4 to 19.8 wt.% NaCl equiv.) and by a general trend of increasing temperatures with increasing salinities. Comparison between Mwitapile and Lufukwe indicates that the stratiform Cu mineralization in the two deposits is controlled by similar sedimentary, diagenetic and structural factors and likely formed from a similar mineralizing fluid. A post-orogenic timing is proposed for the mineralization in both deposits. The main mineralization controlling factors are grain size, clay and pyrobitumen content, the amount and degree of feldspar and/or calcite dissolution and the presence of NE–SW to ENE–WSW faults. The data support a post-orogenic fluid-mixing model for the Mwitapile- and Lufukwe-type sandstone-hosted stratiform Cu deposits, in which the mineralization is related to the mixing between a Cu-rich hydrothermal fluid, with a temperature up to 280 °C and a maximum salinity of 19.8 wt.% NaCl equiv., with a colder low salinity reducing fluid present in the sandstone host rock. The mineralizing fluid likely migrated upwards to the sandstone source rocks along NE–SW to ENE–WSW orientated faults. At Lufukwe, the highest copper grades at surface outcrops and boreholes were found along and near to these faults. At Mwitapile, where such faults are 2 to 3 km away, the Cu grades are much lower than at Lufukwe. Copper precipitation was possibly promoted by reduction from pre-existing hydrocarbons and non-copper sulfides and by the decrease in fluid salinity and temperature during mixing. Based on this research, new Cu prospects were proposed at Lufukwe and Mwitapile and a set of recommendations for further Cu exploration in the Lufilian foreland is presented.

The chemical metathesis of chalcopyrite in the presence of cupric ions was studied in sulphuric acid solutions. The effects of stirring, Cu(II) concentration, temperature and annealing were investigated by leaching and kinetic experiments. The primary reaction involved in the chemical metathesis leads to the formation of covellite, which is followed by an oxidation–reduction couple, with digenite production. This second step was found to be very slow requiring sub-sieve size particles for extensive reaction. The reaction was insensitive to the copper ion concentrations, and practically insensitive to stirring speed. The strain induced by stirred ball milling enhanced the reaction rate markedly due to the recrystallisation process which provides easy paths for diffusion along dislocation and grain boundaries. The kinetics were well correlated with a two-stage product layer diffusion model, with apparent activation energies less than 30 kJ mol − 1 , and ferrous ion was found to be the rate determining diffusion species through the covellite phase (first stage) and covellite and digenite phase (second stage).

A study was made of the leaching of a sulfide copper ore in a NaCl–H 2 SO 4 –O 2 media after pre-treatment by agglomeration with H 2 SO 4(conc) and NaCl. The leaching variables evaluated included the amount of NaCl to be employed, the percentage of solids in the leaching solution, particle size of the raw mineral to be leached, and the preferable method of agitation in the leaching system. Mineralogical characterization of the material to be leached included analysis of the raw ore and of the leached ore residue using reflected-light microscopy, X-ray diffraction, and scanning electron microscopy. The soluble species included djurleite and digenite. The most important parameters in the leaching process proved to be particle size and type of agitation. A total percentage of copper extraction of 70% was achieved using mechanical stirring, which increased to 78% when using compressed air agitation. The best extraction of the copper was achieved when leaching with 3 g/L of chloride, room temperature of 20 °C, and when all particles were

To characterize the hydrothermal processes of East Pacific rise at 9°–10°N, sulfide mineral compositions, textural, and geochemical features of chimney ores were studied using ore microscope, scanning electron microscope, X-ray diffraction analysis, and electron microprobe techniques. Results show that there are three mineral assemblages for the hydrothermal chimney ores, namely: (i) anhydrite + marcasite + pyrite, (ii) pyrite + sphalerite + chalcopyrite, and (iii) chakopyrite + bornite + digenite + covellite. Mineral assemblages, zonational features, and geochemical characteristics of the ore minerals indicate that ore fluid temperature changed from low to high then to low with a maximum temperature up to 400 °C. The chimney is a typical black smoker. The initial structure of the chimney was formed by the precipitation of anhydrites, and later the sulfides began to precipitate in the inner wall.

Copper sulfide (Cu x S, x= 1.8-2) thin films were deposited at 285 °C by spray pyrolysis from aqueous and alcoholic solutions of copper (II) chloride and thiourea with different Cu:S molar ratio. The XRD analysis showed that deposited films are chemically close to chalcocite (Cu 2 S) or to mixtures of copper-rich phases (Cu 2 S, Cu 1.8 S, Cu 1.9375 S) in which chalcocite or digenite (Cu 1.8 S) is predominant. The films containing the single phase Cu 2 S are denser and more homogenous than the films formed by two or more phases. The current-voltage (I-V) dark curves showed the diode behavior of the films, depending on the film thickness.