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Nickel has excellent physicochemical properties and a wide range of applications, nickel resources are mainly found in nickel sulfide ores and nickel laterite ores, and nickel laterite ores are gradually becoming the main raw materials for nickel extraction. Due to the high water-content of nickel laterite ores, high temperature pre-treatment of the ores is usually required in the smelting process to remove hydroxylated water in the lattice of the ores and to prereduction of part of the metal, but this part of the hydroxylated water removal needs to consume a lot of energy and produce physical phase changes, which will affect the prereduction and leaching. However, the removal of this part of hydroxyl water needs to consume a large amount of energy, and produces physical phase changes, which will have an impact on the prereduction and leaching, so it is important to investigate the physical phase changes and kinetic conditions of the dehydroxylation process of nickel laterite ores for the subsequent processing operations. In this paper, the possible chemical reactions during the heating process of nickel laterite ore were simulated and calculated using thermodynamic analysis software, and the physical phase changes during the heating process of nickel laterite ore of silica-magnesium type were investigated using thermogravimetric-differential thermal analysis and XRD analysis, and nonisothermal kinetic experiments were carried out at five heating rates from room temperature to 1 400 °C. Three characteristic peaks were observed at 256.8, 582.8 and 823.0 °C, corresponding to the fuselage dehydroxylation process. The three characteristic peaks corresponding to the dehydroxylation of limonite, dehydroxylation of serpentine, and phase transformation of silicate minerals respectively. A nonisothermal kinetic model solution was used to determine the apparent activation energy and the finger front factor of the reaction. The activation energy of the serpentine dehydroxylation process was calculated by using the Flynn-Wall-Ozawa method and the Kissinger Akahira-Sunose method, and 30 commonly used mechanistic functions were fitted by using the Satava-Sestak method, and the eligible mechanistic functions were retained. The A1/3 function of the Avrami-Erofeev equation was determined to be consistent with the dehydroxylation process, and is integral form was G(α) = + - ln (1-α)] ³, which yielded the activation energy of the serpentine dehydroxylation reaction to be 258.71 kj/mol, lnA being 28.94, and the average linear correlation coefficient of 0.995 1. The serpentine dehydroxylation process is consistent with stochastic nucleation and subsequent growth of serpentines. The process is consistent with the stochastic nucleation and subsequent growth model. [ABSTRACT FROM AUTHOR]

Giant impacts can generate transient hydrogen-rich atmospheres, reducing atmospheric carbon. The reduced carbon will form hazes that rain out onto the surface and can become incorporated into the crust. Once heated, a large fraction of the carbon is converted into graphite. The result is that local regions of the Hadean crust were plausibly saturated with graphite. We explore the consequences of such a crust for a prebiotic surface hydrothermal vent scenario. We model a surface vent fed by nitrogen-rich volcanic gas from high-temperature magmas passing through graphite-saturated crust. We consider this occurring at pressures of 1– 1000 bar and temperatures of 1500– 1700   ∘ C . The equilibrium with graphite purifies the leftover gas, resulting in substantial quantities of nitriles ( 0.1 % HCN and 1 ppm HC3N) and isonitriles ( 0.01 % HNC) relevant for prebiotic chemistry. We use these results to predict gas-phase concentrations of methyl isocyanide of ∼1 ppm. Methyl isocyanide can participate in the non-enzymatic activation and ligation of the monomeric building blocks of life, and surface or shallow hydrothermal environments provide its only known equilibrium geochemical source. [ABSTRACT FROM AUTHOR]

The possibility of selective Cu and Zn leaching from the sample of old pyrite tailings, which is one of the most widespread types of solid waste forming during non-ferrous metal production, using sulfuric acid solutions and water was studied. It was shown that water leaching provided selective extraction of Cu and Zn and comparatively low iron ion extraction. At the same time, acid leaching provided the obtainment of pregnant solutions with high ferric ion concentration, which can be used for oxidative leaching of substandard copper concentrates. Water and acid leaching also provided increased Au recovery by cyanidation. The results suggest that acid leaching can be an effective approach for processing old flotation tailings, which allows the extraction of base metals from these wastes and treating flotation tailings for subsequent cyanidation. Effective flotation treatment methods should also provide environmental load reduction, which is caused by the long-term storage of metal-bearing wastes. [ABSTRACT FROM AUTHOR]

Currently, a widely accepted solution to reduce gypsum precipitation in acid leaching of low-grade uranium ore has not yet been identified. This study aims to delve into the impact of different flow rates on gypsum precipitation in ore through column leaching experiments. Complementary methods such as Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM) were used to characterize slag samples. The results indicate that as the flow rate surged from 63.69 Lh−1m−2 to a whopping 254.76 Lh−1m−2, the gypsum content and types in the slag decreased gradually. This can be attributed to two factors: (1) the elevation of flow rates maintains the ore heap in a lower pH environment, promoting the conversion of SO42− to HSO4−; (2) higher flow rates contribute to increased ore heap porosity, providing more migration pathways for solutions containing high concentrations of Ca2+, SO42−, and HSO4−, thus facilitating the separation of gypsum from the ore. This study affirms the feasibility of employing high-flow pre-leaching to address gypsum clogging issues, offering a new perspective for acid pre-leaching. [ABSTRACT FROM AUTHOR]

The Ozernoe lead–zinc deposit is the largest in Russia in terms of zinc reserves. It has been established that primary layered–banded, massive and brecciated sulfide ores were subject to intensive post-ore deformation and recrystallization, which accompanied dynamic and contact metamorphism. The transformations are expressed in the increase in the size of mineral aggregates and formation of carbonate–quartz–sulfide veins and veinlets with different ratios of constituent minerals. Ore minerals in veins and veinlets are represented by sphalerite, galena, and pyrite in different proportions; chalcopyrite, pyrrhotite, arsenopyrite, and marcasite occur in smaller quantities; and Ag sulfides and sulfosols are rare. The vein minerals are quartz, siderite, and manganese siderite (oligonite); Ba-bearing muscovite (ellacherite) and chlorite are also present. It was established that recrystallization of ores occurred at elevated PT-parameters—up to 535°C and up to 2 kbar—in the presence of relatively highly concentrated fluid phase (salinity up to 21.5 wt % eq. NaCl). Ore transformations are mainly caused by processes of dynamometamorphism. There is still uncertainty both with the age of ore mineralization of the Ozernoe deposit and with the development time of metamorphic processes. This does not allow linking these processes with the stages of geodynamic evolution in the region. [ABSTRACT FROM AUTHOR]

Jinchanghe is a Zn-Pb-Fe-Cu skarn deposit in the northern Baoshan block, southwestern China. It is a typical distal skarn deposit with orebodies in the Cambrian Hetaoping Formation limestone and calcareous siltstone. The skarn minerals display a vertical zonation with garnet skarn in the lower part and pyroxene skarn in the upper part. Economic metals are also zoned with Fe at the base, Cu in the middle, and Zn-Pb in the upper part. The skarn formation and Zn-Pb-Fe-Cu mineralization is divided into four paragenetic stages: a pre-ore stage dominated by prograde garnet and pyroxene, an oxide stage represented by Fe mineralization associated with retrograde ilvaite, actinolite and epidote alteration, a sulfide stage characterized with Cu–Zn-Pb sulfides, and a post-ore stage with barren calcite, quartz and chlorite. Fluid inclusion microthermometry indicates that the hydrothermal fluids of the Jinchanghe skarn system evolved from the pre-ore stage (450–480 °C and 11.7–15.5 °C wt% NaCl equiv), through the oxide stage (230–280 °C and 6.5–12.2 wt% NaCl equiv), the sulfide stage (190–230 °C and 1.3–10.3 wt% NaCl equiv), and eventually to the post-ore stage (120–180 °C and 1.6–4.6 wt% NaCl equiv). Correspondingly, the δ18Ofluid values decrease from 1.8–7.1‰ to 1.0–6.4‰, -1.0 to 1.3‰, and -3.6 to -1.4‰. This indicates that the pre-ore fluids comprise a magmatic component but mixed with some meteoric water, and in the later stages meteoric water has become dominant in the hydrothermal system. Zinc and sulfur isotope compositions reveal that the Zn and S forming the sulfides have a dominantly magmatic origin. The coupled decreases of fluid temperature, salinity, and δ18Ofluid values during the mineralization indicate simultaneous mixing with meteoric water and ore precipitation, suggesting that fluid mixing was critical in ore deposition. The gradual increase of δ13CCO2 values in equilibrium with the hydrothermal calcite (-5.2 to -1.6‰) from the sulfide stage to the post-ore is attributed to the reaction between the fluids and the carbonate wallrocks, implying a role that fluid-rock interaction has taken in the sulfide deposition. Fluid mixing and fluid-carbonate reaction are the two major factors controlling the formation of the Jinchanghe deposit. [ABSTRACT FROM AUTHOR]

Many massive sulfide deposits have been discovered in the Upper Paleozoic rift-related volcaniclastic sequence in South China, among which the Yushui copper deposit is the most important due to its high grade. The deposit has been variably attributed as SEDEX (sedimentary exhalative) or MVT (Mississippi valley type). The Yushui copper deposit in Guangdong (South China) contains stratiform bornite-chalcopyrite orebodies (102.1 kt Cu @ 3.5%, 186.6 kt Pb @ 4.29%, 117.6 kt Zn @ 2.91%, and 339 t Ag @ 112 g/t) developed along the contact between Upper Carboniferous dolostone and Lower Carboniferous pebbly quartz sandstone, which indicates a shallow marine deposition environment. The Yushui deposit comprises an upper massive sulfide orebody and a lower stockwork orebody with intense alteration. In this study, we newly identified Carboniferous tuffs and syn-volcanic faults in the footwall, and exhalites in the hanging-wall. Hematite from the Cu ores yielded a U-Pb age of 320 ± 15 Ma (MSWD = 2.1, n = 57), and hydrothermal dolomite yielded a Sm-Nd isochron age of 308.1 ± 4.6 Ma (n = 7; MSWD = 0.94), which constrains the timing of mineralization at Yushui. These ages are coeval with the Carboniferous host rocks. Combining the evidence from the geological features (syn-volcanic faults, volcanic rocks, exhalites) and hematite trace element compositions, we suggest that the Yushui is a shallow marine VMS (volcanogenic massive sulfide) deposit. The Sr-Nd isotope composition of hydrothermal dolomite (εNd ~−12) indicates that the ore-forming materials were originated from the crustal basement. The Yushui copper deposit was likely formed during the Late Carboniferous continental back-arc extension in eastern South China. The regional extension may have caused enhanced heat flow, which promoted fluid convection in the basement rocks. In addition, we suggest that volcanic rocks and disseminated chalcopyrite-pyrite mineralization in the Lower Carboniferous quartz sandstone and exhalites are good indicators for regional VMS prospecting. [ABSTRACT FROM AUTHOR]

In this work, the characteristics of the exothermic reaction between ammonium nitrate and sulfide ores were explored using COMSOL Multiphysics. This reaction can cause an increase in temperature within the blast holes of sulfide mines and can potentially induce premature explosions of the explosives. Initially, simulations were conducted to observe temperature variations in blast holes before and after the loading of explosives. Then, the impact of blast hole diameter and initial temperature on the thermal environment was assessed. Subsequent analysis focused on the fluid field's dynamics, examining flow rate changes and the concentration of signature gases produced by the reaction. Additionally, the influence of blast hole diameter on these parameters was evaluated. The results show that the blast hole temperature is positively related to its diameter and initial temperature. When the diameter of the blast hole is 120 mm and 165 mm, a significant change in flow rate is observed, with a trend of being rapidly increased and then rapidly decreased. The production of NH3 is always found to be greater than that of the other two gases. As for NO and SO2, their production is characterized by an approximate ratio of 1:2. The numerical simulation results can provide important theoretical guidance for the spontaneous detonation of blast hole in sulfide mines. [ABSTRACT FROM AUTHOR]

Including sulfide ore beneficiation tailings in sulfide ore processing is mainly ascribed to their use in the construction industry. In addition to dump products, various other wastes are formed during processing of sulfide ore materials, and these wastes are sent into circulation for pyrometallurgical processing. This study proposes a device for thermal beneficiation of gold-containing sulfide ore materials using a tubular purge grate. Gas purging through the holes of hollow rings, which are arranged in a staggered order, will evenly distribute bubbles throughout the volume of the slag melt and also evenly mix it. Gas purging of only the molten slag will reduce energy consumption. [ABSTRACT FROM AUTHOR]

The article discusses the features of the chemical composition and the formation of intergrowths of platinum-group minerals, gold, gold-bearing phases, and other ore minerals present in placers collected from the Anabar River in the northeast part of the Siberian platform. Based on an analysis of changes in the phase compositions of these intergrowths of noble metals with other ore minerals on (Pt, Pd)-Fe-Au and Pd-Cu-Au phase equilibrium diagrams, potential trends in the crystallization of natural polymineral alloys from multicomponent low-sulfide metallic liquids are discussed. The similarity of the microstructures of natural and metallurgical alloys indicates that the formation of natural multiphase Au-PGE intergrowths occurred in a similar manner to the crystallization of multicomponent synthetic alloys. The authors suggest that magmatic Au-PGE mineralization occurs during the crystallization of a noble-metal-containing, low-sulfide, Cr-rich oxide melt separated from silicate mafic–ultramafic magma. Magmatic gold–platinum deposits are commonly associated with sulfide or oxide disseminated-schlieren ores in layered mafic–ultramafic intrusions. However, due to the high solubility of gold and platinoids in sulfide minerals, PGMs in sulfide ores occur as isomorphic impurities or as microphases and dispersed inclusions that cannot form placers. Therefore, the authors suggest that magmatic Au-PGE mineralization occurs during the crystallization of an immiscible low-sulfide, high-Cr oxide liquid separated from silicate mafic–ultramafic magma. In the northeast part of the Siberian platform, potential sources for these placers are likely alkaline, high-Ti mafic–ultramafic intrusions, as confirmed by the presence of silicate inclusions in ferroan platinum similar in composition to melteigite. [ABSTRACT FROM AUTHOR]

The winning of critical raw materials from secondary resources, e.g., from abandoned mines, mining residues, electronic waste or low-grade ores, is a potential source with promising outcomes due to innovative and more efficient extraction methods. The research and education mine "Reiche Zeche" at the TU Bergakademie Freiberg, Germany offers a scientific lab in a real application environment for an in-situ bioleaching section from a low-grade sulfide ore vein with on-site associated membrane downstream processing. The evaluation and resumption of previous research activities showed both the feasibility and the potential for further up-scaling. But there was also potential evaluated for improving the effectiveness, especially in terms of individual process elements within the leaching and membrane cycle as well as regarding microbiology. Based on this, further optimization was carried out and effectiveness was evaluated and compared to the prior state. The results regarding the leaching outcome proved that process optimization leads to stable and continuous leaching process operations as well as to improved and more favorable conditions for the microorganisms due to the implementation of a bioreactor and changing the whole leaching operation from a direct into an indirect process. Furthermore, cleaning in place (CIP) resulted in the maintenance of selectivity despite discontinuous membrane process operation. [ABSTRACT FROM AUTHOR]

The large Dongtangzi Zn-Pb deposit is located in the southwest of the Fengxian–Taibai (abbreviated as Fengtai) ore cluster in the west Qinling orogen. The origin of the deposit is controversial, positing diverse genesis mechanisms such as sedimentary-exhalative (SEDEX), sedimentary-reformed, and epigenetic-hydrothermal types. This study combines systematic ore geology observations with high-precision Rb-Sr and Sm-Nd ages of 211 Ma and in situ S-Pb isotopes to constrain the timing and origin of mineralization. In situ S-Pb isotopic studies show that the sulfide ores display a narrow range of δ34S values from 1.1‰ to 10.2‰, with 206Pb/204Pb, 207Pb/204Pb, and 208Pb/204Pb ratios of 18.07 to 18.27, 15.64 to 15.66, and 38.22 to 38.76, respectively. On the other hand, pyrites of the sedimentary period and the granite porphyry dike have δ34S values ranging from 15.8 to 21.4‰ and from 2.1 to 4.3‰ (with 206Pb/204Pb ratios of 18.09 to 18.10, 207Pb/204Pb ratios of 15.59 to 15.61, and 208Pb/204Pb ratios of 38.17 to 38.24), respectively. The above-mentioned S-Pb isotopic compositions indicate that the metallic materials involved in ore formation originated from a mixture of Triassic magmatic hydrothermal fluid and metamorphic basement. By integrating the regional geology, mineralization ages, and S-Pb isotopic studies, we propose that the Dongtangzi Zn-Pb deposit is the product of epigenetic hydrothermal fluid processes, driven by Late Triassic regional tectono-magmatic processes. [ABSTRACT FROM AUTHOR]

The Kodaro–Udokan region is a huge Cu metallogenic province in Southern Siberia, one of the largest on Earth. It contains world-class copper sandstone-hosted Udokan (Cu reserves of 26.7 Mt) and PGE-Ni-Cu Chineysky deposits related to gabbro–anorthosite pluton (Cu—10 Mt; Fe-Ti-V, 30 Gt of ore). Furthermore, there are many small deposits of sulfide ores in sedimentary and igneous rocks in this region as well. For many decades, their genesis has been hotly debated. We studied the mineral composition and the sulfur isotopes in several deposits located at different levels of the stratigraphic sequence and in gabbro intruded in sandstones of the Udokan complex. The differences in ore compositions were found. The Burpala and Skvoznoy deposits consisting of the chalcocite–bornite association are characterized only by negative δ34S. The δ34S values for the Udokan deposits are mostly <0 (up to −28‰). The positive δ34S data characterize the ores of the Chineysky and Luktursky intrusions. Two Cu sandstone-hosted deposits are characterized by complex ore composition, i.e., the Krasny deposit, comprising chalcopyrite–pyrrhotite ores, is enriched in Co, Ni, Bi, Sb, Mo, Pb, Zn, Se, Te, and U and has a wide range of δ34S = −8.1–+13.5‰, and the Pravoingamakitsky deposit (Basaltovy section), consisting of quartz–chalcopyrite veins, has high PGE contents in ores with δ34S = +2.9–+4.0‰. These deposits are located near the gabbro massifs, and it is supposed that their ore compositions were influenced by magmatic fluids. The general regularities of the localization of the deposits in rift zones, and the proximity of mineral and isotopic composition allow us to conclude that the main source of copper could be rocks of basic composition because only they contain high Cu contents. Fluids from deep zones could penetrate to the surface and form Cu sandstone-hosted deposits. [ABSTRACT FROM AUTHOR]

Mineral processing is one of the important methods of resource utilization, and flotation and leaching are the main methods of mineral processing. The conventional reagents used in these methods usually show that they may lead to health, environment, safety, and other related problems. In order to make these methods safer and cleaners, it is necessary to explore the use of more green and environmentally friendly reagents. Ionic liquids (ILs) and deep eutectic solvents (DESs) are known as green solvents because of their wide liquid temperature range, good solubility, high thermal and chemical stability, almost nonvolatile and low toxicity. The application of ILs and DESs as agents in mineral flotation and extraction of valuable metal can provide new alternatives to traditional methods and processes and realize green and clean production. ILs and DESs have been successfully used to high-efficient float some minerals that are difficult to float, such as rare-earth minerals, quartz, and quartz hematite, as well as carbonate asphalt during recent years. Here we focus on the application progress, existing problems, and development direction of ILs and DESs in mineral processing. We introduced characteristics of ILs and DESs, and the research progress of ILs and DESs in green flotation of rare-earth ore, quartz and quartz hematite. The research works of ILs and DESs in the green leaching of chalcopyrite, sulfide ore, gold, and silver ore is summarized. Interactions of ILs and DESs with common minerals of soil also discussed to help understand the impact of ionic liquids on soil and groundwater. Compared with the traditional flotation and leaching reagents, the amount of ILs and DESs used is obviously smaller, and the selectivity and efficiency are better than that of the traditional system. After further research and optimization, it is expected to be developed into a new efficient and green mineral processing technology. [ABSTRACT FROM AUTHOR]

Lead isotope values for volcanogenic massive sulfide (VMS) deposits provide important insights into metal sources and the nature of pre-accretionary tectonostratigraphic terranes and underlying basements. Deposits of this type in New England formed in diverse tectonic settings including volcanic arcs and backarcs, a supra–subduction zone arc, a rifted forearc foreland basin, and a rifted continental margin. Following VMS mineralization on or near the seafloor, components of the tectonostratigraphic assemblages—volcanic ± sedimentary rocks, coeval intrusions, sulfide deposits, and underlying basements—were diachronously accreted to the Laurentian margin during the Paleozoic. Lead isotope data for galena show relatively large ranges for 206Pb/204Pb, 207Pb/204Pb, and 208Pb/204Pb. Evaluation of potential lead sources, using for comparison Pb-isotope data from modern and ancient settings, suggests that principal sources include the mantle, volcanic ± sedimentary rocks, and deeper basement rocks. Integration of the Pb-isotope values with published data such as Nd isotopes for the volcanic rocks and from deep seismic reflection profiles points to the involvement of several basements, including those of Grenvillian, Ganderian, Avalonian, and West African (and (or) Amazonian) affinity. Clustering of Pb-isotope data for VMS deposits within individual Cambrian and Ordovician volcanic and volcanosedimentary settings, delineated by differences in 206Pb/204Pb and µ (238U/204Pb) values, are consistent with lead derivation from at least four and possibly five different tectonostratigraphic assemblages with isotopically distinct basements. Collectively, our Pb-isotope data for New England VMS deposits provide a novel window into the nature of subarc basement rocks during pre-accretionary sulfide mineralization outboard of Laurentia during early Paleozoic time. [ABSTRACT FROM AUTHOR]

New data on the multiple sulfur isotope signature of Archean sulfides from country rocks and magmatic mineralization at the Moran deposit (Kambalda, Western Australia) were combined with previously published geochemical data to constrain the various stages of the dynamic evolution of this magmatic system, unveiling new insights into the transport mechanisms of sulfide liquids in komatiite magmas. Sulfides in the Archean magmatic and sedimentary host rocks of the komatiites display a unique mass-independent sulfur isotope signature (Δ33S), which records a photochemical reaction of sulfur in an oxygen-poor atmosphere prior to the Great Oxidation Event. Sedimentary rocks that are thought to be assimilated by komatiite show a distinctly positive Δ33S signature (+ 0.9 to + 2.4‰). Early ore sulfides situated above these sedimentary rocks contain relatively few valuable metals and display an overlapping Δ33S range (+ 0.6 to + 1.0‰). Subsequent but still early ore sulfides are situated above basalt, as the sedimentary rocks were thermo-mechanically eroded by the sulfide melt, displaying more mantle-like signatures (+ 0.2 to + 0.3‰) and valuable metal content - indistinguishable from the main ore deposit. This reflects a progressive dilution of the contaminant signature by the magmatic isotope signature of the komatiite liquid. Calculated volumes of the interaction of silicate melt and sulfide melt to explain the metal tenor of the ore and its Δ33S signature indicate a decoupling between chemical and isotopic signatures. This can be explained by upgrading the sulfide melt with valuable metals simultaneously with the dissolution of sulfur in the komatiite melt. [ABSTRACT FROM AUTHOR]

As a super-large copper-nickel deposit, Jinchuan copper-nickel sulfide ore is rich in resources. In addition to nickel as the main element, the accompanying valuable metals include copper, cobalt and platinum group elements. With perennial mining, the situation of ore dilution, sliming and complexity in composition is becoming more and more obvious. Due to the use of copper-nickel separation method combined with metallurgy, and serpentine as the main silicate-containing gangue being easy to float, with the continuous depletion of raw ore, the growing needs to meet the qualification requirement for MgO-content have brought great difficulty and challenge to the beneficiation work. As a worldwide problem, the problem of flotation magnesium reduction by flotation of Jinchuan copper-nickel sulfide ore has received widespread attention, and the beneficiation agent for its magnesium reduction problem is also constantly being developed. But in the actual production, often combined with the on-site production and actual cost, some agents to the enterprise efficiency improvement is often not large. This paper summarizes and expounds the technical situation of Jinchuan company in previous years in developing magnesium-lowering agent for the copper-nickel sulfide ore flotation, and the development of such agent for other magnesium-oxide containing ores providing technical reference for the majority of mineral processing workers in copper-nickel sulfide ore magnesium reduction. [ABSTRACT FROM AUTHOR]

The influence of grinding process on the flotation of copper-nickel sulfide ore was summarized. The results showed that the size, shape, ratio, material of grinding media, grinding environment and other related parameters mainly affected the flotation of copper-nickel sulfide ore by affecting the particle size composition of the grinding products and the electrochemical reaction in the grinding process. The grinding media with specific shape, size and proportion can affect the grinding behavior of sulfide minerals and gangue minerals in the ore, and the grinding efficiency can be improved by specific regulation and control combined with the mechanical properties of the ore, the particle size distribution of the sulfide minerals and the gangue minerals in the grinding products was improved, and the flotation index was improved. The material of the grinding medium mainly affected the flotation of minerals by affecting the electrochemical reaction in the grinding process. Due to the galvanic effect, a large number of hydrophilic compounds will be produced in the grinding with active media such as cast iron, which will cover the surface of sulfide minerals and hinder their flotation. Using inert media such as stainless steel can avoid this and reduce the wear loss. In addition, iron ions produced by cast iron and other media may activate gangue minerals and further deteriorate the flotation index. Grinding in different atmospheres can also affect mineral flotation. In nitrogen atmosphere, the electrochemical reaction of grinding medium was weak, and less hydrophilic compounds were produced. Sulfide minerals can generally obtain higher recovery than grinding in air atmosphere, while grinding in oxygen atmosphere will reduce the floatability of minerals. The difference of grinding methods such as dry grinding and wet grinding can also affect the floatability of sulfide minerals by affecting their surface composition. In general, the grinding process had various effects on the flotation of copper-nickel sulfide ore. When the relevant parameters were adjusted, detailed experimental study should be carried out in combination with the specific ore properties to obtain good flotation index. [ABSTRACT FROM AUTHOR]

Copper is an indispensable metal in the new energy era. In order to efficiently develop a low-grade copper ore resource abroad, in view of the important role of process mineralogy in the selection of ore dressing process, the process mineralogy of this ore was studied by using the testing and analysis techniques such as MLA and optical microscope, and important process mineralogy data were obtained, which guided the determination of beneficiation process in the concentrator. The results show that the main metal sulfides in the ore are chalcopyrite and pyrite, and the gangue minerals are mainly quartz and potassium feldspar, followed by muscovite, albite and biotite. Chalcopyrite is basically the copper bearing minerals, and there are a small amount of (blueschene) chalcocite and other copper bearing minerals. Under the condition of -- 74 µm accounting for 62%, chalcopyrite has a good dissociation condition, uniform particle size distribution, and most of them are concentrated in the size range conducive to flotation recovery. Under the separation treatment of three roughing, regrinding of coarse concentrate, classification, three cleaning and one fine cleaning, when the raw ore contains 0.41% copper and 0.24 g/t gold, a copper concentrate containing 20.83% copper and 9.25 g/t gold with copper recovery of 90.43% and gold recovery of 68.60% can be obtained. The efficient exploitation and utilization of low-grade gold-bearing copper sulfide ore resources are realized. [ABSTRACT FROM AUTHOR]

Recently, preoxidation is an effective pretreatment method of refractory gold ore, which has been widely used due to the high desulfurization, arsenic removal, low environmental pollution, and rapid reaction rate. In this paper, we describe the thermodynamic considerations of preoxidation of pyrite and arsenopyrite, the main minerals of the refractory gold ore, and the effect of the pressure oxidation, one of the preoxidation processes on the chlorination leaching. The thermodynamic results indicated that arsenopyrite under acidic conditions is easier to oxidize compared to pyrite and the oxidation decomposition of pyrite and arsenopyrite-type gold ore can be considered mainly for pyrite. The experiment has shown that the arsenic removal rate was higher than the desulfurization rate; it is confirmed that the thermodynamic conclusion of the oxidation of pyrite and arsenopyrite was correct. Comparing the XRD, SEM, and EDX analyses of gold concentrate and pressurized oxidation residue, it can be seen that the surface of pressurized oxidation residue is a fine porous structure and the dense and durable structure of sulfide ore is mainly destroyed. [ABSTRACT FROM AUTHOR]

Depleted gold-bearing sulfide mineral materials can be employed in cement production, construction industry, road construction, and other sectors of the national economy. This will enable metallurgical enterprises to switch to low-waste or nonwaste technologies. Research on and practice of ore beneficiation with a high degree of sulfidity reveal that gold recovery is directly dependent on the degree of ore sulfidity and the content of the main ore sulfide minerals. To increase the efficiency of gold recovery, a device for the enrichment of gold-bearing sulfide materials using centrifugal flotation is developed. [ABSTRACT FROM AUTHOR]

The supergiant Shuangjianzishan (SJS) Ag–Pb–Zn deposit, located in the southern Great Xing'an Range (SGXR), is the largest Ag deposit in China. The SJS deposit can be divided into two ore blocks: the Shuangjianzishan ore block and the Xinglongshan ore block. Given the importance of the Xinglongshan ore block in the SJS deposit, our work is focused on the Xinglongshan ore block. The vein orebodies in the Xionglongshan ore block mainly occur in the NW-, NNW-, and NNE-trending fault zones, and its mineralization is mainly related to a deep concealed syenogranite. Here, we present new geochronology, isotope geochemistry, and fluid inclusion data for the Xinglongshan ore block and provide additional insights into the metallogenic mechanism of the deposit. The dating results show that the syenogranite related to the mineralization formed at approximately 137 Ma, which is coherent with some previous age determinations in sulfides from the ore deposit. The mineralization of the Xinglongshan ore block can be divided into four stages: sphalerite–arsenopyrite–pyrite–chalcopyrite–quartz stage (stage I), sphalerite–galena–pyrite–silver-bearing mineral–quartz stage (stage II), sphalerite–galena–silver-bearing mineral–quartz–calcite stage (stage III), and weakly mineralized quartz–calcite stage (stage IV). Four types of fluid inclusions (FIs) have been identified within quartz and calcite veins: liquid-rich, gas-rich, pure-liquid, and pure-gas FIs. The homogenization temperatures in the four stages exhibit a gradual decrease, with stage I ranging from 253 to 302 °C, stage II from 203 to 268 °C, stage III from 184 to 222 °C, and stage IV from 153 to 198 °C, respectively. The salinity for stages I, II, III, and IV falls within the ranges of 3.4–6.6 wt% NaCl eqv., 2.6–7.2 wt% NaCl eqv., 2.9–7.0 wt% NaCl eqv., and 1.2–4.8 wt% NaCl eqv., respectively, indicative of a low-salinity ore-forming fluid. The δ18Owater and δD values of the ore-forming fluid span from −13.9‰ to 7.4‰ and −145‰ to −65‰, with δ13CV-PDB values between −11.0‰ and −7.9‰. These values suggest that the ore-forming fluid predominantly originated from a mixture of magmatic and meteoric water. The 206Pb/204Pb, 207Pb/204Pb, and 208Pb/204Pb ratios of sulfides range from 18.278 to 18.361, 15.530 to 15.634, and 38.107 to 38.448, respectively. These ratios imply that the ore-forming material was primarily derived from the Early Cretaceous granitic magma, which resulted from the mixing of depleted mantle- and crustal-derived magmas. The fluid mixing was the dominant mechanism for mineral precipitation. The Xinglongshan ore block belongs to a magmatic-hydrothermal vein-type deposit related to the Early Cretaceous syenogranite, and the Shuangjianzishan ore block belongs to an intermediate sulfidation epithermal deposit related to coeval subvolcanic rocks. The Ag–Pb–Zn mineralization at Shuangjianzishan is genetically related to the Early Cretaceous volcanic–intrusive complex. [ABSTRACT FROM AUTHOR]

A detailed textural, mineralogical, and geochemical investigation of beach sands and seabed sediments from Thorikos and Oxygono bays of the eastern coast of Lavrion is performed, with the objective the provenance of the ore types exploited, the processing and beneficiation types employed, and the respective exploitation periods. The Oxygono Bay beach and seabed sands are highly heterogeneous, predominated by lithic clasts originating from surrounding lithologies. Examination of the fine-grained fraction from the seabed core revealed that only the upper 50 cm was affected by recent and ancient mining activity. Combining the mineralogy and geochemistry of Oxygono Bay sands with the radiochronological model of Pappa et al. (2018), four periods of recent exploitation (mid-19th—late 20th century) are distinguished: (1) The "1860–1875 A.D.", involving exploitation of the ancient smelter slags, (2) the "1875–1900 A.D.", with ongoing ancient smelter slag processing and the commencement of underground sulfide ore exploitation, (3) the "1900–1930 A.D.", where heavy mining of the carbonate-hosted Pb–Zn–Ag ore occurs, (4) the "1930–1980"), where the implementation of flotation-type processing assisted in the exploitation of the poor skarn and porphyry-type ores. The latest "1980 A.D.—to date" period depicts the cessation of all mining and processing activities. The southern Thorikos Bay beach sands are homogeneous and fine-grained, are mainly composed of gangue and pyrite, and show elevated Fe, As, Pb, Zn, and Mn content. The southern Thorikos Bay beach sands clearly point to exploitation and processing by flotation of the carbonate-hosted Pb–Zn–Ag sulfide ore, and the tailings were disposed of from the nearby facilities to southern Thorikos Bay without any environmental concern during the "1930–1980 A.D." period. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this paper is to investigate the friction and wear mechanisms in copper-based self-lubricating composites with MoS2 as the lubricating phase, which provides a theoretical basis for subsequent research on high-performance copper-based self-lubricating materials. Design/methodology/approach: Friction tests were performed at a speed of 100 r/min, a load of 10 N, a friction radius of 5 mm and a sliding speed of 30 min. Friction experiments were carried out at RT-500°C. The phase composition of the samples was characterized by X-ray diffraction of Cu Ka radiation, and the microstructure, morphology and elemental distribution were characterized by scanning electron microscopy and energy dispersive spectroscopy. Reactants and valences formed during the wear process were analyzed by X-ray photoelectron spectroscopy. Findings: The addition of MoS2 can effectively improve friction-reducing and anti-wear action of the matrix, which is beneficial to form a lubricating film on the sliding track. After analyzing different changing mechanism of the sliding tracks, the oxides and sulfides of MoS2, MoO2, Cu2O, CuO and Ni(OH)2 were detected to form a synergetic lubricating film on the sliding track, which is responsible for the excellent tribological properties from room to elevated temperature. Research limitations/implications: For self-lubrication Cu–Sn–Ni–MoS2 material in engineering field, there are still few available references on high-temperature application. Practical implications: This paper provides a theoretical basis for the following research on copper-based self-lubricating materials with high performance. Originality/value: With this statement, the authors hereby certify that the manuscript is the results of their own effort and ability. They have indicated all quotes, citations and references. Furthermore, the authors have not submitted any essay, paper or thesis with similar content elsewhere. No conflict of interest exits in the submission of this manuscript. [ABSTRACT FROM AUTHOR]

The article presents the results of thermodynamic prediction and electric smelting of Shalkiya sulfide zinc-lead-bearing ore in the presence of magnetite and coke. Using the HSC-6.0 software package, it was found that under equilibrium conditions in the presence of Fe3O4 and carbon, the reduction and formation of gaseous zinc from ZnS (according to ΔG° = 0) occurs at a temperature of 1205.7 °C, and the formation of ferroalloy at the interaction of the sulfide ore with magnetite and carbon begins at 1200 °C. About 58% of silicon is extracted into the ferroalloy at 1800-1900 ℃; almost all zinc and 83-88% of lead turns into a gaseous state. Electric smelting of the sulfide ore in the presence of magnetite concentrate and coke makes it possible to obtain the FS45 grade ferrosilicon (42-43% of Si); the silicon extraction degree was 84-88%. At the same time, 97.3% of lead and 99.2% of zinc are extracted into the sublimates. The developed method for processing zinc sulfide ores allows us to increase the degree of raw materials' comprehensive use due to the extraction of not only zinc and lead, but also silicon. The technology can be used to process raw materials containing zinc, lead and silica, such as zinc ore concentration tailings. [ABSTRACT FROM AUTHOR]

We present new mineralogical data of cronstedtite from the Southern-2 orebody, located in the South-Western branch of the Talnakh intrusion (Noril'sk area) composed of massive sulfides in which the total amount of oxides and silicates does not exceed 1–3 vol%. The petrographic and mineralogical features of these ores indicated occurrence of fine-grained, fibrous needle like clusters < 50-µm-sized grains of cronstedtite (7.09 Å along its c-axis). This mineral confirmed by a number of analytical techniques (powder X-ray diffraction of balk samples, transmission electron microscopy, scanning electron microscopy, Raman and Infrared spectroscopy). Cronstedtite sporadically contains signals of Al, Ni, Ca and filling the cracks and cavities between sulfides of copper (chalcopyrite) and iron (pyrrhotite, pentlandite). In some cases, cronstedtite contains micron-sized PGM, and associates with magnetite. According the X-ray diffraction analysis of the bulk massive ores besides cronstendtite are established kaolinite, gypsum, calcite, quartz, and cristobalite. The findings of cronstedtite in Noril'sk area have never been mentioned publicly before. Its occurrence is the northernmost known locality in the world. Our results imply that the formation of cronstedtite in the Talnakh intrusion could be possible by the active participation low-temperatures fluids within the relatively near-surface (< 2 km of paleosurface) conditions of intrusion emplacement, in contrast to other deep-seated supergiant Cu–Ni–PGE deposits in the world. The conditions of formation in isolated cavities in fresh pyrrhotite-pentlandite-chalcopyrite massive ores of deep level of the Talnakh intrusion could be favorable for the formation of cronstendtite. [ABSTRACT FROM AUTHOR]

This article explores, for the first time, the processes involved in the formation of drainage water during the oxidation of tailings from sulfide-containing ores at the Krasnorechensk Concentrating Mill (KCM) old tailing dump, reaching a depth of 1.45 m. The study covers a temperature range from –25 to +45°C, using physicochemical modeling through Selector software package. The modeling results indicate that, across all considered temperatures, the solutions exhibit Eh parameters ranging from 0.63 to 0.94 V, showing an increasing trend with depth. The pH of the medium falls within the range of 11.9 to 5.28. The concentrations of sulfide ore elements—Cu, Pb, Zn, As, S—decrease with both increasing temperature and depth during negative temperature conditions. However, in the positive temperature range, their concentrations remain independent of depth, rising towards the 1.45 cm horizon. Conversely, the concentrations of major elements from host rocks—Ca, Mg, K, Na, Al, Si—increase with both temperature and depth. The study identifies the crystallization of minerals such as Fe and Ca, belonging to oxides and hydroxides, sulfates, and carbonates (goethite, fibroferrite, gypsum, and calcite). Cryogenic conditions reveal the presence of 15 ions and molecules of sulfide ore elements in simulated solutions, with their number halving as temperature increases. [ABSTRACT FROM AUTHOR]

This article presents the results of a long-term study on the composition of technogenic and river water hydrochemical samples in the mining systems of the Kavalerovo and Dalnegorsk Districts of the Russian Far East. The objective of this work is to estimate the content of a wide range of elements—Be, Cd, Sr, Li, Co, Ni, Al, Cr, Ba, Cs, Sc, Se, Rb, Y, Tl, Ca, and Mg—in mine, sludge, drainage, and river waters in the considered areas. The study identified a high content of a diverse range of host rock minerals elements and impurities from sulfide ores in the examined waters. The concentration of all considered metals and metalloids in river waters exceeds background values by tens, hundreds, and even thousands of times, reaching tens of thousands in technogenic waters. For a comprehensive understanding of the influence of anthropogenic waters on the condition of river and drinking waters in the considered areas, exceedances of Maximum Permissible Concentrations (MPC) are also demonstrated for elements from sulfide ores: Fe, Mn, Cu, Pb, Zn, and As. For instance, in the river waters of the Kavalerovsk District, there are exceedances of MPC in fishery water bodies for Fe, Mn, Cu, Zn, Sr, Ni, Al, Tl, and Ca, and in drinking waters—for Fe, Mn, Be, Cd, Al, and Ca. In the Dalnegorsk District, MPC in fishery waters for Fe, Mn, Cu, Pb, Zn, Be, Cd, Sr, Ni, Se, Tl, Ca, Mg, Al, and B are exceeded in the waters of the Rudnaya River, while household and drinking MPC for Fe, Mn, Pb, Zn, As, Be, Cd, Li, Ni, Tl, Al, Ca, Mg, and B are exceeded. In drinking water of this area, excess of MPC is noted for Mn, Pb, As, and Ca. Exceedances of indicators range from units to thousands of times. The considered elements, concerning fishery and household drinking MPC indicators, belong to 1, 2, 3, and 4 classes of danger. Conducting a simulation of sulfide oxidation, considering the composition of host rocks, with the Selektor software package allowed us to establish the ionic and molecular forms of several considered elements in a wide temperature range from –25 to 45°C in technogenic and river waters. The results confirm not only the negative impact of technogenic waters on the hydrosphere of the region but also its significant scale for the period 2008‒2021. [ABSTRACT FROM AUTHOR]

The study shows how the statistical approach can provide information on the factors and processes that control the geochemical distribution of elements at the surface of an abandoned tailings pond. In this regard, the case study of a waste deposit resulting from the ore processing plant of Fundu Moldovei was carried out. The facility was concentrating Cu, Pb, and Zn from the polymetallic sulfide ores of the Fundu Moldovei—Leșu Ursului mining district (Romania). The statistics indicate three types of waste, showing specific properties: (i) Waste of the beach, rich in soluble fraction (14.4%) and secondary minerals (e.g., jarosite, ferricopiapite, magnesiocopiapite, pickeringite, and clay minerals). The latter and the related high contents of Al, K, Fe, Co, Ni, Cu, Pb, and Zn are controlled by the water evaporation and subsequent transient pH (2.6–3.5) of the leachates accumulated as puddles. The lower pH and scarce soluble fraction favor a rise in the Cu and Zn contents, while Al, K, Fe, and Co are noticeable at a higher pH when the soluble fraction is abundant. (ii) Waste of the upper dam slope, marked by intense oxidation and a meager occurrence of secondary minerals precipitated from highly acidic pore leachates (average pH of 2.55), namely, jarosite, ferricopiapite, magnesiocopiapite, and coquimbite. The surface waste contains more pyrite and is coarser because of the fine particle removal during rainfall. Unlike the beach waste, in the upper dam tailings, Al, K, Fe, Co, Cu, Pb, and Zn seem to relate mainly to the primary minerals (muscovite, chlorite, and pyrite). (iii) Downslope dam waste is less acidic (average pH of 3.75) than that of the upper slope; it contains secondary minerals stable at a higher pH (e.g., gypsum, apjohnite, dietrichite, clay minerals, and schwertmannite). Calcium, Mn, and Cd are more abundant in the dam waste. They originate from both primary and secondary minerals (e.g., muscovite, chlorite, gypsum, ferricopiapite, and magnesiocopiapite) and correlate with the coarser waste. [ABSTRACT FROM AUTHOR]

Carbon–arsenic-bearing gold ore is a typical complex refractory gold resource. Traditionally, xanthate was often used as a flotation agent to separate gold minerals. But, in this paper, in order to reduce the cost of the agent, kerosene was used as an auxiliary collector, and the gold grade and recovery rate were increased by about 10 g/t and 5.5%, respectively. Through process mineralogy studies of the raw ore, it was found that the ore has an Au grade of 5.68 g/t, most of which is surrounded by sulfide ore, accounting for 79.46%. The main minerals are pyrite, arsenopyrite, and quartz, etc. Their content, shape, particle size distribution, and occurrence state were obtained via microscopic observation and statistical analysis. According to the results of process mineralogy, various flotation conditions were tested, including grinding fineness, kerosene dosage, collector dosage, foaming agent dosage, and the slurry pH value. The optimal chemical system and the process flow of "two roughing, three cleaning and two scavenging" were finally determined, and the concentrate product with a gold grade of 42.83 g/t and recovery of 91.02% was obtained, which verified the feasibility of the kerosene-assisted xanthate flotation of refractory gold. [ABSTRACT FROM AUTHOR]

Based on the results of a comprehensive geological, mineralogical, and geochemical study of ores of the Namovskoe deposit, new data on the specifics of mineralization were obtained. The ores of the deposit were formed in close relation to the Early Cretaceous monzonitoid magmatism against the background of active left-hand movements along the Middle Sikhote-Alin fault. The U–Pb dating of the ore-bearing dyke provided an age of 103 Ma. In addition to native Au, the ores of the deposit contain high concentrations of Ag, Bi, and Cu. A variety of Bi minerals were registered in the ores: sulfide (bismuthinite), telluride (hedleyite), sulfotellurides (tetradymite, joseite-А, and joseite-В), Ag sulfobismuthite (matildite), Pb–Bi sulfosalts (aschamalmite, cannizzarite, cosalite, lillianite, nuffieldite, and galenobismuthite), an intermetallic compound of Au (maldonite), and native Bi. Ag minerals were identified as well: chloride (cerargyrite), sulfide (acanthite), and telluride (hessite). The typomorphic patterns of ore minerals and the geological structure of the Namovskoe deposit assign it to the type of gold deposits formed in a transform continental margin setting. A mantle source of ore mineralization is suggested. [ABSTRACT FROM AUTHOR]

The article describes determination of oxidizability and spontaneous combustion of ore and rocks as a case-study of the Oktyabrsky deposit. The rate of oxidation of sulfide ore increases after watering. The authors present the studies on sensitivity of ore and enclosing rocks to spontaneous combustion, as well as on gas emission in isothermal conditions and in heating. It is found that sulfide ore, hornfels and gabbro-dolerite are sensitive to spontaneous combustion. [ABSTRACT FROM AUTHOR]

In this study, GX2 was applied as a new high-efficiency chalcopyrite depressant to selectively separate molybdenite from Cu-Mo sulfide ores. The flotation performance and its interaction mechanisms with chalcopyrite and molybdenite were investigated using single-mineral and artificial-mixed-ore flotation, contact angle measurements, zeta-potential measurements, infrared spectroscopy, and X-ray optoelectronic spectrum analysis. The results indicated that molybdenite could be selectively separated from chalcopyrite under the optimal flotation conditions of pH 9.0, 80 mg/L GX2, 20 mg/L kerosene, 10 mg/L MIBC, and a flotation time of 3 min, while the molybdenite and chalcopyrite recoveries were around 90% and 5%, respectively. It was confirmed that GX2 could save ten times the depressant dosage compared to that of the Na2S baseline to achieve a similar separation efficiency. The contact angle test, zeta potential, infrared spectrum, and XPS results show that GX2 may be adsorbed on the surface of chalcopyrite via chemical adsorption, and the hydrophilic substances formed change its hydrophobicity, whereas the effect on the floatability of molybdenite is small, resulting in the excellent separation efficiency of chalcopyrite and molybdenite via flotation. [ABSTRACT FROM AUTHOR]

Studies on the dependence of the technological results of non-ferrous sulfide ore (copper—arsenic-bearing and non-arsenic-bearing—lead–zinc, and polymetallic) flotation on the pulp potential Eh are reviewed. Findings on the relation of Eh and collectorless flotation are presented. Changes in the pulp potential due to different gas applications and various reagent additions are considered. The influence of the grinding medium on the pulp Eh and hence on the flotation results is presented through various examples. The relation between the oxidation–reduction potential and reagent effects is exhibited and explained. pH–Eh ranges of different minerals' flotation, as recorded in various studies, are summarized and visualized jointly for all mentioned ores. It is concluded that the pulp Eh value, considered together with the pH value, is a useful means for flotation selection controlling and deserves further research, especially under industrial conditions. Some problems and difficulties in using pulp Eh for flotation control are discussed. [ABSTRACT FROM AUTHOR]

Major and trace elements in polymetallic minerals are crucial subjects of study in ore geology. However, efficient and convenient methods have yet to be developed for processing high-density and hydrophobic sulfide ores, like copper–nickel sulfide ore, which is a strategic metal resource. In this paper, a novel method for the multielement analysis of copper-nickel sulfide ore using total reflection X-ray fluorescence spectrometry (TXRF) combined with slurry sampling was developed. This approach is based on the preparation of a suspension in a liquid at a certain viscosity without sample digestion. The effects of the sample amount and particle size on the analysis results were evaluated. The method validation was achieved through these processes: comparison with inductively coupled plasma atomic emission spectrometry (ICP-AES) results; analysis of certified reference materials, including copper-nickel cobalt ore and cobalt-rich nodule. The dispersants of ethylene glycol and 1% Triton X-100 applied in sulfide ore were also evaluated. For most elements, the relative error and relative standard deviation were under 10% in ethylene glycol. By contrast, suspensions with 1% Triton X-100 showed poorer reproducibility, particluarly in samples with sulfide-rich content, requiring further enhancement. For high-specific gravity sulfide ores, a dispersant of ethylene glycol is recommended to enhance the result of accuracy and reproducibility. [ABSTRACT FROM AUTHOR]

Cawood et al. (this issue) critize our hypothesis of a pre-Klondikean weathering/oxidation event having affected the Aggeneys-Gamsberg ore district. Instead, they reinforce the long-held view that the sulfide deposits of the ore district with its pronounced metal zonation, its unusually high mineralogical variability and numerous geochemical anomalies are the product of amphibolite- to granulite-facies metamorphic overprint of originally syn-sedimentary exhalative deposits. Here we gladly use the opportunity to counter all issues raised and explain further our evidence of oxidation and subsequent re-sulfidation of the original synsedimentary deposits. [ABSTRACT FROM AUTHOR]

Biohydrometallurgy as a section of hydrometallurgy uses specific metabolic capabilities of microorganisms for metal extraction. Biomining is the application of bioleaching for metal extraction from sulfide ores. For recycling, i.e., metal extraction from waste and industrial residues, there are no biohydrometallurgical technologies yet, but promising laboratory studies on metal extraction from solids. In this review article, these are summarized, and perspectives are shown. [ABSTRACT FROM AUTHOR]

We propose that the observed enrichment of sulfur at the surface of Mercury (up to 4 wt.%) is the product of silicate sulfidation reactions with a S‐rich reduced volcanogenic gas phase. Here, we present new experiments on the sulfidation behavior of olivine, diopside, and anorthite. We investigate these reaction products, and those of sulfidized glasses with Mercury compositions previously reported, by mid‐IR reflectance spectroscopy. We investigate both the reacted bulk materials as powders as well as cross‐sections of the reaction products by in situ micro‐IR spectroscopy. The mid‐IR spectra confirm the presence of predicted reaction products including quartz. The mid‐IR reflectance of sulfide reaction products, such as CaS (oldhamite) or MgS (niningerite), is insufficient to be observed in the complex run products. However, the ESA/JAXA BepiColombo mission to Mercury will be able to test our hypothesis by investigating the correlated abundances of sulfides with other reaction products such as quartz. Plain Language Summary: The surface of the planet Mercury is enriched in sulfur, with abundances of up to 4 wt.%. Sulfur on Mercury has previously been interpreted to occur in magmatic sulfide phases. We propose an alternative mechanism for the enrichment of S on Mercury, whereby reduced S‐rich gases react with silicate minerals to form sulfides and quartz. We carried out sulfidation experiments on silicate minerals and glasses and used mid‐infrared spectroscopy to characterize the products of these reactions. The upcoming ESA/JAXA BepiColombo mission to Mercury will allow us to test the sulfidation hypothesis and provide constraints on the origin of the S enrichment on the planet's surface. Key Points: S‐enrichment on the surface of Mercury by sulfidation of silicate mineralsMid‐IR spectroscopy allows the identification of quartz as a main reaction product in mineral and glass sulfidationBepiColombo's Mercury Radiometer and Thermal Infrared Spectrometer instrument will test the sulfidation hypothesis by mapping the surface of Mercury in the mid‐IR spectral range [ABSTRACT FROM AUTHOR]

This work demonstrates the evolution of different architectures of Cu-Co bimetallic sulfide on Ni-foam. A simple solvent-changing strategy has been adopted to develop these architectures through a solvothermal approach. When water and ethylene glycol was used as a solvent, the surface of Ni-foam seemed to be covered with a snowflake-like architecture. On the addition of glycerol instead of ethylene glycol, the growth of spongy rectangular prisms from mud-like bricks was initiated. Analyzing electrochemically, both electrodes deliver excellent capacitance. The electrode developed with water and glycerol was found to be richer in terms of capacitive performance, which gives 1459.7 F/gm (5692.8 mF/cm2) at a higher current density of 5 mA/cm2. An over-33% increment in capacitance was noted when compared with the specific capacitance (areal capacitance) of another electrode which can provide 986.6 F/gm (3157 mF/cm2) at the same current density. Both electrodes are richer in terms of providing higher rate capability above 75%, even if the current density is increased by three times. Furthermore, both electrodes deliver long-lasting storage capability, with above 80% capacitance retention over 10,000 charge–discharge cycles even at a higher current density of 60 mA/cm2. This simple solvent-changing approach can be useful for developing electrode materials with outstanding capacitive performance. [ABSTRACT FROM AUTHOR]

The reaction of n-butylamine with carbon disulfide in the presence of NaOH followed by the reaction with 2-chloroethanol or benzоyl chloride leads to the formation of previously unknown S-organyl-N-butyldithiocarbamates in 83–92% yield. The flotation activity of 2-hydroxyethylbutyldithiocarbamate as an additional collector in the flotation of gold-bearing sulfide ore was studied. [ABSTRACT FROM AUTHOR]

Tsumeb Aragonite Categories Most aragonite occurrences at Tsumeb fall into one of the following five categories: "pure" aragonite, I nicholsonite, tarnowitzite, i aragonite flowstone, and pseudomorphs. Aragonite Flowstone The seepage of groundwater through the dolostone host rocks at Tsumeb commonly resulted in the precipitation of sheets of aragonite resembling frozen waterfalls with gently mammilated surfaces on the walls of the underground mine workings. The Kabwe mine aragonite is currently represented by one large preserved specimen consisting of aragonite on vanadinite (Southwood, Cairncross, and Rumsey [26]) (fig. 52). Aprevious Connoisseur's Choice column (Pohwat [22]) featured aragonite from Western Europe (part 1) and beyond (part 2), the latter making brief mention of specimens from Morocco, and Namibia, South Africa. [Extracted from the article]

The Dovyren Intrusive Complex (Northern Baikal region, 728 ± 3 Ma) includes the dunite–troctolite–gabbronorite Yoko–Dovyren massif (YDM) associated with a sequence of underlying mafic-to-ultramafic sills, locally demonstrating interbedding relations with the most primitive rocks of the pluton. These sills and apophyses contain sulfide mineralization ranging from globular to net-textured and massive ores. Major types of the YDM cumulates and sulfide mineralization were examined for their PGE contents and Re-Os isotopic systematics. The ten analyzed samples included chilled and basal rocks, poorly mineralized troctolite, PGE-rich anorthosite, as well as three samples from a thick ore-bearing apophysis DV10 connected with the YDM. These samples yielded a Re-Os isochron with an age of 759 ± 36 Ma and an initial 187Os/188Os of 0.1309 ± 0.0026 (MSWD = 110), which is in consistent with the previously reported U–Pb zircon age. It is shown that being recalculated to γOs(t) at t = 728 Ma, these isotopic compositions demonstrate three clusters regarding the relationship between γOs(t) and 187Re/188Os: (i) the chilled gabbronorite (YDM) and subcontact olivine gabbronorite (DV10) yielded the most radiogenic values of γOs(t) 10.5 and 10.0 among basal ultramafics, (ii) plagiodunite, troctolite, and sulfide ores showed lower radiogenic compositions, with γOs(t) ranging from 7.3 to 8.7, (iii) olivine gabbronorite, plagioperidotite, and one sample of PGE-rich anorthosite yield very primitive γOs(t) in the range 4.5 to 5.6 (on average 5.2 ± 0.6). The lowest values of γOs(t) for the least fractionated rocks of the YDM suggest a primitive mantle source, formed from a partly contaminated Neoarchean protolith, which is considered to be anomalous in Upper Riphean due to very low εNd(t) of −16 for the most primitive Dovyren magma (Fo88-parent). The highest values of γOs(t) and relative enrichment in the 34S isotope in the chilled gabbronorite (YDM) and subcontact olivine gabbronorite (DV10) evidence that their primitive to evolved magmatic precursors could be affected by a metamorphic fluid enriched in radiogenic 187Os, originating in the exocontact halo due to the thermal decomposition of pyrite from the dehydrated country rocks. This is consistent with the second-stage contamination of the Dovyren magma by the hosting crustal rocks (probably of 10 wt% shists), generating more evolved Fo86-parent magma with higher εNd(t) of −14. [ABSTRACT FROM AUTHOR]

Norilsk sulfide ores are one of the largest known sources of Pd on Earth. Palladium in these ores is presented in platinum-group minerals (PGM) and base metal sulfides (BMS), especially in pentlandite [(Fe,Ni)9S8]. Although several studies demonstrated high concentrations along with heterogeneous distribution of Pd in pentlandites from Norilsk, the form of Pd in pentlandite has not been established. Here, we provide the first evidence for Pd incorporation in the structure of pentlandite from Norilsk ores using X-ray absorption near edge structure (XANES) spectroscopy, synchrotron-based micro-X-ray fluorescence (μXRF), and electron backscatter diffraction (EBSD). We present the first ever measured XANES spectra of Pd in pentlandite and atokite [(Pd,Pt)3Sn] as well as in other common Pd minerals. Divalent Pd in pentlandite was detected by XANES. The Pd spectra in pentlandite show no similarities with Pd spectra in PGM, metallic Pd, PdS, PdCl2, and PdSO4 which signifies that Pd incorporates into the lattice of pentlandite. Substitution of Ni by Pd in the lattice of pentlandite is supported by negative correlations shown by μXRF and electron probe microanalysis (EPMA) and complies with the previous studies. The additional EBSD study demonstrates a resemblance in cell parameters of the Pd-rich and Pd-poor parts of the pentlandite grains and reflects that Pd incorporation into the pentlandite structure does not imply any notable structure distortion. The combination of analytical techniques used in the present study demonstrates the great potential of these methods for understanding the mechanisms of noble metal incorporation into ore minerals. [ABSTRACT FROM AUTHOR]

At present, scholars mainly study the relationship between nanobubbles and useful minerals, often ignoring the influence of bubbles on fine gangue minerals. When selecting nickel sulfide ore, scholars often faced with mudded and irrepressible serpentine, which seriously affects the quality of the concentrate. This mudded serpentine mineral often enters foam products with bubbles. In this study, the role of nanobubbles in the flotation behavior of hydrophilic serpentine was examined. Nanobubbles were successfully prepared via ultrasonic cavitation, with sizes ranging from 50 to 250 nm. The size and number of bubbles produced at 1 min and 2 min of sonication were significantly better than those of the prolonged test group, and it was found that longer sonication time did not produce better results. The stability of the nanobubbles produced via ultrasound was studied, and it was found that the nanobubbles were stable, with no change in size and only a slight decrease in number as the resting time increased. Nanobubbles were introduced into serpentine flotation, we found that the presence of nanobubbles significantly reduced the flotation recovery of serpentine. The presence of nanobubbles reduced the froth entrainment rate of microfine-grained serpentine, which in turn reduced its flotation rate. In the depressant group trials, it was found that the nanobubbles also reduced the amount of depressant. In short, the presence of nanobubbles can prevent the floating of fine hydrophilic gangues during flotation. [ABSTRACT FROM AUTHOR]

The aqueous ions influence the properties of air bubbles and, therefore, the recovery of flotation. This study aims to reveal the synergistic effect of frequently found ions in the flotation of Pb-Zn sulfide ores. In this context, dynamic surface tension measurements, bubble coalescence time, Sauter mean diameter (SMD), bubble size distribution (BSD), and dynamic foam stability (DFS) measurements were carried out using artificial process waters (APWs). APW with the minimum ion concentration is expressed as "APW1" with the ionic strength (I) of 0.03 mol/dm3. The concentration of the ions in APW1 was increased by 3, 5, and 10 times, and thus APW3 (I = 0.08 mol/dm3), APW5 (I = 0.13 mol/dm3), and APW10 (I = 0.26 mol/dm3) were prepared, respectively. The results of this study indicated that the surface tension increased slightly in the presence of APW related to the ion concentration. Potassium ethyl xanthate (KEX) at high concentrations was effective in the reduction of surface tension. As the APW concentration increased, finer bubbles were obtained with a narrower size range. The stability of the foam increased with butyl glycol (BG) and APW concentration. There was no need to use a frother (BG) for the flotation experiments in the presence of APW1 or APWs with higher ionic strength. [ABSTRACT FROM AUTHOR]

A specific feature of a major part of regional metamorphosed metasomatic ores of the Nežilovo area, Pelagonian massif, Republic of North Macedonia is the occurrence of chalcophile elements (Zn, Pb, Sb, Cu, and As) in oxides and oxysalts whereas sulfides and sulfosalts are absent. This paper describes anomalous sulfide-bearing mineral assemblage discovered in small, localized outcrops at the Kalugeri locality belonging to the Nežilovo group of ore occurrences. Based on the data on mineral assemblages and associations, a four stage model is proposed. Pressures of the first stage was estimated to be above 20 kbar using barometry on Ba-rich first generation of phengite and temperatures above 530 °C were estimated by Zr in rutile thermometer. During this stage, sulfide mineralization still occurs with crystallization of sphalerite and galena. In the second stage occurring above 500 °C and above 10 kbar, the first generation of cymrite crystallized showing that barium was present in the system in excess compared to sulfur. The third stage was dominated by Zn-rich phengite, baryte-anglesite solid solution and cerussite formation at temperatures between 500 and 350 °C and pressures between 7.1 and 4 kbar. The final stage of formation is characterized by crystallization of the second generation of cymrite below 350 °C. It is concluded that sulfide-free ores of the Nežilovo type could form as a result of transformation of initial sulfide ores at low-PT conditions and a high barium activity. [ABSTRACT FROM AUTHOR]

The petrography, mineralization, and geochemistry and isotope studies of sulfide ores were used to determine the genesis of the Naweoba and Bagh Volcanogenic Massive Sulfide (VMS) deposits. These deposits consist of minor stockwork, massive sulfide, and gossan zones. They are hosted by basaltic rocks in the Naweoba Block and Bagh Complex of Zhob Valley Ophiolites, respectively. The host rocks are strongly altered to chlorite and sericite. By using whole rock and pyrite in situ analyses, it is found that the Cu concentration is higher compared to Zn and Pb. Similarly, the primary mantle normalized data of Pb, Cu, Ag, Au, and Zn as well as the high Co/Ni ratios (> 1) in pyrite for both deposits indicate that these deposits have a mafic origin dominated by hydrothermal processes. The trace element signature in pyrite and chalcopyrite in these deposits suggests that mineralization formed at high to moderate temperatures. The δ34S values of pyrite (2.4–4.6‰) and chalcopyrite (2.7–5.7‰) indicate that hydrothermal fluids have derived sulfur largely from basaltic igneous rocks. The above signatures are all consistent with a Cyprus-type VMS ore deposits associated with ophiolites. Moreover, it was found that several trace elements (Ni, Co, Se, Zn, Pb, Sb, and As) show systematic variations in pyrite from Naweoba that are correlated to the stratigraphic depth and can be used as a proxy to separate deeper from shallower sulfide ores. [ABSTRACT FROM AUTHOR]

Nickel is a key element for stainless steel and lithium-ion batteries. However, the conventional extraction of nickel from sulfide ores generates large amounts of sulfur dioxide and slag and demands complex-refining processes to produce marketable products. The authors have proposed a sustainable nickel extraction strategy that retained the bulk of sulfur as solid iron sulfide and extracted nickel value into ferronickel simultaneously. This simple thermal treatment comprised two stages and yielded high nickel grade, high nickel extraction, and large ferronickel grains. The present study demonstrates that these grains of ferronickel can be efficiently separated from the nickel-depleted iron sulfide matrix. The high nickel grade (30 mass pct) and relatively low remaining sulfur concentration (4 mass pct) of the recovered ferronickel concentrate make it a potential feedstock for either stainless steel or nickel-containing cathode material. [ABSTRACT FROM AUTHOR]