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Copper sulfide ores frequently co-occur with pyrite, presenting a significant challenge for their selective separation during beneficiation processes. Despite advancements in flotation technology, there remains a critical need for efficient methods to enhance copper recovery while suppressing pyrite interference, particularly without compromising the associated precious metals such as gold and silver. Current practices often struggle with achieving high selectivity and recovery while maintaining environmental sustainability. Here, we investigate the efficacy of a ternary collector mixture consisting of ammonium dibutyl dithiophosphate (ADD), butyl xanthate (BX), and ethyl xanthate (EX) for the selective flotation of copper sulfide from a complex ore containing 0.79% Cu and associated precious metals (0.233 g/t Au and 5.83 g/t Ag). A combination of lime and hydrogen peroxide as inhibitors was employed to suppress pyrite effectively under alkaline conditions (pH = 11.33). The results demonstrate that the optimized ternary collector system (ADD:BX:EX at a ratio of 1:0.5:0.5) significantly improves the copper grade and recovery at an ultra-low dosage of 10 g/t. The optimized flotation method using the combined collectors and inhibitors effectively separated chalcopyrite from pyrite, achieving a copper concentrate with 20.08% Cu content and a recovery of 87.73%. Additionally, the process yielded notable recoveries of gold (9.22%) and silver (26.66%). These findings advance the field by providing a viable and environmentally conscious approach to the beneficiation of sulfide ores, potentially serving as a blueprint for processing similar mineral deposits while minimizing reagent usage and costs. [ABSTRACT FROM AUTHOR]

Extensional tectonics along NE-trending faults, coupled with diapirism, created paleo-highs and subsiding basins, providing the structural framework for subsequent mineralization processes. The preservation of organic matter within the Fahdene and Bahloul Cretaceous formations during the Anoxic Oceanic Events (AOE-1 and AOQ-2) facilitated the extraction of metals from seawater. The association of metals with organic matter, Fe-Mg oxides, and pyrite is revealed by principal component analysis (PCA). The subsequent maturation of organic matter generated hydrocarbons, with thermal cracking leading to the incorporation of organo-metallic ligands into mobile hydrocarbons. Oilfield brines form as a byproduct of this catagenesis. The metal-rich hydrocarbons and basinal brines invaded SO4−2-rich fluids from Triassic evaporites, resulting in the precipitation of sulfates (barite and celestite) and the bacteriogenic (BSR) and/or thermal (TSR) reduction of sulfate to reduced sulfur, which combined with metals to form sulfide ores. This study examines the role of hydrocarbons in the genesis of ore deposits within the diapiric zone, drawing upon a synthesis of literature and geological data. It highlights the interplay between basinal evolution, the organic matter-rich Cretaceous formations (Fahdene and Bahloul), diapiric paleo-highs, and the Alpine orogeny, which are identified as crucial factors in ore genesis in the diapiric zone. [ABSTRACT FROM AUTHOR]

With the booming of renewable clean energies towards reducing carbon emission, demands for lithium-ion batteries (LIBs) in applications to transportation vehicles and power stations are increasing exponentially. As a consequence, great pressures have been posed on the technological development and production of valuable elements key to LIBs, in addition to concerns about depletion of natural resources, environmental impacts, and management of waste batteries. In this paper, we compile recent information on lithium, nickel, and cobalt, the three most crucial elements utilized in LIBs, in terms of demands, current identified terrestrial resources, extraction technologies from primary natural resources and waste. Most nickel and cobalt are currently produced from high-grade sulfide ores via a pyrometallurgical approach. Increased demands have stimulated production of Ni and Co from low-grade laterites, which is commonly performed through the hydrometallurgical process. Most lithium exists in brines and is extracted via evaporation–precipitation in common industrial practice. It is noteworthy that at present, the pyrometallurgical process is energy-intensive and polluting in terms of gas emissions. Hydrometallurgical processes utilize large amounts of alkaline or acidic media in combination with reducing agents, generating hazardous waste streams. Traditional evaporation–precipitation consumes time, water, and land. Extraction of these elements from deep seas and recycling from waste are emerging as technologies. Advanced energy-saving and environmentally friendly processes are under extensive research and development and are crucial in the process of renewable clean energy implementation. [ABSTRACT FROM AUTHOR]

This article presents the results of thermodynamic and experimental studies on the joint processing of a mixture of Shalkiya deposit zinc–lead sulfide ore and its concentration tailings in the presence of coke and magnetite. Using the HSC-6.0 software package, it was established by thermodynamic modeling that the silicon-containing products of the SiO2 reduction in the system under consideration are FeSi, Si, Fe3Si, Fe5Si3, FeSi2, FeSi2.33, and SiOg, which, based on the starting reduction temperature, form an increasing series: Fe3Si (1200 °C); Fe5Si3, Si (1400 °C); and SiOg, FeSi2, FeSi2.33 (1500 °C). The smelting of the zinc–lead sulfide ore and concentration tailings mixture in the case of replacing 55% of the iron contained in the magnetite concentrate with steel shavings iron allowed us to produce FeSi45 ferrosilicon (41.9%–42.1% Si), with the extraction of 85% of the silicon in it, and sublimates containing 26.03% zinc and 13.47% lead, with the extraction of 97% of the zinc and 99% of the lead in them. In comparison with the initial ore-tailings mixture, the resulting sublimates are 11.83 times richer in zinc. [ABSTRACT FROM AUTHOR]

Heap bioleaching is considered to be a less energy-intensive metal-extraction technique compared to other methods, making it particularly attractive for low-grade sulfide ores. It has been successfully applied to recovery of copper, gold, and uranium from ores over decades. Despite its seemingly straightforward nature, heap bioleaching can experience failures if the ore is unsuitable or the heap leach process is not thoroughly investigated and well-developed. Therefore, multidisciplinary approaches are essential for research and development in heap bioleaching, as its performance depends on numerous processes operating across a wide range of length scales. This review focused on the current state of knowledge regarding the understanding of multi-scale mechanisms in heap bioleaching and the use of multidisciplinary approaches at different scales to develop the process. The investigation covered various scales, such as atomic and molecular, mineralogy and microbes, reaction particles, heap bioleaching units and full-scale factory production. Different approaches were employed to gain a comprehensive understanding of the microbial molecular structure and metabolism, the structure and reaction of minerals, microbial–mineral interaction, particles and aggregation states, and multiphase flow transfer, as well as laboratory experiments, modeling, industrialization, and operation optimization. We emphasized the need for collaboration among researchers from different disciplines and stress the importance of considering the coupling effects of physical, chemical, and microbiological factors when running heap bioleaching plants. Such collaboration and coupling are vital for successful implementation and optimization of heap bioleaching processes. This paper aimed to provide a comprehensive overview of current research related to heap bioleaching at different scales and disciplines, and gave implications to heap bioleaching technology development. [ABSTRACT FROM AUTHOR]

This study provides a comprehensive literature review of the distribution, the platinum- group elements (PGE) composition, and mineral chemistry of chromitites associated with Mesozoic Tethyan ophiolites in the Mediterranean Basin. These suites outcrop in the northern Italian Apennines, the Balkans, Turkey, and Cyprus. Most chromitites occur in depleted mantle tectonites, with fewer found in the mantle-transition zone (MTZ) and supra-Moho cumulates. Based on their Cr# = (Cr/(Cr + Al)) values, chromitites are primarily classified as high-Cr, with a subordinate presence of high-Al chromitites. Occasionally, high-Al and high-Cr chromitites co-exist within the same ophiolite complex. High-Cr chromitites are formed in supra-subduction zone (SSZ) environments, where depleted mantle interacts with high-Mg boninitic melts. Conversely, high-Al chromitites are typically associated with extensional tectonic regimes and more fertile peridotites. The co-existence of high-Al and high-Cr chromitites within the same ophiolite is attributed to tectonic movements and separate magma intrusions from variably depleted mantle sources, such as mid-ocean ridge basalts (MORB) and back-arc basin basalts. These chromitites formed in different geodynamic settings during the transition of the oceanic lithosphere from a mid-ocean ridge (MOR) to a supra-subduction zone (SSZ) regime or, alternatively, within an SSZ during the differentiation of a single boninitic magma batch. Distinct bimodal distribution and vertical zoning were observed: high-Cr chromitites formed in the deep mantle, while Al-rich counterparts formed at shallower depths near the MTZ. Only a few of the aforementioned chromitites, particularly the high-Cr ones, are enriched in the refractory IPGE (iridium-group PGE: Os, Ir, Ru) relative to PPGE (palladium-group PGE: Rh, Pt, Pd), with an average PPGE/IPGE ratio of 0.66, resulting in well-defined negative slopes in PGE patterns. The IPGE enrichment is attributed to their compatible geochemical behavior during significant degrees of partial melting (up to 30%) of the host mantle. It is suggested that the boninitic melt, which crystallized the high-Cr chromitites, was enriched in IPGE during melt-rock reactions with the mantle source, thus enriching the chromitites in IPGE as well. High-Al chromitites generally exhibit high PPGE/IPGE ratios, up to 3.14, and strongly fractionated chondrite-normalized PGE patterns with positive slopes and significant enrichments in Pt and Pd. The PPGE enrichment in high-Al chromitites is attributed to the lower degree of partial melting of their mantle source and crystallization from a MOR-type melt, which contains fewer IPGE than the boninitic melt above. High-Al chromitites forming at higher stratigraphic levels in the host ophiolite likely derive from progressively evolving parental magma. Thus, the PPGE enrichment in high-Al chromitites is attributed to crystal fractionation processes that consumed part of the IPGE during the early precipitation of co-existing high-Cr chromitites in the deep mantle. Only a few high-Al chromitites show PPGE enrichment due to local sulfur saturation and the potential formation of an immiscible sulfide liquid, which could concentrate the remaining PPGE in the ore-forming system. [ABSTRACT FROM AUTHOR]

Iran hosts more than 350 Precambrian to Cenozoic sediment-hosted Zn-Pb±Ba and barite-sulfide deposits, including shale-hosted massive sulfide (SHMS, also called SEDEX) and Irish-type and Mississippi Valley-type (MVT) mineralization, and barite is a common mineral in these deposits. In the SHMS deposits, barite is typically found as fine-grained disseminations in thin laminae. In these deposits, the sulfide laminae often occur as diagenetic replacements and as bands containing authigenic and diagenetic barite and pyrite framboids. In the Irish-type Zn-Pb-Ba and stratabound barite-sulfide deposits, barite exhibits various textures, including fine-grained disseminated barite, banded zebra textures, veins, and massive barite lenses. In some of the giant Irish-type deposits, as well as in the stratabound barite-sulfide mineralization, the main stratabound sulfide ore is developed within a barite envelope and is characterized by the replacement of barite and pyrite by chalcopyrite, galena, and sphalerite. In the MVT deposits, the formation of barite is often related to dolomitization, and sulfide mineralization involves the replacement of the dolomitized carbonate rocks, as well as associated barite. Fluid inclusion studies on the Irish-type deposits indicate that the temperatures and salinities of the sulfide-forming fluids are higher compared to those of the barite-forming fluids. Fluid inclusion analyses of coarse-grained barites from Irish and MVT deposits reveal their hydrothermal origin. The δ3⁴S values of sulfide minerals (pyrite, sphalerite, and galena) in Irish-type deposits exhibit a broad range of low values (mostly −28 to +5‰), primarily revealing a process of bacterial sulfate reduction (BSR). However, the textures (replacement, colloform, and banded) and more positive sulfur isotope values (+1 to +36‰) in the SHMS Zn-Pb deposits suggest that bacterial sulfate reduction (BSR) plays a less significant role. We suggest that thermochemical sulfate reduction (TSR) connected to the direct replacement of barite plays a more relevant role in providing sulfur for the sulfide mineralization in the SHMS, barite-sulfide, and MVT deposits. Based on the textual evidence, sulfur isotopic data, and fluid inclusion studies, barite has been identified as a key controller for the subsequent Zn-Pb mineralization by providing a suitable host and significant sulfur contribution in the sediment-hosted Zn-Pb and stratabound barite-sulfide deposits. This implies that diagenetic barite might be a precursor to all types of sediment-hosted Zn-Pb mineralization. [ABSTRACT FROM AUTHOR]

The Dalaku'an mafic–ultramafic intrusion, located in the western segment of the East Kunlun, presents conducive conditions for the magmatic Cu-Ni sulfide deposits. According to the detailed petrographic observation, the amphiboles within distinct rock types were analyzed by EPMA analysis. The crystallization conditions, such as temperature, pressure, oxygen fugacity, and water content of the magma, were calculated to explore the genesis of the intrusion. The amphiboles were divided into three types: Amp-I, characterized by low silicon content but enrichment of aluminum, titanium, and alkali, predominantly comprising Tschermakitic hornblende and Magnesio-hornblende with mantle-derived traits; Amp-II, exhibiting elevated silicon content but diminished levels of aluminum, titanium, and alkali, primarily constituted of Magnesio-hornblende; whereas Amp-III manifests as Actinolitic hornblende, indicative of crustal origins. The calculated temperatures of amphiboles ranged between Amp-I (955–880) °C, Amp-II (852–774) °C, and Amp-III (761–760) °C; the pressures ranged between Amp-I (454–274) MPa, Amp-II (194–93) MPa, and Amp-III (101–84) MPa; the oxygen fugacities (△NNO) ranged between Amp-I (0.93–2.17), Amp-II (1.55–2.52), and Amp-III (1.89); and the water contents (H2Omelt) ranged from (6.69–8.67) to (5.90–7.32). The magma experienced multiple stages of crystallization and underwent complex magma evolution at different depths. The high oxygen fugacity and water content could be attributed to the subduction of the oceanic crust. The magma source of the Dalaku'an intrusion was metasomatized by fluids from subducting plates, thereby originating within a post-collision extension. [ABSTRACT FROM AUTHOR]

Copper leaching presents an environmentally friendly alternative to traditional sulfide ore processing methods. This study investigates an efficient leaching process for copper concentrate, utilizing a solution of sulfuric acid (H2SO4) and potassium iodide (KI) in a chloride medium (NaCl), enhanced by hydrogen peroxide (H2O2) at room temperature. A significant aspect of this research was optimizing the KI concentration to minimize iodide sublimation into iodine gas (I2). Through the experimental design, the optimal dosages of reagents were determined, leading to maximized copper extraction of approximately 27% in 45 min of testing at room temperature. The results showed that it is possible to obtain a suitable pregnant leach solution (PLS) (i.e., in the range of 3 to 8 g/L of Cu) for treatment in available copper solvent extraction (SX) plants with a cost of less than 4.5 USD/t Cu, according to the economic analysis carried out. The results of this study determine the most effective operational conditions for leaching and ensure a suitable PLS for SX plants in a cost-effective and environmentally friendly manner. This approach could significantly contribute to more sustainable practices in the mining and processing of copper ores. [ABSTRACT FROM AUTHOR]

The demand for non-ferrous copper metals has increased dramatically with the development of the global economy; accordingly, some refractory copper sulfide ores with low grade and their associated minerals are beginning to be utilized, making the flotation separation of copper concentrates exceptionally difficult, especially the separation of chalcopyrite and pyrite. In this paper, S-allyl-O, O′-dibutyl phosphorodithioate (ADTP) was synthesized by a one-pot method and used as a chalcopyrite collector in the flotation separation of chalcopyrite and pyrite. Flotation experiments results have shown that ADTP exhibits better selectivity and greater collecting power for chalcopyrite under neutral or weak base conditions. The 95% recovery of chalcopyrite can be achieved at pH 8.0 and 8.0 mg/L ADTP. From the analysis results of the contact angle, the SEM-EDS spectrogram, and elemental mapping, it was found that ADTP adsorbed uniformly on a chalcopyrite surface and made a significant contribution to the hydrophobicity of the surface. Confirmed by FTIR and XPS analysis, ADTP was able to form P–S–Cu bonds on a chalcopyrite surface, proving that it was adsorbed on the chalcopyrite surface in the form of chemisorption. [ABSTRACT FROM AUTHOR]

The goal of the present work was to study the recovery of copper, nickel, and platinum group metals (PGMs) (Pt and Pd) from low-grade copper–nickel ore containing pyrrhotite, pentlandite, and chalcopyrite by column bioleaching followed by cyanidation. The ore sample contained the following: Ni—0.74%, Cu—0.23%, Fe—14.8%, Stotal—8.1%, and Ssulfide—7.8%. The Pt and Pd contents in the ore sample were 0.2535 and 0.515 g/t, respectively. Biological leaching in columns was carried out at 25, 35, and 45 °C for 140 days. A mixed culture of acidophilic microorganisms was used as an inoculum. Cu and Ni extraction depended on temperature, and at 45 °C, copper and nickel recovery was the highest, being 2.1 and 1.8 times higher than that at 25 °C, respectively. As a result, up to 35% of nickel and up to 10% of copper were recovered by bioleaching within 140 days. Bioleaching resulted in an increase in Pt and Pd recovery by cyanidation, but the effect on Pd recovery was insignificant. Pt recovery varied in the range of 3–40% depending on process conditions; Pd recovery was 44–55%. [ABSTRACT FROM AUTHOR]

Sulfide ore dust is at risk of explosion. To analyze the concentration distribution of sulfide ore dust in the ore loading, transporting, and unloading operations, the migration and dispersion processes of sulfide ore dust were simulated by using FLUENT software and taking the dust generation rate, roadway air velocity, and dust source position as variables. The concentration of sulfide ore dust was analyzed from the four-dimensional perspective of time and space. The results show that the maximum concentration of sulfide ore dust is determined by the dust generation rate. The roadway air velocity exhibits dual effects on the migration and deposition of sulfide ore dust. The ore loading position significantly impacts the distribution of sulfide ore dust, manifesting in varying degrees of superposition effects. Based on the results, this paper proposes a comprehensive dust reduction measure in the form of water curtain and dynamic ventilation, effectively minimizing the concentration of sulfide mine dust within the roadway. [ABSTRACT FROM AUTHOR]

The effect of microwave treatment on the grinding and flotation performance of a typical copper–nickel sulfide ore was evaluated, based on the determination of its microwave absorption capability, grinding and flotation indexes such as crack percentage, mineral liberation degree, particle size distribution, relative work index (RWI), metal enrichment ratio and recovery. There were obvious differences between the microwave absorption capabilities of the main minerals in the ore, as demonstrated by their different microwave penetration depths. They also induced temperature differences between sulfide minerals and gangue minerals which could reach 418 °C after microwave treatment for 20 s. It was shown that microwave treatment could effectively improve the grindability of the ore, as proven by the increase in fine particles smaller than 0.074 mm and the decrease in RWI after grinding due to the higher crack percentage and mineral liberation degree. Moreover, microwave treatment affected the ore floatability because of the generation of cuprite, retgersite, and rozenite with poor floatability when the treatment time was extended. By microwave treatment for a proper time, 20 s, an optimal balance between the grindability and flotation performance could be achieved. Compared with the untreated ore, the RWI of the ore decreased by 11.5%. After flotation, the Cu and Ni enrichment ratios of the flotation concentrate increased by 0.3 and 0.2, respectively. Meanwhile, their corresponding recoveries increased by 4.2% and 3.1%. This study provides new insights for the treatment of copper–nickel sulfide ore to enhance the grinding and flotation process. [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]

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]

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]

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]

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]

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 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]

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]

Flotation performance can significantly be affected by seasonal variations due to the changes in water temperature and pulp temperature, type and concentration of dissolved ions in process water. Extreme temperature conditions could be the major factor affecting flotation performance and mask the influence of water chemistry. Therefore, the interactive effects of the temperature and water chemistry should be taken into consideration, particularly for mine sites experiencing extreme temperature conditions. In this paper, effects of temperature, sulphate (SO42−), thiosulphate (S2O32−) and calcium (Ca2+) ions on the flotation performance of a Cu-Pb-Zn complex sulfide ore were investigated using a statistical experimental design and modelling approach. The results were evaluated using ANOVA and regression analysis to determine the significant parameters and derive individual regression models for each flotation response using Design Expert software version 6.0.8. Individual regression models were developed for mass pull, water recovery, grade and recovery of the sulfide minerals using the statistically significant main effects and their interactions. The models were used to determine the concentration of the dissolved ions and pulp temperature required to achieve the maximum zinc recovery, maximum zinc grade or the optimum zinc grade and recovery. The results showed that the water chemistry (i.e., the concentrations of Ca2+, SO42− and S2O32−) affected the flotation performance significantly at low temperature (25 °C). At high pulp temperature (60 °C), however, the temperature was the dominant parameter and masked the effects of water chemistry. Details of the statistical experimental design, discussions of the effects of experimental factors and their interactions on flotation performance, and the development of regression models are presented in this paper. [ABSTRACT FROM AUTHOR]

Quasi-equilibrium directional crystallization was performed on a melt composition (at. %): 18.50 Cu, 32.50 Fe, 48.73 S, 0.03 Pt, Pd, Ag, Au, Te, As, Bi, Sb, and Sn, which closely resembles the Cu-rich massive ores found in the platinum-copper-nickel deposits of Norilsk. Base metal sulfides (BMS) such as pyrrhotite solid solution (Fe,Cu)S1±δ (Poss), non-stoichiometric cubanite Cu1.1Fe1.9S3 (Cbn*), and intermediate solid solution Cu1.0Fe1.2S2.0 (Iss) are progressively precipitated from the melt during the crystallization process. The content of noble metals and semimetals in the structure of BMS is below the detection limit of SEM-EDS analysis. Only tin exhibits significant solubility in Cbn* and Iss, meanwhile Pt, Pd, Au, Ag, As, Bi, Sb, and Te are present as discrete composite inclusions, comprising up to 11 individual phases, within their matrices. These microphases correspond to native Au, native Bi, hessite Ag2Te, sperrylite Pt(As,S)2, hedleyite Bi2Te, michenerite PdTeBi, froodite PdBi2, a solid solution of sudburite-sobolevskite-kotulskite Pd(Sb, Bi)xTe1−x, geversite PtSb2, and a multicomponent solid solution based on geversite Me(TABS)2, where Me = Σ(Pt, Pd, Fe, Cu) and TABS = Σ(Te, As, Bi, Sb, Sn). Most of the inclusions occur as thin layers between BMS grain boundaries or appear drop-shaped and subhedral to isometric grains within the sulfide matrix. Only a small fraction of the trace elements form mineral inclusions of sizes ≤ 0.5 μm in Poss, most likely including PtAs2 and (Pt,Pd)S. It is likely that the simultaneous presence of noble metals (Pt, Pd, Au, Ag) and semimetals (As, Te, Bi, Sb) in the sulfide melt leads to the appearance of liquid droplets in the parent sulfide melt after pyrrhotite crystallization. The solidification of droplets during the early stages of Cbn* crystallization may occur simultaneously with the cooling of later fractions of the sulfide melt, resulting in the formation of Iss. In addition, abundant gas voids containing micro-inclusions were observed in Cbn* and Iss. These inclusions showed similar chemical and mineral compositions to those in BMS matrices, i.e., the presence of gas bubbles did not affect the main features of noble metal fractionation and evolution. Therefore, it is reasonable to assume that ore particles suspended in the melt are either trapped by defects at the crystallization front or transported towards gas bubbles via the Marangoni effect. [ABSTRACT FROM AUTHOR]

Iron is one of the most stubborn impurities in quartz minerals, and the iron content partly determines the various applications of quartz. Iron can exist in quartz in the forms of iron minerals, fluid inclusions, and lattice impurities. The removal of iron and the consequent purification of quartz minerals are the key processes to obtaining high-quality quartz. Iron removal methods including conventional pre-treatment, magnetic separation, acid leaching, microbiological, roasting, and flotation, as well as combined iron removal methods in quartz ore, are herein summarized. The separation mechanism of quartz and iron impurities and the latest research progress were explained and summarized, and the development prospects of quartz purification in the future were proposed based on the current progress and limitations of quartz iron removal. [ABSTRACT FROM AUTHOR]

This article discusses the results of a fluid inclusion studies in barite collected at the Jan Mayen vent field area (Troll Wall and Perle and Bruse) and Loki's Castle vent field on the Mohns Ridge segment of the Arctic Mid-Ocean Ridge. Three mafic-hosted volcanogenic massive sulfide deposits were examined within the active vent fields that adequately correspond to the geological settings of ultraslow-spreading ridges and P–T conditions. Hydrothermal sediments were investigated to determine the temperature and salinity of the fluids responsible for barite precipitation. The hydrothermal origin of the barite was confirmed by its morphology. Fluid inclusions are two-phase and homogenize into the liquid phase on heating at temperatures below 287 °C. The salt concentration in fluids trapped in inclusions is 2.6–4.4 wt.% NaCl eq. The crystallization temperatures varied from 276 °C to 119 °C and from 307 °C to 223 °C for the Jan Mayen and Loki's Castle vent fields, respectively. The data obtained allowed us to confirm evidence of fluid phase separation in the hydrothermal systems and to expand our knowledge of the temperature and salinity of mineral fluids previously known from recent direct measurements during the cruises within the G.O. Sars research vessel. The fluid inclusions data obtained from barites emphasize the fluid features characteristic of volcanogenic massive sulfide deposits, the similarities and differences among the studied hydrothermal sites and allow comparisons with similar products from other active hydrothermal systems. [ABSTRACT FROM AUTHOR]

The fractal dimension is widely used in many fields as a parameter to characterize the geometric complexity and geometric distribution relationship of research objects. To study the surface characteristics of sulfide ore particles, the fractal theory was applied to quantitatively characterize the surface fractal dimension Ds of sulfide ore microparticles in three particle size ranges, 60–100 mesh, 100–140 mesh and >200 mesh, based on the area–perimeter method. Using an optical microscope, grain projection images of the particles were obtained. The grain shape and characteristics of sulfide ore particles were studied by means of an image processing system. The results demonstrate that the grain shape of sulfide ore particles can be expressed by fractal dimension, and the particle surface fractal dimension ranges from 2.4392 to 2.5492. It was found that the fractal properties begin to decrease due to the increasing of the particle size. The larger the fractal dimension, the finer the particles are. The fractal dimension of sulfide ore particles can be used as an important indicator of their particle shape distribution characteristics, which can provide important information for further study of the relevant physical and chemical properties of sulfide ore particles and provide a new theoretical method and basis for the adhesion and removal of sulfide ore dust. With the quantitative description of the fractal distribution of sulfide ore particles, a new way to study the adhesive force between particles is offered for further research. [ABSTRACT FROM AUTHOR]

Nowadays, refractory gold ore production around the world accounts for about 30% of total gold production, and the low leaching rate of such gold concentrate seriously limits the efficient utilization of gold resources. The alkaline preoxidation process can improve the leaching rate of this kind of gold deposit and has good development and application prospects. Therefore, it is of great significance to study the oxidation and dissolution behavior of pyrite in an alkaline environment. In this paper, the oxidation process of gold-bearing pyrite in an alkaline electrolyte was studied using electrochemical techniques, and the oxidation products of a pyrite electrode in an alkaline solution were characterized using XPS, SEM, and other analytical methods. The results show that the optimum pH for pyrite electrochemical oxidative dissolution is about 12, and the oxidation potential of pyrite should be above 0.8 V. In the process of alkaline oxidative dissolution of pyrite, part of the S element enters the electrolyte in the forms of Sx2−, S2O32−, SO32−, and SO42−, and a small amount of the S element is adsorbed on the surface of the electrode in the form of S0 and becomes a part of the passive layer. The Fe element is adsorbed on the surface of the electrode in the forms of Fe(OH)2, Fe2O3, and Fe2(SO4)3, which become the main components of the passivation layer. This study provides a theoretical basis and reference data for the chemical preoxidation treatment of gold-bearing sulfide ores. [ABSTRACT FROM AUTHOR]

The use of thiosulfate to extract gold from refractory ores is promising because of its non-toxicity and high selectivity. Sulfide minerals (i.e., pyrite, arsenopyrite, chalcopyrite), major gold carriers in refractory gold ores, however, hinder gold extraction due to the high consumption of a lixiviant. In this study, a new method to improve gold extraction from sulfide bearing gold ores is proposed based on the model experiments using a mixture of gold powder and arsenopyrite-bearing sulfide (HAsBS) ore. The effects of HAsBS ore on gold leaching in ammonium thiosulfate solutions were investigated, and it was found that gold extraction in the presence of HAsBS ore was suppressed because of the unwanted decomposition of thiosulfate on the surface of sulfide minerals. To improve gold extraction in the presence of the sulfide minerals, this study investigated the effects of the pretreatment of HAsBS ore using ammonium solutions containing cupric ions and confirmed that HAsBS ore was oxidized in the pretreatment and its surface was covered by the oxidation products. As a result, thiosulfate consumption was minimized in the subsequent gold leaching step using ammonium thiosulfate, resulting in an improvement in gold extraction from 10% to 79%. [ABSTRACT FROM AUTHOR]

Porphyry Mo deposits are the most important type of Mo resource. They result from a high oxygen fugacity of the parent magma, which acts as an effective indicator for evaluating the mineralization. In the ore-forming system of porphyry Mo deposits, sulfur exists mainly as sulfate in highly oxidized magma but as sulfide in ores. What triggers the reduction in the mineralization system that leads to sulfide precipitation has not yet been determined. Most of the previous studies have focused on the origin and evolution of the ore-forming parent magma, and the effects of reductive surrounding rocks on porphyry mineralization have been ignored. In this study, a comprehensive geological–geochemical investigation and review have been performed on the typical porphyry Mo deposits, the Nannihu-Sandaozhuang, Yuchiling, and Shapingou deposits in China, and the Mt. Emmons deposits in America. Black carbonaceous sedimentary layers commonly surround porphyry Mo ores, which are widely altered and discolored during mineralization. CH4 is commonly present in fluid inclusions in the main mineralization stage, and the δ13CV-PDB values of calcite and fluid inclusions from the altered surrounding rocks and ore minerals are generally low and significantly different from those of marine sedimentary carbonate rocks, indicating that the involvement of reductive components from carbonaceous surrounding rocks might be key to the redox state transformation leading to mineral precipitation. On the other hand, the CH4 produced by the thermal decomposition of organic matter or carbonaceous reaction with H2O can diffuse into the ore-forming system along the structural fractures and reduce the SO42− in the ore-forming hydrothermal fluids to form sulfide precipitation without direct contact between the intrusion and the carbonaceous surrounding rocks. Moreover, the CH4 content controls the location of the orebody formation with the high content producing orebodies mainly in the porphyry intrusion, while the low CH4 content results in the orebodies mainly occurring at the contact zone between the porphyry and carbonaceous surrounding rocks. Compared to the magmatic stage of mineralization, the involvement of reductive components in the carbonaceous surrounding rocks during the hydrothermal stage is more favorable for forming giant/large Mo deposits. The highly oxidized porphyry with reductive carbonaceous surrounding rocks or Fe-rich volcanic rocks offers a new indicator for efficiently evaluating porphyry Mo mineralization. [ABSTRACT FROM AUTHOR]

The Huoshaoyun zinc–lead deposit, a giant non-sulfide deposit in Xinjiang, is one of the most significant discoveries of zinc–lead deposit in China and globally in recent years. The deposit is dominated by zinc–lead non-sulfides, with minor occurrences of sulfides such as sphalerite, galena, and pyrite. The non-sulfide minerals include smithsonite, cerussite, anglesite, and Fe-oxide. This study focuses on the mineralogical characteristics of sulfide and non-sulfide ores, as well as the trace element characteristics of sphalerite, smithsonite, and Fe-oxide. Mineralogical analysis reveals that smithsonite is derived from the oxidation of primary sulfide minerals and can be classified into three types that are generated during different stages of supergene oxidation. The three types of smithsonite are formed through replacing the sphalerite and host limestone, as well as directly precipitating in the fissures and vugs. Trace element analysis of sphalerite indicates that it is rich in Cd, Tl, and Ge, but poor in Fe and Mn. The ore-forming temperature, calculated using the GGIMFis geothermometer, is mostly within the range of 100~150 °C. Moreover, the trace element characteristics, ore-forming temperature, and S and Pb isotope compositions of the sulfide ores of the Huoshaoyun deposit are similar to those of the Jinding and Duocaima MVT lead–zinc deposits, which are also located in the Eastern Tethyan zinc–lead belt. This suggests that the sulfide orebody in the Huoshaoyun Zn-Pb deposit could also be the MVT deposit. Study of the trace element of the non-sulfide minerals shows that the Mn and Cd are relatively enriched in smithsonite, while Ga, Ge, and Pb are enriched in Fe-oxide. This can be attributed to distinct geochemical properties of the trace elements in the non-sulfide minerals of the Huoshaoyun deposit and is consistent with those of the other oxidized MVT deposits, thus indicating the supergene oxidation process of this deposit. [ABSTRACT FROM AUTHOR]

On the other hand, these compounds (alunite, jarosite, and beudantite) can be used to immobilize elements such as arsenic and lead, among others. Conclusions Jarosite, beudantite, and alunite are members of the alunite supergroup. Jarosite, beudantite, and alunite are members of the alunite supergroup [[1]]. Contributions In their work, Cruells and Roca [[3]] developed a review of different aspects related to jarosite-type compounds: jarosite, beudantite, and alunite. [Extracted from the article]

The preparation of high-purity sulfur and pyrrhotite by pyrolysis holds great potential to realize the high-value utilization of pyrite concentrate (FeS2), i.e., a by-product during the flotation of sulfide ore. In this study, the pyrrhotite obtained from the pyrolysis of pyrite concentrate was taken as the study object, and the effects of acid types, initial acidity, leaching time, leaching temperature, oxygen pressure, and liquid-to-solid ratio on the leaching behavior of pyrrhotite under oxygen pressure, were explored. The results show that elemental sulfur and hematite-based iron residue can be obtained by oxygen pressure leaching of pyrrhotite. It is found that the optimal experimental conditions for pyrrhotite oxygen pressure leaching are hydrochloric acid with 0.8 mol/L of initial acidity, 5 h of leaching time, 0.8 MPa of oxygen partial pressure, and 9:1 of liquid to solid ratio at 150 °C; moreover, the yield of sulfur reached 88.37%. Under optimal conditions, the leaching ratios of Fe, Pb, and Zn were 19.8%, 92.25%, and 99.11%, respectively. The sieved leaching residue was roasted at a low temperature of 500 °C, where the grade of Fe in the obtained hematite iron powder was 61.46%, and the grades of Pb, Zn, and S were 0.082%, 0.024%, and 0.1%. Clearly, the results meet well with the standard of the first grade of pyrite cinder, and this process realizes the comprehensive recovery of Fe and S resources in pyrolysis slag, which provides a superb technical route for the high-value utilization of pyrite concentrate. [ABSTRACT FROM AUTHOR]

With a focus on the Cu isotope geochemistry of chalcopyrite, this paper analyzed the Cu isotope geochemistry of the Qibaoshan crypto-explosive breccia-type Cu–Au polymetallic ore district in Wulian, Shandong Province, North China Craton (NCC). Combined with the results of the in situ sulfur isotope analysis of sulfides, a certain reference and evidence for the study of the genetic mechanism of the epithermal-porphyry Cu polymetallic metallogenic system were provided. The results of the in situ isotope analysis show that the δ34S values of the main sulfides in the Qibaoshan Cu–Au polymetallic ore district range from −6.81‰ to +3.82‰ and are likely to be attributed to the mixing of the derived mantle with the surrounding sedimentary rock assimilation. The ore-forming mechanism may be related to the progressive cooling and transition of the earliest hydrothermal fluids that were dominated by H2S under relatively reducing conditions, followed by a gradual transition from oxidation to reduction. The Cu isotopic composition of the sulfides in ores (δ65Cu = +0.169‰–+0.357‰) decreases with depth, which is likely caused by the upward transport of heavier Cu isotopes. The upper part of the crypto-explosive breccia pipe in the Qibaoshan area may be relatively more gaseous, resulting in the enrichment of δ65Cu. As the gas phase decreases and the liquid phase increases with depth, the δ65Cu value gradually decreases. This indicates the transition from a low-temperature phyllic alteration to a high-temperature K-feldspar alteration. Large, concealed pluton intrusions or orebodies may be present at a depth of the Qibaoshan area. The heavy δ65Cu characteristic is a potential indicator for tracing the fluid activity of the porphyry system and searching for Cu mines. The results provide a reference for the study of the genetic mechanisms of the epithermal-porphyry Cu polymetallic metallogenic system. [ABSTRACT FROM AUTHOR]

The Norilsk ore district is one of the world leaders in the production of platinum metals. Long-term research focused on the detection of sulfide platinum-copper-nickel ores contributed to the accumulation of a large volume of scientific material on the geology and mineralization of the Norilsk area. Despite this, the issue of the composition of the initial melt for ore-bearing intrusive complexes and its degree of enrichment with noble metals remains open. Intrusive rocks of the Norilsk region are rarely analyzed for their ratio of noble metals. However, the analysis and comparison of geochemical parameters of different types of intrusions allows us to draw important conclusions not only about the composition of the initial magmas of ore-bearing complexes, but also about the formation conditions of the intrusions. This study demonstrates the distribution of platinum metals, gold and silver in the main petrographic differentiates of the Kharaelakh, Talnakh, Vologochan intrusions and Kruglogorsk-type intrusion. The regularities and variations of the distribution of metals depend on the host rocks. There are two series of rocks in the inner structure of the ore-bearing intrusions: 1. Picritic and taxitic gabbro-dolerites enriched in PGE-Au-Ag mineralization which forms disseminated ores at intrusion bottoms (ore-bearing rocks). 2. Olivine-, olivine-bearing, olivine-free gabbro-dolerites and leucogabbro with poor sulfide mineralization at the upper part of the intrusions (ore-free rocks). There is a distinct correlation between PGE, Cu, S and to a lesser extent correlation with Ni in the first rock group, which is a characteristic of sulfide PGE-Cu-Ni deposits. In the second group, correlations are also revealed, but the correlation coefficients are lower. The main element controlling the distribution of platinum metals is copper. The taxitic gabbro-dolerites of the Talnakh intrusion are the most enriched by noble metals. According to noble metal patterns the rocks of the Kharaelakh intrusion show the highest degree of melting of the initial mantle material during the formation of parental magmas chambers. Despite some differences, the geochemical features of the studied rocks indicate the similar characteristics of the accumulation of gold, silver and platinum metals in the intrusions of the Talnakh, Kruglogorsk and Zubovsk types, which allow suggesting the close conditions for the formation of ore mineralization of these intrusions. [ABSTRACT FROM AUTHOR]

With excessive consumption of sulfide ores, using low-grade Pb-Zn mixed ores to obtain Zn has attracted more attention. Acid leaching is an effective method for Zn recovery; however, a high concentration of inorganic acid brings severe environmental issues, including acidic wastewater, contaminated soil, etc. Compared with inorganic acid, organic acid showed lower acidity and toxicity. Herein, we applied an effective method for Zn recovery from carbonate-type Pb-Zn mixed ore (CMO), by combining organic acid leaching with mechanical activation. Among the organic acids applied (lactic, malonic, citric, amber, acetic, and tartaric one), lactic acid was selected for its high leaching efficiency. The optimum condition was identified via response surface methodology, with a lactic acid concentration of 1.15 mol/L, L/S ratio of 20, leaching time of 75 min, and temperature of 75 °C. The effect of mechanical activation on Zn leaching was further investigated. The leaching efficiency increased to 90.1% after mechanical activation, which was the highest leaching efficiency for organic acid leaching. Mineralogical characterization showed that the bulk minerals were milled into small particles while the proportion of amorphization increased. Such activation effects improved the acid-solubility of Zn speciation. This work provided a potential green method for metal recovery from low-grade sources. [ABSTRACT FROM AUTHOR]

Diethyldithiocarbamate (DDTC) is employed in the sulfide ore flotation process due to its excellent collection performance. Herein, we investigated the interfacial adsorption behavior of DDTC on the four main mineral phases of high-sulfur residue: sulfur, pyrite, sphalerite, and lead sulfate. The adsorption behavior of DDTC and H2O, namely, the adsorption structure and the energy and electron localization function cross section, were explored using density function theory calculation. The results were helpful in constructing a coadsorption model of DDTC and H2O, which was validated by pure mineral flotation and characterization of Fourier transform infrared spectra. The coadsorption model indicated that the adsorption of DDTC on sulfur, sphalerite, and lead sulfate was weak with physical bonding, while its adsorption on pyrite was strong with chemical bonding. Practical bench-scale high-sulfur residue flotation was performed, and the result was different from that obtained from pure mineral flotation. Our developed model predictions and mineral fugacity pattern analysis were synergistically used to explain this difference. Overall, this work proposes for the first time a coadsorption model of DDTC and H2O and provides important insights into interfacial adsorption in high-sulfur residue flotation. [ABSTRACT FROM AUTHOR]

The magmatic process within upper crust encompasses various contents such as the transition between magmatic and hydrothermal systems and changes in oxygen fugacity (ƒO2), which ultimately play key roles in the formation of porphyry Cu deposits (PCDs). However, tracing these magmatic processes, especially in porphyry systems, is not an easy task. This study reported the detailed process of magmatic fluid exsolution and systematical variation of magmatic ƒO2 within the upper crust of a Tongchang–Chang'anchong porphyry Cu deposit, based on detailed investigations of mineral crystallization sequences and compositional features of the minerals in the fertile porphyries. Results indicate that the fertile porphyries show a high initial ƒO2, with ΔFMQ ≥ +3.0 (ΔFMQ is the deviation of logƒO2 from the fayalite–magnetite–quartz (FMQ) buffer). The magmatic ƒO2 (ΔFMQ) continued to decrease to ~+2 until fluid exsolution occurred at ~790 °C due to wall-rock contamination. The magmatic fluid exsolution process caused a temporary increase in the ƒO2 (to ΔFMQ = ~+3.4). The high magmatic ƒO2 during this process (790–750 °C) resulted in a higher content of ore-forming materials in the exsolved magmatic fluid. When the temperature dropped below 750 °C, the magmatic ƒO2 began to continuously decrease and eventually reached ΔFMQ = ~+0.6. The lower magmatic ƒO2 hindered the further migration of ore-forming materials through the exsolved fluid during this process (< 750 °C). Results of this study indicate that the initial magma during the upper crustal magmatic process of PCDs generally has a high ƒO2, and the contamination of reduced components can significantly decrease the magmatic ƒO2. The early magmatic fluid exsolution process can maintain a high magmatic ƒO2 condition, thereby efficiently extracting ore-forming minerals and producing ore-forming fluids, which is the key to the formation of PCDs. The latter continuous decrease in magmatic ƒO2 during the fluid exsolution process may be the reason preventing the Tongchang–Chang'anchong porphyry Cu deposit to form a giant PCD. [ABSTRACT FROM AUTHOR]

Induced polarization (IP) effects in transient electromagnetic (TEM) measurement play a significant role in the detection of minerals, such as sulfide ore, clay ore, etc. However, due to the complex impacts caused by the polarization parameters, the structure of the earth, and the measurement system configuration, the IP effects cannot be easily measured and interpreted. We paid more attention to the vertical component of the ungrounded-TEM system in previous work; however, we will now attempt to utilize the horizontal component to enhance the precision of the measurement and interpretation. We quantitatively discussed the behavior of the horizontal and vertical magnetic fields of the towed-TEM (tTEM) system. We simultaneously introduced the vertical and horizontal components into the Jacobian matrix of the 1D laterally constrained inversion to build the joint inversion. Compared to the vertical component, the horizontal component always shows earlier and bigger sign reversals and contains more IP information. Inversion with the single horizontal or single vertical component showed poor accuracy in the deep and shallow layers, respectively. The joint inversion with both components could correct the errors. Including the horizontal component in the detection and interpretation facilitates an improved resolution for polarizable minerals. [ABSTRACT FROM AUTHOR]

Campiglia Marittima (hereafter Campiglia) has a long record of attracting interest on its ore deposits that have been intermittently exploited from the Copper Age to the late XX century. Since the XIX century, Campiglia has been a key locality for the debate on skarn-forming processes due to the presence of mining activities ensuring access to ever new rock exposures. The pioneering study of vom Rath and the comparison with attractive chemical model (e.g., Korzhinskii's theory) in the XX century made Campiglia a "classic" example of skarn ore deposit, from the causative intrusion to the marble host rock. In recent years, detailed field investigations integrated by petrographic, geochemical, and isotopic analyses revealed a more complex and stimulating geological history. The Campiglia skarn was later intruded by mafic magma causing textural reworking and chemical redistribution as well as the reverse telescoping process with Fe-Cu sulfides overprinting previously formed Pb-Zn ore. This work aims to trace the evolution of the scientific thinking on the Campiglia ore deposit by comparison with existing skarn-forming models and, ultimately, shows that the current skarn-forming model(s) cannot fully explain the textural and geochemical features of the Campiglia skarn. [ABSTRACT FROM AUTHOR]

Typomorphic features of placer gold of the Anabar region were studied as predictive-exploration criteria. The target of the study was to determine the typomorphic features of placer gold related to the intermediate sources (paleo-placers) and the supposed nearby primary ore occurrences. Two varieties of placer gold were identified. The first variety is well-rounded high-fineness lamellar gold with a highly modified internal structure. This native gold is associated with intermediate sources, Neogene–Quaternary watershed pebble beds. The second type includes slightly rounded gold with a wide variation in fineness (494‰–999‰). Its indicator is a block heterophase internal structure. The set of typomorphic features of this variety of placer gold indicates the vicinity of the primary source, what was the prerequisite for constructing prospecting traverses in order to find ore occurrences. As a result of these studies, hydrothermal-metasomatic formations with gold-sulfide mineralization were identified. The main primary substrate for them is fractured near-fault carbonate rocks of the Cambrian and Vendian–Cambrian age. Along with this, hydrothermalites developed on slightly cemented fine-pebble quartz conglomerates of the Middle Permian age were found in the core of exploration wells. Two types of metasomatic rocks are identified: quartz-potassium feldspar and jasperoid. The main ore minerals were galena and pyrite, different ratios by sites were revealed. Gold was identified in the form of small particles in the carbonate and siliceous substrate of hydrothermal-metasomatic formations. The lithological factor was one of the leading favorable factors for the ore formation due to the presence of near-fault highly permeable fractured carbonate and slightly cemented terrigenous rocks. The structural control of the studied ore occurrences is determined by their localization in the Mayat–Logoy and Dogoy–Kuoy faults of the Molodo–Popigay system of discontinuous faults. We assume a two-stage formation of the gold ore occurrences: during the first stage, the ore components in the form of primary hydrothermal-sedimentary ores in the near-gault zones were formed. The second stage was related to the processes of the Mesozoic tectonic-magmatic activation, when the intrusion of basite dikes initiated the mobilization of ore components the gold-sulfide occurrences were formed in the near-fault zone as a result of silicic-potassic metasomatosis of the carbonate and terrigenous rocks. [ABSTRACT FROM AUTHOR]

10.3390/en14165005 23 Wu J., Fu Q., Zhang J., Sun B. A Fast Calculation Method for Improving the Steering Arm of Mining Trucks with Macpherson Suspension. The study area is made up of thick quaternary alluvium deposited on top of older basement rock, and previous studies, including drilling and geo-electrical resistivity surveys, have been conducted in the area, but none of them managed to conclusively precisely determine the basement rock type and depth. Pilecka et al. [[4]] investigated the impact of high energy mining-induced tremors on building damage in the Upper Silesian Coal Basin (USCB), Poland, by analyzing one of the highest energy tremors (E = 4.0 × 10 SP 8 sp J). Mining is an essential sector for economic development, as it provides valuable resources that are crucial for modern living. [Extracted from the article]

In the LF refining process, argon blowing at the bottom of ladle can play an important role in unifying the composition and temperature of molten steel and removing inclusions. However, unreasonable bottom argon blowing process can also cause many problems. Slag entrapment and slag surface exposure may occur, affecting the steel quality. Since the working conditions of different enterprises are very different, corresponding optimization is required for specific parameters. There were some problems in 70t ladle of a steel plant, such as unclear control of bottom argon blowing system in different refining periods, unobvious floating removal effect of inclusions in ladle, high total oxygen content and large fluctuation, etc. In this study, a 1:3 physical model was established according to the similarity principle. Then, on this basis, the experimental schemes with different blowing hole positions and argon flow rates were designed for simulation experiments. By means of mixing time measurement, flow field display and oil film measurement, the optimal argon blowing position was double holes 6, 12 (2/3R), and the included angle between them was 135°. The optimal argon flow rate for wire feeding and soft blowing should be 7.6 L/min (corresponding to the actual production of 180 L/min) and 0.6 L/min (corresponding to the actual production of 15 L/min), respectively. According to this scheme, the industrial experiments showed that the contents of total oxygen and nitrogen in the whole process were reduced, the surface density of inclusions in billet was reduced by 11.81% on average, and calcium sulfide and various inclusions containing aluminum were reduced to varying degrees. [ABSTRACT FROM AUTHOR]

In order to interpret spectral induced polarization (SIP) data measured in the field for the purpose of mineral exploration, laboratory investigations are necessary that establish relationships between electrical parameters and mineral properties. For massive ores, and in particular for seafloor massive sulfides (SMSs), samples may be difficult to obtain, and it is often not desired to cut cylindrical plugs out of the available hand pieces. We suggest a method to obtain the electrical spectra of hand pieces from measurements on the samples embedded in a non-polarizing medium, in our case quartz sand. As such, destroying potentially precious samples is not necessary. The frequency-dependent phase spectrum of the sample is calculated by dividing the bulk spectrum with a so-called dilution factor, which is obtained from numerical simulation and has a real and constant value. We evaluate the method with a set of SMS samples where conventional cylindrical plugs are available. We can estimate the phase shift maximum of 73% of the samples with a deviation less than 50% from the reference. The estimation quality slightly decreases if the dilution factor is approximated by the volumetric share of the sample. We consider the performance acceptable if the general difficulty to obtain reproducible and representative laboratory measurements for massive sulfides is taken into account. [ABSTRACT FROM AUTHOR]