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Lead sulfide (PbS) has substantial potential for applications in many fields, such as optical devices and solar cells. Although PbS can be obtained from complex lead-antimony sulfide ores by vacuum distillation, the evaporation mechanism of PbS under vacuum is still unclear. Herein, the evaporation kinetics of PbS at 973 K to 1173 K and 5 to 1000 Pa were investigated using a vacuum thermogravimetric furnace. The practical evaporation rate of PbS was obtained through linear and nonlinear fitting of the experimental data compared with the original theoretical evaporation rate and corrected for the Langmuir maximum evaporation coefficient. The evaporation coefficients and critical pressures of PbS at 973 K, 1023 K, 1073 K, 1123 K, and 1173 K were 0.5225, 0.4056, 0.2080, 0.1995, and 0.1007 as well as 12.49, 16.67, 20.83, 24.19, and 30.15 Pa, respectively. Experimental results indicate that the evaporation rate conforms to the logistic nonlinear model, and the critical pressure is positively correlated with temperature. This paper provides a kinetic data base for PbS vacuum evaporation and also provides a reference for improving the process conditions and production equipment parameters of PbS vacuum distillation. Meanwhile, it improves and develops the theory and practice of vacuum distillation for the preparation of high-purity sulfides and fills the gap of basic kinetic data of nonferrous sulfides. [ABSTRACT FROM AUTHOR]

The purpose of this study was to reduce the propensity for spontaneous combustion of sulfide ores through the combined action of microorganisms and inhibitors and to assess the flame retardant effect. The sulfide ore samples were first pretreated with biodesulphurisation. The samples were then sprayed with a foam blocker to prevent re-oxidation of the ore and further reduce the spontaneous combustion tendency of the sulfide ore. The experimental results showed that the highest desulfurization rate of 24.26% was achieved for ore samples with a particle size between 140–160 mesh. A combination of 0.05% hexadecyltrimethylammonium bromide (CTAB), 0.11% lauramidopropyl betaine (LAB-35), 0.13% sodium alcohol ether sulfate (AES), 0.11% propanetriol foam stabilizer, 7% water glass and 3% sodium bicarbonate arresting agent was the most effective. The oxidation weight gain of the desulphurised ore sprayed with the resist was only 3.16%. The oxidation weight gain of the desulphurised ore without the addition of the resist was 3.98% and the oxidation weight gain of the undesulphurised ore was 6.01%. This method is effective in reducing the tendency of spontaneous combustion of sulfide ores. [ABSTRACT FROM AUTHOR]

Sphalerite (ZnS) is a sulfide found in a large variety of ore deposits and is frequently hosted in metamorphic terranes that have undergone deformation and related recrystallization. However, the deformation mechanisms of sphalerite are still poorly understood because recrystallization evidence is barely visible under an optical microscope and may reflect complex and frequently multistage mechanisms. Furthermore, sphalerite may host up to a few thousands of parts per million of critical metals such as gallium (Ga), germanium (Ge), and indium (In). Metamorphic conditions and dynamic recrystallization may have induced local or total redistribution of these elements. Modern techniques such as electron backscattered diffraction analyses (EBSD) and laser-induced breakdown spectroscopy (LIBS) applied on sphalerite allow for the examination of grain boundaries, crystal-plastic deformation, and internal chemical diffusion, which classically reflect active deformation mechanisms. In this study, a microstructural and in situ chemical comparison between four sphalerite types (types 1, 2, 3, and 4) has been made for the first time. The four sphalerite types present different deformation imprints, although they are hosted in a similar geological setting: the Pyrenean Axial Zone and the Montagne Noire Variscan massifs (France). Based on EBSD and LIBS mapping, we describe two regional sphalerite growth stages composed of dark red crystals with polygonal shape (type 1, Bentaillou-Liat deposit) and light- to dark-brown euhedral crystals (type 3, Saint Salvy deposit). New investigation at microscale on sphalerite grains from the Saint-Salvy deposit shows late Cu-Ge-Ga enrichment not only in specific sector zonings but also along grain boundaries, growing crystal edges, and in low-angle misorientations or twin boundaries. Following a deformation event that probably occurred during the Pyrenean-Alpine orogeny, these two sphalerite mineralizations have both endured plastic deformation in a dislocation creep regime and dynamically recovered by subgrain rotation (SGR) mechanism. Two mechanisms of Cu-Ga-Ge spatial redistribution are observed and are key processes for the crystallization of Cu-Ga-Ge-rich minerals in sphalerite veins. The first mechanism involved the in situ redistribution of Cu-Ga-Ge contents from a pre-existing concentration in the sphalerite lattice (type 3, Arre deposit), creating Ge-sulfides (briartite), probably during Pyrenean-Alpine orogeny. Formation of this type of Ge-mineral may be related to solid-state diffusion processes. The second mechanism is associated with the circulation of a Cu-Ga-Ge-rich fluid in surrounding rocks. In the pre-existing polygonal sphalerite from Late-Variscan veins (type 2, Pale Bidau deposit), millimeter-size bands of small (<50 μm), recrystallized sphalerite grains are locally observed. Those domains contain inclusions of Cu (chalcopyrite) and Ga and Ge minerals (brunogeierite, carboirite). Fluid-induced diffusion in the polygonal sphalerite aggregates may occur with superimposed dynamic recrystallization, such as the Late-Variscan veins (type 2, Pale Bidau-type). During post-Variscan time, this fluid enriched in Cu-Ga-Ge largely circulated in the upper-crust of this Variscan terrane. This study highlights the key importance of coupled textural (EBSD) and in situ chemical analyses (LIBS) of diverse sphalerite types at a regional scale to indirectly unravel the origin of vein mineralization, and their related critical metal distribution. [ABSTRACT FROM AUTHOR]

To control spontaneous combustion of sulfide ores, the compound inhibitor was prepared by selecting physical resistance raw materials(Na2CO3), chemical resistance raw materials(Melatonin), Cetyltrimethylammonium bromide(CTMAB) and hydroxyethyl cellulose(HEC). With the help of the simultaneous thermal analyzer, different concentrations of inhibitors were prepared and the thermal behavior of the ore samples with 10, 15, and 20 wt% inhibitor at four heating rates of 5, 10, 15, and 20 K/min was determined. The Flynn-Wall-Ozawa method was applied to calculate the activation energy of sulfide ores with different concentrations. The results showed that: Gradually increasing the heating rate will increase the reaction intensity of each ore sample in the first weight loss stage of thermal decomposition, and then reduce the mass of the ore samples involved in the second weight loss stage; The thermal stability of each resisted ore sample is better than that of the original ore sample; The increase in the concentration of inhibitor can inert the reaction process of ore samples in the thermal decomposition stage, weakening the exothermic effect of ore samples; The inhibitor with 15 wt% had a better effect on preventing spontaneous combustion of sulfide ores, and its property value is higher than other concentrations. [ABSTRACT FROM AUTHOR]

Copyright of Nonferrous Metals (Extractive Metallurgy) is the property of Beijing Research Institute of Mining & Metallurgy Technology Group and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract\nKEY POINTSThe Dugald River Shear Zone is a structurally complex, anastomosing shear zone that hosts high-grade Zn mineralisation within the Dugald River Slate. The Dugald River Zn–Pb–Ag mine is situated within the Mount Isa Inlier, Australia and developed through two phases of mineralisation with high-grade Zn mineralisation intimately associated with the development of the brittle–ductile Dugald River Shear Zone. The first phase of mineralisation occurred during the regionally extensive, D2 ductile fold and axial planar cleavage forming event and resulted in the development of a sulfide horizon. This horizon was a preferential site for strain partitioning during early D4 ductile deformation, which resulted in transposition-related concentration and thickening of a sulfide horizon marking the second phase of mineralisation. The Dugald River Shear Zone developed during D4 wherein strain rate incompatibilities between a ductile-deforming sulfide horizon and the brittle-deforming Dugald River Slate resulted in the development of a Riedel shear zone. A high-resolution 3D model of the shear zone was constructed from robust drilling and mapping datasets in which releasing and restraining bends highlight the thickening and thinning of ore lenses, respectively. The 3D model with detailed structural analysis and observations allows for predictive modelling of dilational zones within throughgoing Y-shears, which are prospective sites for remobilisation of high-grade Zn sulfides as the ore body developed coevally with progressive shearing.Detailed structural analysis provides 3D modelling parameters and exploration vectors.The Dugald River Shear Zone developed as an evolved Riedel shear network during dextral transpression.Understanding the shear zone’s 3D geometry and kinematics allows for predictive modelling of ore lens distribution and identification of dilational zones, which are crucial for exploration and mining strategies. [ABSTRACT FROM AUTHOR]

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]

Laozuoshan Gold Deposit is a large-scale gold deposit located in Northeast China, within the central part of the Jiamusi Block in the eastern section of the Khingan-Mongolia orogenic belt. This area represents a complex tectonic zone, influenced by the subduction and transitions of the Paleo-Asian Ocean, the Mongolia-Okhotsk Ocean, and the Paleo-Pacific Ocean. To explore the nature and composition of the ore-forming fluids and the sources of metallogenic materials, systematic studies on C-H-O isotopes from ore-forming fluid inclusions and S-Pb isotopes from ore minerals were conducted. Results show that δ13CPDB values range from 3. 932 ‰ to 5. 390 ‰, δ18OH2O from 2. 17 ‰ to 5. 60 ‰, and δD from-90. 482 ‰ to -90. 569 ‰, indicating that the ore-forming fluids are primarily derived from deep magmatic sources, with meteoric water mixing during the late mineralization stage and partial interaction with the carbonaceous rock units of the Mashan Group. Sulfides from the ore bodies have δ34S values ranging from 3. 3 ‰ to 5.1‰, sulfides from the mineralized alteration zones have δ34S values between 3. 9 ‰ and 5. 3 ‰, and sulfides from the mixed rocks and granites range from 3. 5 ‰ to 5. 2 ‰, suggesting that the ore-forming fluids were relatively weakly reducing. The Pb isotopic ratios of ore minerals are 206Pb/204Pb=18. 165-18. 571, 207Pb/204Pb=15. 452-15. 613, and 208Pb/204Pb=37. 764-38. 396, while magmatic rocks have 206Pb/204Pb=18. 151-18. 655, 207Pb/204Pb=15. 526-15. 634, and 208Pb/204Pb=37. 855-38. 050, indicating that the ore bodies and the magmatic rocks share a common origin, with ore-forming materials sourced from magmatic rocks. Given that the granodiorite closely associated with mineralization is the product of partial melting of the lower crust, it is further inferred that the ore-forming materials are crust-derived. Based on the geological characteristics of the deposit, it is concluded that Laozuoshan Gold Deposit is a weakly reducing skarn-type gold deposit. [ABSTRACT FROM AUTHOR]

The flotation characteristics of chalcopyrite, galena and sphalerite in the system with dextrin, sodium humate (HA-Na), cationic guar gum (CGG) and DP115 (modified polyacrylamide) as inhibitors and Z-200 as collector were investigated. The results showed that compared with the traditional system of adding macromolecular organic inhibitor first and then adding Z-200 collector, the three sulfide minerals showed different flotation behaviors in the system of adding Z-200 first and then adding macromolecular organic inhibitor. Chalcopyrite was basically not affected by dextrin, while dextrin more strongly inhibits galena, sphalerite was slightly activated by lower dosage of dextrin and was equivalent to that of adding dextrin first and then adding Z-200, and higher dosage of dextrin slightly enhanced the inhibition of sphalerite. HA-Na weakened the inhibition of three sulfide minerals. The inhibition of CGG on sphalerite, especially chalcopyrite, was enhanced, while the inhibition of galena was basically equivalent to that of CGG when added first. Chalcopyrite was basically not affected by DP115, and the lower amount of DP115 more strongly inhibited galena and sphalerite, while the inhibition of higher amount of DP115 on galena and sphalerite was basically the same as that of adding DP115 first and then Z-200. The research results can provide reference for the selection of organic macromolecular inhibitors and the improvement of flotation separation efficiency when Z-200 was used as collector in the flotation separation of copper-lead-zinc sulfide ore. [ABSTRACT FROM AUTHOR]

With the gradual reduction of easily beneficiated copper sulfide ore resources, the recovery and utilization of refractory copper oxide ore has become an important research direction in the field of mineral processing. The grade of copper and gold in a gold-copper ore is 1.86% and 3.52 g/t, respectively. The particle size of independent gold minerals in the ore is mine, basically below 1 µm, or wrapped in metal mineral or gangue minerals in the form of line particles, and the oxidation rate of copper in the ore is 91.85%, so the ore belongs to refractory ore. In order to recover the valuable components in the ore to the greatest extent, different flotation product schemes are compared according to the ore properties, and the segmented Rotation process is determined to recover gold and copper in the ore, that is, copper sulfide minerals and gold-bearing sulfide minerals are preferentially floated from the ore to obtain qualified gold-copper concentrate. Copper oxide minerals are recovered from the tailings of selective flotation, and a copper concentrate product wkh gold valuation is obtained, thus the valuable components in the ore are recovered and utilized by a segmented flotation process. On the basis of detailed flotation condition tests, a small locked-cycle test was carried out, and finally a gold-copper concentrate with 15.39% Cu and 152.39 g/t Au and copper concentrate wkh 28.02% Cu and 10.39 g/t Au were obtained. Overall, the total concentrate had copper grade of 24.73% and gold grade of 47.41 g/t, wkh the total recovery of copper being 87.41% and the total recovery of gold being 88.32%. [ABSTRACT FROM AUTHOR]

Aiming at the problems of cassiterite overgrinding and sulfide minerals undergrinding in the grinding process of cassiterite polymetallic sulfide ore, this paper investigated the influence of grinding time, mill filling rate and other factors on the particle size distribution of grinding products and the efficiency of grinding technology based on the conditions of different grinding media. The results show that grinding times positively correlated with the yield of qualified and overgrinding particles in the grinding products, and negatively correlated with the yield of undergrinding particles, and the content of Φ20 mm steel balls in the combination of steel bals in the grinding media has a greater impact on the qualified and overgrinding particles, and has a smaller impact on the undergrinding particles. Grinding time has a greater impact on the efficiency of grinding technology, when the grinding times certain the higher the content of Φ20 mm steel balls in the media combination, the higher the efficiency of grinding technology. Mill filling rate and grinding products in the qualified particle yields positively correlated but the impacts less than the grinding time, grinding media ball combination of Φ20 mm steel ball content has a greater impact on this law whereas the impact of filling rate on yields of over-grinding and under-grinding particles is small. Mill filling rate has a certain effect on the efficiency of grinding technology, when the mill filling rates certain the higher the content of Φ20 mm steel bals in the media combination the higher the efficiency of grinding technology. The results of the study can provide reference for the optimization of grinding media in cassiterite polymetallic sulfide ore filling production and mitigation of cassiterite overgrinding and sulfide ore undergrinding. [ABSTRACT FROM AUTHOR]

Copyright of Industrial Minerals & Processing / Huagong Kuangwu yu Jiagong is the property of Industrial Minerals & Processing Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Pressure hydrometallurgy is one of the special metallurgical technologies, which is widely used in the separation, extraction, metal reduction and mineral synthesis of alumina, laterite nickel ore, sphalerite and gold ore. The development history of pressurized hydrometallurgy technology in China for more than 60 years shows that the production process, technical equipment and scale have reached the world advanced level. In the face of the increasingly fierce competition in the domestic and foreign non-ferrous metal market, energy conservation, emission reduction and environmental protection awareness, as well as the more stringent technical requirements of the production process, the pressure hydrometallurgy technology has increasingly shown its inherent technical advantages in the efficient and clean utilization of complex and low-grade refractory minerals, the pressurized hydrosynthesis and preparation, pressurized hydrohydrogen reduction and low-carbon metallurgy. In this paper, the development and characteristics of pressure hydrometallurgy technology are described, with emphasis on the research progress of clean production of alumina pressure hydrometallurgy, oxygen pressure leaching of sulfide ore and pressure hydrometallurgy of vanadium slag. Finally, the development prospect and direction of pressure hydrometallurgy technology in the future are prospected. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Beijing University of Technology is the property of Journal of Beijing University of Technology, Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The research explores the impact of basicity on the softening and melting behaviors of limonite laterite nickel ore sinter. With the global decline of sulfide nickel ore resources, the extraction of nickel metal from laterite nickel ores has become a primary method. This study conducts a comprehensive experimental analysis and simulation of the behavioral characteristics of laterite nickel ore sinters and the properties of the soft melting zone to understand its key influencing factors and mechanisms in the blast furnace smelting process. Due to the unique composition of laterite nickel ore sinter, its softening zone position in the blast furnace is generally higher. Increasing the basicity can significantly improve the position and range of the softening zone, and when the basicity reaches 1.3, the permeability of the furnace material is optimal. Simultaneously, increasing the basicity can mitigate the adverse effects of the difficult‐to‐reduce and difficult‐to‐melt substance, chrompicotite, and its reduction products. [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]

Germanium (Ge) is a critical raw material for emerging high-tech and green industries, resulting in considerable recent interest in understanding its distribution and geochemical behavior in ore deposits. In this contribution, the distribution of Ge and related trace elements in the Fule Pb-Zn(-Ge) deposit, South China, is investigated to reveal the distribution of Ge in the hydrothermal ores and during sulfide weathering, using multiple microanalytical techniques, including scanning electron microscopy, electron probe microanalysis and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). In the Fule MVT deposit, sphalerite (ZnS) is the most significant Ge-carrier relative to other sulfides, though the five recognized textural types of sphalerite display progressive depletion in Ge from the first sphalerite generation to the late one. In the early stage, sphalerite with fine-grained chalcopyrite inclusions has the highest Ge concentrations, probably accounting for a significant proportion of the total Ge. We interpret that high Ge concentrations in the early sphalerite may be attributable to high Cu activity in the mineralizing fluids. During oxidative weathering, Ge was redistributed from its original host, sphalerite, to the weathering product willemite (Zn2SiO4) rather than smithsonite (ZnCO3), with high levels of Ge (up to 448 μg/g) present in the willemite. The formation of abundant willemite largely prevents the dispersion of Ge during weathering. In principle, willemite-hosted Ge should be fully recoverable, and the Zn-silicate ores may, therefore, be a potential target to meet future demand. This study provides new information on how Ge behaves from sulfide- to weathering-stage in MVT systems, which directly impacts Ge mobility and deportment changes and the development of metallurgical strategies for Ge recovery. [ABSTRACT FROM AUTHOR]

This article provides a detailed exploration of the geography, mining history, and mineralogy of the Elkhorn Mountains in southwestern Montana. It focuses on the Elkhorn and Radersburg mining districts and discusses the specific mines and minerals found in the area. The article also delves into the concept of epitaxy, which involves the growth of crystals on preexisting crystals, and explains the different types of oriented intergrowths. The authors conducted a study on the epitactic relationship between quartz and hemimorphite minerals, observing their structural similarities and suggesting a shared framework as the reason for this relationship. The article concludes with acknowledgments to mine owners and individuals who assisted in the research. [Extracted from the article]

Exponential increasing demands for base metals have made meaningful processing of their quite low-grade (>1%) resources. Froth flotation is the most important physicochemical pretreatment technique for processing low-grade sulfide ores. In other words, flotation separation can effectively upgrade finely liberated base metal sulfides based on their surface properties. Various sulfide surface characters can be modified by flotation surfactants (collectors, activators, depressants, pH regulators, frothers, etc.). However, these reagents are mostly toxic. Therefore, using biodegradable flotation reagents would be essential for a green transition of ore treatment plants, while flotation circuits deal with massive volumes of water and materials. Pyrite, the most abundant sulfide mineral, is frequently associated with valuable minerals as a troublesome gangue. It causes severe technical and environmental difficulties. Thus, pyrite should be removed early in the beneficiation process to minimize its problematic issues. Recently, conventional inorganic pyrite depressants (such as cyanide, lime, and sulfur-oxy compounds) have been successfully assisted or even replaced with eco-friendly and green reagents (including polysaccharide-based substances and biodegradable acids). Yet, no comprehensive review is specified on the biodegradable acid depression reagents (such as tannic, lactic, humic acids, etc.) for pyrite removal through flotation separation. This study has comprehensively reviewed the previously conducted investigations in this area and provides suggestions for future assessments and developments. This robust review has systematically explored depression performance, various adsorption mechanisms, and aspects of these reagents on pyrite surfaces. Furthermore, factors affecting their efficiency were analyzed, and gaps within each area were highlighted. [ABSTRACT FROM AUTHOR]

Chalcopyrite and galena are primary raw materials for producing Cu and Pb metals, respectively. Flotation is still the main method to recover these two minerals. So far, lots of work has been done to recover them from low-grade refractory ores, whereas the efficient separation of these two minerals remains a major challenge. In this review, the crystal, surface, floatability and needed reagents were discussed. Firstly, the crystalline structures were introduced, including physical and chemical properties, and followed by surface properties from a density functional theory simulation perspective. As reviewed, the surface properties were closely related to their floatability, such as the degree of surface oxidization, particle size, galvanic interactions, metal ions, and so on. Moreover, the floatability of minerals could be influenced by flotation reagents, and therefore a range of new collectors and depressants were described. The review aimed to provide a deep understanding on the factors affecting Cu/Pb flotation separation as well as to develop new depressants helping to guide the flotation separation of Cu/Pb/Zn polymetallic sulfide ores for researchers. [ABSTRACT FROM AUTHOR]

Sulfur forms an immiscible liquid upon saturation in magma, and sulfide droplets are commonly found in fresh mid-ocean ridge basalt (MORB). Scanning electron microscopy (SEM) analysis revealed that the fine-grained and weakly phyric MORB samples exhibited hypocrystalline to vitreous textures. Transmission electron microscopy (TEM) of MORB glasses exhibits nanoscale sulfide droplets (10-15 nm) with rounded shapes and smooth edges, showing crystalline and homogeneous composition. Elemental distribution included S, Fe, Cu, and Ni, while Si, Al, and O were lacking. Prior research clarified the immiscibility between sulfide and silicate melts, impacting the size distribution of sulfide droplets. This is the first report on nanoscale sulfide droplets within MORB glasses, and these results suggest that nanoscale sulfide droplets represent the initial phase of sulfide saturation. Such an insight may prove useful in understanding how siderophile and chalcophile elements behaved during sulfide crystallization. In addition, this study determines the immiscibility of sulfides and silicate melts that occur in the early nanometer stage. Therefore, it is speculated that immiscibility phenomena may occur in the nanometer stage during magma evolution. [ABSTRACT FROM AUTHOR]

Mineralogical features of two orebodies, lenses (C-3 and C-4), at the central part of the Oktyabr'sky deposit have been investigated. Multidirectional mineralogical zoning in the northern and southern orebodies is shown, confirming the hypothesis of their formation from various magmatic flows, which have individual features and their own modes of formation. The southern C-3 and northern C-4 orebodies differ in their mineralogical associations: C-3 is characterised by a high-sulfur association of sulfides; and C-4 contains minerals with a sulfur deficit (talnakhite, sugakiite). Variations in Fe and Ni ratios in pentlandite are controlled by the volatility of sulfur during ore crystallisation. Direct crystallisation zoning is observed in the disseminated ores of the C-4 orebody (borehole RT-107), where the fugacity of sulfur ($f_{S_2}$) increases from bottom to top. In contrast in orebody C-3 (borehole RT-30) $f_{S_2}$ decreases in the same direction. This reverse zoning coincides with the vectors of the evolution of ore systems in various blocks of the Main Ore Body of the Oktyabr'sky deposit. The difference in typomorphic features of disseminated ores of the southern and northern orebodies is confirmed by differences in the associations of platinum-group element minerals (PGMs). Disseminated ores in picritic gabbro-dolerites and massive pyrrhotite ores in the exocontact of the intrusion within the southern orebody differ in the specialisation of PGMs: the former is characterised by minerals of the Pd–Bi–Sb–Te system, the latter by only Pt minerals. The similarity of these types of ores lies in the similar reverse mineralogical and geochemical zoning from top to bottom along the sections, caused by the evolution of the sulfide melt in this direction. The formation of reverse zoning of disseminated ores (zones of 'marginal reversion') is probably due to the action of a mechanism of repeated influx of a melt of an increasingly primitive composition into the upper parts of the crystallising flow. Unidirectional trends in massive and disseminated ores are more likely to be due to the action of the same type of mechanism. [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]

The production of critical metals for emerging clean technologies also requires more sustainable, cleaner and cost-effective processing options. The recovery of cobalt (Co) via pyrometallurgical or hydrometallurgical methods has proved to be successful and practicable; nevertheless, these processes are difficult to manage, have a high operating cost, and produce secondary waste products. In recent years, bioleaching has increasingly gained favor as a method for extracting Co from ores, concentrates, and tailings. The availability of Co in primary and tailings resources, as well as the bioleaching approaches from these deposits are discussed in this paper. Bioleaching of Co has been investigated from primary sources such as Cu-Co deposits, polymetallic Ni-Co-Cu deposits, Co sulfides and arsenides, Ni-Co laterites, and secondary sources including tailings materials. The microorganisms and methods utilized in Co bioleaching from these sources, as well as parameters influencing the bioleaching process, and ways for improving Co bioleaching efficiency, have all been thoroughly discussed in this review. This study examines the potential of different microorganisms to solubilize Co from sulfide and laterite deposits by performing an in-depth meta-analysis of the individual research findings to enable inter-study comparisons and identify research gaps. The reviewed laboratory studies and existing industrial practices for Co bioleaching in this paper intend to offer some inspiration for further research into innovative technologies that may be used to sustainably extract Co, mainly from ores, concentrates and tailings resources. [ABSTRACT FROM AUTHOR]

Arsenic containing non-ferrous metal and precious metal sulfide ore will produce acidic high concentration arsenic solution in the smelting process, which has the characteristics of high arsenic concentration, complex composition, large changes, strong toxicity and difficult to store, such as direct discharge without treatment, will have a great impact on the environment and human health. In this paper, the principles, advantages and disadvantages of chemical precipitation method, evaporation enrichment method and metal powder method are reviewed, as well as the research progress of each method, so as to provide reference for the development of arsenic removal technology. [ABSTRACT FROM AUTHOR]

The De'erni Cu–Zn-Co deposit is a typical altered ultramafic-hosted volcanogenic massive sulfide deposit comprising four lenticular main orebodies (0.57 Mt Cu, 1.27% Cu average ore grade; 0.03 Mt Co, 0.09% Co average ore grade; 0.16 Mt Zn, 1.04% Zn average ore grade) hosted in serpentinite and a 200-m-thick basalt was found below the No. I orebody. Serpentinite spinel Al2O3, TiO2, Cr#, and Mg# indicate a mantle-source. Serpentinite magmatic-hydrothermal genesis is indicated by the following: (i) high Rb/Y and Th/Zr ratios, low Nb/Zr ratios, and low δ65Cu values; (ii) altered magnetite rims on spinel being characterized by high Cr, Ni, and Ti, and low Ga contents; (iii) pyrite appears along the boundary of spinel grains and has a higher Co and Ni content than pyrite in ores. Therefore, the ultramafic host rocks are formed by strong fluid alteration of primary mantle rocks. The compositional zoning of Co, Cu, and Zn in euhedral coarse-grained pyrite from massive sulfide ore suggests that metal enrichment was associated with three fluid phases, with a clear temporal interval between the fluid activity that introduced Co/Cu enrichment and Zn enrichment (Zn-rich veins in magnetite cross-cut early spinel). Serpentinite exhibits a higher Zn content and decoupling of Ni and Co contents compared to Dur'ngoi ophiolite serpentinite distal from the orebody, implying primary ultramafic rocks may have provided Co to the ores. The apparently high Cu content of the Dur'ngoi ophiolite basalt in comparison with ophiolite basalts worldwide indicates basalt may have supplied the Cu. [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]

Copyright of Geology & Exploration is the property of Geology & Exploration Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

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]

To test the ability of geochemical surfaces in serpentinizing hydrothermal systems to catalyze reactions from which metabolism arose, we investigated H2‐dependent CO2 reduction toward metabolic intermediates over silica‐supported Co−Fe catalysts. Supported catalysts converted CO2 to various products at 180 °C and 2.0 MPa. The liquid product phase included formate, acetate, and ethanol, while the gaseous product phase consisted of CH4, CO, methanol, and C2−C7 linear hydrocarbons. The 1/1 ratio CoFe alloy with the same composition as the natural mineral wairauite yielded the highest concentrations of formate (6.0 mM) and acetate (0.8 mM), which are key intermediates in the acetyl‐coenzyme A (acetyl‐CoA) pathway of CO2 fixation. While Co‐rich catalysts were proficient at hydrogenation, yielding mostly CH4, Fe‐rich catalysts favored the formation of CO and methanol. Mechanistic studies indicated intermediate hydrogenation and C−C coupling activities of alloyed CoFe, in contrast to physical mixtures of both metals. Co in the active site of Co−Fe catalysts performed a similar reaction as tetrapyrrole‐coordinated Co in the corrinoid iron‐sulfur (CoFeS) methyl transferase in the acetyl‐CoA pathway. In a temperature range characteristic for deeper regions of serpentinizing systems, oxygenate product formation was favored at lower, more biocompatible temperatures. [ABSTRACT FROM AUTHOR]

Highlights: Mo–MXene/Mo–metal sulfides with semiconductor junctions and Mott–Schottky junctions are designed. Built-in electric field are constructed in semiconductor–semiconductor–metal heterostructure, enhancing dielectric polarization and impedance matching. Density functional theory calculations and Radar cross-section simulations confirmed the excellent electromagnetic wave absorption ability of heterostructures. The exploration of novel multivariate heterostructures has emerged as a pivotal strategy for developing high-performance electromagnetic wave (EMW) absorption materials. However, the loss mechanism in traditional heterostructures is relatively simple, guided by empirical observations, and is not monotonous. In this work, we presented a novel semiconductor–semiconductor–metal heterostructure system, Mo–MXene/Mo–metal sulfides (metal = Sn, Fe, Mn, Co, Ni, Zn, and Cu), including semiconductor junctions and Mott–Schottky junctions. By skillfully combining these distinct functional components (Mo–MXene, MoS2, metal sulfides), we can engineer a multiple heterogeneous interface with superior absorption capabilities, broad effective absorption bandwidths, and ultrathin matching thickness. The successful establishment of semiconductor–semiconductor–metal heterostructures gives rise to a built-in electric field that intensifies electron transfer, as confirmed by density functional theory, which collaborates with multiple dielectric polarization mechanisms to substantially amplify EMW absorption. We detailed a successful synthesis of a series of Mo–MXene/Mo–metal sulfides featuring both semiconductor–semiconductor and semiconductor–metal interfaces. The achievements were most pronounced in Mo–MXene/Mo–Sn sulfide, which achieved remarkable reflection loss values of − 70.6 dB at a matching thickness of only 1.885 mm. Radar cross-section calculations indicate that these MXene/Mo–metal sulfides have tremendous potential in practical military stealth technology. This work marks a departure from conventional component design limitations and presents a novel pathway for the creation of advanced MXene-based composites with potent EMW absorption capabilities. [ABSTRACT FROM AUTHOR]

Natural studies of the South Urals hydromineral deposits, as well as the results of study of the ion and gaseous composition of underground waters, show that the liquid run-off from massive sulfide deposits of the region are promising serious deposits of secondary raw materials. The dump waters are mineral resources for rare metals, the contents of which are comparable with the average content of 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]

Facing the situation of nickel resource shortage and increasing nickel demand, it is an important task for the development of nickel industry to realize efficient utilization of low-grade nickel sulfide ore. In this work, the process of NaCl roasting-water leaching was proposed to simultaneously extract valuable metals from low-grade nickel concentrate. Based on the thermodynamic analysis of roasting process, the effect of several key factors on metal extraction was investigated. The results show that the extraction of Ni, Cu and Co can reach approximately 94.08, 92.81 and 91.85 pct, respectively, under the following optimum conditions: temperature 400 °C, time 90 minutes, NaCl dosage 100 pct and concentrate particle size 70–88 µm. The evolution behavior and mechanism of metallic minerals are determined through thermodynamic analysis, differential thermogravimetric analysis, and phase composition analysis of roasted product. The kinetics of the roasting process based on the differential thermal and thermogravimetric experiment was analyzed by Kissinger method and Doyle-Ozawa method. The average apparent activation energy of metallic minerals being chlorinated is determined as 400.12 kJ/mol and the kinetic equation was expressed as d α dt = 2.41 × 10 12 e - 400.12 RT (1 - α) 1.27 . [ABSTRACT FROM AUTHOR]

The effect of adding orders of inorganic regulators such as zinc sulfate, copper sulfate, sodium sulfite and sodium sulfide on the flotation of chalcopyrite, galena, and sphalerite was studied under the Z-200 collector system. The results of microflotation tests showed that compared with adding inorganic regulator before the Z-200, when the inorganic regulator was added after the Z-200, there were differences in the effect on the flotation of the three kinds of sulfide minerals: the depressing effect of zinc sulfate on chalcopyrite, especially galena, was significantly weakened, and the depressing effect of zinc sulfate on sphalerite was weakened at lower dosage, but stronger at higher dosage. Copper sulfate slightly enhanced the depressing effect on chalcopyrite, had a strong activation effect on galena, especially at lower dosage, the activation effect of copper sulfate on sphalerite was significantly enhanced at lower dosage, and was weakened at higher dosage. Sodium sulfite weakened its depressing effect on chalcopyrite, especially galena, and enhanced the depressing effect on sphalerite. Sodium sulfide weakened its depressing effect on chalcopyrite, had a similar activation effect on galena at lower dosage, while its depressing effect was enhanced at higher dosage, and enhanced its depressing effect on sphalerite at low dosage. The research results can provide reference for the selection and the adding sequence of inorganic regulators in the flotation separation of sulfide ores under the Z-200 collector system. [ABSTRACT FROM AUTHOR]

In Guangxi, a polymetallic sulfide ore tailings sample, highly abundant in -0.013 mm particle size, comprises 56.3% of the total, exhibiting severe sliming phenomena. The main valuable metal is Sn with a grade of 1.45%. It mainly exists in the form of fine cassiterite, in -0.013 mm particle size, with a distributing rate of 84.76%. Due to its small mass, large specific surface area, and high surface energy, fine cassiterite faces longstanding issues in mineral processing, such as low recovery and poor concentrate quality. This study primarily investigated fine cassiterite flotation behaviour using both single collectors and collector combinations. The results showed that the collector combination achieved higher tin recovery than the single collector, although the latter provided a higher grade of tin concentrate. The experiment adopted a collector combination ratio of GXU-Sn2 : GXU-Sn3= 1 : 2 for the laboratory locked-cycle test, achieving a final tin concentrate grade of 30.92% and a total recovery of 81.13%, with a flotation recovery of 85.06% through a process of "one rougher, two cleaners, and two scavengers" . To confirm the feasibility of the optimal reagent scheme and flowsheet determined in the laboratory for continuous industrial production, extended pilot tests on fine cassiterite were conducted in a pilot plant in Guangxi, ultimately yielding a tin concentrate with a grade of 15.07%, a total recovery of 74.69%, and a flotation recovery of 84.88%. These results affirm that the laboratory-developed reagent scheme is operable and stable in flotation indicators. Through laboratory-scale trials and extended continuous pilot tests, it was demonstrated that fine cassiterite could be efficiently recovered through extensive flotation experiments with the proper reagent scheme and flowsheet. This provides valuable technical reference for the future efficient recovery of low-grade fine tin ores and the development of novel collectors. [ABSTRACT FROM AUTHOR]

Aiming at the problem of over-grinding and under-grinding and the influence of grinding mode and feed size on ore grinding effect. Cassiterite polymetallic sulfide ore was taken as the research object. The grain size distribution of grinding minerals and grinding behavior characteristics were explored based on batch grinding test, by changing grinding method, feed sizes, grinding time and other factors affecting grinding. It was shown by the results that attrition grinding process was a low-energy grinding, the force of ore was small, and the under-grinding was easy to occur, whereas drop grinding and impact grinding processes were high-energy grinding, the ore was subjected to greater force, more fully broken, easy to occur over-grinding phenomenon. The variation amplitude of grinding technical efficiency E and grinding mineral substance tw was stable with grinding time under grinding conditions, and the product size distribution was uniform. Grinding technical efficiency E and grinding product t10 were changed obviously with the grinding time under drop grinding and impact grinding, and the change range was large, and in general, the two grinding indexes are greater than that of attrition grinding. Complicated and without obvious rule was the relationship between the grinding behavior of ore and the feeding size. A theoretical basis for the subsequent research on the strength and interaction of attrition and impact forces in the dropping state was provided by the research results. [ABSTRACT FROM AUTHOR]

Arsenic contamination not only complicates mineral processing but also poses environmental and health risks. To address these challenges, this research investigates the feasibility of utilizing Hyperspectral imaging combined with machine learning techniques for the identification of arsenic-containing minerals in copper ore samples, with a focus on practical application in sorting and processing operations. Through experimentation with various copper sulfide ores, Neighborhood Component Analysis (NCA) was employed to select essential wavelength bands from Hyperspectral data, subsequently used as inputs for machine learning algorithms to identify arsenic concentrations. Results demonstrate that by selecting a subset of informative bands using NCA, accurate mineral identification can be achieved with a significantly reduced the size of dataset, enabling efficient processing and analysis. Comparison with other wavelength selection methods highlights the superiority of NCA in optimizing classification accuracy. Specifically, the identification accuracy showed 91.9% or more when utilizing 8 or more bands selected by NCA and was comparable to hyperspectral data analysis with 204 bands. The findings suggest potential for cost-effective implementation of multispectral cameras in mineral processing operations. Future research directions include refining machine learning algorithms, exploring broader applications across diverse ore types, and integrating hyperspectral imaging with emerging sensor technologies for enhanced mineral processing capabilities. [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]

Copyright of Journal of Engineering & Architectural Faculty of Eskisehir Osmangazi University / Eskişehir Osmangazi Üniversitesi Mühendislik ve Mimarlık Fakültesi Dergisi is the property of Eskisehir Osmangazi University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This article presents tangible geological evidence for the coexistence of porphyry copper and epithermal gold systems within single polygenic deposits and provides a paleothermophysical model for their origins. A brief metallogenic analysis of the Southern Caucasus and Northern Iran has shown that such deposits are confined to long-living calc-alkaline island arcs and were formed during their orogenesis. Examples of complex Sonajil (Iran), Gharta, and Merisi (Georgia) deposits are considered. The investigation has shown that for combined porphyry and epithermal ore formation, some preconditions are suggested to exist: (i) a source of anomalous energy that exceeds the thermodynamics of the enclosing environment; (ii) the existence of a temperature gradient that determines conventional flows of fluids composed of endogenous and meteoric constituents (proven by rhythmical zoning of ore lodes); (iii) the stability of such conditions for a period of sulfide ore formation. However, such a process of sulfide ore formation cannot explain the formation of high sulfidation gold deposits. The precipitation of native gold requires phreatic collapse in the ore conduit channel, already after the formation of hydrothermally altered rocks, and this event results in the creation of either hydrothermal breccias often with jigsaw-fit texture or brecciated vuggy silica where host rocks and hydrothermally altered rocks are cemented by a gold-bearing quartz matrix. [ABSTRACT FROM AUTHOR]

This study provides a comprehensive characterization of various hydrothermal systems in Southern Peru ranging from the faulted Precordillera's steep topography up to the volcanic High Cordillera (>4,000 m asl). The objective is to investigate thermal anomalies that may potentially serve as new geothermal resources. Our integrated approach combines: (a) geochemistry from 14 hot springs sampled throughout the Tacna region, and (b) 3D numerical modeling of coupled groundwater and heat transfer considering topography and faults embedded in homogeneous permeability. Water and gas analysis indicates that the springs located near volcanoes discharge Na‐K‐Cl waters with high temperatures (>87°C), high Total Dissolved Solid concentrations (TDS >3,452 mg/L), and free gases dominated by CO2 (>90 vol%). Springs located along the regional faults in the Precordillera discharge Ca‐SO4 and Na‐K‐Cl waters with moderate temperatures (27–53°C), intermediate TDS concentrations (464–2,458 mg/L), radiocarbon ages between 1.4 and 7.9 kyr, and free gases dominated by N2 (>95 vol%). The Aruma springs, which are located at the transition between the High and the Precordillera, display intermediate characteristics. Numerical models accurately replicate the locations and temperatures of the fault‐related springs only for permeable faults (>10−14 m2), revealing the creation of 100‐km long thermal plumes along faults, locally rising up the 150°C‐isotherm to about ∼1,000 m below the surface. This approach clearly distinguishes the spring origins, which are volcanic in High Cordillera and tectonic in Precordillera. Moreover, we highlight that steep topographic gradient and permeable reverse faults in the Andean forearc may generate considerable thermal anomalies, opening perspectives for the geothermal exploration. Plain Language Summary: Geothermal energy is an essential part of the transition to green energies. It consists of using the Earth' natural heat to generate electricity or provide direct heating. In the Peruvian Andes there is significant geothermal potential near volcanoes that constitute an efficient heat source. However, these are distant from many of the population hubs, mostly located along the Pacific Coast. In the Tacna region, Southern Peru, we observe hot springs aligned along faults near the city. We hypothesize that these faults act as pipes for the hot fluids making them suitable for geothermal energy extraction. The geochemical compositions of various hot springs in the region are compared with 3D numerical models simulating hydrothermal flows. We found that springs along volcanoes and those along faults have different geochemical signatures, evidencing different subsurface pathways. Numerical models accurately replicate the positions and temperatures of the observed and sampled hot springs and reveal significant thermal anomalies around compressional faults. Our findings open up promising perspectives for the geothermal exploration in the Andean forearc. Key Points: The geochemical properties of Southern Peru's hot springs are influenced by their spatial correlation with volcanic or tectonic featuresBy combining permeable faults and topography, 3D hydrothermal modeling replicates the temperatures and locations of observed springsDetection of regional topography‐driven thermal plumes along faults in the Andean forearc opens perspectives for geothermal exploration [ABSTRACT FROM AUTHOR]

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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]