Sulfide Research Articles

Selective fabrication of hydrophilic BiOCl deposition layer on bismuthinite surface for efficient molybdenite/bismuthinite separation

Molybdenite and bismuthinite are valuable components arising from Mo–Bi sulfide ore, and their recoveries are considerably limited by separation efficiency. Herein, calcium hypochlorite (Ca(ClO)2) was first introduced as bismuth depressant for efficient separation of molybdenite and bismuthinite, and its depression mechanisms were investigated through a series of analytical techniques supplemented with solution chemistry and thermodynamic calculations. Flotation results showed that Ca(ClO)2 had a stronger depressing ability than conventional depressant sodium sulfide and exhibited superior selectivity for bismuthinite against molybdenite. At pH around 8.0, the high-selective separation of Mo–Bi bulk concentrate was realized, where more than 96% of molybdenite was recovered and over 98% of bismuthinite was depressed. Solution chemistry and thermodynamic analysis indicated that the bismuthinite surface was preferentially oxidized by Ca(ClO)2 to SO2- 4 and Bi3+. The former dissolved into solution and existed as stable ions, whereas the Bi3+ further interacted with Cl− and was hydrolyzed as BiOCl precipitates. Surface analysis demonstrated that the deposition of BiOCl on the bismuthinite surface not only made its surface rougher but also enhanced its surface hydrophilicity. In comparison, the surface of molybdenite was slightly oxidized and it remained hydrophobic as confirmed from scanning electron microscopy with energy dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, and contact angle results. The difference in surface characteristics resulted in the selective adsorption of collector on the surface of molybdenite rather than that of bismuthinite, thus improving the floatability of molybdenite and drastically deteriorating the floatability of bismuthinite. This work suggests that Ca(ClO)2 could be a promising depressant for bismuthinite in the flotation separation of Mo–Bi sulfide ore.

Fluidized-bed flotation of coarse molybdenite particles: Matching mechanism for bubble and particle sizes

Fluidized-bed flotation is a novel process with combined features of flotation and density separation. The application of fluidized-bed flotation in grinding circuit to reject coarse gangues for sulfide ores has been increasingly attracting attentions. Previous studies have focused on the effect of mineral liberation on coarse particle separation. Little work has yet been conducted to simultaneously investigate the effect of mineral liberation, particle and bubble sizes on the fluidized-bed flotation efficiency. The lack of this work has hindered the process optimization to some extent. In this study, three sizes of bubbles (498 μm, 1200 μm, 1952 μm) were generated to separate molybdenite ores under three particle size fractions (150–450 μm, 450–700 μm and 700–1000 μm) in a fluidized-bed flotation column (80 mm in diameter). For the 150–450 μm and 450–700 μm particles, small bubbles of 498 μm could achieve separation by effectively reducing the particle density. For the 700–1000 μm particles with greater mass, intermediate bubble of 1200 μm was required to reduce the particle density for separation. No separation was observed for the three particle size classes with the oversized bubbles of 1952 μm due to high bubble detachment probability. It was concluded that fluidized-bed flotation is a consequence of matched bubble and particle sizes affected by the exposure rate of hydrophobic mineral and its distributing discreteness, the underlying mechanism for which was discussed. It is believed that the outcomes of this work could facilitate the optimization of fluidized-bed flotation in coarse gangue rejecting for sulfide ores.

Effect of platy gangue minerals in sulfide flotation: Part 2: Mechanisms

The presence of the usually unwanted, hydrophilic ore particles (gangue) in a mineral flotation froth plays a critical role. While they reduce the grade of the concentrate, they are also an important influence on the dynamical structure of the froth and its ability to transport value particles into the launder for ultimate recovery. This paper discusses how the shape and size of these gangue particles affect their transport through the froth zone under conditions typical of commercial sulfide flotation, but without hydrophobic ore particles present.Advective transport of gangue particles via entrainment depends on slurry drag due to the upward motion of air bubbles and the drainage effects of gravity on the liquid and solid phases confined in the network of fluid channels in the froth. In a companion paper (Bhambhani et al., 2023a) a significant increase in gangue transport rates through the froth zone was observed when a copper sulfide ore was mixed with platy mica (higher aspect ratio) compared to when the same ore was mixed with globular (lower aspect ratio) silica. It was hypothesized that this increased upwards transport rate was related to the greater upward drag experienced by the platy mica particles as compared to the lower aspect-ratio silica particles of comparable size. This hypothesis was tested by conducting froth sampling experiments, reported here, under increased upward drag conditions for the suspension and thus increased upward advective forces on the particles. It was observed that the entrainment vs particle size curves shifted upwards for the coarser sizes for both mica and silica. This was unexpected. It was additionally hypothesized that as the particle size approached the size of the channels (Plateau borders), through which settling particles must pass if they are to move downward, the particles become more confined and on average experience less downward motion. Platy mica particles of a certain sieve size are more susceptible to confinement in the channels than their lower aspect-ratio counterparts due to their reduced mass per particle. This was suggested from froth sampling experiments where drag and drainage were balanced in one case, and more drag dominated in the other.

An appraisal of the principal concerns and controlling factors for Arsenic contamination in Chile

Although geogenic Arsenic (As) contamination is well-recognized in northern Chile, it is not restricted to this part of the country, as the geological conditions favoring As release to the human environment exist across the country as well, although not at the same level, based on comparatively fewer studies in central and southern Chile. The present work provides a critical evaluation of As sources, pathways, and controls with reports and case studies from across the country based on an exhaustive bibliographic review of its reported geogenic sources and processes that affect its occurrence, systematization, and critical revision of this information. Arc magmatism and associated geothermal activities, identified as the primary As sources, are present across the Chilean Andes, except for the Pampean Flat Slab and Patagonian Volcanic Gap. Metal sulfide ore zones, extending from the country’s far north to the south-central part, are the second most important geogenic As source. While natural leaching of As-rich mineral deposits contaminates the water in contact, associated mining, and metallurgical activities result in additional As release into the human environment through mining waste and tailings. Moreover, crustal thickness has been suggested as a principal controlling factor for As release, whose southward decrease has been correlated with lower As values.

MINERALOGICAL AND GEOCHEMICAL RESEARCH ON EVIDENCE OF ALAKUL METAL PRODUCTION AT THE VOROVSKAYA YAMA MINE (SOUTHERN TRANS-URALS)

The article discusses the processes of Alakul metal production at the Vorovskaya Yama copper mine (Southern Trans-Urals, middle of the 2nd millennium BC). The study sources are the materials of the 2021 excavation site including ruined remains of heating facilities, metallurgical slag and slagged ceramics. The research employed optical and electron microscopy, XRF and LA-ICP-MS methods. It was established that technological operations at the deposit were not limited to the extraction of copper ore and its primary enrichment. In addition, metal was smelted from sulfide or oxidized-sulfide ores in the immediate vicinity of the mine entry; however, it was done outside the studied areas of the structures. Secondary remelting of copper and tin bronze products was performed in ceramic crucibles using heating facilities inside structures.

Recovery of non-ferrous metals from sulfide ores by bioleaching on the example of the Allarechensk technogenic deposit

The possibility of processing sulfide copper-nickel raw materials by heap bioleaching due to the environmental attractiveness of this approach is becoming an increasingly relevant topic for mining and processing. On the example of the Allarechensk technogenic deposit ore, the effectiveness of the bioleaching method for the copper and nickel recovery has been considered. The content of metals in the original ore sample: nickel – 2.42 % and copper – 0.75 %. The ore grinded to the size of –5+3 mm has been irrigated with a solution containing a strain of Acidithiobacillus ferrivorans. The S : L ratio is 4 : 1, the flow rate is equal to 0.1 mL/min. In pregnant solutions, the pH and redox potential values have been controlled, and the concentrations of ferrous and ferric iron, copper, and nickel ions have also been measured. The experiment duration is 11 months, 8.9 % nickel and 6.1 % copper have been recovered. Copper has been extracted from pregnant solutions by cementation on iron, the maximum recovery is 97.3 %. Thus, it has been shown that the proposed scheme for the recovery of metals is promising for the processing of sulfide raw materials, in particular, low-grade ores and enrichment waste.

Novel application of depressant sodium mercaptoacetate in flotation separation of chalcopyrite and pyrite

The development of flotation reagents with high selectivity and strong depression ability is of great significance in the efficient enrichment of copper sulfide ores. In this work, a new depressant, sodium mercaptoacetate (SMA) has been explored for the flotation separation of chalcopyrite and pyrite, and the depression mechanism of SMA was studied by Fourier Transform Infrared spectrometer (FTIR), adsorption tests, local electrochemical impedance spectroscopy test (LEIS), Time of Flight Secondary Ion Mass Spectrometry (ToF-SIMS) and X-ray photoelectron spectroscopy (XPS). Micro-flotation tests showed that SMA strongly depresses pyrite in the pH range of 6–10. When the dosage of SMA is 2.5 × 10−5 mol/L, the dosage of SBX is 1 × 10−5 mol/L, and pH = 6.5, the concentrate with a Cu grade of 31.93% and chalcopyrite recovery of 85.97% can be obtained, in which the pyrite recovery was only 4.18%, respectively. The strong chemical adsorption between SMA and Fe atomic sites exposed on the surface of pyrite reduces the hydrophobicity of pyrite and hinders the adsorption of SBX. In comparison, SMA has less adsorption on the surface of chalcopyrite and hardly affects the further adsorption of SBX. It was shown that SMA could be used as an effective depressant for pyrite in the flotation separation of chalcopyrite and pyrite.

A case study on marmatite- pyrite/pyrrhotite selective flotation with two-step pulp regulation

Zinc occupies a vital position in modern industrial production, and zinc metal is mainly extracted from marmatite or sphalerite. Marmatite or sphalerite is often associated with pyrite and pyrrhotite in natural polymetallic sulfide deposits. Therefore, how to well achieve the selective separation of marmatite or sphalerite from associated pyrite and pyrrhotite is an important issue, because it is directly related to the efficient and sustainable utilization of zinc-bearing sulfide mineral resources. In this paper, a systematic research taking the selective separation of marmatite from high-sulfur sulfide ores as its core, was conducted. The results confirmed that pulp redox potential (Eh) as well as dissolved oxygen (DO) dominated the selective separation of marmatite from associated pyrite and pyrrhotite, and the Zn recovery and Zn grade of zinc concentrates could be greatly improved by controlling Eh. As a result, an effective and feasible operating mechanism with two-step Eh regulation was first established. The findings are expected to help scholars understand the marmatite-pyrite/pyrrhotite (Zn-S) selective flotation better, favor the beneficiation of high-sulfur polymetallic sulfide ores in study or practice, and provide important inspirations for the theoretical research or practical utilization on other similar sulfide resources, especially those containing pyrrhotite.

The galvanic interaction enhanced the flotation separation of chalcopyrite and galena with humic acid as galena depressant

Depression of galena remains a challenge in the flotation separation of the copper/lead sulfide ores. Current technologies still suffer from considerable drawbacks, primarily due to the utilization of numerous hazardous, expensive, and poorly selective inhibitors. In this work, the influence of galvanic interaction between galena and chalcopyrite on their flotation separation with humic acid as galena depressant was investigated using a combination of the flotation experiment, minerals dissolution experiment, zeta potential, XPS and electrochemical analysis. The results indicated that the recovery of galena rapidly decreased to 34.7% when the conditioning time was extended to 20 min, which was 50% lower than that without chalcopyrite. The dissolved Pb2+ in the pulp increased by 2.2 times in the presence of chalcopyrite. The galvanic interaction between galena and chalcopyrite enhanced the oxidation of galena, leading to an increase in oxysulfide and hydroxide components on the galena surface. The accelerated oxidation of galena is conducive to the humic acid adsorption, achieving an efficient depression of galena flotation at a short conditioning time. This work demonstrated that enhancing the galvanic interaction between galena and chalcopyrite by extending the conditioning time was a viable and eco-friendly approach to achieve the flotation separation of chalcopyrite and galena with humic acid as a depressant.

Genesis of the Giant Huoshaoyun Non-Sulfide Zinc–Lead Deposit in Karakoram, Xinjiang: Constraints from Mineralogy and Trace Element Geochemistry

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.

Overcoming stereological Bias: A workflow for 3D mineral characterization of particles using X-ray micro-computed tomography

Mineral separation processes operate on properties of individual particle, which can currently be quantified with 2D characterization techniques, namely 2D automated mineralogy. While 2D automated mineralogy data have driven significant developments in particle-based separation models, this data inherently correspond to 2D slices of 3D objects, which leads to stereological bias in the quantification of geometric particle properties. X-ray micro-computed tomography (µCT) is a 3D imaging technique that can quantify particle geometry. However, µCT only collects limited information regarding material composition, making mineral identification quantification a challenge. To overcome this challenge, we present a workflow that utilizes individual particle histograms and corrects image artefacts caused by µCT measurements, such as partial volume effect. We demonstrate the application of the workflow to perform 3D mineral characterisation of a sulfidic gold ore, where mineral phases that are commonly mistaken with µCT could be distinguished: pyrite and chalcopyrite, gold, and galena. Results were verified by comparison with inductively coupled plasma mass spectrometry and 2D automated mineralogy. As a result, the workflow provides the user with a detailed 3D particle dataset containing the modal mineralogy and surface compositions, size, and geometrical properties of each particle in a sample – essential data for modelling mineral separation processes.

THE ROLE OF SULFATE-REDUCING BACTERIA IN BIOMONITORING OF RIVER ECOSYSTEMS

Biomonitoring is one of the important stages in the consistent study of the sustainable development of aquatic ecosystems and their biological diversity. Against the background of the global impact on the hydrosphere, there is a need to select priority indicators and methods for determining the environmental risk in case of pollution of river ecosystems. Newly arriving substances are involved in complex biogeochemical processes in the water column, migrate as part of suspensions, or settle to the bottom. During the freezing period, a special place is occupied by cryogenic biochemical processes occurring in ice. Microbiological studies of the Amur River near the city of Khabarovsk showed that the water quality diff ered signifi cantly in winter. In the under-ice water and ice sampled off the coast, a diff erent composition of organic matter (OM) has been recorded for many years. After the fl oods (2013, 2019), a high number of sulfate- reducing bacteria was recorded in individual ice layers, which aff ect the dynamics of the transformation of natural and anthropogenic substances. This is due to the fact that in the area of Khabarovsk, during the period of ice cover formation, humifi ed OM spreads along the left bank, coming from the Zeya and Bureya reservoirs during technological discharges of water and from the fl oodplain, and along the right bank – waters contaminated with OM, mainly anthropogenic character. Long-term studies of the potential activity of sulfate- reducing bacteria in the Amur and its channels (Amurskaya, Pemzenskaya) make it possible to predict the formation of hydrogen sulfi de zones and the likelihood of mercury methylation over a wide temperature range. The indicator of resistance of cryomicrobial communities to high concentrations of mercury can be used for a retrospective assessment of the environmental risk of mercury pollution of rivers during the freeze-up period.

Geology, sulphide geochemistry and geochronology of the Romsås Ni-Cu-Co mineralisation, Norway: Implications for ore formation and regional prospectivity

The Romsås intrusion, located in the southern portion of the Idefjorden lithotectonic unit, is part of a cluster of small to medium-sized mafic intrusive bodies which host NiCu sulphide mineralisation, referred to as the Indre Østfold metallogenic area. The Romsås is an almost 1 km-long intrusion with rounded shape, comprising undifferentiated quartz-norite with local orbicular texture. The assemblage, comprising cumulus orthopyroxene and plagioclase, is partly recrystallised and altered, thus orthopyroxene is partly replaced by amphibole, whereas plagioclase is locally replaced by epidote. Locally, garnet, amphibole, plagioclase and magnetite define a granoblastic texture as product of amphibolite-facies metamorphism. Several sulphide-rich lenses, normally up to 5 m wide, occur within the Romsås intrusion and display a sharp contact with the host noritic rocks. The textures vary from disseminated, net-textured and massive sulphides. The sulphide assemblage is homogeneous within the deposit and consists mainly of pyrrhotite, followed by pentlandite, and minor chalcopyrite, with variable alteration of pentlandite.This contribution provides the first systematic characterisation of the Romsås Ni-Cu-Co mineralisation and constraints for its formation and geodynamic setting. We have measured the concentrations of S, PGE, TABS+ (Te, As, Bi, Sb and Se) and other chalcophile elements in both whole rock and sulphide minerals from different ore textures, and UPb and Hf isotope systematics in zircon. The Ni and Cu concentrations in 100% sulphides are around 2% and 1%, respectively. The PGE concentrations in all sulphide-bearing samples are low, generally below 0.3 ppm, with Pt and Pd displaying a broad positive correlation and Pt/Pd ratios varying from 1 to 2. Different ore types are modelled to have formed from a mantle-derived parental magma with higher Cu/Pd ratios and lower Pd contents than mantle values, interpreted as the result of 5% prior crystallisation under sulphide-saturated conditions. Negative mantle-normalised Nb anomalies relative to Th, As and Sb suggest around 10% of assimilation of a component similar to lower crust by the parental magmas. Moreover, S/Se ratios greater than mantle values likely reflect the combined effect of Se depletion during early sulphide removal and external S addition upon crustal assimilation. The Romsås Ni-Cu-Co mineralisation likely formed as a result of sulphide segregation in response to external S addition during several magma pulses. The composition of the sulphide ores can be modelled by an R-factor of around 500. A significant budget of the chalcophile elements is not hosted by sulphide minerals and must be thus accounted for other discrete phases, such as platinum-group minerals. Nevertheless, trace elements distribution in sulphides supports only local remobilisation of chalcophile elements and records compositions comparable to sulphides from pristine NiCu deposits worldwide. Sulphide alteration may have led to exsolution of a parcel of chalcophile elements from sulphide lattice. A UPb zircon crystallisation age of 1551 ± 10 Ma, εHft values between ca. 3.5 and 6, and regional geological considerations suggest that the intrusion formed as part of an arc or back-arc rift setting in the Idefjorden lithotectonic unit. The Romsås sulphide mineralisation represents another example of magmatic sulphide deposit formed at an arc-related geodynamic setting, normally unconventional for the formation of this type of deposit. Therefore, our findings support that arc-related settings in Idefjorden lithotectonic unit, southern Norway, should also be regarded as potential for the formation of Ni-Cu-PGE deposits.

Geological, geochemical and fluid inclusion features of Kömürlükdere and Göçükdibi Cu-Zn ore (Central Pontides, Turkey): Implications for their genesis

The Kömürlükdere and Göçükdibi Cu-Zn ores are located in the Central Pontide orogenic belt, where Besshi-type deposits (such as Hanönü, Zeybek, Sayyayla [Kastamonu]) have been discovered in last two decades. The Göçükdibi and Kömürlükdere ores are hosted in metabasites and quartz schist that belong to the Middle Jurassic Kunduz metamorphic rocks in the accretionary complex in the Central Pontides. The ore bodies show stratiform features, parallel to schistosity, within an alternation of metabasite and quartz schist succession. The average thicknesses of the ore zone and ore levels within the ore zone are 12 m and 3 cm, respectively. The ore bodies contain chalcopyrite, sphalerite, and magnetite, with dominant pyrite formed during the ore formation phase. Meanwhile, hematite, covellite, malachite, and goethite minerals formed during the supergene processes.Microprobe studies showed that the Fe and Cd content of sphalerite varies from 0.08 to 1.12 wt%, indicating Fe-poor sphalerite, and 0.08–0.27 wt%, respectively. The Zn/Cd ratios (average 274.4 for Kömürlükdere, 288.6 for Göçükdibi) of the sphalerite are comparable to those of the worldwide volcanogenic-massive sulfide (VMS) ore system related to andesitic-basaltic source rocks. The Co/Ni ratio (mean 3.2) of pyrite shows volcanogenic pyrite.The average δ34S of the stratiform pyrites is 3.9 ‰ (ranging from 2.06 ‰ to 5.34 ‰), indicating that the sulfur comes from a large homogeneous source, possibly magmatic. The average homogenization temperature (Th) and salinity of fluid inclusions obtained from quartz and sphalerite are 313 °C and 7.7 % equiv. NaCl, respectively, and similar to those of the global VMS deposits.The metabasites contain an average of 164 ppm Cu, 127 ppm Zn, and 2.2 ppm Sb, which shows enrichment several times greater than the background value of the basalts. Meanwhile the ore levels contain an average 0.23 % and 0.83 % Cu and Zn values, respectively. The trace metal enrichment of associated metabasites and the ore zones is evident for elements such as Cu, Zn, Cd, As, and Sb, indicating that they both precipitated in the same basin as syngenetic, and that there was repeated pulses of metal-rich fluids exhaled into the basin.Field observations and analytical data (mineral chemistry, sulfur isotope, fluid inclusion, etc.) show that the Kömürlükdere and Göçükdibi Cu-Zn ore bodies occurred as Besshi-type deposits within the Middle Jurassic Central Pontide Supercontinent, which developed in the marine environment appropriate to the accretionary complex located along the southern margin of Eurasia.

Distribution of Co, Se, Cd, In, Re and other critical metals in sulfide ores from a porphyry-skarn system: A case study of Chengmenshan Cu deposit, Jiangxi, China

Chengmenshan Cu deposit is a large porphyry-skarn copper deposit, located in the Jiutui ore district, Middle–Lower Yangtze River metallogenic belt, Eastern China. The deposit is enriched in tellurium, selenium, rhenium and cadmium; however, the occurrence and distribution of these metals are unclear. In this study, we report cobalt, selenium, cadmium, indium, rhenium and other critical metals in pyrite, chalcopyrite, and sphalerite from sulfide ores of Chengmenshan deposit. In-situ LA-ICP-MS trace element analysis and mapping of minerals were conducted to determine their trace element concentrations and reveal the distribution and occurrence of critical metals in different sulfides. Three ore types have been identified in Chengmenshan deposit, named: porphyry ore, skarn ore and strata-bound ore. Based on mineral assemblages, ore fabrics, and crosscutting relationships between the veins, Chengmenshan deposit is divided into three mineralization stages: pre-ore stage of skarn mineralization, syn-ore stage of sulfide mineralization, and post-ore stage of carbonation. The pyrite and sphalerite can be divided into two generations: Py1, Py2, and Sp1, Sp2, respectively. The critical metals exhibited an uneven distribution and closely related to sulfide minerals. Telluride minerals in the deposit mainly include hessite, tetradymite, joseite. Rhenium is mainly enriched in molybdenite (128 to 496 ppm, average 276 ppm); cobalt is mainly enriched in pyrite, and the value of the three types of ore in the early stage (Py1) higher late stage (Py2); Se in chalcopyrite is slightly higher than pyrite and sphalerite; Cadmium is mainly enriched in sphalerite (up to 3000–6000 ppm), and is relatively low in pyrite and chalcopyrite; Indium is distributed in chalcopyrite and sphalerite, and the values of sphalerite are higher than chalcopyrite; the Ga distribution was sphalerite > chalcopyrite > pyrite. The enrichment and distribution of Co, Cd, In in Chengmenshan porphyry-skarn deposit system were mainly control by the fluid temperature. The Cu-Mo (Re), Cu-Fe (Co, Se) and Cu-Pb-Zn-Ag (Te, Cd, In, Tl) mineralizations constitute Chengmenshan porphyry-skarn mineralization system, and show a Mo-Re to Cu-Co-Se-Te-Ga to Cu-Pb-Zn-Ag-Te-Cd-In pattern from granite to distal stratum in space.

Gold–Sulfide Mineralization in the Manitanyrd Region, Polar Urals, Russia

This article describes the characteristics of gold–sulfide–quartz and gold–sulfide (gold–arsenic) ore occurrences in the Manitanyrd region of the Polar Urals. Ore occurrences are confined to NE-trending shear zones and have the common features of a geological structure. The host rocks are metamorphosed volcanic and volcanic–sedimentary rocks. We analyzed the mineral and chemical composition of the ore mineralization in all studied ore occurrences, showing that they belong to the same mineral type—pyrite–arsenopyrite, with a variable ratio of the main minerals. Arsenic pyrite is present in all ore occurrences. Two stages of ore formation were distinguished: early gold–pyrite–arsenopyrite with finely dispersed gold and late gold–galena–chalcopyrite–sphalerite with coarse gold, fahlore, and sulfosalts Pb, Cu, Bi, Sb. Native gold of the first generation, finely dispersed in arsenopyrite and pyrite, had an average to high fineness (800‰–1000‰) with a relatively low dispersion. Native gold of the second generation was larger, and its fineness in ore occurrences varied; in one of them, it varied from 300‰ to 950‰, while in others, it varied from 800‰ to 950‰. The isotope composition of sulfur in sulfides (δ34S) ranged between −0.2‰ and −8.0‰. δ34S values of sulfides in the range of −0.2‰ to −3.5‰ were similar to meteorite, indicating the participation of a single deep magmatic source of sulfur in the ore formation. According to the study of fluid inclusions, the formation of ore quartz veins occurs in the temperature range of 467–109 °C. The similarity of the geological–structural, mineralogical–geochemical, and isotope–geochemical features of the gold–sulfide–quartz and gold–sulfide occurrences in the area suggest their formation in a single hydrothermal system.

მადნეულის სპილენძის მადნების მამდიდრებელი ფაბრიკების მიმდინარე კუდების კომბინირებული ტექნოლოგიით დამუშავების საკითხები

Madneuli copper enrichment plant works since 1975. This plant works on copper sulphide ores from Madneuli and Sakdrisi deposits. In some ores due to difficulties of blotting secondary copper sulphides, recovery of copper in commercial production is low – 60-65%. At the same time, concentration of copper in tails is 0.17-0.19% and concentration of gold in tails 0.3-0.6 gr/t. In this article we consider combine technology of processing rich flotation tiles: preinrichment by gravity (use centrifugal concentrator and/or short noise hydrocyclone). Gravity concentrate with au and cu 5.47 gr/t, and 0.93%, respectively proceed hydrometallurgicaly (cyanidation) this technology makes possible rise recovery of gold and copper in commercial product by 20-25% and 17-20%.

Limit of recovery: How future evolution of ore grades could influence energy consumption and prices for Nickel, Cobalt, and PGMs

The unique properties of certain metals have made them indispensable in manufacturing advanced technological devices and for use in the green economy. However, these metals are not infinite, and the average ore grades in mines have been decreasing in recent decades. This study examines energy consumption as a function of ore grade decline for Nickel, Cobalt, and platinum group metals (PGMs), using simulations created with HSC Chemistry software. A limit of recovery (LOR) for each commodity was also defined. A comparative analysis of the evolution of ore grades, energy costs, and market prices was additionally carried out. According to the simulations, extracting nickel from sulfide ore tailings would be profitable if the price doubled. As for Cobalt, it would only be feasible if the market price increased considerably. For PGMs, even if the ore grade reached the LOR, it would still be profitable to recover them under certain circumstances explored in the paper.

Enhanced Recovery of Zn from Carbonate-Type Mixed Oxidized Ore (CMO) by Combining Organic Acid Leaching with Mechanical Activation

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.

Nickel isotope ratios trace the process of sulfide-silicate liquid immiscibility during magmatic differentiation

Sulfide-silicate liquid immiscibility (i.e., the coexistence of two liquid phases in equilibrium) plays a significant role in the processes of planetary-scale differentiation, the formation of Earth’s crust, and the genesis of magmatic sulfide ore deposits. The stable isotope geochemistry of nickel can potentially take advantage of fractionation signals produced in magmatic systems where immiscible sulfide and silicate liquid have equilibrated. Variations in Ni isotope ratio beyond those found in sulfide-undersaturated basaltic rocks can provide a hallmark of fractionation processes that control chalcophile and siderophile element abundances. We report high-precision Ni isotope ratio data for a stratigraphically-controlled sequence of Siberian Trap basalts in a volcanic edifice centered over the world’s largest concentration of magmatic sulfide ore deposits at Noril’sk-Talnakh, Russia. Nickel isotope ratios (δ60Ni (‰) = [(60Ni/58Ni)sample/(60Ni/58Ni)SRM986-1] × 1000) in the basaltic rocks range from +0.07 ± 0.02‰ to +1.00 ± 0.04‰ and correlate negatively with Ni and precious metal abundance levels, indicating extensive Ni isotope fractionation due to sulfide saturation of the silicate magma. A Rayleigh fractionation model fits the observed results and enables a precise estimate of the fractionation factor (α) between sulfide liquid and silicate melt to be 0.99965 (i.e., 103*lnα = −0.35). Our study illustrates the application of Ni isotope ratio data in understanding sulfide-silicate liquid immiscibility and the broader implications with respect to the formation of the largest known magmatic sulfide ore deposits in association with the Siberian Trap.