Search Results (19)

Given the importance of nickel in lithium-ion batteries and the expectation of the growth in electric vehicles and electrical devices, the demand for nickel in battery production is expected to increase dramatically. Nickel is primarily sourced from laterite saprolite ore, and there is now substantial interest in moving from ferronickel smelting technology to nickel matte technology in its processing to produce high-grade nickel. This research involved a thermodynamic modelling and lab–scale experiment on the smelting of nickel matte. Nickel concentrate from laterite saprolite was used, and CaS, produced from commercially available gypsum, was employed as a sulfurizing agent. The matte smelting experiment was conducted at 1500 °C to optimize CaS and C consumption. During smelting with CaS, matte particles form, although sufficient reduction of nickel and iron from the concentrate is not achieved. By consuming carbon, the reduction potential of iron is increased, and this process, along with enriching the matte with iron, aids in the transportation of nickel. At a nickel grade in the matte with a Ni/Fe ratio of approximately 1, the nickel recovery only reached 63%. Upon achieving a nickel recovery exceeding 93%, the Ni/Fe ratio reached 0.44, corresponding to a nickel grade reduction to 22.78%. By employing analytical techniques and thermodynamic modelling, we have successfully determined the sulfidizing of nickel, identified the ideal CaS and C additions, and characterized the structure and quality of the slag produced during nickel matte smelting, supplying vital technological data necessary for practical application. Full article

Black nickel coatings are pursued for both decorative purposes and advanced applications, including solar collectors, space technologies, and optical devices. The term “black nickel” typically refers not only to nickel but also to nickel alloys that can exhibit the characteristic black coloration, either bright or matte. This review provides an in-depth look at various techniques for producing black nickel coatings, focusing on both electrodeposition and electroless deposition methods. The discussion covers the different bath compositions and deposition conditions used to achieve the distinctive black color. The origins of black coloration in electrodeposited nickel and its alloys are shown in detail, emphasizing the crucial role of bath components and the formation of black compounds such as oxides, sulfides, and/or the nickel–zinc intermetallic compound. This review also highlights the necessity of oxidizing acid etching to blacken Ni–P electroless deposits, leading to the formation of a thin layer of black nickel oxides on a porous surface. The key properties of black nickel coatings are discussed, along with their relevance for various practical applications. Full article

The relevance of this research is due to the need to stabilize the composition of the melting products of copper–nickel sulfide raw materials. Statistical methods of analyzing the historical data of the real technological object and the correlation analysis of process parameters are described. Factors that exert the greatest influence on the main output parameter (the fraction of copper in a matte) and ensure the physical–chemical transformations are revealed: total charge rate, overall blast volume, oxygen content in the blast (degree of oxygen enrichment in the blowing), temperature of exhaust gases in the off-gas duct, temperature of feed in the smelting zone, copper content in the matte. An approach to the processing of real-time data for the development of a mathematical model for control of the melting process is proposed. The stages of processing of the real-time information are considered. The adequacy of the models was assessed by the value of the mean absolute error (MAE) between the calculated and experimental values. Full article

The results of studies on the distribution of rare elements among the products of distillation processing of polymetallic mattes are present in this article. Schemes of the developed technological equipment for the implementation of the extraction processes of rare elements via the vacuum distillation of mattes are presented. Technological tests were performed with a matte of lead, copper, and antimony plants at 1100–1250 °C and a pressure of up to 700 Pa. It was established that As, Cd, Bi, In, and Ge, by more than 90% in total, are extracted into condensate and dust in the distillation process of volatile components from mattes of lead production. At the same time, antimony is distributed between the distillate residue and condensate. Antimony by 90.47%, arsenic by 78.83% and cadmium by 98.72% are distributed into sulfide condensate and dust in the distillation of copper production matte. From the matte of the antimony plant, Sb and Bi (90.76% and 89.78%, respectively) are transferred into the condensate and cyclone dust. Arsenic is distributed between the liquid and vapor phases. Based on calculations, Se and Te will be mainly concentrated in the distillation residue. High-grade copper mattes obtained in processing mattes from lead and copper plants can be further used to obtain metallic copper by converting. The condensate and dust can be processed separately or with the dust of the mainline production for rare metal extraction. Antimony matte processing condensate containing more than 70% Sb can be directed to the process of crude antimony refining. Full article

The resource utilization of cyanide tailings has significant environmental and economic benefits. The efficient recovery of gold from low-grade cyanide tailings containing 1.71 g/t Au was performed by a chlorination roasting–flotation process. The effects of roasting temperature, calcium chloride, internal coke, external coke, copper sulfide concentrate, and kaolin on the recovery rate of concentrate, gold grade, and sorting efficiency were investigated. The optimized process parameters were as follows: 16 wt% calcium chloride dihydrate, 6 wt% internal carbon, 1 wt% external carbon, 9 wt% copper sulfide concentrate, 2 wt% kaolin, and roasting temperature of 730 °C. The sorting rate, gold grade, and recovery rate of gold concentrate can reach 88.48%, 33.46 g/t, and 76.7%, respectively, and the gold grade of tailings was as low as 0.17 g/t. In the matte phase, gold can be enriched in the form of gold grains. Therefore, through chlorination roasting, the trapped gold can be released and deposited on the surface of the matte phase due to the transformation from hematite to magnetite. The gold-deposited metal sulfide can be effectively recycled through flotation. These results have potential guiding significance for the efficient recovery of gold from cyanide tailings. Full article

The practicability of a pyrometallurgical scheme for raw material processing is established as a result of the analysis of methods intended to dearsenate and process gold-arsenic concentrates as well as equipment for the process execution. The conceptual design of vacuum equipment without forced movement of the dispersed material in the sublimator and of the reaction zone materials is proposed. In-process tests for the sublimation of arsenic sulfides from gravity and flotation concentrates received from the Bakyrchik deposit were executed at the pilot facility. As a result, it was found that more than 97–99% of arsenic passes into the gas phase and condenses in a sulfide form suitable for compaction by smelting. More than 99.5% of precious metals are concentrated in the sublimation residue. As a result of smelting residue from the sublimation of arsenic sulfides in a cyclone furnace, together with copper concentrates to copper matte, the gold recovery was 93.7–93.9% of the total amount loaded. Silver was 65.7–68% concentrated in copper matte, with a considerable amount in the dust. If the cyclone smelting dust is involved, the recovery rate of gold and silver can be increased to 97–99% and 94–95%, respectively. As a result of crucible smelting, the degree of recovery of gold in matte was 95.4%, with its content in slag being 3.6 g/t. The received matte according to the proposed scheme can be directed to the conversion process by obtaining blister copper, which is subjected to electrolytic refining with the recovery of gold from slimes. Full article

Annually, hundreds of thousands of tons of slags are involved in the reverberator and flash smelting as well as converting operations of Cu-Fe sulfide concentrates to produce matte in the Sar Cheshmeh copper smelter plant, Iran, disposed in the landfill and cooled in air. Due to their relatively high average copper content (about 1.5 wt%), a mineral processing plant based on the flotation process has recently been established to produce thousands of tons of Cu-sulfide concentrate after slag crushing and fine grinding operation. In order to make the flotation process more efficient, more knowledge is required on the form and origin of the copper losses in the slag. To achieve this, mineralogical studies of the slags using optical microscopy, X-ray diffraction (XRD), and scanning electron microscopy (SEM) methods have been carried out. Mineralogical analyses showed the main part of copper losses into the semi- to fully-crystallized magnetite-rich reverberator and flash slags characterized by crystal–glass matrix ratio ≤ 1 is moderate to coarse particles of Cu-Fe sulfides, i.e., chalcopyrite (CuFeS₂) and bornite (Cu₅FeS₄), that are mainly chemically entrapped. In contrast, the mechanically entrapped fine- to coarse-grain (from 20 up to 200 µm) spherical-shaped of high-grade matte particles with chalcocite (Cu₂S) composition containing droplets or veinlets of metallic copper (Cu⁰) are the dominant forms of copper losses into the converter slags characterized by crystal–glass matrix ratio > 1. From the value recovery point of view, our result show that the fully crystallized slags containing moderate- to coarse-grain copper-bearing particles will result in efficient recovery of a significant amount of entrained copper due to better milling response compared to semi-crystallized ones due to locking the fine- to moderate-grain copper particles in the silicate glassy matrix. Laboratory-scale grinding experiments showed that normal (≤74 μm) to fine (≤44 μm) grinding of high- Cu grade slags lead to a significant increase in the liberation degree of copper particles. in contrast, the increase in fine particle fractions (<37 μm) due to re-grinding or ultra-fine grinding of the originally low-Cu grade slags does not lead to the liberation of copper particles, but it will reduce the efficiency of the flotation process. This study suggests that the highest rate of copper recovery of the slag by the flotation process will be obtained at particle size 80% passing 44 µm which has also reached the optimal liberation degree of copper-bearing particles. Full article

In order to realize the high-value utilization of copper slag, a process for preparing Cu–Fe alloy through the reduction of copper slag is proposed. The sulfur in the alloy exists in the form of matte inclusions, which is different from sulfur in molten iron. The reaction of CaO with Cu₂S is difficult. It is necessary to add a reducing agent to promote desulfurization. To avoid the introduction of other elements, Fe–Mn and CaC₂ additions were used as desulfurizers for the desulfurization of Cu–Fe alloy. The thermodynamics of the desulfurization reaction were calculated and the experimental process was studied. It was found that the Gibbs free energy of desulfurization reactions was negative for Fe–Mn and that CaC₂ can reduce the sulfur in the alloy to 0.0013% and 0.0079%, respectively. The desulfurization process affected the shape of copper in the alloy. Part of copper in this alloy exists in the form of nano-copper spheres, and the size of the spheres is found to increase after desulfurization. Reducing agents can facilitate the desulfurization process of stable sulfides. Full article

The conversion of copper sulfide mattes lacks fundamental kinetic information for understanding the process. This work presents the results of the experimental measurement of the rate of oxidation of molten white metal by supplying individual air bubbles. The bubbles were characterized from information collected during the experiments and through theoretical and empirical correlations. Conversion tests were carried out at different temperature conditions and injection dynamics of the oxidizing gas. The results indicate that the conversion is controlled by the transport of oxygen into the bubble. A dependency between the characteristics of the injector and the shape, size and surface of the bubbles was identified. The oxidation rate of the white metal depended on the characteristics of the bubbles and the oxygen available for conversion. The results of this research provide relevant information to improve the operation of industrial conversion furnaces by controlling gas injection through the tuyeres. The criterion for improving conversion systems is the balance between the retention of the bubbles in the molten white metal and their size, such that the availability of oxygen for the conversion is guaranteed. Full article

Nickel laterite ore is used to produce nickel metal, predominantly to manufacture stainless steel as well as nickel sulfate, a key ingredient in the batteries that drive electric vehicles. Nickel laterite production is on the rise and surpassing conventional sulfide deposits. The efficiency of mining and processing nickel laterites is defined by their mineralogical composition. Typical profiles of nickel laterites are divided into a saprolite and a laterite horizon. Nickel is mainly concentrated and hosted in a variety of secondary oxides, hydrous Mg silicates and clay minerals like smectite or lizardite in the saprolite horizon, whereas the laterite horizon can host cobalt that could be extracted as a side product. For this case study, 40 samples from both saprolite and laterite horizons were investigated using X-ray diffraction (XRD) in combination with statistical methods such as cluster analysis. Besides the identification of the different mineral phases, the quantitative composition of the samples was also determined with the Rietveld method. Data clustering of the samples was tested and allows a fast and easy separation of the different lithologies and ore grades. Mineralogy also plays a key role during further processing of nickel laterites to nickel metal. XRD was used to monitor the mineralogy of calcine, matte and slag. The value of mineralogical monitoring for grade definition, ore sorting, and processing is explained in the paper. Full article

One of the stages of extracting gold and platinum from sulfide materials and circulating slags is the melting stage in ore-thermal and electric furnaces, where the melt is separated into matte and slag. Gold, platinum, and non-ferrous metals are concentrated in the matte. However, a significant portion of them ends up in the slag, which reduces recovery and increases environmental pollution. The main reason for their transition to slag is the flotation of sulfide droplets by gas bubbles, a significant proportion of which occurs during the decomposition of sulfides. Gold and platinum are associated with matte droplets during flotation. Evaluation of adhesion showed that it is large and comparable to the cohesion of these metals. One of the options to reduce the loss of valuable components is to add fluxes to the slag. The influence of calcite and fluorite on the distribution of gold and platinum over the melting products of copper–nickel sulfide materials (matte and slag) has been experimentally studied based on the above theoretical concepts of droplet flotation. When calcite was added to sulfide ore, there was a significant decrease in the sulfur content in the slag (more than 3 times). This, in turn, led to a decrease in non-ferrous metals in the slag by 2–3 times, with gold from 0.45 to 0.29 g/t and platinum from 2.15 to 2.06 g/t. The addition of fluorite to the mixture of copper–nickel matte and model slag (CaO/SiO₂/Al₂O₃ = 40/40/20) significantly reduced the sulfur content and non-ferrous metals by 1.5 times, whereas gold was not found in the slag. The decrease in the number of sulfides in the slag is mainly because the listed additives reduce its viscosity. This leads to acceleration of the coagulation of sulfide drops, which are inevitably carried into the slag during flotation, and increases the rate of their settling to the slag–matte boundary, where they merge with the matte mass. Full article

One possible way of recovering metals from spent lithium-ion batteries is to integrate the recycling with already existing metallurgical processes. This study continues our effort on integrating froth flotation and nickel-slag cleaning process for metal recovery from spent batteries (SBs), using anodic graphite as the main reductant. The SBs used in this study was a froth fraction from flotation of industrially prepared black mass. The effect of different ratios of Ni-slag to SBs on the time-dependent phase formation and metal behavior was investigated. The possible influence of graphite and sulfur contents in the system on the metal alloy/matte formation was described. The trace element (Co, Cu, Ni, and Mn) concentrations in the slag were analyzed using the laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) technique. The distribution coefficients of cobalt and nickel between the metallic or sulfidic phase (metal alloy/matte) and the coexisting slag increased with the increasing amount of SBs in the starting mixture. However, with the increasing concentrations of graphite in the starting mixture (from 0.99 wt.% to 3.97 wt.%), the Fe concentration in both metal alloy and matte also increased (from 29 wt.% to 68 wt.% and from 7 wt.% to 49 wt.%, respectively), which may be challenging if further hydrometallurgical treatment is expected. Therefore, the composition of metal alloy/matte must be adjusted depending on the further steps for metal recovery. Full article

Bronze mirrors, considered important grave goods, were widely used before glass mirrors in ancient times. Most excavated bronze artifacts are covered with corrosive materials and lose their original colors. More importantly, identifying corrosion characteristics and the manufacturing techniques used for these artifacts are essential for proper artifact preservation. In this study, Early Iron Age bronze mirrors excavated from the Korean Peninsula were examined to determine their microstructures, corrosion characteristics, and production techniques using various analytical methods, such as Micro-Raman spectroscopy and field emission electron probe microanalysis. As a result, sulfides containing iron suggested chalcopyrite use during production or that the sulfides originated from copper, iron, and sulfur residual matte. The analysis also detected corrosion layers with high tin oxide (SnO₂) levels and selective corrosion in the α + δ eutectoid phase on the artifact’s surface. In the corrosive layer, cuprite, malachite, and cassiterite corrosion products were detected, and nanocrystalline SnO₂ was identified as a characteristic of long-term soil erosion. Identifying these artifacts’ corrosion characteristics and manufacturing techniques is essential and can greatly contribute to proper artifact preservation. Full article

By-products from zinc hydrometallurgy are classified as hazardous waste with strong leaching toxicities. Even though numerous research papers are dedicated to valorizing valuable metals in it, the primary management route is still disposal or partial reuse, such as the Waelz process. Presented experimental research investigates possibilities of sulfidization and further processing as a technologically sustainable route for valuable metals valorization from non-standard jarosite-PbAg sludge. The comprehensive thermodynamic analysis was done by HSC Chemistry^®, through optimizing process parameters, i.e., temperature, sulfur addition, and selection of possible additives. Technological possibility of magnetic separation, flotation, and smelting of sulfidized material was also investigated; the results were below the values that allow practical application, due to the obtained texture of sulfidized jarosite, which does not allow the liberation of minerals. Smelting tests were performed on sulfidized jarosite with sulfur and without and with carbon as additive. By smelting sulfidized jarosite-PbAg sludge with added carbon in sulfidization stage at 1375 °C, obtained products were matte, slag, raw lead, and dust in which base, critical, and slag forming components were valorized. Valuable metals were concentrated in smelting products so as to enable further processing, which also could be interesting in the case of treatment of complex, polymetallic, and refractory primary materials, which represent a significant contribution to the circular economy. Full article

At present, copper smelting slag is not effectively recycled and is wasted. Copper smelting slag contains Fe_xO at more than 40 mass%. For the utilization of copper slag as a Fe resource, it is necessary to separate the Cu in the slag. For copper recycling from slag, FeS-based matte can be introduced to use sulfurization to concentrate Cu from the slag into the sulfide and finally recover the copper. In a previous paper, a kinetic model was developed to simulate the coupled reactions between the multicomponent slag and FeS-based matte by using previously reported thermodynamic data. Building on this work, we carried out equilibrium experiments to supplement the thermodynamic data used in the previously developed model. An empirical formula for the Cu₂O activity coefficient of Cu₂O-FeO_X-CaO-MgO-SiO₂-Al₂O₃ system slag was obtained. In addition, the effect of alumina content in the slag on the Cu₂O activity coefficient in the slag was investigated. The model was also supplemented to account for MgO solubility. By the developed model and the industrial conditions, we investigated the effect of slag composition on the behavior of Cu between matte and Cu₂O-FeO_X-CaO-MgO-SiO₂-Al₂O₃ system slag for the copper loss. Full article