Case-based analysis of mechanically-assisted leaching for hydrometallurgical extraction of critical metals from ores and wastes: application in chalcopyrite, ferronickel slag, and Ni-MH black mass

Study on the synergistic mechanism of sulfuric acid and ammonium sulfate on the extraction of metals from ferronickel slag by roasting

Recovery of magnesium from ferronickel slag to prepare hydrated magnesium sulfate by hydrometallurgy method

It is unknown whether Ferronickel slag (FNS)-ordinary Portland cement (OPC)-based pervious concrete (FOPC) is feasible. To this end, a feasibility study was conducted on FOPC. Firstly, a detailed microscopic examination of the FNS powder was conducted, encompassing analyses of its particle size distribution, SEM, EDS, and chemical composition. These analyses aimed to establish the suitability of a composite of FNS and OPC as a composite cementitious material. Subsequent experimentation focused on evaluating the compressive strength of the composite paste material with varying mixed proportions, revealing a slight reduction in strength as the FNS substitution rate increased. Furthermore, the study designed eighteen different mix proportions of FOPC to investigate the key physical properties, including porosity, density, compressive strength, and the coefficient of permeability. Findings indicated that increases in the cementitious material proportion correlate with enhanced concrete strength, where the ratio of cementitious to aggregate increased by 6.7% and 16.5%, and the strength of FOPC increased by 10-13% and 30-50%, respectively. Conversely, a rise in the FNS substitution rate led to a reduction in compressive strength across different mix ratios. Additionally, the ratio of paste material to aggregate was found to significantly influence the permeability coefficient. These comprehensive performance evaluations suggest that incorporating FNS into OPC for pervious concrete applications is a feasible approach, offering valuable insights for the promotion of waste reuse and the advancement of energy conservation and emissions reduction efforts.

A research using ferronickel slag, the by-product of ferronickel production, as raw material for magnesium extraction was carried out. It is essential to upgrade the value of ferronickel slag instead of used directly for reclamation materials. Moreover, the accumulation due to increasing ferronickel demand as well as the environmental contamination due to various potentially toxic elements contained in the ferronickel slag could be prevented. The general objective of this study is to utilize the ferronickel slag for magnesium materials. The specific objective is to determine the optimum conditions of magnesium extraction in the process of alkali fusion followed by hydrochloric acid leaching. A novel method for magnesium extraction from ferronickel slag was carried out through reducing silica content followed by acid leaching method. Alkali fusion of the mixture of ferronickel slag and Na2CO3 at 1000?C for 60 minutes, followed by water leaching at 100?C for 60 minutes with solid to liquid percentage of 20 % was carried out to separate the silica. The leaching residue resulted from water leaching was then leached using hydrochloric acid solution to extract magnesium. The leaching temperature and time as well as the hycrochloric acid concentration were varied in the acid leaching process. Alkali fusion process proved the sodium silicate can be generated and that it can be separated in the water leaching to the leached solution. Meanwhile, the leaching residue was leached using hydrochloric acid to extract the magnesium. The highest magnesium extraction percentage is 82.67% that resulted from an optimum acid leaching condition with temperature of 80?C for 30 minutes using 2M HCl solution. Based on the kinetics study, the activation energy (Ea) for the leaching reaction of magnesium at atmospheric pressure between 32?C to 80?C is 9.44 kJ/mol and affected by diffusion and chemical reactions.

The compactness of aggregates has a significant impact on the workability of self-compacting concrete. The bulk density of aggregates is an effective parameter for evaluating the compactness of aggregates, reflecting the degree of compactness of the aggregate system. This study aims to explore the theoretical calculation model and application of the bulk density of green ferronickel slag as aggregates in self-compacting concrete. The influence of different particle size distributions and ferronickel slag content on the bulk density of the aggregate system was analyzed. Based on the calculation method of the maximum bulk density of aggregates, the bulk density of the aggregate system was calculated for different particle size distributions and nickel-iron slag content, and the effect of nickel-iron slag content on the compactness of the aggregate system was analyzed.

This paper aims to evaluate mechanical behavior (compressive and flexural strength) of reactive powder concrete (RPC) with ferronickel slag (FNS) as quartz sand replacement. Standard laboratory tests were performed i.e. sieve analysis to determine the particle size distribution of the FNS, slump and density tests as well as compressive and flexural tests on the RPC. Promising results were obtained in this study. An increased consistency and density were observed upon increasing the FNS content. The utilization of FNS could lead to a compressive strength value of 86 MPa at 28 days. A higher strength enhancement in the early curing days (7 days) was observed than in the longer curing days (28 days), when FNS mixes were compared to reference mixes. The flexural strength result demonstrated two different phenomena at two different ages, where there was a slight rise at 7 days and relatively no increment at 28 days when FNS mixes were compared to the reference mixture.

Lithium-ion portable batteries (LiPBs) contain valuable elements such as cobalt (Co), nickel (Ni), copper (Cu), lithium (Li) and manganese (Mn), which can be recovered through solid-liquid extraction using choline chloride-based Deep Eutectic Solvents (DESs) and bi-functional ionic liquids (ILs). This study was carried out to investigate the extraction of metals from solid powder, black mass (BM), obtained from LiPBs, with various solvents used: six choline chloride-based DESs in combination with organic acids: lactic acid (1:2, DES 1), malonic acid (1:1, DES 2), succinic acid (1:1, DES 3), glutaric acid (1:1, DES 4) and citric acid (1:1, DES 5 and 2:1, DES 6). Various additives, such as didecyldimethylammonium chloride (DDACl) surfactant, hydrogen peroxide (H2O2), trichloroisocyanuric acid (TCCA), sodium dichloroisocyanurate (NaDCC), pentapotassium bis(peroxymonosulphate) bis(sulphate) (PHM), (glycine + H2O2) or (glutaric acid + H2O2) were used. The best efficiency of metal extraction was obtained with the mixture of {DES 2 + 15 g of glycine + H2O2} in two-stage extraction at pH = 3, T = 333 K, 2 h. In order to obtain better extraction efficiency towards Co, Ni, Li and Mn (100%) and for Cu (75%), the addition of glycine was used. The obtained extraction results using choline chloride-based DESs were compared with those obtained with three bi-functional ILs: didecyldimethylammonium bis(2,4,4-trimethylpentyl) phosphinate, [N10,10,1,1][Cyanex272], didecyldimethylammonium bis(2-ethylhexyl) phosphate, [N10,10,1,1][D2EHPA], and trihexyltetradecylphosphonium bis(2,4,4-trimethylpentyl) phosphinate, [P6,6,6,14][Cyanex272]/toluene. The results of the extraction of all metal ions with these bi-functional ILs were only at the level of 35-50 wt%. The content of metal ions in aqueous and stripped organic solutions was determined by ICP-OES. In this work, we propose an alternative and highly efficient concept for the extraction of valuable metals from BM of LiPBs using DESs and ILs at low temperatures instead of acid leaching at high temperatures.

The effects of hydride chemistry, particle size, and void fraction on micro fuel cell performance

A fundamental study of the reductive leaching (decomposition) of chalcopyrite was performed in both sulfate and chloride media. This was done to understand the physical chemistry of the leaching reactions and the possibility of developing a process flowsheet. The main objective of reductive leaching is to achieve the enrichment of chalcopyrite by rejection of iron and sulfur. A chalcopyrite concentrate containing around 60% chalcopyrite and analyzing around 28% copper was leached under reducing conditions using metallic iron. Various parameters were studied to understand their effect on leaching kinetics, including : temperature, particle size, agitation, acid concentration, molar ratios, and others. The leaching data were analyzed to determine the leaching mechanism and develop a kinetic model. The leaching reaction was found to be rapid on fresh surfaces of the concentrate, but slows markedly in one hour, as a film of products, mainly chalcocite, forms on particle surfaces. Iron was also found to enter the leach solution as soluble ferrous ions and sulfur is released as hydrogen sulfide. The general leaching reaction may be written as : 2CuFeS₂ (s) + Fe(s) + 6H⁺ (aq) -> Cu2S(s) + 3Fe²⁺ (aq) + 3H2S(g) The proposed mechanism is a series of reactions. It is envisaged to be composed of two parts : a corrosion mechanism, which is iron dissolution, and galvanic mechanism, which is chalcopyrite reduction. The kinetic analysis indicated that the leaching reaction, which is electrochemical in nature, follows the shrinking core model under product layer diffusion control, and the rate determining step is the transport of one or more of reaction species, through the product layer. The reaction was dependent on the initial acid concentration, chalcopyrite particle size and molar ratio of iron to chalcopyrite. Moreover, the reaction was independent of the rate of agitation beyond that required to provide a well-mixed reaction mixture. Under stoichiometric conditions, room temperature and atmospheric pressure, the conversion (decomposition of chalcopyrite to simpler copper sulfides) was always below 60%, unless the initial amount of the reductant was increased or very fine chalcopyrite particles were used. For the studied experimental conditions, the developed parabolic leaching model for sulfate media takes the form : [chemical formula1] and for chloride media, [chemical formula2] The parabolic leaching behavior was confirmed from the successful estimation of the related thermodynamic and kinetic properties of the leaching systems. The analysis of temperature dependence indicated that leaching increases with increasing temperature up to 65 °C. The apparent activation energy for leaching in sulfate media was estimated to be ~33 kJ/mol, and for chloride media, ~26 kJ/mol under stoichiometric conditions, in the temperature range 25-65 °C. Chemical analysis was extensively used based on wet chemistry methods, which were capable of demonstrating the general reaction stoichiometry including the…

Lithium-ion batteries are pivotal to modern technological devices, powering everything from smartphones and laptops to electric vehicles (EVs) and renewable energy storage systems. As the global adoption of these technologies accelerates, the demand for critical raw materials (CRMs)—such as Li, Ni, Co, Mn, and graphite—continues to rise, as they are essential for battery production. To reduce resource consumption and promote a circular economy in Li-ion battery production, effective recycling of these batteries is essential [1]. Currently, two main recycling processes are employed for Li-ion batteries: pyrometallurgical and hydrometallurgical methods. Pyrometallurgical processes involve high-temperature treatments to extract metals but are inefficient in recovering materials like graphite and lithium. In contrast, hydrometallurgical processes have the potential to recover all battery materials. However, the use of non-selective acid leaching as a primary step produces a solution containing both the target metals and various impurities. To recover metals as battery-grade salts, several purification and separation stages are required mining the environmental and economic feasibility of this kind of processes [2].Furthermore, lithium recovery is particularly challenging due to its high solubility and the presence of Na, introduced during the recycling process through the use of NaOH. These challenges necessitate additional purification and concentration steps, which increase reagent consumption and energy demand [3].From this perspective, the selective extraction of lithium from end-of-life Li-ion battery black mass, avoiding complex separation procedures and implementing concentration methods that exclude energy-intensive evaporation, could significantly enhance Li recovery efficiency.The aim of this study is to develop a selective lithium extraction process from the electrode powder (black mass) of end-of-life Li-ion batteries. The proposed method mimics the charging process in standard Li-ion batteries, utilizing the black mass as the anode in an electrochemical cell but in aqueous electrolyte. During this process, metals in the black mass undergo oxidation in the solid phase, forming insoluble oxides, while lithium is selectively extracted (delithiated) by transferring Li⁺ ions into the electrolyte solution. Simultaneously, water reduction reactions occur at the cathode, generating hydroxyl ions (OH⁻) and hydrogen gas (H₂). By separating the cathode and anode compartments with an anion exchange membrane, the process enables the concentration of a LiOH solution on the cathode side. Commercial Li-ion battery cathode materials (LiCoO2, LiMn2O4, and LiNi1/3Mn1/3Co1/3O2) and black mass were used to compare lithium recovery performance. Linear sweep voltammetry was conducted to identify the oxidation potentials of both active metals and impurities present in the black mass. Potentiostatic delithiation was then carried out at different fixed charges (duration) and applied potentials. The extent of delithiation (i.e., lithium extraction) was quantified by digesting and analyzing the anode electrodes at the end of each experiment.The lithium extraction yield was up to 99% for LiCoO2, LiMn2O4, and LiNi1/3Mn1/3Co1/3O2, while for the black mass powder, the maximum yield was 82%. To investigate the lower lithium extraction efficiency from black mass compared to commercial cathode materials, the role of impurities in the black mass was thoroughly evaluated. In the potential range applied during delithiation, copper, originating from the metallic current collector as an impurity, is oxidized alongside the cathode material metals, thereby consuming charge that would otherwise be used for the desired oxidation reaction. However, the small amount of Cu in the black mass cannot alone explain the reduced lithium delithiation efficiency compared to commercial cathode materials. XPS measurements revealed the oxidation of the carbon fraction present in the black mass, which consists of graphite and conductive carbon, indicating that, likely, amorphous conductive carbon undergoes partial surface oxidation. The selectivity of the process was confirmed by analyzing both the electrolyte solution and digesting the cathode counter electrode, as dissolved transition metals could undergo electrodeposition at the cathode, leading to an underestimation of metals if only the electrolyte solution is analyzed. The proposed recycling concept, based on the charge mechanism of LIB cathode materials in water, could be considered a promising strategy for green hydrogen production in an integrated water electrolyzer, with lithium as a high-value product derived from the anode side, where oxygen is typically producedAcknowledgmentsThis work was carried out within the Horizon Europe Project RHINOCEROS project, grant no. 101069685.[1] S. Bhattacharyya, S. Roy, R. Vajtai, Small (2024) 2400557. https://doi.org/10.1002/SMLL.202400557.[2] P. Gao, P. Yuan, T. Yue, X. Zhao, B. Shen, J Energy Storage 68 (2023) 107652. https://doi.org/10.1016/J.EST.2023.107652.[3] T. Kanagasundaram, O. Murphy, M.N. Haji, J.J. Wilson, Coord Chem Rev 509 (2024) 215727. https://doi.org/10.1016/J.CCR.2024.215727.

The modelling of particulate leaching reactors— the population balance approach

Separation of nickel and calcium by solvent extraction using mixtures of carboxylic acids and alkylpyridines

Review: 159 refs.

A review of the beneficiation of calcareous phosphate ores using organic acid leaching

Effects of mechanical activation on the digestion of ilmenite in dilute H2SO4