Hydrometallurgical Technologies Research Articles

Comparative environmental and economic assessment of emerging hydrometallurgical recycling technologies for Li-ion battery cathodes

The growing demand for electric vehicles has led to a growing concern for battery recycling, particularly for critical raw materials. However, there is insufficient investigation into the environmental and economic impacts of hydrometallurgical recycling methods. In this study we explored emerging hydrometallurgical technologies in economic and environmental perspective to establish conceptual routes to recover Co, Ni and Mn oxides from waste LiNi0.33Mn0.33Co0.33O2 cathode materials from spent Li-ion batteries. After, life cycle assessment and costing techniques were utilized to compare the environmental and economical performances of each conceptual route. Recovery efficiency of metal oxides through each route was also considered as a key factor. Results suggested that deep eutectic solvent-based leaching produces the highest impact under many impact categories while electrolysis-based leaching showed the least. Under purification technologies assessed, ion-exchange based purification showed significantly lower impact under many categories except stratospheric ozone depletion. Solvent based purification has been identified as the worst technology for purification. Hydroxide based calcination has been identified as the most environmentally sustainable calcination method compared to oxalate calcination. The route consists with inorganic leaching, ion-exchange based purification and hydroxide calcination showed the lowest environmental impact (emission effect at 33.8 kg CO2 eq), with lower economic impact ($ 119) and the highest recovery efficiency (78 %) per 1 kg of cathode active materials. However, using electrolysis-based leaching can slightly increase the impacts with lower recovery efficiency (75 %) and better economic performance ($104/kg of cathode active materials). Terrestrial ecotoxicity was identified to be the most affected impact category for the recovery processes. It is recommended that technologies like deep eutectic solvent-based leaching, solvent extraction and environmentally sustainable technologies like supercritical fluid extraction need further studies prior to industrial applications.

Hydrometallurgical Technology for Producing Rhenium(VII) and Cobalt(II) from Waste

This paper presents a method for obtaining cobalt(II) perrhenate from waste derived from two types of materials, i.e., Li-ion battery scrap, or more precisely, battery mass, and superalloy scrap. Both of the above-mentioned materials are a source of Co. However, a source of rhenium is perrhenic acid produced from ammonium perrhenate (recycled) by the ion exchange method using resins. Co(OH)2 can be precipitated from solutions resulting from the leaching of Li-ion battery mass, sludge from the Zn-Pb industry and superalloy scrap. The compound, after proper purification, can be used in a reaction with perrhenic acid to form Co(ReO4)2. The reaction should be conducted under the following conditions: time 1 h, room temperature, 30% excess of cobalt(II) hydroxide, and rhenium concentration in HReO4 from about 20 g/dm3 to 300 g/dm3. This work shows that with the use of Co(OH)2, obtained from waste, an anhydrous form of cobalt(II) perrhenate can be obtained, containing < 1000 ppm of the cumulative metal impurities.

Lithium recycling from artificial leachate of spent lithium-ion batteries using track-etched membranes for hybrid electrobaromembrane method

Lithium recycling is still poorly developed, but an important source of raw materials for the production of lithium salts. The hydrometallurgical technologies are usually employed to extract lithium from spent lithium-ion batteries. Reagent free membrane technologies such as electrobaromembrane method (EBM) can be used at this stage for the separation of Li+ ions and Co2+, Ni2+, Mn2+. The essence of the method is the simultaneous use of an opposing electric field and a pressure gradient in the device. Non-selective track-etched membrane with wide pores is used for ions separation. The selectivity of EBM separation is achieved due to the different mobility of the separated ions in the electric field. Under optimal conditions, this allows some of the more mobile ions to overcome the barrier of the oncoming convective flow, while others follow it. For the first time, the EBM method was used for long-term extraction of Li+ ions from an artificial leachate solution of spent LIBs. A solution containing the main macro components of typical leachate was processed at 0.3 bar and 125 A/m2 for 50 h. The fluxes of separated Li+, Co2+, Ni2+ and Mn2+ ions through the track-etched membrane were as follows 0.2, −0.02, −0.03 and − 0.08 mol/(m2 × h), respectively. A modification of the track-etched membrane with PDADMAC, which carries a positive charge, has been approved, which makes it possible to increase the rejection of doubly charged ions for more effective lithium isolation.

Summary of Pretreatment of Waste Lithium-Ion Batteries and Recycling of Valuable Metal Materials: A Review

The recycling of used lithium-ion batteries has become a growing concern. As a large number of rare metal elements are present in waste lithium-ion batteries, recycling them can significantly improve resource utilization and reduce the material cost of battery production. The process of recycling used lithium-ion batteries involves three main technology parts: pretreatment, material recovery, and cathode material recycling. Pretreatment includes discharge treatment, uniform crushing, and removing impurities. Material-recovery technology mainly involves traditional pyrometallurgical and hydrometallurgical technologies, as well as the developing biometallurgy technology. Analysis of existing data shows that pretreatment technology is crucial for the recycling of used lithium-ion batteries. Hydrometallurgical technology and pyro-hydrometallurgical technology are expected to be the most suitable industrialization technology paths in the future, with biometallurgical technology and direct recycling technology providing a low-pollution development direction. This article summarizes the different pretreatment techniques and valuable metal-recovery pathways. The advantages and disadvantages of each method were evaluated. The economic costs, environmental benefits, and degree of industrialization of each method were assessed. The possible development directions of various methods are summarized to provide reference for future research.

Recycling of Rhenium from Superalloys and Manganese from Spent Batteries to Produce Manganese(II) Perrhenate Dihydrate

This work presents the research results on the development of an innovative, hydrometallurgical technology for the production of manganese(II) perrhenate dihydrate from recycled waste. These wastes are scraps of Ni-based superalloys containing Re and scraps of Li–ion batteries containing Mn—specifically, solutions from the leaching of black mass. This work presents the conditions for the production of Mn(ReO4)2·2H2O. Thus, to obtain Mn(ReO4)2·2H2O, manganese(II) oxide was used, precipitated from the solutions obtained after the leaching of black mass from Li–ion batteries scrap and purified from Cu, Fe and Al (pH = 5.2). MnO2 precipitation was carried out at a temperature < 50 °C for 30 min using a stoichiometric amount of KMnO4 in the presence of H2O2. MnO2 precipitated in this way was purified using a 20% H2SO4 solution and then H2O. Purified MnO2 was then added alternately with a 30% H2O2 solution to an aqueous HReO4 solution. The reaction was conducted at room temperature for 30 min to obtain a pH of 6–7. Mn(ReO4)2·2H2O precipitated by evaporating the solution to dryness was purified by recrystallization from H2O with the addition of H2O2 at least twice. Purified Mn(ReO4)2·2H2O was dried at a temperature of 100–110 °C. Using the described procedure, Mn(ReO4)2·2H2O was obtained with a purity of >99.0%. This technology is an example of the green transformation method, taking into account the 6R principles.

Life cycle assessment of methods for recycling retired ternary lithium batteries

Electric car sales in China are soaring. However, the battery life service is generally short, leaving room for dramatic waste related to different types of ternary lithium batteries. Since batteries contain substantial amounts of toxic substances, wrong recycling methods may significantly rise environmental pollution. Currently, China's Li-ion batteries recycling technologies are poor and research dealing with the environmental impact of recycling waste ternary lithium batteries by traditional hydrometallurgical technologies in China is not sufficient. In this paper, a life cycle assessment framework was carried out to analyze the environmental impacts of recycling LiNixCoyAl1-x-yO2 (NCA) and LiNixMnyCo1-x-yO2 (NMC) batteries using conventional hydrometallurgical techniques implemented in traditional Chinese plants. The freshwater ecotoxicity, human carcinogenicity and marine ecotoxicity of NCA batteries were higher than those of NMC batteries when the batteries were recovered by the traditional hydrometallurgical recovery method. The traditional recycling method would bring more toxicity to the environment and the traditional hydrometallurgical route is not suitable for recycling NCA-type ternary lithium batteries. Moreover, the recycling process of all three types of batteries displayed an impact on the environment with negative growth and the highest impact on the environment during the initial stage of recycling. Overall, new directions and technical updates for China's power battery recycling enterprises were provided, which can be useful for future planning.

Preparation of complex titanium-containing coagulants from large-scale mineral concentrates and their use in wastewater treatment

Relevance. Development of new, highly effective reagents for treatment of wastewater of various origins is a complex and extremely important task. An equally pressing issue remains the development of technologies for processing large-scale mineral products, which currently have not found an economically feasible technology for their processing and have received the status of “waste”. The development of a technology for producing reagents using waste as a raw material will not only have an economic effect but will also significantly minimize the level of negative impact on the environment and take a step towards the implementation of the Zero Waste concept. Aim. Development of technology for processing large-scale titanium-containing raw materials to obtain complex titanium-containing reagents and study of their effectiveness in wastewater treatment from various industries. Methods. To study the phase composition of the samples, the X-ray diffraction method was used, and the determination of metal content in acidic solutions and wastewater was carried out by atomic emission spectroscopy. Results and conclusions. The authors have proposed the technology for production of complex titanium-containing coagulants, which includes hydrometallurgical technology for sulfuric acid processing of large-capacity mineral raw materials – titanite. Aluminum hydroxide was introduced into the resulting solutions to adjust the chemical composition and neutralize free sulfuric acid. The resulting aluminum sulfate transforms into the most stable form of 18-aqueous crystalline hydrate, absorbing moisture from the solution, realizing chemical dehydration. The study of the composition of solid samples of coagulants showed that the predominant phase in the composition of the complex coagulant is aluminum sulfate, and the content of titanium compounds ranges from 1 to 14 wt %. It was established that by varying the ratio of mineral raw materials:sulfuric acid it is possible to vary the amount of modifying additive titanium compounds in the complex reagent. It was proven that the use of complex titanium-containing coagulants in wastewater treatment allows reducing the consumption of coagulants by 25–35%, increasing the efficiency of water purification, minimizing residual concentrations of pollutants, and also significantly increasing the rate of sedimentation of coagulation sludge in comparison with traditional sulfate aluminum.

Технология переработки сухих отходов сорбции и растворов хлоридов сурьмы

Reducing the loss of valuable components during the processing of complex gold-antimony ores, increasing the extraction of antimony during the flotation of sulfide minerals, is an urgent scientific problem. The aim of the study is to maximize the extraction of gold and antimony from dry sorption waste after gold cyanidation, and to improve the reagent regime of the antimony mineral flotation process. Research objectives are as follows: evaluation of the technology efficiency for processing dry sorption waste; extraction of gold from the cake of acidic leaching of antimony; production of various antimony-containing products from solutions of antimony chlorides; study of the possibility of replacing lead with a mixture of zinc and copper cations to hydrophobize the surface of antimony sulfide minerals during flotation. The object of the research is man-made and natural mineral raw materials containing gold and antimony. The following research methodology and methods are used: information analysis, evaluation of existing scientific developments, methods of theoretical and experimental research. A new technological solution has been proposed: acidic (a mixture of hydrochloric acid and hydrogen hydroxide) hydrometallurgical technology for processing dry sorption waste in order to extract gold and antimony. Acid treatment makes it possible to completely transfer antimony into solution, significantly improves the quality of the cake for subsequent cyanidation and gold extraction, reduces the volume of material for processing by cyanidation, and simplifies cyanidation technology. Sb2S3 activation and the possibility of lead (Pb(NO3) replacement have been studied 2) a mixture of zinc and copper (ZnSO4 and CuSO4) during the flotation of antimony ores from the Khipkoshinsky deposit in the Transbaikal Region. This has made it possible to create favorable conditions for interaction with xanthogenate and hydrophobize the surface of sulfide minerals. Theoretically, hydrogen sulfide substitutes such as NaCNS, KCNS, CuCNS for use in the flotation process were evaluated.

Optimization of Lithium Separation from NCA Leachate Solution: Investigating the Impact of Feed Concentration, Pressure, and Complexing Agent Concentration

Recycling lithium batteries (LIB) has emerged as an attractive solution in the global pursuit of environmentally friendly practices. The aim of achieving zero–waste hydrometallurgical technology is within reach. This research focuses on utilizing the low-pressure nanofiltration process to address this challenge by separating lithium ions from other ions and achieving a desirable permeate flux. The NCA battery leachate concentrate was obtained through a hydrometallurgical process involving sulfuric acid–peroxide. To ensure the prevention of potential nanofiltration membrane (TS80) fouling, the concentrate is initially filtered using an ultrafiltration membrane (UH004) to remove any particles. The research investigates the impact of pressure (4, 6, and 7 bar), solution concentration (concentrate, 10x, and 50x dilution), and the concentration of the complexing agent (EDTA) on the desired separation performance. The investigation reveals that pressure variations exhibit consistent rejection rates, remaining stable above 80%. A similar trend is observed with the addition of EDTA, which consistently yields rejection rates above 80%. However, when examining different feed concentrations, the rejection of lithium falls below 80% for leachate concentrates. In summary, satisfactory results are obtained by employing nanofiltration with a TS80 membrane at a pressure of 7 bar, a dilution factor of 10x, and using a 0.02M EDTA complexing agent. Meanwhile, it was found that the separation factors (Li⁺/Ni²⁺ = ~8.6, Li⁺/ Co²⁺ = ~7.3, Li⁺/Al³⁺ = ~4.9) and permeate flux ±46.58 L m⁻² h⁻¹. The findings demonstrate good selectivity along with relatively high flux.

Hydrometallurgical technologies of processing low-grade and low-quality copper concentrates

Hydrometallurgical technologies of processing low-grade and low-quality copper concentrates

TITANOMAGNETITE CONCENTRATE PROCESSING BY SORPTION CONVERSION

A hydrometallurgical technology for processing titanomagnetite concentrate has been proposed and justified. It includes the decomposition of the concentrate in low-concentration sulfur-acidic solution in the presence of sulfonic cation exchanger in H+ form with the transfer of the main part of the metals of the titanomagnetite concentrate into the sorbent and obtaining a residue enriched with ilmenite, desorption of metals from the saturated sulfonic cation exchanger with a 5 M sodium chloride solution, fractional hydrolytic precipitation and separation of titanium hydroxide, vanadium-enriched iron hydroxide, pure hydroxide iron and mixtures of iron and manganese hydroxides, regeneration of sulfonic cation exchange resin. The optimal parameters for carrying out individual processes have been determined. The technology practically does not consume sulfuric acid and does not generate liquid waste.

Removal of Cu and Sb from waste acid process of copper smelters for minimizing waste generation

The demand for waste minimization in copper smelters has been attracting widespread interest, particularly in the recent global trend towards ESG (environmental, social governance) standards. The typical waste acid process of primary copper smelters is composed of hydrometallurgical technologies such as valuable Cu recovery by single-stage sulfide precipitation followed by a couple of neutralization steps to remove impurities (including H2SO4 and Sb). In this study, a two-stage sulfide precipitation technique capable of removing > 99% of Sb as Sb2S3 and Sb2O3 was introduced prior to the neutralization with the goal of minimizing the generation of large volume of Sb(OH)3 with CaSO4 as waste. Moreover, SO2 in waste acid was identified as the primary cause for the low efficiency of Sb removal by single-stage sulfide precipitation. In addition, an alternative neutralization method facilitated with a slurry mixing technique under optimum pH ≤ 2.5 was introduced in order to valorize the waste neutralization cake as salable gypsum. The phenomena of changing gypsum particle morphology with pH were elucidated by establishing a gypsum particle settling mechanism, which is associated with drag force and inter-particular force. The technical feasibility of the proposed methods was preliminarily assessed on a laboratory scale and verified on a pilot scale.

Computational fluid dynamics study on the effect of stirring parameters on solid–liquid suspension in the slurry electrolysis square tank

As a sustainable hydrometallurgical technology, slurry electrolysis (SE) offers certain advantages in the treatment of complex ores and secondary electronic waste. It is therefore of considerable interest to understand the solid–liquid suspension in the stirred tank for overall process control. Here, a computational fluid dynamics (CFD) model based on the Eulerian-Eulerian framework combined with the kinetic theory of granular flow was employed to investigate the effects of varying the impeller speed (70–150 rpm), solids volume fraction (8–21 %), and particle specific gravity (2–6.7) on solid–liquid suspension behavior in a square tank equipped with electrodes and impeller. The results show that as the impeller rotating speed increases, turbulent kinetic energy is gradually transferred from the lower part of the electrodes to the region near the impeller shaft and between the membrane bags. The solids volume fraction was found to have little effect on the final liquid flow fields, but significantly increased the power consumption. The homogeneity and power consumption were quantified as functions of specific gravity, allowing the degree of homogeneity to be predicted under different operating conditions.

A new concept for carbon dioxide elimination from combustion plants flue gases

The production of energy from thermal power plants by burning fossil fuels is expected to remain a major part of the global energy mix for a significant period of time. The issue of pollutant emissions remains on the agenda, especially carbon dioxide (CO2) due to its large quantities released. The article proposes a new concept for the elimination of carbon dioxide and other gaseous pollutants from the waste gases of combustion plants. Based on the assessment of the thermodynamic feasibility of the processes, metals and alloys were selected and initial tests were performed for the transformation of model waste gases from thermal power plants into solid products that could be further utilized by hydrometallurgical technologies. Removals achieved at small scale laboratory experiments were >89 % CO2, > 71 % CO, > 96 % NOx and > 60 % SO2.

In Situ Electroplating of Ir@Carbon Cloth as High-Performance Selective Oxygen Evolution Reaction Catalyst for Direct Electrolytic Recovery of Lead

The hydrometallurgical technology provides an efficient and sustainable green lead recovery process from lead acid batteries. Methanesulfonic acid has been widely considered as a green solvent for lead electrolytic recovery. However, the competitive precipitation of PbO2 at anode and higher overpotential for OER limit the lead recovery efficiency. In this work, an anodic oxygen evolution reaction (OER) catalyst with a low Ir mass fraction of 7.2% is obtained by electroplating iridium on carbon cloth (CC), exhibiting a lower overpotential of 256 mV, longer lifetime of 10 h, and better stability in the 0.5 M MSA solution. When CC-Ir is used as an anodic catalyst for lead recovery in the lead methanesulfonate electrolyte, only a lesser Pb precipitation product with Pb atom mass fraction of 1.42% is found after electrolysis of 10 h, demonstrating the suppression effect of CC-Ir for a PbO2 side reaction. This work proves that the anodic catalyst plays an important role in the lead electrolytic recovery process, which can inhibit the side reaction, reduce the energy consumption, and increase recovery efficiency.

Use of leaching cake from refractory lining of dismantled electrolysers in cement production

A hydrometallurgical technology has been proposed for processing the refractory part of the lining of aluminum production electrolysers dismantled and disabled for overhaul. Fluorine-containing compounds are transferred to the solution, which allows obtaining cryolite for being used in the electrolysis process. It is recommended to use solid residue from leaching (cake) with a minimum content of alkalis and fluorine as an additive to the mixture for cement production. According to the results of experiments on obtaining portland cement by traditional firing technology, the limiting content of alkali metal oxides (not higher than 4.5% by weight, calculated as Na2O) in the leaching cake was determined, the optimum content of this additive in the charge is from 5 to 12% depending on chemical composition of lime used.

Hydrometallurgical technologies of processing arsenic raw materials

Methods presented in Russian and foreign scientific literature sources for processing high-arsenic copper raw materials to convert arsenic into low-soluble and stable compounds are reviewed. Hydrometallurgical processing methods are shown to be applicable for converting environmentally hazardous components into inert solid wastes while avoiding the formation of gaseous emissions. The isolation of arsenic when processing raw materials involves its oxidation and precipitation in the form of low-soluble and stable compounds. Methods for arsenic oxidation using oxygen, hydrogen peroxide, ozone, mixture of oxygen and sulphur dioxide, sodium hypochlorite are compared. Methods of oxidation by iron and permanganate ions, bacteria (biooxidation), as well as by introducing an activated carbon catalyst, are also considered. Precipitation approaches include neutralization by lime, precipitation of sulphides, co-precipitation of arsenic with iron ions, precipitation of scorodite, and encapsulation technology. As a result of the performed analysis, the authors present a promising approach for solving the problem of processing high-arsenic copper concentrates to comply with standards governing arsenic emissions into the environment, including the comprehensive processing of these raw materials using autoclave oxidation. In addition to the ensuring effective precipitation of arsenic in the form of a low-toxic compound (scorodite), this method can be used to isolate valuable components (copper, gold, silver) with their subsequent extraction into individual finished products. The obtained results establish a direction for a further in-depth study of the problem.

МИРОВЫЕ ТЕНДЕНЦИИ РАЗВИТИЯ ТЕХНОЛОГИЙ ГИДРОМЕТАЛЛУРГИЧЕСКОЙ ПЕРЕРАБОТКИ НИКЕЛЕВЫХ РУД НА ДЕЙСТВУЮЩИХ ПРЕДПРИЯТИЯХ

The paper provides a critical analysis of sources, a generalization of factual and theoretical material on the main hydromet-allurgical technologies for processing nickel ores. It has been established that the use of autoclave leaching of ores is the most common method of processing. This process takes place mainly in capacitive reactors with a stirrer. It was found that, depending on the type of ore, there are two main ways to carry out autoclave leaching: acid leaching under high pressure and the Caron process (ammonia leaching during roasting). The review shows that sulfuric acid leaching is predominantly used in Cuba and Western Australia, as well as in Finland, South Africa and Canada. Nitric acid leaching is being used in pilot plants in Australia at the CSIRO facility. Chlorine leaching is used in Japan, Norway, France and Canada. Ammonia processes have been implemented in Cuba, the Czech Republic and Australia, as well as in Brazil, Canada and the Philippines, India and Gag Island in Indonesia. The article presents the latest achievements in the field of extraction of nickel and cobalt from productive solutions, as well as the advantages and disadvantages of existing schemes at operating enterprises in the world. Having analyzed the main technologies for processing nickel ore, we can say that traditionally Ni and Co are extracted from productive solutions after leaching in one of three ways: 1. Precipitation of mixed nickel and cobalt sulfide; 2. Precipitation of mixed nickel and cobalt hydroxide; 3. Direct solvent extraction. The analysis showed that the most optimal and least time-consuming process, providing a relatively high degree of extraction of target metals, is extraction. Impurity removal is most expediently carried out by precipitation, however, the loss of nickel and cobalt should be taken into account.

Separation of Cobalt, Samarium, Iron, and Copper in the Leaching Solution of Scrap Magnets

With the growing awareness of protecting the urban environment and the increasing demand for strategic materials, recycling of SmCo magnets has become imperative. This paper provides a series of methods regarding the available hydrometallurgical technologies for recycling scrap magnets. This study aimed to recover samarium (Sm), cobalt (Co), copper (Cu), and iron (Fe) from acid leachate of SmCo scrap by using precipitation and ion exchange. IRC748 showed a good adsorption capacity for Fe and Cu. Elution tests were conducted using sulfuric acid at the concentration of 2N as eluents. Precipitation was performed first using a selective chemical precipitation method, and the Sm was first precipitated as a sodium samarium sulfate powder. Then, the samarium-deprived solution was placed in the beaker, and the addition of oxalic acid promoted cobalt oxalate precipitation. Furthermore, the leachate, which is rich in Cu and Fe, was mixed with oxalic acid to obtain the copper oxalate precipitation. This study successfully recovered SmCo magnets through ion exchange and precipitants.

Development of an Innovative Technology for the Complex Extraction of Nickel and Cobalt from Iron-Silicate Ores

This article studies the development of a new hydrometallurgical technology for the complex extraction of nickel and cobalt from iron-silicate ores. As a result the following algorithm of actions for obtaining high percent of extraction (for nickel 97,0 %, for cobalt 92,8 %) is offered: Crushed ore from the Batamshy deposit (-200 mesh) is treated with dissolving reagents to transfer cobalt and nickel from the solid phase into solution with subsequent filtration and washing, where 1.0% to 7.5% (by mass) calcium hypochlorite and 3.0% to 6.0% (by mass) ammonium fluoride in 10% technical hydrochloric acid solution (by volume) are used as dissolving reagents. Dissolution is carried out at room temperature for 120 minutes at a ratio of Solid to Liquid 1:10 (S:L = 1:10) and under constant stirring by horizontal-circular rotation of 100 revolutions/minute. The implementation of the method makes it possible to significantly increase the degree of extraction, simplify the technological process and avoid complications in operation hardware design.