Extraction of Valuable Metals from Titanium-bearing Blast Furnace Slag by Acid Leaching

To realize the resource utilization of the valuable metals in the titanium-containing blast furnace slag,the process route of “hydrochloric acid leaching-electrolysis-carbonization and carbon dioxide capture-preparation of calcium carbonate” was proposed.In this study,the influences of process conditions on the leaching rates of calcium,magnesium,aluminum,and iron and the phases of the leaching residue were investigated for the leaching process.The experimental results show that the HCl solution could selectively leach the elements from the titanium-containing blast furnace slag.The better leaching conditions are the HCl solution concentration of 4 mol/L,the leaching time of 30 min,the ratio of liquid volume to solid gas of 10 mL/g,and the stirring paddle speed of 300 r/min.Under the conditions,the leaching rates of calcium,magnesium,aluminum,and iron can reach 85.87%,73.41%,81.35%,and 59.08%,and the leaching rate of titanium is 10.71%.The iron and the aluminum are removed from the leachate to obtain iron-aluminum water purification agents,and the magnesium is removed from the leachate to obtain magnesium hydroxide.The leaching residue phase is dominated by perovskite,followed by magnesium silicate and tricalcium aluminate,and the titaniumrich material could be obtained from the leaching residue by desiliconization.

Recovery of valuable metals from zinc leaching residue by sulfate roasting and water leaching

Zinc leaching residue(ZLR),produced from traditional zinc hydrometallurgy process,is not only a hazardous waste but also a potential valuable solid.The combination of sulfate roasting and water leaching was employed to recover the valuable metals from ZLR.The ZLR was initially roasted with ferric sulfate at640°C for1h with ferric sulfate/zinc ferrite mole ratio of1.2.In this process,the valuable metals were efficiently transformed into water soluble sulfate,while iron remains as ferric oxide.Thereafter,water leaching was conducted to extract the valuable metals sulfate for recovery.The recovery rates of zinc,manganese,copper,cadmium and iron were92.4%,93.3%,99.3%,91.4%and1.1%,respectively.A leaching toxicity test for ZLR was performed after water leaching.The results indicated that the final residue was effectively detoxified and all of the heavy metal leaching concentrations were under the allowable limit.

Efficient recovery of valuable metals from waste printed circuit boards by microwave pyrolysis

The recycling of waste printed circuit board(WPCBs) is of great significance for saving resources and protecting the environment. In this study, the WPCBs were pyrolyzed by microwave and the contained valuable metals Cu, Sn and Pb were recovered from the pyrolyzed WPCBs. The effect of pyrolysis temperature and time on the recovery efficiency of valuable metals was investigated. Additionally, the characterization for morphology and surface elemental distribution of pyrolysis residues was carried out to investigate the pyrolysis mechanism. The plastic fiber boards turned into black carbides, and they can be easily separated from the metals by manual. The results indicate that 91.2%, 96.1% and 94.4% of Cu, Sn and Pb can be recovered after microwave pyrolysis at 700 °C for 60 minutes. After pyrolysis, about 79.8%(mass)solid products, 11.9%(mass) oil and 8.3%(mass) gas were produced. These gas and oil can be used as fuel and raw materials of organic chemicals, respectively. This process provides an efficient and energy-saving technology for recovering valuable metals from WPCBs.

Physicochemical and environmental characteristics of alkali leaching residue of wolframite and process for valuable metals recovery

Physicochemical and mineralogical characteristics of an alkali leaching residue of wolframite were studied by XRD,SEM−EDS,chemical phase analysis,mineral liberation analyzer(MLA),and TG−DSC methods.Batch leaching tests,toxicity characteristic leaching procedure(TCLP)tests and Chinese standard leaching tests(CSLT)were conducted to determine the environmental mobility of toxic elements.The results show that,due to the high contents of W,Fe,Mn,Sn,and Nb,the residue is with high resource value,but the content of a toxic element,As,is also high.The existing minerals of the investigated elements mainly occur as monomer particles,but it is difficult to extract these valuable metals by conventional acid leaching due to their mineral properties.The release of As increases over time in acidic environment.The leaching concentration of all investigated harmful elements through TCLP is within the limiting value,while the leaching concentration of As through CSLT exceeds the limiting value by more than 4 times,so the residue is classified as hazardous solid waste based on the Chinese standard.A process for valuable metals recovery from this residue was proposed.Preliminary experimental results indicated that the main valuable metals could be extracted effectively.

Valuable metals recovery from spent ternary lithium-ion battery:A review

Ternary lithium-ion batteries(LIBs),widely used in new energy vehicles and electronic products,are known for their high en-ergy density,wide operating temperature range,and excellent cycling performance.With the rapid development of the battery industry,the recycling of spent ternary LIBs has become a hot topic because of their economic value and environmental concerns.To date,a con-siderable amount of literature has reported on the recycling of spent ternary LIBs designed to provide an efficient,economical,and envir-onmentally friendly method for battery recycling.This article examines the latest developments in various technologies for recycling spent ternary LIBs in both research and practical production,including pretreatment,pyrometallurgy,hydrometallurgy,pyro-hydrometallurgy,and direct regeneration.Suggestions for addressing challenges based on the benefits and disadvantages of each method are made.Finally,through a comparison of the feasibility and economic benefits of various technologies,the challenges faced during battery recycling are summarized,and future development directions are proposed.

Pyrometallurgical recycling of end-of-life lithium-ion batteries

The global importance of lithium-ion batteries(LIBs)has been increasingly underscored with the advancement of high-performance energy storage technologies.However,the end-of-life of these batteries poses significant challenges from environmental,economic,and resource management perspectives.This review paper focuses on the pyrometallurgy-based recycling process of lithium-ion batteries,exploring the fundamental understanding of this process and the importance of its optimization.Centering on the high energy consumption and emission gas issues of the pyrometallurgical recycling process,we systematically analyzed the capital-intensive nature of this process and the resulting technological characteristics.Furthermore,we conducted an in-depth discussion on the future research directions to overcome the existing technological barriers and limitations.This review will provide valuable insights for researchers and industry stakeholders in the battery recycling field.

Optimization of brine leaching of metals from hydrometallurgical residue

An orthogonal array,L16(45),was used to examine the effects of four parameters,including NaCl concentration,H2SO4 concentration,temperature and pulp density,on the recovery of Cu,In,Pb and Zn from a hydrometallurgical residue via brine leaching.The results show that temperature of leaching solution has a significant effect on the recovery of Cu,In and Zn,while H2SO4 concentration has an obvious influence on these metals extraction.Both pulp density and NaCl concentration significantly affect Pb extraction.Based on the orthogonal array experiments,the optimum conditions for the extraction of Cu,In,Pb and Zn from hydrometallurgical residue are NaCl concentration of 250 g/L,H2SO4 concentration of 1.00 mol/L,temperature of 85℃,and pulp density of 100 g/L.After 1 h of treatment at these optimum conditions,over 91% of the metals are extracted from the residue.Brine leaching is therefore suitable for the recovery of metals from hydrometallurgical residues.

Properties, hazards and valuable metal recovery technologies of red mud: A review

This review presents a summary of the research conducted thus far on the recovery of various types of valuable metals from red mud. The composition, properties, environmental hazards, and current status of comprehensive utilization of red mud were studied. A number of studies have been conducted on the use of red mud as a modifying additive for cement, the development of various catalysts based on red mud, and the recovery of various valuable metals from red mud. Furthermore, we examine several techniques for extracting various types of valuable metals from red mud, including pyrometallurgical recovery, wet leaching recovery, and emerging biobased technology recovery. We investigate the underlying principles, processes, research progress, and the potential for industrial application of these methods, and assess the advantages and disadvantages of each from the perspectives of economic and environmental benefits. Although these methods have certain disadvantages, in general, the recovery of various types of valuable metals from red mud is an effective way to solve the problem of red mud and the supply of metal raw materials. In conclusion, this paper presents an overview of the current state of red mud development and utilization, as well as the various methods employed for the recovery of valuable metals from red mud.

Progresses in Sustainable Recycling Technology of Spent Lithium-Ion Batteries

The number of lithium-ion batteries(LIBs)is steadily increasing in order to meet the ever-growing demand for sustainable energy and a high quality of life for humankind.At the same time,the resulting large number of LIB waste certainly poses safety hazards if it is not properly disposed of and will seriously harm the environment due to its inherent toxicity due to the use of toxic substances.Moreover,the consumption of many scarce precious metal resources is behind the mass production of batteries.In the light of severe environmental,resources,safety and recycling problems,recycling spent LIBs have become an essential urgently needed action to achieve sustainable social development.This review therefore critically analyses the value and the need for recycling of spent LIBs from a variety of resources and the environment.A range of existing technologies for recycling and reusing spent LIBs,such as pretreatment,pyrometallurgy,hydrometallurgy,and direct recycled methods,is subsequently summarized exclusively.In addition,the benefits and problems of the methods described above are analyzed in detail.It also introduces recycling progress of other LIB components,such as anodes,separators,and electrolytes,as well as the high-value cathode.Finally,the prospects for recycling LIBs are addressed in four ways(government,users,battery manufacturers,and recyclers).This review should contribute to the development of the recycling of used LIBs,particularly in support of industrialization and recycling processes.

Comprehensive recovery of lead, zinc, and iron from hazardous jarosite residues using direct reduction followed by magnetic separation

Lead, zinc, and iron were recovered from jarosite residues using direct reduction followed by magnetic separation. The influence of the coal dosage, reduction temperature, and reduction time on the volatilization rates of lead and zinc and the metallization rate of iron were investigated. The results show that the volatilization rates of lead and zinc were 96.97% and 99.89%, respectively, and the iron metallization rate was 91.97% under the optimal reduction roasting conditions of a coal dosage of 25.0 wt% and reduction roasting at 1250°C for 60 min. The magnetic concentrate with an iron content of 90.59 wt% and an iron recovery rate of 50.87% was obtained under the optimum conditions in which 96.56% of the reduction product particles were smaller than 37 μm and the magnetic field strength was 24 k A/m. Therefore, the results of this study demonstrate that recovering valuable metals such as lead, zinc, and iron from jarosite residues is feasible using the developed approach.

A Mini-Review on Metal Recycling from Spent Lithium Ion Batteries

The rapid growth of lithium ion batteries （LIBs） for portable electronic devices and electric vehicles has resulted in an increased number of spent LIBs. Spent LIBs contain not only dangerous heavy metals but also toxic chemicals that pose a serious threat to ecosystems and human health. Therefore, a great deal of attention has been paid to the development of an efficient process to recycle spent LIBs for both economic aspects and environmental protection. In this paper, we review the state-of-the-art processes for metal recycling from spent LIBs, introduce the structure of a LIB, and summarize all available technologies that are used in different recovery processes. It is notable that metal extraction and pretreatment play impor- tant roles in the whole recovery process, based on one or more of the principles of pyrometallurgy, hydrometallurgy, biometallurgy, and so forth. By further comparing different recycling methods, existing challenges are identified and suggestions for improving the recycling effectiveness can be proposed.

Comprehensive Recycling Technology of Waste Residues in Zinc Hydrometallurgy

In order to improve the refining effect of zinc ore and promote the development of this industry,taking the hydrometallurgical zinc smelting process as an example,this paper first establishes a model for the recycling of waste residues in the hydrometallurgical process,proposes optimization measures based on proven comprehensive recycling technology for purifying residues to obtain higher valuable metal recovery rate,and provides reference for those in relevant fields.

Engineering classification recycling of spent lithium-ion batteries through pretreatment:a comprehensive review from laboratory to scale-up application

The lithium-ion batteries(LIBs)have been widely equipped in electric/hybrid electric vehicles(EVs/HEVs)and the portable electronics due to their excellent electrochemical performances.However,a large number of retired LIBs that consist of toxic substances(e.g.,heavy metals,electrolytes)and valuable metals(e.g.,Li,Co)will inevitably flow into the waste stream,and their incineration or landfill treatment will cause severe risks to ecosystem and human beings.The sustainable and efficient treatment or recycling of valuable resources from spent LIBs should be fully recognized for environmental and resource security.As one of the most important processes for spent LIBs recycling,the pretreatment is an indispensable step,which is directly related to the subsequent metal extraction and separation processes.Although considerable progresses have been made regarding the pretreatment technologies,there are few summarized reports concerning critical processes of spent LIBs recycling,especially combination of currently available recycling technologies with industrialized applications during pretreatments.Therefore,comprehensive review of the current prevailing pretreatment technologies in laboratory to existing scale-up applications is quite necessary to reveal cutting-edge development in the field of pretreatment.In this review,the current pretreatment technologies are systematically categorized and introduced,along with critical discussions.This review focused on the various options for pretreatment processes itself,instead of general spent LIBs recycling technologies without the focused topics that have been sophisticatedly reviewed by previous studies.Here,the deactivation,discharge,dismantling,separation,liberation of active material and electrolyte treatment have been summarized with the in-depth discussion of the technology development and current status of each category.Finally,current states of industrial development are also reviewed and discussed for the development of efficient and environmentally friendly recycling technologies for future applications.This review tends to present a focused topic concerning the pretreatment of spent LIBs to potential readers with a comprehensive illustration of the development on both cutting-edge technologies and scale-up applications.

Recent advances in the recovery of transition metals from spent hydrodesulfurization catalysts

Hydrodesulfurization(HDS)catalysts are widely used in petrochemical industries,playing a crucial role in desulfurization process to get high-quality oil.The generation of Al-based spent HDS catalyst is estimated to be 1.2×105 tons per year around the world.The spent HDS catalysts have been regarded as an important secondary resource due to their abundant output,considerable metal value,and regeneration potential;however,if improperly handled,it would severely pollute the environment due to high content of heavy metals.Thus,the recovery of valuable metals from spent HDS catalysts is of great importance from both resource utilization and environmental protection points of view.In this work,recent advances in the spent HDS catalyst treatment technologies have been reviewed,focusing on the recovery of valuable transition metals and environmental impacts.Finally,typical commercial processes have been discussed,providing in-depth information for peer researchers to facilitate their future research work in designing more effective and environmentally friendly recycling processes.

Coextraction of vanadium and manganese from highmanganese containing vanadium wastewater by a solvent extraction-precipitation process

High-manganese containing vanadium waste-water(HMVW)is commonly produced during the vanadium extraction process from vanadium titano-magnetite.HMVW cannot be reused and discharged directly,and is harmful to the environment and affect product quality due to heavy metals in the wastewater.The wastewater is usually treated by lime neutralization,but valuable metals(especially V and Mn)cannot be recovered.In this study,an efficient and environmentally friendly method was developed to recover valuable metals by using a solvent extraction-precipitation process.In the solvent extraction process,98.15%of vanadium was recovered,and the V2Os product,with a purity of 98.60%,was obtained under optimal conditions.For the precipitation process,91.05%of manganese was recovered as MnCO3 which meets the III grade standard of HG/T 2836-2011.Thermodynamic simulation analysis indicated that MnCO3 was selectively precipitated at pH 6.5 while Mg and Ca could hardly be precipitated.The results of X-ray diffraction and scanning electron microscopy demonstrated that the obtained V2Os and MnCO3 displayed a good degree of crystallinity.The treated wastewater can be returned for leaching,and resources(V and Mn)in the wastewater were utilized efficiently in an environmentally friendly way.Therefore,this study provides a novel method for the coextraction of V and Mn from HMVW.