The cathode material of spent ternary lithium-ion battery is rich in valuable metals such as Li, Ni, Co and Mn, and efficient separation and recovery of these metals is crucial for environmental protection. The principles, conditions and effects of chemical precipitation, solvent extraction and electrochemical deposition for the separation of dissolved Li, Ni, Co and Mn are evaluated and analyzed. According to the failure mechanism of NCM cathode material, the development status, advantages and disadvantages of direct regeneration strategy of solid-state sintering, hydrothermal method and lithium based eutectic molten salt method, and indirect regeneration strategy of coprecipitation method, sol-gel method and electrochemical method are systematically reviewed. The challenges faced in the separation of valuable metals such as lithium, nickel, cobalt and manganese and the recycling of electrode materials are summarized, and the improvement direction is put forward to provide important guidance for the efficient recycling of valuable metals in the cathode materials of spent ternary lithium-ion batteries.

The characteristics, industrial application status and research progress of hydrometallurgy for low grade laterite nickle ore by reduction roasting—normal pressure ammonia leaching and high-pressure acid leaching (HPAL), as well as the development of three generations of HPAL technology are summarized. The nickle-cobalt precipitation and enrichment technology and the application are introduced. The processes advantages and disadvantages of the H₂S precipitation, MgO precipitation, direct NaOH precipitation are analyzed. The effectiveness of new precipitation process with alkali conversion and crystal seed activation has been explored. The development prospect of laterite nickel hydrometallurgical process is also prospected.

Combined extraction of nickel and cobalt from nickel chloride solution using di (2-ethylhexyl) phosphonic acid (P204) and triisooctylamine (N235) as extractants was studied. The effects of organic phase P204 volume fraction, phase ratio, solution pH, saponification rate, organic phase N235 volume fraction, Cl^- mass concentration, and reaction temperature on the purification and impurity removal of nickel chloride solution were investigated. The results show that after removing impurities by P204 extraction, N235 is used to extract cobalt and molybdenum from P204 raffinate, the mass concentrations of Ni²⁺ is 218.10 g/L, and the mass concentrations of Cu²⁺, Fe³⁺, Co²⁺, and Zn²⁺ in the residual solution 1.1, 1.2, 1.0 and 0.1 mg/L, respectively, under the conditions of 20% volume fraction of P204 in the organic phase of the P204 extraction and impurity removal process, V_O/V_A=1. 5/1, raw material solution pH=3.5, saponification rate of 50%, reaction temperature of 40~50 ℃, and N235 volume fraction of 16% in the organic phase of the N235 extraction process, V_O/V_A =1.2/1, Cl^- mass concentration≥280 g/L, reaction temperature of 40~50 ℃, P204 Raffinate pH=3.0, and hydrochloric acid acidification concentration of 3 mol/L, which can meet the requirements of producing high quality electrodeposited nickel cathodes.

Arsenic containing non-ferrous metal and precious metal sulfide ore will produce acidic high concentration arsenic solution in the smelting process, which has the characteristics of high arsenic concentration, complex composition, large changes, strong toxicity and difficult to store, such as direct discharge without treatment, will have a great impact on the environment and human health. In this paper, the principles, advantages and disadvantages of chemical precipitation method, evaporation enrichment method and metal powder method are reviewed, as well as the research progress of each method, so as to provide reference for the development of arsenic removal technology.

P204 was used to extract copper and cobalt from low concentration cobalt sulphide concentrate leaching solution. The effects of pH of extraction solution, extractor concentration, extraction ratio and time on the extraction efficiency were investigated. The results show that under the conditions of pH=4, P204 volume fraction of 25%, extraction ratio V_O/V_A=1/1, extraction time of 3 min, reverse extractant sulfuric acid concentration of 0.10 mol/L, and reverse extraction ratio V_O/V_A=2/1, the test of two-stage countercurrent extraction, four-stage countercurrent stripping is carried out on the purified liquid of cobalt sulfide concentrate, the mass concentration of cobalt and copper in the raffinate is 338.80 mg/L and 2.96 mg/L, the extraction rate of copper is 98.32%, and 90.03% of cobalt remains in the water phase. Copper and cobalt can be effectively further separated by stripping, which is conducive to preparation of high purity cobalt sulfate.

Aging of biochar can affect its stability and persistence of heavy metals immobilizing in soil, resulting in changes in its inertness. Using peanut shell (PS) as raw material, peanut shell biochar (PSB) was prepared by pyrolysis under the condition of 600 ℃ and hypoxia. Oxidized biochar (OPSB), leached biochar (LPSB) and acidified biochar (APSB) were prepared Y by simulated field oxidation, leaching and acidification of PSB. The effects of these three aging methods on the adsorption efficiency and mechanisms of Cd²⁺by the biochar were investigated using isothermal adsorption models, kinetic models, FT-IR and XRD. The results show that oxidative aging process an significantly enhance the accumulation of oxygen-containing functional groups (—COOH, —OH, etc.) on the surface of the biochar, thereby increasing the adsorption capacity of OPSB for Cd²⁺by 10.13%. Leaching aging process can not cause significant changes in functional group content but result in substantial loss of soluble minerals, leading to a significant decrease adsorption capacity of LPSB for Cd²⁺ by 13.35%. Acidification aging process can affect the adsorptive activity of Cd²⁺ on the surface of the biochar, resulting in a reduction in adsorption capacity of APSB for Cd²⁺ by 26.52%. All four types of biochar exhibite effective adsorption for Cd²⁺, the OPSB showing optimal affinity followed by PSB, LPSB, and APSB. The Langmuir isothermal adsorption model provides better fitting for describing the Cd²⁺adsorption process by all four types of biochars under low pH conditions. Furthermore, the adsorptions processes by all four types of biochars are predominantly governed by physical electrostatic interactions, which is suitable to be described by quasi-first-order kinetic model.

In view of the problems that alkali to solanite concentrate turned red and acid soluble slurry thickened into foam during comprehensive recovery, which led to product discoloration and decreased production capacity, scanning electron microscopy (SEM) and infrared spectrum analysis were used to analyze the composition of ore pollutants, and the removal effect of calcination method on monazite concentrate contaminants were studied through condition test and pilot plant tests. The results show that the alkali transformation color is mainly caused by the organic matter containing carboxyl group, benzene ring or cycloalkane covering the monazite surface. Under the conditions of calcination temperature of 400 ℃ and calcination time of 40 min, the COD removal rate of alkali to pulp is greater than 94%, and the organic matter removal effect is good, which can solve the problem of 30% reduction in production and processing capacity, reduce power consumption and energy consumption, remove occupational health and other safety and environmental risks caused by fluting in production, and ensure the recovery rate of uranium and rare earth. This method improves the processing process of monazite and has a certain popularization value.

The determination of arsenic content in phosphorus pentoxide by atomic fluorescence spectroscopy method was studied, and the acid medium, acidity, reducing agent concentration, pre reducing agent, and masking agent were determined. The results indicate that the method has good linearity in the range of 1.0~50.0 μg/L, the correlation coefficient is r>0.999, the detection limit is 0.06 μg/L, quantification limit is 0.21 μg/L. The relative standard deviation (RSD) of the 8 sample analysis results is 1.94%, and the spiked recovery rate are 92.87%~101.30%. The test results show no significant difference from the DDTC silver salt method, and this method is a reliable method for detecting arsenic content in phosphorus pentoxide, because it is more convenient and less reagent used.

With the rapid expansion of the scale of nuclear energy, the proper treatment of radioactive waste generated by the nuclear industry has become one of the most important issues for the further development of nuclear energy. Cyclodextrin, as a kind of cyclic oligosaccharide composed of several glucopyranose units, has a good prospect of application in the field of radioactive ions adsorption and separation, because of its special molecular structure of internal hydrophobicity and external hydrophilicity. However, due to the presence of a large number of hydroxyl groups in the cyclodextrin molecules, they are easily soluble in water. Generally, the solidification of cyclodextrins to insoluble solids is always needed before being used as adsorption materials. Depending on the different methods of "solidification", cyclodextrin based adsorbent materials can be divided into three types:loaded cyclodextrin materials, cyclodextrin polymer materials, and cyclodextrin inclusion complex materials. The synthesis and application research advances of the three types of cyclodextrin adsorbent materials in radioactive ion adsorption and separation are summarized, the related adsorption mechanisms are discussed. Besides, the perspectives of the cyclodextrin based adsorbents in the field of radioactive ion adsorption are presented.

Manganese dioxide in pyrolusite was directly reduced to manganese sulfate by high-temperature roasting with ammonium sulfite as reducing agent, so as to achieve efficient extraction of pyrolusite. The effects of mass ratio of ammonium sulfite to pyrolusite, roasting temperature and time, leaching temperature and time on the extraction rate of manganese were investigated, and the optimum process conditions were determined. The results show that the optimal conditions are the mass ratio of ammonium sulfite to pyrolusite of 0.75∶1, roasting temperature of 500 ℃, roasting time of 1.5 h, leaching temperature of 25 ℃, leaching time of 30 min. Under the conditions, the leaching rate of manganese and iron is about 93% and about 9.5%, respectively. The extraction effect of manganese is good.