As an important secondary resource rich in Nd, Pr, Dy and other rare earth elements, the recycling of NdFeB permanent magnet waste is not only related to the supply security of rare earth strategic resources, but also has great significance for reducing environmental pollution and promoting sustainable development. The source, basic physical and chemical characteristics of NdFeB permanent magnet waste and the recycling technology of rare earth elements are summarized. The basic principles and research progress of fire, wet and other recycling processes are reviewed. The advantages and disadvantages of the technology are analyzed. The future development direction of NdFeB waste recycling rare earth technology is prospeced, in order to promote the technological progress and sustainable development in this field.

The extraction of lithium from fly ash by roasting activation with sodium carbonate and leaching with sulfuric acid was studied. The effects of mass ratio of fly ash to sodium carbonate, roasting temperature, roasting time, liquid-solid mass ratio, sulfuric acid concentration, acid leaching temperature and acid leaching time on the leaching rate of lithium were investigated. The dynamic analysis of the leaching process was carried out by using the core-shrinkage model. The results show that under the condition of 800 ℃, fly ash and sodium carbonate are mixed and roasted for 180 min according to the mass ratio of 1∶1, and then leaching with 2 mol/L sulfuric acid at 90 ℃ for 120 min, remarkable leaching effect can be obtained, and the leaching rate of lithium can reach 99.97%, the leaching process is mainly controlled by diffusion. The study has a certain guiding significance for the leaching and recovery of lithium from solid waste resources.

In view of the "bimodal" particle size distribution phenomenon of U₃O₈ raw materials, the process concept of rapid dissolution of fine U₃O₈ and continuous dissolution of large U₃O₈ at the bottom of the equipment was put forward, and a tank-type continuous dissolution device was designed. The rationality of the proposed tank-type dissolution device, the feasibility of the continuous dissolution process of U₃O₈ in nitric acid, and its applicability to different raw materials were verified through micro, small-scale,and pilot tests. The results show that under the conditions of the nitric acid concentration of 6 mol/L, dissolution temperature of approximately 60 ℃, and residence time of 40 minutes, U₃O₈ from different sources can be effectively dissolved, the uranium mass concentration in the dissolution solution is 350~400 g/L.

The environmental problems caused by the increase in the storage amount of red mud have seriously restricted the development of China's alumina industry, so it is increasingly important to strengthen the comprehensive utilization of red mud. The recovery of sodium and aluminum from the red mud of an aluminum plant in Yunnan by calcification-carbonization method was studied. The calcified and carbonized red mud was characterized by XRD and SEM-EDS. The results show that the optimum conditions of calcification are reaction temperature of 65 ℃, reaction time of 36 h, calcium-sodium ratio of 4/1 and liquid -solid mass ratio of 4/1.Under the conditions, the sodium oxide recovery is the highest, 59.94%. The optimum conditions of carbonization are reaction time of 3 h, reaction temperature of 110 ℃, liquid to solid mass ratio 5/1, carbon dioxide pressure of 1.1 MPa, and the aluminum recovery rate is 16.15%. The hydrated sodium aluminosilicate in the red mud is converted into hydrated garnet during calcification, and sodium is released. Hydrated garnets decompose into CaCO₃, CaSiO₃ and Al(OH)₃ during carbonization. The method can provide a new idea for comprehensive recovery and utilization of red mud.

Monoclinic lithium vanadium phosphate(Li₃V₂(PO₄)₃, LVP) is considered to be one of the most potential lithium ion battery cathode materials, with high capacity, good safety, long service life, excellent low temperature function and other advantages. However, the low electronic and ionic conductivity of LVP has limited its development. In this paper, the structure and electrochemical reaction mechanism of LVP cathode materials are introduced, the main preparation methods and modification research progress of LVP cathode materials are reviewed, and the future development direction and application prospect of LVP cathode materials are prospected.

The magnetic porous magnesium oxide(m-MgO) was prepared with nano-ferric oxide (Fe₃O₄) as the core and MgCl₂ as the magnesium source, and was used for adsorption of U(Ⅵ) in aqueous solution. The physicochemical properties of MgO and m-MgO were characterized by FT-IR, XRD, VSM and Zeta potential. The effects of solution pH, temperature, and oscillation time on the adsorption of U(Ⅵ) by MgO and m-MgO were investigated. The results show that the optimal conditions for uranium adsorption by MgO and m-MgO are pH=3.5, adsorbent dosage of 10 mg, and oscillation time of 720 min. The adsorption process conforms to the pseudo-second-order kinetic model and the Sips isotherm adsorption model, with a theoretical adsorption capacity of 454.16 mg/g, and the increase of temperature is conducive to the spontaneous adsorption. Therefore, m-MgO is expected to be used to separate and recover uranium from radioactive wastewater.

The preparation of electronic grade phosphoric acid by deep removing arsenic from wet-process phosphoric acid is an important technical link to develop phosphorus chemical industry with high quality and promote the technological transformation of phosphorus chemical industry. Electronic grade phosphoric acid requires a mass fraction of arsenic less than 1×10^-7 kg/kg, but because the physicochemical parameters of arsenic and phosphorus are similar, how to achieve the deep separation of arsenic from phosphoric acid has become the key to the preparation of electronic grade phosphoric acid. In this paper, the main international and domestic quality standards for electronic grade phosphoric acid products are systematically reviewed, and the harm of arsenic to electronic grade phosphoric acid etched microelectronic components is summarized. The research progress, advantages and disadvantages of chemical precipitation, crystallization, electrodeposition, electrodialysis and adsorption are summarized, and the development trend of electron grade phosphoric acid prepared by wet phosphoric acid is prospected.

With the rapid development of the new energy vehicle industry and the energy storage field, the comprehensive recycling of a large number of spent LiFePO₄ batteries has become a key challenge and urgent demand for the sustainable development of new energy in China. This paper summarizes the principle, advantages and disadvantages, research and application status of major strong dissociation technologies for retired LiFePO₄ battery cathode materials, including pyrometallurgy, hydrometallurgy, mechanochemistry, electrochemical metallurgy, etc., and further expounds the innovation progress of strong dissociation technology in improving the recovery efficiency of valuable components, reducing costs and reducing environmental impact. The future development trend is also prospected.

In order to selectively remove nickel ions from the desulphurization tailing of pyrolusite and improve the purity of manganese sulfate, the spongy nickel-imprinted chitosan adsorbent Ni²⁺-IIP was prepared by ion imprinting method and chemical foaming method on chitosan matrix, and its competition and selective adsorption behavior in simulated binary solution were discussed. The effects of temperature, adsorption time and desulphurization tailing pH on the adsorption amount and removal rate of nickel ions and the loss rate of manganese ions in the desulphurization tailing of pyrolusite were also investigated. The results show that in the simulated binary solution, Ni²⁺-IIP still maintains high selectivity for nickel ions, although there is competitive adsorption between manganese and nickel ions. In the actual desulphurization tailing of pyrolusite, under the conditions of pH=5.0, adsorption temperature of 40 ℃ and adsorption time of 1 440 min, the adsorption capacity and rate of removal of Ni²⁺is 15.3 mg/g and 90%, respectively,and the loss rate of manganese ions is about 11%. After 5 adsorption—desorption cycles, the adsorption capacity of Ni²⁺-IIP for nickel ions in the desulphurization tailing reduces 13.1%,and the regeneration performance is good. Ni²⁺-IIP can selectively remove nickel ions from the desulphurization tailing, and purify the manganese sulfate solution.

Extraction and separation of iron, aluminum and heavy metal nickel from electroplating sludge by P204 stepwise extraction process was studied. The effect of pH on the extraction process was discussed. The results show that the leaching solution of electroplating sludge after pretreatment with sulfuric acid was rich in nickel, and the insoluble substances were mainly calcium sulfate and silicon.Using 20%P204+80%sulfonated kerosene as organic phase, the extraction rates of Fe and Al can reach 99.9% and 97.6%, respectively, while the nickel loss rate is less than 2% under the conditons of V_O/V_A=1/1, electroplating sludge leaching solution nitial pH=0.9. When the pH of the raffinate is adjusted to 4.5, V_O/V_A =1/1, and the organic phase is 15%P204+85% sulfonated kerosene, the nickel extraction rate can reach 98% after four-stage extraction. The nickel-rich solution is obtained by four-stage strripping with 2 moL/L sulfuric acid, and nickel sulfate crystals with 22% nickel mass fraction are obtained by evaporation and crystallization.