Multicomponent melting separation slag,obtained from NdFeB waste by H₂ selective reduction and melting separation,was used as raw material for hydrochloric acid leaching.The influence of reaction factors on the leaching rate of rare earth under the conditions of low temperature and atmospheric pressure and high temperature and high pressure was investigated.And the kinetics of the leaching process was also analyzed.The experimental results show that the optimal leaching conditions at low temperature and atmospheric pressure are hydrochloric acid concentration of 2.84 mol/L,liquid-solid ratio of 10∶1,time of 60 minutes and temperature of 85℃,and the leaching rate of rare earth reaches 96.04%.The leaching process is controlled by a mixture of diffusion and chemical reactions,with an apparent activation energy of 29.25 kJ/mol,a preexponential factor of 2.0209 s^-1,and reaction orders related to the hydrochloric acid concentration and particle size of 1.49 and-0.55,respectively.The optimal leaching conditions at high temperature and high pressure are hydrochloric acid concentration of 2.03 mol/L,liquid-solid ratio of 10∶1,time of 30 min and temperature of 110℃,and the leaching rate of rare earth reaches 98.13%.The reco-vered rare earth oxides mainly contain Pr4O7 and Nd₂O₃ with a purity of 99.56%.The leaching process is controlled by internal diffusion,with an apparent activation energy of 9.63 kJ/mol and a preexponential factor of 3.57×10^-3s^-1.

For the ammonia-nitrogen wastewater produced from ion-absorbed rare earth separation plants,the influence of production process and emission requirements on wastewater treatment process is analyzed,and the technological route of ammonia recycling in the wastewater is proposed.A combined process based on dissolved air floatation is applied to remove the organic extractant from the wastewater.The electrocoagulation technology is used to remove heavy metals in depth.The ammonia-nitrogen in wastewater is recovered in the form of NH₃·H₂O by steam stripping technology,and ammonia-nitrogen resource utilization is realized while the wastewater is discharged to the standard.The ammonia-nitrogen content of de-aminated wastewater can be reduced to less than 15 mg/L.For the treatment of 1 m³ wastewater,the steam consumption is about 90110 kg/m³,the treatment cost is about 110 to 130 yuan/m³,and the value of recovered NH₃·H₂O is about 140 yuan/m³,which can completely offset the treatment cost.The process is technically and economically feasible.

Iron ions and other impurities existing in the leaching solution of vanadium-containing minerals seriously affect the separation and enrichment of vanadium.In this paper,P204 and P507 were used as extractants to extract vanadium from the simulated leaching solution containing V(Ⅳ)and Fe(Ⅱ)by solvent extraction.The effects of pH value,vanadium concentration and iron concentration on the vanadium extraction effect and vanadium-iron separation effect were investigated.At the same time,the structural changes of the organic phase before and after extraction were also analyzed.The results show that the effect of pH on vanadium extraction and vanadium-iron separation is significant.P204 is more suitable for the vanadium-iron separation under strongly acidic conditions(pH1),while P507 is more appropriate under sub-strongly acidic conditions(pH=2).When the pH value is 2,the concentration of V⁴⁺is 0.07 g/L,the concentration of Fe²⁺is 14 g/L,the O/A ratio is 1.5,the temperature is 25°C,and the stirring time is 10 min,the extraction rate of vanadium by P507 reaches above 99%,and the extraction rate of iron is below 5%,showing a good separation effect of vanadium and iron.The infrared spectrum shows that the extraction of vanadium by P204 and P507 is a cation exchange process,which is presented by the replacement of H~+with VO²⁺in P—OH functional group of the extractant.

With the restart of domestic nuclear power in recent years,nuclear grade zirconium sponge has been widely emphasized as the primary raw material for nuclear grade zirconium alloy in the industry,accelerating the development of the domestic nuclear grade zirconium sponge industry.This study briefly reviews the research progress of the nuclear grade zirconium sponge in China,discusses the common industrial preparation processes of the nuclear grade zirconium sponge,summarizes the advantages,disadvantages,and applications of the main production processes,and analyzes the development trend of the nuclear grade zirconium sponge preparation process in the future from a technical perspective.Some suggestions on cost reduction,efficiency increase,and environmental protection are also put forward.

Water leaching copper-separated residue is an important intermediate product in the hydrometallurgy process of copper anode slime,which is rich in rare and precious metals such as Te,Au,and Ag,and has high recovery value.The leaching rate of tellurium is low due to its encapsulation phenomenon.With the enhancement of ultrasonic wave,the leaching rate of tellurium reaches 93.15%under the optimal process conditions of the ultrasonic power of 150 W,addition amount of NaClO₃ of 1.5 times the mass of the copper-separated residue,liquid-solid ratio of 9 mL/g,NaOH concentration of 1.2 mol/L,reaction temperature of 90℃,and reaction time of 30 min.The kinetics of the leaching process conforms to the Avrami model,and the apparent activation energy is 26.02 kJ/mol.The leaching process is controlled by a mixture of diffusion and interfacial chemical reactions with the kinetic equation of-ln(1-X)=2379.153×e^-3.1297/Tt^0.63.

High-pressure hydrogen reduction method has the advantages of being green and environmentally friendly,low energy consumption,high production efficiency and being easy to automate production.The theore-tical basis of high-pressure hydrogen reduction technology is introduced,the current research progress in the preparation of precious metals and heavy metals by high-pressure hydrogen reduction at home and abroad is reviewed,and the future development direction of this method is prospected.

Copper-manganese resistance alloy strips were prepared by melting,machining,and heat treatment.The effects of solid solution temperature,cold rolling reduction,annealing temperature and annealing holding time on resistivity and temperature coefficient of resistance of the alloy were studied.The experimental results show that the best experimental scheme is the solid solution temperature of 900℃,cold rolling reduction of 90%,annealing temperature of 350℃,and annealing holding time of 1 h.The resistivity and temperature coefficient of resistance of the obtained alloy are relatively low,which are 24.1μΩ·cm and 60×10^-6/℃,respectively.

Using aluminum nitrate(Al(NO₃)₃·9H₂O)as the oxidizing agent,glycine(C₂H₅NO₂)as the reducing agent,and samarium nitrate(Sm(NO₃)₃·6H₂O)as the modifier,γ-Al₂O₃ powders were synthesized by solution combustion method.The products were characterized by XRD,SEM,BET and TG-DTG.The effects of roasting temperature and modifier addition on the phase of the products were analyzed and discussed.The experimental results show that theγ-Al₂O₃ powders with high thermal stability could be prepared under the molar ratio of aluminum nitrate(Al(NO₃)₃·9H₂O)to glycine(C₂H₅NO₂)of 3∶5,addition of modifier Sm(NO₃)₃·6H₂O of 1%,roasting temperature of 1025℃,and roasting time of 4 h.And theγ-Al2O(3)powders have the characteristics of large specific surface area and stable structure,which can be used as the carrier of catalyst.

Mn-modified sulfuric acid activated rare earth tailings catalyst was prepared by impregnation method to investigate the effects of sulfuric acid concentration and Mn modification amount on the denitration activity of the catalyst,and its performance was analyzed by BET,XRD,H₂-TPR and NH₃-TPD.The results show that with the sulfuric acid concentration of 3 mol/L,the reaction temperature window of the catalyst is 350~450℃and its best denitration efficiency of 67%is reached at 400℃.After the addition of 5%Mn,the reaction temperature window of the catalyst moves down to 250~350℃and the N₂ selectivity is maintained above 70%with the best denitrification efficiency reaching 86%at 300℃.With the increase of the sulfuric acid concentration,the specific surface area of the catalyst first increases and then decreases,while the pore volume and pore size decrease rapidly.The sulfuric acid activation increases the number of acidic sites on the catalyst surface and improves the adsorption and desorption ability of the catalyst to NH₃.Mn element exists in the amorphous form on the catalyst surface.The stronger redox ability of the manganese-modified catalyst in the low temperature section is the main reason for its lower reaction temperature window compared with the sulfuric acid activated catalyst.

Rare earth elements have a 4f shell electronic configuration without complete electron occupation and lanthanide contraction,and have unique physicochemical properties.When rare earth was applied to new functional materials as additives or catalysts,it can significantly improve the comprehensive perfor-mance of the material and promote the efficient utilization of rare earth elements.Currently,rare earth functional materials play an important role in fields including alloy targets,permanent magnets,luminescence,catalysis,hydrogen storage,polishing,electrodes,ceramics,shielding,and antibacterial.In this paper,the classification of the rare earth functional materials is introduced in detail,the latest relevant research progress and application status of rare earth functional materials in various technical fields in recent years are reviewed,and the development potential and trend of the rare earth functional materials are discussed.