The research progress on recovery process of associated rhenium during molybdenum metallurgy in recent years is reviewed, and the processes of solvent extraction and ion exchange are particularly introduced. Finally, the development prospects of rhenium recovery methods are presented,

By continuous saponification of organic phase, sharing of lotion and stripping liquid, and a series of measures for energy saving and emission reduction, rare earth extraction separation process is optimized and improved. The consumption of energy, materials and new water, and the costs of wastewater treatment are reduced. The cyclic utilization rate of wastewater reaches 95 %. The improved process not only achieves cleaner production, but also increases economic efficiency of the enterprise.

The model of electric field and thermal field coupling in 3 kA rare earth neodymium electrolytic cell was established by a numerical Simulation software COMSOL with certain height of cathode and anode and insertion depth. By comparing the simulation results of the electric and thermal fields in the rare earth electrolytic cell before and after coupling, it is found that the distribution of the electric field between the cathode and the anode after coupling is more chaotic than that before Coupling, and the difference of the electric potential before and after coupling is 0.03 V. The distribution patterns of thermal field are basically consistent before and after coupling, and the temperature distributed between the cathode and the anode reaches the maximum. After coupling, the temperature gradually rises with obvious difference before and after coupling,and the difference of the highest temperature is about 24 ℃. there is a certain interaction between these physical fields in rare earth electrolytic cell, further reflecting the rationality of coupling process.

Using coal powder as reducing agent, carbon thermal reduction of ilmenite with 61.85 % TiO2 was performed at 1 573-1 873 K,and the phase transformation and microstructure of reaction products were studied by XRD and SEM. The results show that when carbon-oxygen ratio of carbon to all oxides in ilmenite is higher than 1 ： 1,all the reduction products are TiC and Fe. So the TiC/Fe composites can be obtained from ilmenite by carbon thermal reduction, providing reference for the comprehensive utilization of Fe and Ti in ilmenite ore.

Fluorination roasting pretreatment was adopted to improve Ge extraction rate from low-grade Ge concentrate. The effects of fluoride dosage, roasting temperature and roasting time on Ge extraction rate were investigated by single factor optimization experiment and orthogonal experiment. The results show that NaF dosage and roasting temperature have great effects on Ge extraction rate, and the roasting time should not be too long. Under the fluorination roasting pretreatment conditions of the mass ratio of NaF dosage to Ge concentrate of 1 ： 1, roasting temperature of 800 ℃ and roasting time of 2 h,Ge extraction rate reaches the maximum value of 99.16%. This method is also applicable to the secondary extraction of Ge from chlorination distillation residue,and Ge extraction rate reaches 91.58% with greatly reduced Ge content in the residue. There is no HF generated in the whole extraction process. In addition,this method has many advantages, such as low equipment requirements, simple operation and environment-friendly process. Keywords： germanium concentrate; germanium extraction; fluorination roasting; chlorination distillation; NaF

The germanium content in the coal ash containing germanium was measured with titration meth- od,and other chemical components were tested by ICP. The phase composition of the coal ash containing germanium was studied by ore microscope,XRD and SEM-EDS. The results show that the content of SiO2 and iron oxide are the highest, followed by Al2O3 ,CaO and MgO, the carbon content greatly fluctuates, and arsenic content is also high. Before carbon removal,germanium dispersedly exists in various phases of the coal ash containing germanium. Germanium content is relatively higher in the phases with high SiO2 and iron oxide content, and lower in carbon particles. After carbon removal, germanium-rich phase appears in coal ash containing germanium, mainly existing in the form of Mg3 Fe3 GeO3 complex oxide and inlaid in oxides such as SiO2 and CaO.

TaW10 alloy was fabricated by hot isostatic pressing with hydrogenation-dehydrogenation powder as the raw material. And then TaW10 alloy was subjected to heat treatment at 1 800-2 200 ℃.The relationships between heat treatment temperature and oxygen content or mechanical properties of TaW10 alloy were studied. The results show that with heat treatment temperature improved, the fracture mode of TaW10 alloy changes from brittle cleavage fracture to brittle intergranular fracture and then to ductile dimple fracture. The strength increases firstly and then decreases with heat treatment temperature improved, and reaches the highest value at 2 100℃.When the heat treatment temperature is up to 2 150 C,TaW10 alloy starts to show ductile deformation characteristics. TaW10 alloy has sharply declined oxygen content after heat treatment at 2 000 ℃,and then there is no obvious change of oxygen content with further im- proved heat treatment tempreature. TAW10 alloy has good strength and ductility only when its oxygen content is sufficiently low and its heat treatment temperature is above 2 150 ℃

A series of calix]-8]arene phosphate derivatives with high extraction efficiency to light rare earth ions and a certain selectivity were synthesized by one step of substitution reaction. The results show that the extraction ratio of La and Ce light rare earth is up to 98% with the calix[8]arene phosphate derivatives,10% higher than that with calix[8-]arene. Under the same conditions and with the calix[8]arene phosphate derivatives,La extraction ratio is 6 % higher than Ce extraction ratio. Efficient extraction separa- tion of La and Ce ions can be achieved by multi-stage centrifugal extraction fractionation.

The microstructure of the double main phase rare earth permanent magnet Nd2 Fe14 B-Ce2 Fe14 B prepared by SPS was studied. The results show that the double main phase rare earth perrpanent magnet Nd2Fe14B-Ce2Fe14B with high density can be obtained in a spark plasma sintering furnace with lower sintering temperature and less holding time, and its microstructure is composed of uniformly distributed and independent Nd2 gel4 B phase and Ce2 Fe14 B phase. Annealing can promote the crystallization of the sintered magnet and spark plasma sintering can inhibit the diffusion of rare earth elements in the double main phase rare earth permanent magnet Nd2 Fe14 B-Ce2 Fe14 B. With the increase of annealing temperature, The diffusion distance increases of the rare earth elements between Nd2Fe14 B phase and Ce2 Fe14 B phase.

Mechanical properties and microstructure of laser welding joint of TC15 titanium alloy were studied by tensile test, hardness test and metallographic analysis. The results show that depth-to-width ratio of welding line ranges between 4 and 6. Columnar crystals are distributed in weld area symmetrically aside the weld center line,and they are mainly large grains of βphase. The heat affected zone consists of fine grain zone,coarse grain zone and recrystallization zone. And the grains nearby the fusion line are significantly coarsened. The weld zone has relatively stable hardness distribution and close hardness to the coarse grain zone. The weld sample with low welding current has the minimum tensile strength, and its fracture is in the weld zone. With welding current increasing,the welding joint has improved tensile strength.