Based on the present K2TaF7 process flowsheet and actual production , study is made of the effects of KCl dosage, crystal temperature and concentration on the recovery of K2TaF7. Improvement measures are put forward to reduce the production cost and improve product recovery.

Study is made of the electrical conductivity and neodymium solubility of Nd2O3-NdF3-LiF fusion salt system. Regression equations were fit according to experiment data. Analysis is made of the effects of temperature, content of LiF and Nd2O3 on the physical property. The results show that increase of temperature and LiF content and decrease of Nd2O3 can improve electrical conductivity of the fusion salt system, while decrease of LiF content and increase of Nd2O3 can decrease neodymium solubility in the fusion salt. The research results can provide criteria for proper selection of electrolyte composition for Nd production by F salt electrolysis.

Methods of SEM,TEM,laser particle analyzer,X-ray diffraction and specific surface area are applied to test the particle size of self-made superfine WC powder. Discussion is made on the effect of the testing principle and particle shape on the testing accuracy of the particle size. Through analysis of the test results,study and comparison is made of superiority and limitation of several superfine particle characterization.

The nucleation mechanism and kinetics of HAP by electrodeposition was studied through constant -potential experiments. The results showed that there were differenti-t transient curves at different potential. However,it was found that linear relationship existed between i-t^1/2 at different potential with three-dimensional instantaneous nucleation. Crystal is grown faster with the negative shift of the additional potential,indicating that additional potential plays a remarkable role in the crystal growth.

Based on the contrast tests between the WC/steel composite material （ code GJH-2 alloy） and the Gx cast alloy used in bar or wire mill for guide rollers, discussion is made on the future application of the WC/steel composite material in the hot-worked die. The contrast test results showed that GJH- 2cermet is characterized by good high-temperature wear resistance under corresponding heat treatment at 450-650℃ with heavy load and sliding velocity above 2 m/s.

The surface and microstructure of the deep-drawn tantalum shell is observed by scanning electron microscope and optical microscope and effect of deformation and annealing treatment on the microstructure of tantalum plates is studied. It shows that grain refinement is very important to assure good surface quality of deep-drawn Ta shell. More cold-rolled deformation prior to annealing is good for finer grain for pure Ta produced by electron-beam smelting,with 90% rolling deformation, initial recrystallization temperature about 800 ℃ ,finer grain can be obtained after annealing at 850 ℃ for 40 min. And proper high-temperature short-time annealing can make grain finer.

The composition and hot-pressing parameters of WC/SiCw ceramic composite were optimized through orthogonal experiment. Compared with those of the pure WC, the bending strengh, fracture toughness and Vicker＇s hardness of the optimized WC/SiCw composite are increased by 50%, 30% -40%, and 10% - 15 % respectively. The cutting test results show that the optimized WC/SiCw composite ceramic cutting tool material exhibit superior turning properties to similar hard alloy material, indicating that it is feasible to toughen the WC ceramic cutting tool material by using SiCw instead of metallic binding phase.

High-purity europium metal containing less than 300 ×10^-6 oxygen can be obtained by 2-step distillation and ingot casting. 2-layer packing is applied filled with Ar and with RE degasser in the exterior layer to avoid oxidization of europium metal during storage and transportation to ensure batch production.

Research is made on the influence of sinter pile stuff on recovery of Sm metal during La thermal reduction of Sm2O3. The recovery of metal Sm in the different parts of the crucible were acquired by the chemistry analysis and hot weightness methods. The porosity of La slag in the differ part pot was measured by hydrostatic weighing,indicating the phenomenon of sinter pile stuff in the pot bottom during La thermal reduction of Sm2O3 ,Based on the test results the sinter pile stuff was analyzed according and optimization test was made with higher recovery.

Steel-bonded cemented carbide powder mixture（TLMW50） processed by explosive compaction was successfully bonded to the surface of carbon steel through liquid phase sintering. In order to determinate the mechanical property of steel-bonded cemented carbide TLMW50 cladding, study is made of the effect of different sintering temperature at 1 335-1 350℃ on the hardness and bonding strength of the cladding through 3-point bending and hardness test. The test results showed that the hardness of TLMW50 cladding and bonding strength between TLMW50 cladding and carbon steel substrate was increased with the increase of the sintering temperature, a good metallurgical bonding condition in sinter interface and good mechanical property of the cladding were found at 1 350℃.