The new HCO3- type quaternary ammonium salt OMEA was synthesized for vanadium extraction from vanadium-containing solution gained by blank roasting-pressurized alkaline leaching-desilicification of vanadium-containing carbonaceous shale. The comparative tests with OMEA and N263 quaternary ammo- nium salt were conducted. The results show that the vanadium extraction rate of 200 g/L OMEA system and 150 g/L N263 system decreases with the increase of pH value of the vanadium-containing solution. The vanadium extraction saturation capacity of the two kinds of extraction agents is relatively low,OMEA system has lower extraction proportionality than N263 system,indicating that the utilization of OMEA quaternary ammonium salt is higher, and its vanadium binding capacity is stronger too. During the stripping process,NaOH solution has good striping effect on loaded organic phase,and the stripping rate of OMEA system is 3~ higher than that of N263 system. Repeated regeneration of OMEA and that of N263 quater- nary ammonium salt extraction agents with strong stability has little effect on vanadium extraction saturation capacity. Thus, OMEA has good prospects in the process of alkaline leaching-vanadium extraction of vanadium-containing carbonaceous shale,to resolve the problems of tow saturation capacity and long phase separation time existing in N263.

The experimental study was conducted on NaOH leaching and ion exchange separation of gallium -rich material obtained by concentrate roasting-calcine sulfuric acid selective enriching of alunite. The re- sults show that during the NaOH leaching, the gallium leaching rate can reach 98.84% under the conditions of 75 % NaOH concentration, 15 rain leaching time, 3 ： 1 liquid-solid ratio, 300 r/min agitating velocity. During the ion exchange,the gallium adsorption rate is 71.4% under the conditions of the NaOH concentration of 150 g/L in adsorbed solution,Rexp-31 resin dosage of 150 g/L,spray rate of 5 mL/min,resin bed height of 15 cm. The gallium desorption rate can is 88.16% ,under the conditions of NaOH and Na2S concentration in the desorption agent of 160 g/L and 50 g/L,respectively, liquid-solid ratio of 10 ：1, de- sorption duration of 1 h.

Nb（OH）5 was obtained from niobium liquid by fractional precipitation, and then Nb2O5product was prepared by washing, drying and calcination. Process control conditions ofNb2O5particle size were studied. The results show that the obtained Nb2O5 product has average particle size （D50） of 1-5 μm by the process as follows：bubbling 0.1 MPa ammonia into the feed liquid, neutralizing niobium liquid pH to 4,natural cooling for 16 h,quickly bubbling 0.3 MPa ammonia to complete reaction （precipitation end pH = 9） ,washing,drying at 240 ℃ for 6 h and calcination at 860 ℃. When niobium liquid concentration increa- ses to a certain range, the final Nb2O5product has increased average particle size. With increased calcination furnace temperature,the average particle size of the calcined Nb2O5 product increases.

Analysis is made on the main factors affecting impurity separation in each process step of tantalum and niobium traditional hydrometallurgy,and the methods are introduced to reduce product impurity content. The latest development is reviewed of impurity separation technology during tantalum （niobium） oxide production.

Water model physical experiment platform for electrolysis process of 3 kA neodymium electroly- zer was established based on the similarity theory to study influence of anode wall upward slopes on bubble escape in final electrolyzation stage. The time-varying parameters such as bubble shape, diameter, contact area and sliding distance were studied by water model experiment on the wall with different upward slope angles of 3°,5°,7°,10° and 20°. The results show that when wall upward slope angle is too large,the time of bubble escape increases, bubble clusters disappear, and meanwhile anode effect occurs to reduce current efficiency and increase production costs. In accordance with the actual electrolysis process,anode wall upward slope angle should not be too large,and 3° is the best option.

The preparation method of Ti-enriched slag was studied by hydrochloric acid leaching of impurities from red mud. The effects of hydrochloric acid concentration, leaching temperature, liquid-solid ratio and leaching time on titanium dioxide grade of Ti-enriched slag were investigated. Phase transformation and action mechanism of the acid leaching process were analyzed by ICP-AES and XRD. The results show that under the conditions of hydrochloric acid concentration of 30%,leaching temperature of 80 ℃,liquidsolid ratio of 7 ： 1 and leaching time of 60 min, the titanium dioxide grade of Ti-enriched slag can reach 24 %. With the increase of concentration of hydrochloric acid, calcite in the red mud disappears, the hema- tite,cancrinite and perovskite gradually dissolve, but the brookite and quartz haraly dissolved.

The process conditions were investigated of silicon extraction and calcium silicate preparation from the filter residue in the process of titanium extraction of roasted titanium slag with concentrated sulfuric acid. The main process steps include alkali-solution and calcification. The effects were investigated of NaOH-residue mass ratio, reaction temperature, reaction time and liquid-solid mass ratio on SiO2 extraction rate from the filter residue during alkali-solution. The optimum operating conditions of alkali-solution are obtained as follows： reaction temperature of 190 ℃ ,NaOH-residue mass ratio of 3 ： 1 ,liquid-solid mass ratio of 4.5 ： 1 and reaction time of 60 min. And SiO2 extraction rate is 74.09 % under the above conditions. The effects were investigated of reaction temperature and reaction time on calcification rate of sodium silicate solution during calcification. The optimum operating conditions of calcification are obtained as follows： reaction temperature of 100 ℃ and reaction time of 45 min. And the calcification rate of sodium silicate solution is 94% under the above conditions. Calcium silicate powder product contains 44.36% CaO and its main phase is CaSiO3 ,having loose and porous morphology and micron-level particle size.

WO3 and W powders were prepared with Cr-doped APT as raw material,and their physicochemical properties were studied. The results show that Cr-doped WO3 and W powders have consistent crystal structure with ordinary WO3 and W powders,and Cr exists in the form of Cr2O3 in the two powders. Compared with ordinary W powder,Cr-doped W powder has smaller particle size, good uniformity and complete crystal structure. Cr can effectively inhibit vapor deposition and growth of W power during reduction, but the oxygen index is slightly higher. Cr distribution in both WO3 and W powders is of good macroscopic and microscopic uniformity.

Using the refractory powders of pure molybdenum as raw material, the molybdenum billet with relative density of 96.45% was prepared by high-pressure torsion at 350 ℃ temperature and 1.5 GPa pressure. The rules of pore evolution and densification strengthening were analyzed with various detection methods in the process of high-pressure torsion. The effect was studied of height to diameter ratio of prepressed molybdenum billets on the microstructure and properties of high-pressure torsion molybdenum billets. The results show that the smaller the height to diameter ratio, the greater the material equivalent shear strain,and the higher the relative density and hardness value of high-pressure torsion molybdenum billets. Furthermore,its internal sub-grain size refinement and microscopic strain accumulation are more obvious. When the height to diameter ratio is reduced from 0.5 to 0.3, the dislocation density caused by grain refinement and strain accumulation increases from 1.67 ×10^14 m 2 to 3.03×10^14 m-2.

TiN coatings were deposited on the surface of cemented carbide substrate by multi-arc ion plating. The effect was studied of total gas flow on the surface morphology and mechanical properties of TiN coatings. The surface morphology of the coatings was observed by SEM. The pixel distribution of the coat- ings was analyzed by ImageJ software. And the mechanical properties of TiN coatings were evaluated by automatic scratch spectrometer and nanoindenter. The results show that with total gas flow increasing, both the amount and size of microparticles on coating surface increase, the adhesion force of the coatings in- creases firstly and then decreases, but its micro-hardness decreases firstly and then increases. When the total gas flow is 300 mL/min,the coatings have the most gas pits and the highest adhesion force of 106.4 N. When the total gas flow is 100 mL/min,the coatings have the highest micro-hardness of HV3 021.