Multi-pass plane strain compression tests of commercially pure titanium were carried out on Gleeble—3800thermal simulation test machine to simulate practical hot rolling process,and the deformation temperature is 650～800 ℃ and the strain rate is 1s^（-1） or 5s^（-1） .Based on the data of true stress and strain,softening rate and work-hardening rate,softening behavior and dynamic recrystallization critical strain of commercially pure titanium were investigated during multi-pass deformation.The results show that softening rate of commercially pure titanium increases with deformation temperature rising and strain rate decreasing in the interval,and its recrystallization critical strain decreases with deformation temperature increasing.There is linear relationship between dynamic recrystallization critical strainεcand peak strain ε_p of ε_c=0.467 6ε_p.

The three-roll spiral rolling model of TC17 titanium alloy rod was established by using the finite element analysis software DEFORM-3D.The whole rolling process was numerically simulated and the change laws were analyzed of equivalent stress and strain of the rod with 30 mm or 50 mm reduction.And then the experimental study was carried out.The results show that it is feasible to simulate three-roll spiral rolling process of the titanium alloy rod.Controlling reduction can improve the forming quality of the rod,and the metal flow in the rod mainly occurs on the surface during rolling.

Superfine WC and electrolytic nickel powder were used as the principal raw materials,the total carbon content in the mixture was adjusted,and then WC-15Ni non-magnetic cemented carbide with high properties was prepared by vacuum sintering and hot isostatic pressing（HIP）treatment.The effects were investigated of different carbon content and HIP treatment on the microstructure and properties of the sample.The results show that either too low or too high total carbon content in the mixture can deteriorate the properties of non-magnetic cemented carbide.When the carbon content in the mixture is 6.13%（mass fraction）,the material gets good performance with transverse rupture strength up to 3 300 MPa.In addition,HIP treatment can effectively eliminate the residual pores in the non-magnetic cemented carbide,stabilizing and improving its mechanical properties.

The principle and impact factors are introduced of zinc melting method in waste cemented carbide recovery.The existing problems and their solution methods are discussed of zinc melting method in waste cemented carbide recovery.And the latest development is emphatically introduced of zinc melting method in waste cemented carbide coating recovery,the existing problems are analyzed,and the suggestions are proposed on future development of zinc melting method in waste cemented carbide recovery.

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.