The technology and process for gallium industrial production and gallium extraction from coal ash are summarized.In view of the advantages and disadvantages of each gallium recovery process,the current research on the application of resin method in acid system is emphatically analyzed.The proposals are put forward for development of gallium recovery technology in hydrochloric acid system.

Titanium with the purity higher than 4N5 was prepared with iodination method and electron-beam smelting method.During iodination,TiI4 was produced in 800-900Khalogenation area from crude titanium,then TiI4 reacted with crude titanium to synthesize TiI2,and meanwhile TiI2 decomposed at 1 200-1400K.Surface morphology,micro-area chemical composition and impurity content of the samples were analyzed by SEM,EDS and GDMS,respectively.Based on experiments and thermodynamic analysis,the temperatures in halogenation area and decomposition area and the reason for existence of Cr and Ni impurities are determined to provide a theoretical basis for the future control of metal impurity content and experimental condition optimization.

A hydrometallurgical method was studied for platinum extraction from spent auto-catalyst in an autoclave,and then a process flowsheet was suggested for efficiently recovering platinum group metals from spent auto-catalyst with low energy consumption and low waste emission.Spent auto-catalyst pretreated with oxygen and hydrogen was put into a glass bottle together with hydrochloric acid,sodium chloride and sodium chlorate.And then the bottle was put into an autoclave filled with 145℃ water to extract Pt at1 013.25 kPa oxygen pressure（1 418.55 kPa total pressure）.The possible reactions were proposed of platinum extraction in the autoclave.Effects were emphatically studied of redox pretreatment of spent catalyst successively with oxygen and hydrogen on Pt extraction.The results show that the platinum extraction rate of non-pretreated spent catalyst is 82%.Pretreated with O2 and H2,the spent catalyst has increased platinum extraction rate by 10% and 6%,respectively,showing that the effect of O2 pretreatment was better than that of H2 pretreatment.The optimal conditions of O2 pretreatment are 300-400 ℃ pretreatment temperature,2.0hpretreatment duration and 150-200mL/min O2 flow.The optimal conditions of H2 pretreatment are 300-600 ℃ pretreatment temperature,2.0hduration and 150-250mL/min H2 flow.The Pt extraction rate is 99% under the optimal conditions.

The rare earth solution obtained by alkali fusion and acid leaching of waste rare earth aluminate trichromatic phosphors usually includes high content aluminum.Therefore,sodium or potassium organic salt selective precipitation method was presented to purify the solution,and the effects were investigated of solution pH,initial aluminum content,temperature and selective precipitant dosage on aluminum removal.Experimental results show that under the conditions of initial rare earth solution pH higher than 2.8,room temperature and atmospheric pressure and precipitant dosage more than 1.3times the theoretical amount,the concentration of residual aluminum in the solution is less than 0.22g/L,aluminum removal efficiency reaches 98.6%,and rare earth loss rate is only 0.83%.

Research progress of tungstate functional materials is reviewed.Process flowsheet is introduced of tungstate preparation with micro-emulsion method,ion exchange method and chemical precipitation method,respectively.And the applications of tungstate materials are summarized in the fields of luminescence,catalyst,photocatalyst,negative thermal expansion,corrosion,electrolyte and antibacterial.

Using ammonium metatungstate（AMT）,cobalt acetate and organic carbon as raw materials and deionized water as solvent,WC-6Co nanocomposite powder was prepared by the new technology of spray drying-calcination-ball milling-continuous reduction carbonization.Specific surface area,phase composition and morphology of the powder were analyzed by nitrogen adsorption method,X-ray diffraction（XRD）and scanning electron microscope（SEM）,respectively.The effects of ball milling on the performance of W-Co composite oxide powder were investigated as well as specific surface area change of the powder during continuous reduction carbonization.The experimental results show that ball milling before continuous reduction carbonization can effectively crush the powder.And the powder has better crushing effect and more uniform particle size distribution by increasing ball to powder ratio or extending ball milling time.When the ratio and time are 10∶1and 240 min,the powder has the optimal crushing and dispersing effect with 11.62m2/g specific surface area.Ball-milled W-Co composite oxide powder is agglomerated,sintered and pre-alloyed during continuous reduction carbonization to generate WC-6Co composite powder with an average particle size of 80 nm.

The sintered bar of high-carbon niobium-tungsten alloy HCNb521 was processed by twice electron beam smelting to control carbon,zirconium and gas content in the alloy.The microstructure of the smelting ingot was investigated after high temperature annealing.And the trade-off study was made on the mechanical properties of high-carbon niobium-tungsten alloy sheet HCNb521 and ordinary niobium-tungsten alloy sheet Nb521.The results show that the increase of carbon content promotes the formation of more secondary strengthening phase in niobium-tungsten alloy to improve alloy intensity.Electron beam smelting can effectively control component content of niobium-tungsten alloy ingot.Compared with ordinary niobium-tungsten alloy,high-carbon niobium-tungsten alloy material has slightly better mechanical properties.

The influences were investigated of smelting speed and tungsten element segregation on service performance of tantalum strip as superconducting wire barrier.The results show that the tantalum ingot can be purified and its microstructure also can be improved by slowing down the first smelting speed and raising up the second smelting speed,and therefore the product of tantalum strip has fine and homogeneous microstructure.By strictly controlling the tungsten content in the raw materials（≤0.002%）and reducing welding points or applying other welding equipment without tungsten welding pins,tungsten impurity into the ingot can be avoided and tungsten segregation in the ingot can be reduced to prevent fracture of tantalum strip during the service.

The effect was studied of quenching at different temperature on microstructure and hydrogen storage properties of 40Ti-40V-10Cr-10 Mn alloy.The results show that the unquenched sample is V-based solid solution with body centered structure having two close characteristic diffraction peaks of BCC-1phase and BCC-2phase.The sample quenched at 1 473 Khas a single BCC-1phase.Both the samples quenched at1 573 Kand 1 673 Kconsist of BCC-1phase,BCC-2phase and C14-Laves phase with hexagonal closepacked structure.The results of kinetic mechanism study show that the hydrogen absorption kinetic process of all the samples can be described by chemical reaction mechanism,while their equations of kinetic mechanism are significantly different and thus their hydrogen absorption rates are different.With the increase of quenching temperature of the samples,their hydrogen absorption capacity at 298 K decreases firstly and then increases（getting the minimum at 1 573 Kand the sample quenched at 1 673 Kclose to the unquenched sample）,their hydrogen desorption capacity and hysteresis at 298 Kare gradually improved,and their hydrogen desorption capacity at 373 Kalso decreases at first and then increases（getting the minimum at 1 573 Kand the sample quenched at 1 673 Khigher obviously than the unquenched sample）.

Ti35alloy bar was annealed at 700 ℃for 8h,and then investigated by full immersion corrosion tests and polarization curves and electrochemical impedance spectroscopy in 8mol/L nitric acid.The experimental results show that through a long time of annealing,the grain size of Ti35 alloy bar obviously increases,its corrosion current density decreases,impedance arc radius significantly increases,phase angle platform broadens and modulus value increases,resulting in its corrosion resistance greatly improved in concentrated nitric acid.