The extraction properties and mechanism of three different extraction systems （P350, P507 and P20：l） for P and Sc were studied. Based on comparison, P204-TBP-kerosene system is the best extraction system for separation of Sc and Pb. The ideal organic phase composition is 25% P204＋4% TBP＋ 71% kerosene, and the suitable feed liquid acidity is 5.4 mol/L. Under the above conditions, Sc extraction rate is 98.78% and P extraction rate is 20.99%. P204 extraction system is suitable for a wide range of feed liquid acidity and P content,and the recovered products can be used directly as a raw material into a high-purity scandium oxide production line. This method has simple and economical process and high recovery rate with the value of popularization and application.

Magnesium chloride and calcium chloride were used to co-precipitate silicon and phosphorus from sodium vanadate solution. The effects of precipitant dosage, solution pH value, purification temperature and time on silicon and phosphorus removal were investigated. The optimum process conditions are as follows： cMg∶（cSi＋cP）=1.3,cCa∶（cSi＋cP）=0.4,pH value of 9. 5,reaction duration of 3 h and temperature of 80 ℃. Under these conditions,the precipitation rates of silicon and phosphorous reach 95.67 % and 88.01 %, respectively,while the precipitation rate of vanadium is only 3.72%. The above method has excellent tech- nical indexes and broad prospects for industrial applications.

The zinc smelting process of oxygen pressure leaching of zinc sulfide concentrate is introduced, the enrichment degree of Ge in the process is analyzed, and the typical technological flowsheet is shown. The oxygen pressure leaching process of zinc sulfide concentrate can enhance the recovery of Ge associated in zinc sulfide concentrate. Ge leaching rate in the above process is high,and high-grade germanium-rich slag can be obtained from the leaching solution by neutralization precipitation or replacement method. In production practice,the leaching rate of Ge can reach 95% and the recovery rate of Ge can reach 75% ,and Ge can be enriched by about 50 times in the replacement residue.

NiCrWCAl alloy coatings with different aluminum contents were fabricated on Q235 steel sub- strate by argon arc cladding technology. The microstructure and properties of cladding coatings were investigated by using inverted microscope, X-ray diffractometer, hardness tester and electrochemical workstation. The results show that the fabricated NiCrWCAl alloy coatings have refined grains,uniformly dispers- ed fine precipitates and compact microstructure with the increase of the aluminum content in a certain range. The cladding coatings mainly consist of fcc-structure γ-Ni solid solution, γ′-Ni3A1 phase, bcc-structure β-NiAl phase,and Cr7 C3 and WC hard phases. As the aluminum content increased, the average hard- ness of cladding coatings firstly increases and then decreases. The microhardness distribution of the clad- ding coating is ideal with 7% aluminum content,and its average HV0.2 value is 550. After addition of alu- minum element, NiCrWC alloy coatings have more positive corrosion potential, and the corrosion resistance of cladding coatings gradually intensifies with aluminum content increasing. When the aluminum content is 7 % ,the cladding coating displays the lowest corrosion rate and excellent corrosion resistance with a corro- sion current density （icon） of 0. 872 μA/cm2and a polarization resistance （Rp） of 113.7 kΩ· cm2.

The microstructure, phase composition and mechanical properties of Ti-40Al-3.5Nb-0.8Mo-0.3Y superalloy were studied by scanning electron microscope,X-ray diffractometer and tensile test. The results show that the chaotic βphase in Ti-40Al-3.5Nb-0.8Mo-0.3Y alloy can effectively improve high tempera- ture resistance of the alloy. Hot isostatic pressing and homogenization processes improve the density of the alloy. The tensile strength of the alloy at room temperature is 583 MPa, with flat tensile fracture morpholo- gy and brittle transgranular cleavage fracture characteristics. When the tensile test temperature gradually rises from room temperature to 760 ℃ ,the tensile strength of the alloy continuously declines,and the elon- gation of the alloy gradually rises of brittle fracture characteristics.

La0.6Sr0.4CoO3 perovskite-type oxide was prepared with sol-gel method, and the effect of calcina- tion temperature on its electrocatalytic properities in bifunctional oxygen electrodes was particularly stud- ied. The phase and morphology of La0.6Sr0.4CoO3 perovskite-type oxide were analyzed by XRD, SEM and BET,and the steady-state polarization curves and steady-state galvanostatic curves of the cathode and an- ode of the bifunctional oxygen electrodes were plotted in a three-electrode system. The results show that increasing the calcination temperature is advantageous for decreasing the impurities in La0.6Sr0.4CoO3 per- ovskite-type oxide. When the calcination temperature reaches 800 ℃, pure La0.6Sr0.4CoO3 perovskite-type oxide is obtained with the highest catalytic activity,and the bifunctional oxygen electrode owns the lowest electrochemical polarization and the highest stability.

The static nitriding and bottom-blown nitrogen nitriding processes of Sm-Fe melt were re- searched. The phase, morphology and composition of nitrided alloy samples were investigated through XRD,SEM and EDS, respectively. And the effects of the two nitriding processes were compared. The results show that during static nitriding of Sm-Fe alloy melt,the surface of the sample is easy to form highmelting-point refractory Sin2O3. Sm2O3 covers Sm-Fe alloy surface to hinder the diffusion of N atoms into the melt,and therefore the static nitriding method fails to achieve the desired nitriding effect. The nitrogen element is found in Sm2Fe17 phase of the alloy sample after bottom-blown nitrogen nitriding,and the main peak of Sm2Fe17 phase shifts to a smaller angle,indicating that N atoms enter Sm2Fe17 phase and the nitriding effect is good.

Jarosite was prepared from titanium white waste water by adding potassium chlorate and potassi- um hydroxide. The effects of reaction temperature,solution pH and reaction time on Fe precipitation rate were investigated. And microstructure and phase composition of the precipitated product were also ana- lyzed. The results show that the precipitation rate of Fe from titanium white waste water is more than 99% under the conditions of temperature of 95 ℃, solution pH of 2.0 and reaction time of 40 min. The precipita- ted product is the acicular crystal of jarosite. In addition to the significant decrease of SO4^2-and Fe2＋ concentrations in the filtrate,the contents of the rare metal ions such as Ti,V and Sc are almost unchanged, which is beneficial for the separation and purification of rare metals in the next process step.

The industrial method for lithium isotope （6Li and 7Li） separation is using amalgam. However, this method requires the use of plenty of toxic mercury, causing serious human health and environmental problems. Gallium is a kind of liquid metal like mercury. Phase equilibrium diagrams of Hg-Li and Ga-Li are compared, and it is found that the two systems are very similar. Therefore, gallium may replace mercu- ry to separate lithium isotope. Gallium-indium alloy of lower eutectic temperature was selected to separate lithium isotope. The results show that the lighter isotope 6 Li is preferentially fractionated into gallium-indium alloy with single-stage lithium isotope separation factor of 1.01. Gallium-indium alloy has the poten- tial for the separation of lithium isotope with certain development prospects.

The texture and microstructure evolution law of hot-pressed sintered beryllium ingot during warm-rolling was studied by electron backscatter diffraction （EBSD）. The results show that slip is the main deformation mechanism during warm-rolling. With the increase of rolling deformation, the grains are gradually elongated and refined. When the reduction reaches 37.9%, the basal texture in rolled beryllium sheet reaches a maximum value. And then continuously increasing the reduction, all the texture, grain size and mierohardness of beryllium material no longer change significantly. The annealing process is required during or after rolling of beryllium material. The annealing process has a certain weakening effect on the basal texture of beryllium sheet,which can improve its internal microstructure and rolling performance.