Flotation property of a Peru As-containing Cu-Mo ore was studied. The results show that the qualified copper concentrate containing 26.65% Cu,0. 637% Mo and 0. 348% As can be obtained from the closed-circuit flotation process with modified thiourea Mac-12 as the collector and AH-1 as the inhibitor for arsenic minerals. And the recovery rates of Cu,Mo and As in the copper concentrate are 88.15%, 85.77% and 33.80%, respectively.

Tantalum and niobium were recovered from primary slime of low-grade tantalum-niobium ore one stage rougher-one stage scavenger with spiral chute and then two stage tabling. Yield and grade of t resultant tantalum-niobium concentrate are 0. 019% and 29.10%, respectively,and the recovery is 41.44 in the closed circuit process. Therefore, fine grade tantalum-niobium ore can be effectively recovered.

High-content chromium in sodium tungstate solution results in phase separation difficulty of sub- sequent processes during waste tungsten recovery by sodium carbonate melting. In view of the above prob- lem, chromium removal together with molybdenum removal by vulcanization was studied through process principle analysis and comparison tests. And the optimal conditions of the relevant process were deter- mined. The results show that when sodium sulfide dosage is four times of the theoretical amount, pH is controlled at 8- 9, and the appropriate temperature and aging time are selected, chromium removal efficiency is high to meet production requirements of the subsequent extraction process, and the quality of the product APT reaches the APT-0 level in GB/T 10116--2007.

Ti-Al amorphous composite coating was prepared on the surface of TC4 （Ti6A14V） substrate by mechanical alloying. Phase composition and microstructure of the coating were studied using SEM, XRD and EDX. Microhardness and friction and wear properties of the substrate and the coating were tested. The results show that with increased milling time, the thickness of the coating effectively increases and the structure becomes more uniform and compact. After milling for 6 h, Ti-Al amorphous composite coating forms on the surface of the substrate, its thickness is about 185μm and its maximum hardness reaches HV0 1425, more than twice the average hardness of the substrate. The friction coefficient of the coating effectively decreases by 6 h milling,and the wear resistance of TC4 material significantly improves.

Al-Al2O3-ZrO2-Y2O3composite coating was prepared successfully on the surface of 304 stainless steel by mechanical alloying at room temperature. The structure and morphology, micro-hardness and high-temperature oxidation resistance of the coating were investigated by related experiments. The results show that with milling time increasing, the thickness of the coating increases at first and then decreases. The coating prepared by milling for 8 h is the densest with average thickness of 200/~m. When the milling time is prolonged to 14 h, part of the coating is peeled off and its thickness decreases. The micro-hardness of the coating is significantly higher than that of the substrate, and declines gradually from the top surface to the inner substrate. The maximum micro-hardness of the coating is up to HV0.1 525, more than 2 times the hardness of the substrate. Furthermore, the high-temperature oxidation resistance ofAl-Al2O3-ZrO2-Y2O3 composite coating is high.

V-Ti-Fe alloy was prepared by metallothermic reduction, and impacts of the material mass ratio of V20s to TiO2 （denoted as R） on liquidus temperature of the slag and composition of the alloy were investi- gated. The results show that with R decreasing, liquidus temperature of the slag obviously increases, the content of Ti,A1,O also increases in the resultant alloy,but the content of Si is almost unchanged. The re- suits from XRD,SEM and EDS show that the resultant alloys have vanadium-based solid solution structure. There is a certain Ti segregation in alloy,for titanium-rich phase is detected. When the value of R is 0.6,obvious A1-O inclusion can be detected in the alloy.

. A356 aluminum alloys modified with yttrium were prepared at different melt cooling rates, and then their microstructure and tensile properties were studied. The results show that with melt cooling rate decreasing,a-Al primary crystal has bigger grains and irregular distribution,and its secondary dendrite arm spacing increases. Meanwhile,the microstructure of eutectic silicon is transformed from granule or fibre to flake or needle, and the tensile properties of the alloy significantly decrease resulting in the transition from ductile fracture to brittle fracture. The rare earth element of yttrium is sensitive to the melt cooling rate. Only at relatively high melt cooling rate, yttrium can promote eutectic silicon growing up according to modification morphology.

The D76.2 mm and L50 mm-size LaB6 polycrystal was prepared by pre-pressing of LaB6 powder, followed by repeated hot-pressing sintering. The product has a relative density of more than 95 %,and its shape is complete without defects.

Fine-grained CoO powders were prepared directly by solid phase synthesis-heating blasting de- composition with COSO4 ·7H2O and NH4 HCO3 as the materials. And their composition and morphology were characterized by SEM,XRD,IR and chemical titration. The results show that fine-grained CoO pow- ders of pure octahedral morphology can be obtained under the conditions of excessive NH4 HCO3 and 650-750 ℃ reaction temperature,having the advantages of simple process and high efficiency.

Experiments were carried out to research the hardness, tensile strength and fracture toughness of high volume fraction SiCp/A1 composite. The results show that with the volume fraction of SiC particles increasing,Vickers hardness of the composite monotonically increases, but tensile strength and fracture toughness increase at first and then decrease, both up to the maximum value when SiC volume fraction is 55%.