<Abstrcat>Study is made on the technical requirements for the tests and production of ultra-pure tantalum oxide/ultra-pure niobium oxideDescription is made of the bench-scale tests,pilot tests and commercial-scale tests on the ultra-pure tantalum oxide/ultra-pure niobium oxide.It also describes the technical index and its application.

Based on concentration-pH graph,study is made of relationship between pH and equilibrium concentration of some representative metal ion in the solution containing CO^2-_3.In terms of thermodynamic analysis,the characteristic and the pH conditions of carbonate deposition,the possibility of separating metals by the process of carbonate deposition is discussed.

Preliminary feasibility study is made of extracting Ga、Nb、Li and Sc from bauxite ore containing rare metals.Research is made on the process of bauxite ore sintering,followed by agglomerate alkaline pickling,residue acid leaching.The result showed that over 90% of gallium goes to leachate together with Al.Sc and Nb is upgraded from acid-leach residue.Sc can be quantitatively dissolved into concentrated HCl with Nb difficult to dissolve and Li distributed in alkaline/acid leach solutions.The test results showed that extracting of gallium、scandium、lithium and niobium from bauxite ore is technically feasible.The key factor lies in economic feasibility.It is suggested to put in red mud pretreatment in order to reduce the cost of extracting rare metals.

<Abstrcat>Study is made on the effects of mixed carbon content on the spark plasma sintering binder-free nanostructured WC cemented carbides in respect of the sintering behavior,phase make-up,densification,hardness and grain size.The results showed that direct sintering of pure nano-WC resulted in 300～400 nm sample with high densification and hardness,but the main phase changed into WC_1-x and W_2C.With 0.05～0.25% carbon mixed,there is a little WC_1-x.With 0.4% carbon mixed,correct phase can be got.With 0.5% carbon mixed,free carbon appears.After ball mixing,the powder can be sintered at lower temperature and when sintering at 1 800 ℃ the grain grows rapidly and unevenly.

<Abstrcat>W-15Cu dual-phase pseudo-alloy is produced from different particle sized W powder by infiltration.The thermal conductivity is measured and SEM is used to observe the copper network.The effect of tungsten particle size on the sintering and thermal conductivity of W-15Cu is analyzed in this article.

Study is made of the preparation of niobium suboxide by Mg reduction.Niobium Suboxide powder is prepared by mixture grinding-reduction roasting-acid washing for impurity removal-drying.Study is made through XRD and SEM on the product phase and microscopic morphology.Anode is made from niobium suboxide powder with the process similar to that of tantalum electrolytic capacitor.The anode electrical property is tested with anode testing method of electrolytic capacitor.The results showed that Mg reduction process is difficult to control with complex product phase,coarse particle size,simple particle shape.The resultant anode is characterized by low specific capacity,high ESR and high leakage current.

The high-temperature anti-oxidized Si-Cr-Ti coating improved on C-103 niobium alloy is prepared by slurry sintering with the addition of active Zr element and Y_2O_3.Static anti-oxidization test at 1 200 ℃,thermal shock test from room temperature up to 1 200℃ and intermittent oxidization weighting test at 1 200℃ were made.Investigation is made into the morphology, structure,and element distribution and phase distribution of the coating by SEM,EDS,and XRD.The results showed that the coating consists of tow layers.The out layer,the main body of the coating,is made of the complex phase of(Nb,Cr,Ti,Zr)Si_2, the inner layer,the intermediate diffusion transition layer,is made of the dense NbSi_2 phase and associated with minor amount of Nb_5Si_3.The addition of modified Zr and Y_2O_3 can increase the density of the coating and widen the diffusion transition layer to improve the anti-oxidation properties of the coating system with flat interface between the diffusion transition layer and the substrate/main body of the coating.The diffusion transition layer is dense and can effectively prevent the further extension of cracks and oxygen diffusion into the substrate.

<Abstrcat>Study is made of the effect of Ti(CN) content on the structure and mechanical property of cemented carbides through tests by stepwise sintering and with different Ti(CN) contents.The test results showed that the increasing of Ti(CN) content can result in thicker gradient layer,larger hardness,greater magnetic force and lower strength and density.

<Abstrcat>Description is made of the basic principle of mechanical activation and its importance for decomposition of some minerals.It is pointed out that mechanical activation can accelerate the decomposition process and also improve the leaching rate for the purpose of energy- saving and lower consumption.The paper describes the research and application in Russia.of mechanical activation for decomposition of tungsten concentrate.

<Abstrcat>Study is made of the effect of hot-rolling heating temperature and deformation rate on Mo plate structure,property and product rate.The results showed that higher hot-rolling temperature resulted in larger brittleness and smaller elogation and bending angle,as will distintlt reduce the cold-rolling processing property and directly affect the finished product property and product rate.The ～1 300 ℃ cogging temperature and >20% deformation rate is good for Mo plate rolling.