Equilibrium diagrams of Ca-W-P-H_2O system are established on the basis of thermodynamic data.The diagrams,which are constructed under conditions of 25 ℃and 0.01 mol/L and 0.5 mol/L of total phosphorus-containing ions concentrations[P], show the effect of system pH value and total phosphorus-containing ions on system equilibrium.The results showed that phosphate solution is an efficient reagent for scheelite decomposition.High [P] is beneficial for the decomposition,but extras phosphate will cause difficulty in purification.In view of stringent requirement of ammonium paratunngstate as the intermediate product for impurity P,the author believe better decomposition can be obtained by proper improvement of pH value with low-concentration free P.

Nano-ITO powder is prepared with sol-gel process.Study is made on the effects of different dispersants on powder agglomeration.The structure and morphology of powders are analyzed through differential thermal analysis(DTA),X-ray diffractometer(XRD),scan electron microscope(SEM).The result shows that the two dispersants have obvious effects on reduction of agglomeration of ITO powder,No.2 dispersant is better than No.1,but the grain size of powder with No.2 dispersant is smaller than that with No.1 dispersant, and both of them have little effect on the structures and morphology of the said product.

Study is made of the feasibility of RE extraction from RE-containing bauxite ore newly found in somewhere in China.In order to know whether is it existed in the adsorption phase,investigation is made on the feasibility of extracting rare earths by means of ion exchange method,i.e.percolation and agitation leaching with saltsolution.According to the IEX test results and based on the conclusion of XRD about alumina,the results of selective rare earths leaching,we concluded the rate of adsorption type in all of the rare earths mineral that existed in bauxite ore is very low,the majority is independent rare earths mineral.

Research is made on the technological improvement of the original precipitation and pressure washing for preparation of NbO(H)_5.Comparison is made between the calcinators for NbO(H)_5.The results showed that the problem of F removal out of NbO(H)_5 washing solution from precipitation of high-concentration(Nb_2O_5>120 g/L)Nb solution can be solved through pretreatment with the addition of diluent.The new pressure washing process is characterized byhigher washing water temperature,more pulp-conditioning times,higher F-removal efficiency, water-saving and more up-to-standard Nb_2O_5 product

Ultra-fine tungsten powder is prepared by hydrogen reduction from blue tungsten oxide.Research is made on the effect of temperature,boat charge and hydrogen flowrate on granularity of W-powder.The results showed that reduction temperature is critical for the preparation of ultra-fine W-powder from blue tungsten oxide under appropriate technological conditions.

Study is made of the grain growth of tungsten carbide (WC)in the early stage of sintering TEM and XRD analysis is made of the change of grain during sintering,based on which the mechanisms of grain growth are discussed. Results showed that grain growth occurred during heating at 1 000 ℃ with some grains grown up to 100 nm at 1 100℃.At 1 200℃,even more dramatic grain growth occurred with some grains up to 400 nm.The shape of WC grains become regular during sintering.And WC grains are grown up based on the grain rotation combination mechanism and local liquid-phase sintering in the early stages of sintering.

Study and analysis is made of the effect of the high-temperature wear test parameters on high-temperature wear resistance of WC/steel composites material under different heat-treatment condition.The results showed superior high-temperature wear resistance of WC/steel composites material in the condition of heavy load,higher temperature at 450～650 ℃ and speed of.above 2 m/s.

A simple and economic spinning process for specially shaped tantalum alloy products is developed.Discussion is made in detail on the influence of thickness uniformity of the slab wall (feed stock),longitudinal feed speed,reduction and the tailstock inner arc radius.Corresponding solutions are presented.

Description is made of a new technology for preparing WC powder by carburizing in a mixture gas medium developed by professor V.P.Bondarenko research group of Institute for Superhard Materials of the National Academy of Sciences in Ukraine.WC powders is prepared with CH_4 as the raw material instead of the solid carbon black powder.Upon gas carburization,C-controllable WC powder is prepared,followed by normal compaction,sintering to obtain cemented carbide.The properties of the alloy products are in accordance with the former Soviet Union State Standard(GOST)3882—74.Description is also made of the basic principle of the technology,powder and alloy properties.

Study is made of the literatures in respect of specific saturated magnetization value of pure Ni,Co and WC-Co cemented carbide.In more than 20 articles are indicated that the specific saturated magnetization value is about 4π times of the normal value( A·m^2/kg).The results showed that for the measured value,this is due to the author's mistake in the unit conversion of electric magnetism quantity; while for the calculated value based on related data,it is due to the fact that the measured specific saturated magnetization value is about 4π times of the normal value.Corresponding description is also made of the definition of the related physical quantity and corresponding unit conversion expression are presented for the convenience of discussion.