With the same sintering process,the influence was studied of different coatings painted on boat surface on deformation of the sintered cemented carbide product.The morphology was observed by SEM and element energy spectrum was analyzed by EDX for the besmeared surfaces with two kinds of coatings,and their volatilization rates were compared at different temperature.The sizes were measured and compared of cemented carbide products sintered in the boats painted with different coatings.The results show that the coating B has less impurity and higher C to O ratio,and the carbon content uniformity and deformation are greatly improved of the cemented carbide product sintered in the boat painted with the coating B.By adjusting sintering process,deformation and carbon content inhomogeneity can be improved of the cemented carbide product sintered in the boat painted with the coating A.

湖南稀土金属材料研究院始建于1958年,为国有独资科技型企业,是我国最早从事稀土材料应用研究与幵发的单位,是军工稀土新材料研制幵发的配套单位。该院巳通过军品科研生产许可认证和IS09001中国质量认证。该院建立五十多年来,承担了上千项军工配套科研及新产品试制任务,取得各类成果230余顶,先后研制幵发出:各沖稀土金属,稀土合金钢,军用电子管阴极材料,稀土棒材(铈、镧),稀土硅铁中间合金。

The process was studied of scheelite synthesis by calcination of wolframite and calcium carbon- ate,and the effects were systematically investigated of calcium carbonate dosage, calcining temperature and calcining time on seheelite synthesis from wolframite. When calcium carbonate dosage is 1.6 times the the- oretical amount,calcining temperature is 800 ℃ and calcining time is 2 h, wolframite can be completely synthesized into scheelite.

The traditional magnesium salt purification process is difficult to purify crude sodium tungstate solution with high As content （above 0.2 g/L）, so MgSO4-FeCl3 mixed method is put forward to purify the solution. Experimental results show that crude sodium tungstate solution with 0. 240.8 g/L As can be effectively purified by adopting 5 times the theoretical amount of MgSO4 solution at first and then adding 0.5 times the theoretical amount of FeCl3 solution under the conditions of 70℃ and pH9～10.

Sulphuric acid curing of vanadium-containing carbonaceous shale can be carried out under the con- dition of self-heating by adding the admixture of S during the process. Pilot-scale test results show that va nadium-containing carbonaceous shale can be leached with water at room temperature after the pretreat- ment of self-heating acid curing,and the leaching rate of V2O5 is 85.1%. The process has the advantages of short flowsheet, simple equipment, mild reaction condition, high V2O5 leaching rate, low energy consump tion and environment friendly flowsheet.

V2O3 was produced with ammonium polyvanadate （APV） as the raw material in an airtight re- sistance furnace, based on the combined reduction of the nascent hydrogen resulted from self-decomposition of ammonium polyvanadate and additional carbonaceous reductant. The results show that at 1 000 ℃ and with the addition of less than 3% coke powder,the high purity V2O3 with w（V）≥66 % and w（C）≤0.05% can be obtained by 3 h reduction in the resistance furnace,and the commercial production can be realized.

The process from V2 O5 , K2 SO4 respectively. valuable elements of the raw material of vanadium, potassium and silicon were recovered by hydrometallurgical waste vanadium eatalyst in sulfuric acid industry to produee qualified and water glass, with recovery of vanadium, potassium and silicon over 90%, 94% and 95 %,respectively.

Based on the existing theoretical research results about temperature field in rare earth electrolytic cell,and taking a 6 kA Pr-Nd electrolytic cell as the research object,the relationship between electrolysis temperature and the technical indexes of the rare earth molten salt electrolysis was analyzed according to the measured data during electrolysis production and chemical test results of RE metal products. The re sults show that electrolysis temperature plays an important role in normal electrolysis process. The opti mum electrolysis temperature is 1 090 ℃ to achieve efficient and stable production of the Pr Nd electrolytic cell.

A series of new ionic liquids were synthesized composed of WO2-4 anion and N-methylimidazole cation, including 2- （1-propyl-3-methyl-imidazole） tungstate （ [C3 mim]2 [WO4 ] ）, 2- （ 1-butyl-3-methyl-imid azole ） tungstate （ [-C4 mim]2 [WO4 ] ）, 2-（1-pentyl-3-methyl-imidazole） tungstate （ [-C5 mim]2 [-WO4 ） and 2-（1-hexyl-8-methyl-imidazole） tungstate （[C6 mim]2 [WO4]）. And then the above ionic liquids were char acterized and verified for their structure.

The spray conversion method for preparing WC-Co nano-composite powders is introduced. This method has the advantages of short process, uniform component distribution and low manufacturing cost, so it is thoroughly studied,resulting in various processes derived from it and developed for preparing WC- Co nano-composite powders.