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.

Alumina-doped molybdenum powders were prepared by hydrothermal synthesis combined with low-temperature calcination and two-stage reduction, and mass fraction of Al2O3 were 0,0. 25%,0. 5%, 0.75% and 1% in the molybdenum alloy powders. The morphology and phase composition of molybdenum alloy powders were analyzed using SEM and XRD,respectively. And the influence of A12 Oa dosage on mo- lybdenum alloy powders was investigated at different preparation stages. The results show that Al2O3 dos- age has a certain effect on the uniformity, particle distribution and particle size of the powders. Increasing Al2O3 content has dispersion effect on aggregation of molybdenum alloy powders. After two-stage hydro- gen reduction, flaky MoOa particles is completely reduced to spherical Mo particles,and the mixed powders are mainly composed of Mo and a-Al2O3 without other phases, α-Al2O3 can refine the molybdenum parti- cles ,and the refinement effect of molybdenum particles is more obvious with alumina increasing.

The latest development is reviewed of domestic and foreign studies on rare earth ion substituted strontium ferrites in recent years. The effects are analyzed in detail of simple substitution with single rare earth ion or combined substitution with rare earth ion and transition metal ion on the chemical composi- tion,crystal structure and magnetic properties. And then the application prospect of strontium ferrites ispointed out.