The crystalline rare earth (La、Ce、Pr、Nd) carbonates were precipitated using ammonium bicarbonate as precipitant. Chemical analysis of the composition of these compounds has been carried out. X-ray powder diffractomtry, IR spectrum and TGA、DTA of these compounds have been studied. The compositions of the rare earth carbonates have been determined to be RE2(CO3)3 ·xH2O(RE=La2、Ce、Pr、Nd, x=2、3 、4 ).

Ammonium tungstate is made from scheelite by acid dissolution. Then ammonium tungstate is obsorbed by activated carbon at pH 1 .8 and absolved at strong base. Tungstic acid is precipitated at pH1.Tungstic acid is then dissolved in hot ethandiol and it is reprecipitated under HC1 condition. The purified precipitate burns at elevated temperature and high pure tungsten trioxide can be obtained. Tungsten trioxide is 99. 9% (by scanning electron microscopy, ICP, photometric analysis).This method has the advantages of simple operation, easy post treatment and improved efficiency over the ion exchange or solvent extraction method.

The raw materials of various tungsten oxides strongly affect the particle size of tungsten powder. Therefore, it is highly important to make the right production and choice of the tungsten raw material in the production of tungsten powder. The fine tungsten powder has been effectively obtained by hydrogen reduction of purple tungsten oxide.

This paper has studied the interface recombination characteristics of HIP diffusion bonding of cemented carbide to metals such as industrial fineiron. Carbon steels including A3 steel .45# steel and T10 steel. The formation reason and the controlling means of the detrimental interfacial brittle phase (Fe3W3C ) have been expounded.

The influence of different particle sizes of nickel powder on the structure and properties of WC-9%Ni cemented carbide has been investigated. Moreover. harmful effect of the Ni-aggregation on properties of alloys is discussed.

A series of experiments have been made using the composites of the rare earth oxide and inorganic conmpound as enamel paste suspending agent to replace the clay fully or mostly. This technology had succeeded and obtained industrial use.

W-Ni-Cu Tungsten alloys can be produced by the thermal decomposition-reduction of the W powder mixture with Ni(NO3)2, CuCl2solutions or with Ni(CH3COO)2, Cu(CH3COO)2 solutions. Both manufactured alloys are available for use. The characteristics and problems of the processes using two different mixtures were studied in details. It was clearly shown that the use of the first mixture during reduction results in a lot of toxic gases, which are harm to the environment, and the second mixture is favourable for environment protect and product quality during reduction.

The ore properties of rare earth (RE) ore of Southwest Territory, China, and its beneficiation technology have been studied. The ore is strongly weathered to produce 20% black slime. RE available for commercial use in ore is occurred in two phases: mineral and colloidal. The main (>96%) RE mineral of mineral phase is bastnaesite. The bastnaesite concentrates (30%、 50% and 60% REO) can be obtained by gravity separation or gravity-flotation combined process at 65% recovery of RE. RE minerals of colloidal phase is absorbed in non-crystal minerals of Fe-Mn oxide. It can be recovered by hot HC1 leaching-purification with liquid ammonia-oxalic acid precipitation route at 74.3% of RE, and lead can be obtained as byproduct. The ore and the black weathered minerals are rich in cerium family RE (∑CeO2>90%, CeO2>La2O3>Nd2O3).

The application of new phosphoric extractant Cyanex 272 to the liquid-membrane separation. preconcentrating and extraction of metal ions is described. Comments are made on the present study.

The concept of comented carbide products with unhomogeneous structure. and their applications and developments have been introduced.