Using the thin layer static method, the oxiding kinetics of W powder have been studied. The powder for study is classified by fluidized new technique. Results show that oxidization of W particles also follows the parabola-straight line oxidization mechanisin. On the basis of the exper imental results the mathematical model of oxidization for W powder has been established.

Technological conditions for concentr ation of rare earths from Nacl-type leachate with emulsive liquid membrane have been studied. These conditions include the oil-inner ratio(R,), the keroseneliquid paraffin ratio in the membrane phase, the surfactant quantity,the inner phase acidity, the rare earth concentration in the leachate,the aqua-emulsion ratio(Rwe), the use of P507 or P204, the stirring time ane so on. Through experiments the suitable formulation for the concentration of rare earths with emulsion liquid membrane(N205-P50(-keroseneliquid paraffin-HC1) and some better operation conditions are obtained.The concentration of emulsion liquid membrane concentrated rare earths can reach 100g/L and the rare earth extraction efficiency can reach 96%.

The influence of technical conditions on dephosphorization & deferrization during prereduction in the 'Two step' metallurgy of Nb and Fe has been studied. Optimized technical conditions for Nb/Fe>1. 0 Nb/P>10 Nb-rich slags are obtained. Analysis is made on the Nb-rich slags nad semi-steel structures of by-products.

During the fractography of W-Ni-Cu alloy, various defects such as pore, pollution and ingredient segregation and so on. have been found. This paper analyzes the technological factors causing formation of these defects and gives suggestions for process improvement.

The paper gives a summary of the development of annularspace centrifugal extractors both at home and abroad. The focus is the research and commercial-scale test of the big-diameter annular-space centrifugal extractors with illustration of the design and calculations.The design has obtaind patent in China.

A new pulping and scrubbing unit for removal of fluorine ion impurity from Nb2O5 is recommended and described. By comparision with traditional open unit, tins equipment has the advantages of lower energy consumption, faster pulping and scrubbing, lower labour omtemsoty and much less repairing work. It can also be used for scrubbing operation in hydrometallurgy.

The structure and application of box-type vacuum dryer are described in the paper. The practice shows that the equipment is rather flexible. efficient, and able to ensure the product quality and improve efficiency.

The qualitative and quantitative analysis is made of therelationship between production ability(M) and engineering ability (Cp).the results show that engineering ability is one of the important factors which effects the production ability.

The TiO2, TFe, Al2O3, SiO2, MnO in ilmenite have been measured by XRFA using pelletized powder samples. After separating the calibration curve into two sections or correcting the matrix effects,areasonable accuracy has been obtained. The analysis ranges are as follows: TiO2 7-50%, TFe 20-38%, Al2O3 0.70-30%, SiO2 0. 15-32%,MnO 0. 17-0.80% The results of XRFA agree with those of chemical analysis. The calculations of the equilibrium of metal volume meet the demands of beneficiation. Therefore, this method is an accurate, simple fast and economical one for ilmenite analysis.

Study is made of Ta lining in the graphite tube for analysis of GSD standard samples by atomic absorption. Results show that thismethod can be used to determinate trace rare earths with high sensitivity,accurate results and long service life of Ta sheet.