Monazite is leached by caustic soda. The leached residue isselectively dissolved by HCl with obtained 'selectively dissolved'residue. The later subjects to H_2SO_4 leaching and extraction. This paperdesert bes the results of study on the extraction of U from the H_2SO_4 leached solution with tertiary amine N235 for the separation from Thand rare earth. The results show that >99.5% uranium extraction yieldis obtained and ThO_2/U in the stripped U solution is (1.8-3.8) × 10￣(-3),RE_xO_y/U is (1.0-1 .6) ×10￣(-3) while U/ThO_2 in U raffinate is only(3.5-5. 6) × 10￣(-6).

Detailed description is made of the sources of Ca impurityand its removal method during APT production by ion exchange processIt is mentioned in the paper that Ca mainly comes from process water and ammonium chloride and occurs in the form of CaWO_4 in the process.For Ca removal to improve APT quality, the following methods maybe made: adoption of pure water instead of tap water, regular treatmentof ion exchange resin with acid or alkali, and filtration of (NH_4)_2WO_4solution.

Application and upgrade of Ge recovery process using Breagent are presented. Practice shows that discontinuous addition of YW-100, instead of continuous, can lowered the YW-100 consumption to1/6-1/4 and reduced the emulsion during solvent extraction The use ofback extractant (B reagent) concentration of 0.5-1 .0 mol/L, instead offormer 2.0-2 .3 mol/L, can eliminated the two-stage cake scrubbing andevaporization operations, thus the environmental problem arising fromthe need for regular discharge of the excessive circulating solution hasbeen solved, Ge recovery is improved and consumption of B reagent isreduced.

According to the theory of non-uniform structure of mininghard metals, a high-quality low-cobalt (Co 6%) mining hard metal isdeveloped from high-grade WC powder and high-purity, ultra-fine Copowder with advanced SIP technology. The product proves satisfactoryin use.Its quality is near to that of similar Sandvik product.Mass production of this product has started.

The straightening of Ta wire of various condition(as-anne aled. as-cold worked and stress-relieved tempered) are studied togetherwith the effects of springback.

叙述了ＴＷ－５００型Ｖ形混料器在硬质合金生产中的使用情况及其改进设计．

Our experiments show that solid solution elements (such asW. Mo. Ti) in binder of Ti (CN) ceramic-metal can not be dissolvedcompletely in concentrated HCl acid at 30℃, which is not in agreementwith results reported in(3), but can be dissolved completely in concentrated HCl acid plus sulphuric acid at 80℃. Method presented in thispaper can simply and effectively be used for quantitive determinationof solid solution elements in binder of Ti(CN) ceramic-metal.

In this paper, it has been reported that the total rare earthsin phosphate fertilier, which is extracted by CL-PMBP column chromatography and washed off by formic acid, is determined by spectrophotometry with arsenazo Ⅲ in the presence of KCl. For each of threesamples, the statistical results show that the standard deviation is lessthan 1.6% and the RSD is less than 7%. Comparing with the results measured by PMBP-benzene solvent extraction spectrophotometry, the relat ive error is less than 3%.

In view of the inadequate resources of cobalt, two new typesof cemented carbide of 'N' and 'T' have been developed and produced inour factory. They have all been used in the field of rock drilling.Thepractice has shown that the new types of cemented cabride have the practicaltechnology, good use effect and lower production cost than conventionalcemented carbide.

This paper describes application and development for Niobium market.