The solution of acidic ammonium molybdate is precipitated with the hexamine. Its precipitate is employed to generate the ammonium heptamolybdate in basic condition and the hexamine can be completely recovered.

The working characteristics of tungsten alloy hammaring block are introduced. The Jinning ways between tungsten alloy anvil and base seat are analysed. Among them the 'V' type joining can get the contact close-connected with auto-lock effect, which results in good conductibility and heat radiation of anvil, greatly improving the life of utensil system.

Using optical microscope and JCXA-733 type electron probe microanalyse. by means of images of SEI, BEI and CXSI, the fracture behaviour of the industrial specimen Of WC-Co-Ni cemented carbide is observed and analysed, with discussion of alloy strength factors.

The paper summarizes the ways of scrap hard metal reclamation in the world and presents the status in China, and comments that improving the quality of the reclamated hard metals is a task of top priority, and the reclamation should be progressed technically and on a large tale.

Small Ta wire is the key raw material for production of Ta capacitor. The factors related to wire's brittleness have been studied. Doping of wire with Y or Si can improve this property. Doped wire with Y has more resistence, than with Si, but the doping process more complicated.

During processing of W contact materials, we meet the product's quality problems, such as split, cracks, uneven crystal size distribution in fractures, and inconsistent with requirements to rod concentricity, flatness, etc. To solve the problems, analysis and experiments were made. Product quality and rate of finished product has been improved using the following measures: tungsten slugs are forged under different temperature according to their grain size type; rotary forging is controlled by working rate; dimension parameters of the die, such as ellipticity, diameter-fixing length, etc. are subjected to controll.

Research was made on Na solution dosing methods during Na reduction of K2TaF7. Results show that the resistence method is practical with high sensitivity, resulting in increase of quality of Ta powder and the method also useful for dosing of other electroconductive solution.

The paper summarized the negative thermal expansion coefficient compounds and their contraction mechanism reported in recent 20 years. The focal point is on the recent progress of the very low thermal expansion coefficient materials and isotropic heat contraction compounds as well as the contraction model which was described to be the coupled rotation of the essentially rigid polyhedral bullding blocks of the structure.

The development of hard alloy roll collar, significance for research of composite hard alloy collar, their properties, research progress and use at home and abroad are presented with cornments on future study.

Its principle and control factors are presented.