H3 PO4 leaching method in presence of oxidizer was used to study the decomposing of the low-cobalt cemented carbide scraps.Based on the results of exper iment, a proper reclamation route was founded. The paper describes the experiment.

Study is made of infIuence of taree concentration-varied commercial para-octanol solvents on Ta & Nb extraction and stripping properties.The results show that there are different extraction and stripping results for Ta & Nb when the concentration of para-octanol solvent is changed.For the treatment of high-grade tantalite & niobite and low-grade tantalum ilmenorutile,para-octanol solvents with different concentration can be used to improve the product quality,recovery of Ta and Nb and the operating conditions.

The fatigue crack growth rate da/dN of a high damping ZnAl eutectoid alloy containing trace Ce has been measured and compared.The writers consider that the lower da/dN value of the alloy is related to the higher internal friction value with Ce-free Zn-Al a11oy.

Study is made on the influence of Ce on the non-metallic inclusions and the properties of the ZG75CrMo steel.The results show that addition of Ce to ZG75CrMo steel could decrease the contents of inclusions.lodify their characteristis,and result in greatly incrase.in plasticity,toughness,thermal fatigue resistance and high temperature oxidation resistance of the steel,

Effects of the addition of the trace rare earth oxides on the physical and mechanical properties of WC-8Ni cemented carbide are studied.By X-ray diffraction, scanning electron microscopy(SEM) as well as transmission electron microscopy,the microstructure of the WC-8Ni alloy containing the rare earths were analysed and distri bution of the rare earths in the alloy,their effects on the texture and structure,and the strengthening mechanism of WC-8Ni alloy were investigated.It has pointel out that the physical and mechanical properties of WC-8Ni with rare earths can come near of up to that of YG8.

A new type of thin-wall diamond core drill bit is developed through the analysis of drilling feature on the R.C and granite structures.In comparison with the existing manual drilling and electro-hammer drilling, this new bit can easily cut all the building materials such as reinforced concrete and granite,etc with accurate drilling dimension and good surface finish.There will be no damage to the wall,no dust or noise during drilling. The machine can be miniaturized because it needs less drilling power and pressure.

The structures of both type of disintegrated furnaces are described in the paper.Contrast experiments are made between the two for comparision of their results.Practice shows that the newly developed horizontal disintegrated furnace can meet the requirements for quility cemented carbide production.

The paper describes the good characteristic of Al2O3-TiC composite(AG2 ceramic) tips and makes a comparison between the said tip and cemented carbide tip for cutting unworkable materials.

In view of the difference of the effective stability constants of the EDTA complexes of Ni and Co in strong alkaline medium, a method has been developed to determine Ni and Co in cemented carbide continuously by residual titration with calcium salt The method is rapid,accurare and the relative standard deviation is less than 2%.The results are basically same to the standard value or to the results obtained by classical method which titrate Ni and Co respectively after precipitating separation.

This paper describes the direct titration of cobalt at PH 5～6 in hexamethylenetetramine medium using xylenol orange and malachite green as indicator and EDTA as titratant. This method is simple and fast and has been satisfactorily used for the determination of cobalt in cobalt-containing fine organic chemicals,such as paint drier isooctoatal cobalt and rubber adhesion promoter cobalt borate acylate.