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.

This paper presents the development of wolframite digesting-solvent extraction-crystallization technique in China and its commercial practice for fourteen years at Zhuzhou Cemented Carbide Factory, Hunan.This advanced technique, offers the advantages of simple flowsheet, high metal recoveries and excellent product quality.Owing to its successful application, China has caught up with the world advanced levels in metallulgy of wolframite.

The precipitation process of the insoluable matters in aqueous solution is discussed,including the processes of nucleation,crystal growth,coagulation,aging and so on.The properties of precipitate is determined by these processes.

The paper has introduced the technological characteristics and parameters of the process to extract Zr and Hf with tribytyl pnosphorate in mixed acid system,together with its design and practice.

From the point of view of the technology-mineralogicalcharacteristic of Shizhuyuan tungsten middling, present metallurgicalprocesses for treatment of tungsten ores have been compared and screened and with reference to development work at home and abroad, a new mechanically activating soda leaching process is proposed. Laboratorytests discovered that the proposed process can effectively decomposedthe middling up to 98 6%-99% under the following conditions: sodaconsumption less 300% of stechiometric, T<200℃, t<1 5h.