Scrap Carbide Recycling And Recycled Materials, Process Optimization Studies

There are many methods to reclaim waste and old cemented carbide, and the properties of the products prepared by different techniques differ from each other. It is very important to do research on the reclaimed materials and make use of the tungsten resource to the maximum extent. In the present study, Zinc-reclaiming technique was used to reclaim waste and old hard alloy that was supposed to be used in the industrial production. And a abecedarian discussion on how to improve the use-value of the products was made.A research of the influence of the Zinc-reclaiming technique on the quality of the reprocessing mixture was made. The discharge rate of the mixture, the residual quantity of Zn and some other factors which influence the qualities of the material differ with different processing parameters such as the quantity of Zn and so on. Chemical analysis, optical spectrum analysis and otherwise were used to investigate the content of impurities. The particle size average and the distribution of size were tested by many methods. XDR was used to analyse the integrity of the subgrains in the reprocessing WC. And in order to find out the best processing parameters, the changing rules of the hardness, strength and wear-resisting property of the reprocessing material under different wet grinding time and different sinter temperature were studied. And the properties of the wire-drawing dies, the aiguilles and bits made by optimal reprocessing material were compared with those made by virgin material.Adopting appropriate technique parameters and using new furnace can achieve the reduction of the residual quantity of Zn and the improvement in the production efficiency. The content of Zn in the reprocessing material reclaimed by Zinc-reclaiming technique is higher than in the virgin material. However the crystal forms of the reprocessing material is more integrated and its distribution of size is narrower. And these characteristics were helpful to improve the properties of the final products. Because the particle size average, distribution of size and the crystal form of the reprocessing ones were different from the original ones, the processing parameters differ to produce the hard alloy. However the products of reprocessing material produced by optimal processing parameters do not show large drop in the properties than the ones produced by the virgin material. There is little difference between the wire-drawing dies, the aiguilles and bits made by reprocessing material and original material. Therefore the hard alloy made by reprocessing material reclaimed by optimal processing parameters can replace the hard alloy made by virgin material.The major results can be summarized as follows:1. The reduction of the losing of carbide can be achieved by reduce the size of the blocks and using new furnace to improve the efficiency of melting. And appropriate amount of C can be added to reduce the content of oxygen. And the reduction of the Zn residual quantity can be achieved by guarantee the time of melting and the content of Zn.2. The amounts of Si, Mg, Fe, Ca, Ni and so on are higher in the reclaimed material than in the virgin material. There is little difference between the particle size of the reclaimed WC and the grain size of the waste, material. The relationship between the gain size of the alloy and the wet-grinding time is almost linear in a region.3. The strength is higher as the melting temperature increases from 1370℃to 1450℃after wet-grinding. The strength decreases and the hardness increases as the wet-grinding continues from 24h to 72h. The wear-resisting property increases with the increase of the wet-grinding time. And it reaches its maximum at 1390-1430℃. The optimal processing parameter is to melt at 1410℃after wet-grinded for 48h. And the properties of the reclaimed material are as follows: HRA: 89.7, wear-resistance: 3.42×10^-2 , strength: 215 kg/mm²4. There is little difference between the reclaimed material and virgin material in the cutting experiment. And the reclaimed material acts better in the impact experiment but worse in the wire-drawing experiment. Butthe differences are not big.5. The cemented carbide goods produced by reclaimed material can achievealmost the same properties of the goods produced by virgin material though adopting appropriate processing parameters.