High Purity Tungsten Carbide Recycle from Waste Tungsten Cobalt Alloy

Generally speaking, it is a good way to separate tungsten carbide powder by electrolysis. The methods of recovering tungsten carbide by the usual electrolysis process are not completely electrolyzed, the cobalt can not be completely separated and removed and the surface wear of the crusher and ball mill is introduced into the process. The Fe, Ni, Co and other impurities in the tungsten carbide powder are over 0.6%, respectively, and the production of high performance cemented carbides is produced. There is a big gap between the high purity technical standards of Fe, Ni and Co, which are not more than 0.1%, so that the scope of the use of tungsten carbide in the electrolysis process is greatly limited.

In order to solve the technical problems of high content of Fe, Ni, Co and other impurities in tungsten carbide in the recovery of existing waste tungsten-cobalt carbide, some scholars have proposed to recover Fe, Ni and Co in tungsten carbide through process reengineering. A method of recovering high-purity tungsten carbide from a tungsten-cobalt-based waste cemented carbide whose impurity content is controlled to 0.1% or less, respectively. The main process is as follows:

1.Taking the recycled hard metal cutting blade as an example, the recycled metal cutting blade is used as the raw material for YG6 and YG8 to be cleaned with tap water and detergent, and then classified and removed after drying.

2.The waste hard alloy after classification is broken into particles with a diameter of less than 5 millimeters in diameter with a roller crusher. The particles are selected and then washed with deionized water to remove the impurities brought in by the previous process, and into electrolysis in the electrolyzer to remove most of the bonding phase in the alloy. The electrode reaction of electrolysis takes cobalt as an example: anode: Co - 2E - Co²⁺ cathode: 2H⁺ + 2E - H² after electrolysis, formed a tungsten carbide particle with a porous structure of sea cotton. After electrolysis, it continues to be cleaned with deionized water.

3.Using 300 liter special ball mill to ball milling the particles after electrolysis cleaning, the amount of ball milling is 250 kg, the amount of ball is 900 kg, the deionized water is 100 litres, and the ball milling time is 3 hours. The slurry after the ball milling is precipitated in the stainless steel trough through 200 mesh screens, and the material on the sieve is collected again and electrolyzed again, the precipitation time is 8 hours.

4.Because some of the bond phase elements still remain in the tungsten carbide after electrolysis, the precipitated slurry should be removed to the steam heating kettle to be injected into the steam heating kettle, and the concentration of hydrochloric acid is 10%, which is heated and stirred. The temperature is kept for 3 hours at about 90-95. And then naturally cool down.

5.Clean water will be above the material after hydrochloric acid treatment to the PH value of 6-7; after the material precipitation into the steam vibration dryer for drying.

6.Screen the dry powder with vibrating screen. Mesh number is 200 mesh. After the sifted powder was treated, the reduction temperature was 900 degrees.

7.The reduced powder is treated in batch, the bulk is 800 kg and the batch time is 25 minutes. After batch, it is a qualified tungsten carbide powder, and its purity is close to the original tungsten carbide.

The above method can control the impurity content of Fe, Ni and Co in the recovered tungsten carbide within 0.1%. It is close to the standard of the primary tungsten carbide. In addition, the recovery process only adds the equipment of magnetic separation and acid cleaning. Compared with the usual recovery process, the investment is low, the cost of manufacturing is small, and it has high technical and economic value.

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