Liquid Form Synthesize Tungsten Carbide

Tungsten carbide is the main raw material for the production of hard alloy. The uniformity of the alloy powder is not ideal. It has a great influence on the pressing of the hard alloy. We can try new method:

1. Pre-prepare for 270 ~ 330g/L ammonium tungstate solution, 800 ~ 850g/L cobalt nitrate solution and 100 ~ 130g/L chromium nitrate solution.

2. The concentration of ammonia in ammonium tungstate solution is between 50 and 70g/L, then add the solution to a thermal reactor. After that, add cobalt nitrate solution, through heating, concentrating and evaporating, the ammonia volatilized to pH value and reduced to 8.5 to 9. Then add chromium nitrate solution and continue heating. When the pH value is reduced to 7 ~ 7.5, stop heating.

3. The mixed solution after cooling by vacuum filtration solid-liquid separation, tungsten cobalt chromium coprecipitation crystal was obtained. After drying the coprecipitation crystal, it is then calcined at 700~750°C high temperature furnace, then tungsten cobalt chromium compound metal oxide was obtained.

4. Hydrogen as a reducing agent with a flow rate of 80 cubic meters / hour and dew point < -80°C. The tungsten cobalt chromium composite metal oxide was reduced at a temperature range of 710~840°C, and the reduction time lasts 4~5 hours. Reduction of tungsten cobalt chromium metal reducing powder with fully mixed tungsten cobalt and chromium.

5. The reduction of tungsten cobalt chromium metal reducing powder with carbon dioxide gas to isolate the air. Use low temperature to cool down for 7~9 hours at 20~24°C. There will be passivation through cooling process of tungsten cobalt chromium metal powder surface. Ensure that the tungsten cobalt chromium metal reducing powder is not oxidized in the process of transfer and carbon distribution. Then add carbon to the tungsten and cobalt chromium metal reduction powder after cooling, then ball milling, ball milling time lasts for3~5 hours, make tungsten cobalt chromium metal reduction powder and carbon fully mixed evenly.

6. Tungsten cobalt chromium metal reducing powder with carbon distribution on high temperature continuous automatic molybdenum wire furnace. The tungsten carbide cobalt chromium metal composite powder was prepared by carbonization for 3~4 hours at the temperature of 1100~1150°C.

7. Sieving composite powder of carbonized 80 mesh after ball milling. Through the airflow again 40 mesh to prepare products. This step is used to remove coarse particles and agglomerates in the composite powder, so that the final product has high purity, high carbon content, uniform distribution and complete granularity.

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