Preparation method of high-stability high-purity extra-coarse tungsten carbide powder

A preparation method of a high-stability high-purity extra-coarse tungsten carbide powder contains the following steps of: (1) grinding a high-purity extra-coarse tungsten carbide powdered raw material with its chemical purity being greater than or equal to 99.98 wt%, and carrying out size grading to obtain the required average granularity and a high-purity extra-coarse tungsten powder according to the particle size distribution; (2) carrying out carbon addition by the use of carbon black according to the total carbon content of the obtained tungsten carbide powder being 6.13+/-0.05%, followed by ball milling and mixing to obtain a ball-milling mixture; (3) filling the obtained ball-milling mixture into a graphite boat and a carbide furnace, and carrying out high-temperature carbonization at 1600-2500 DEGC for the carbonization time of 1-10 hours; and (4) carrying out coarse crushing on the obtained carbonized material, followed by grinding and crushing, and carrying out size grading to obtain the high-purity extra-coarse tungsten carbide powder. The method provided by the invention can be adopted to produce the high-purity extra-coarse tungsten carbide powder with good crush resistance, morphology and structure and excellent thermal stability. The high-purity extra-coarse tungsten carbide powder is used to prepare an extra-coarse crystal cemented carbide product with high performance.