Process of Preparing High-Sodium Ammonium Paratungstate by Doping Method
Coarse-grained cemented carbide demonstrates exceptional thermal conductivity and resistance to thermal fatigue,rendering it highly promising for applications in mining tools and hard surface materials.As the main intermediate product of tungsten,ammonium paratungstate(APT)with high-alkaline metal content facilitates the production of coarse particles of tungsten carbide powder for the preparation of coarse-grained cemented carbide.This investigation employed an ammonium tungstate solution as a raw material to explore the initial sodium content in the solution,as well as the types and quantities of additives,crystallization rate,and the influence of APT washing times on sodium content in APT crystals.The results indicate that the type of additives has no effect on the sodium content in APT crystals,but the amount of sodium hydroxide,crystallization rate,and APT washing times have a greater impact.By controlling the adding amount of sodium hydroxide at a sodium-tungsten mass ratio of 4‰ and achieving a crystallization rate of 90%,high-sodium APT products with a sodium content exceeding 0.029%can be produced after four rinses with pure water.Furthermore,other impurity elements meet zero-grade requirements of national standards.
high-sodium content in APTadding amountcrystallization rateAPT washingcoarse-grained cemented carbide
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