It’s shown in the studies that the main factors controlling ammonium paratungstate particle size are oversaturation, temperature and stirring speed. Preparation of APT fine particles stirred by gas A with a strong intensity. Since the gas is vigorously stirred, crystals were broken into a lot of small nuclei, it is difficult to form large particles. And gas takes away the heat and ammonia, which can control the pot temperature around 70 ℃, while increase the over-saturation of the solution, is conducive to the preparation of APT fine particles.

 

This approach has been applied in production, the resulting APT is epigranular with surface regularity. Preparation of coarse APT stirred by gas B with a gentle intensity. Since the stirring gas, it’s ensure that the resulting APT will not precipitate and full contact with the solutes. The gas release heat during condensation, not only increase the pot temperature, but also can effectively control the oversaturation of the solution to increase due to the condensation of gas, which is easy to output the coarse particles APT. In this method the test results are obvious, the average particle size of the resulting APT can be more than 50μm, and the particle size distribution is even, particles are regular. The further applications is now in study.