Monoclinic ammonium paratungstate with different particle size can be obtained by different heating stages. The changes of particle size and surface area at each stage in rapid thermal decomposition of monoclinic APT can be concluded by differential thermal analyzer (DTA) and laser particle size analyzer, which can guide the preparation of tungsten oxide with desired particle size.
Rapid Thermal Decomposition of Monoclinic Ammonium Paratungstate
1. Monoclinic APT was heated to 600°C at a rate of 9°C/min in argon (Ar) for differential thermal analysis.
2. The temperature of each inflection point of the differential thermal analysis chart was raised, and the product was analyzed with DTA and laser particle size analyzer.
The results show that:
1. The extent of product particle refining is the maximum at 253.3°C, secondly at 232.9°C.
2. The extent of product particle coarsening is the maximum at 297.4°C, secondly at 432.1°C.
3. The change in particle size at 150.2°C and 500°C is not apparent when heating at rate of 9°C/min in Ar.
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