Violet tungsten oxide powder may be used to prepare ceramic microsphere. And violet tungsten oxide may be produced by calcining ammonium paratungstate (APT) under a mild reducing atmosphere. In this process, what effects do the furnace temperature, feed amount and furnace speed have on the preparation of violet tungsten oxide?
Other process conditions unchanged, the morphology of violet tungsten oxide appears as a needle-like crystal form if the furnace temperature is too low; the morphology of violet tungsten oxide appears as a rod-like crystal form if the furnace temperature is high. Both the needle shape and the rod shape are intrinsic crystal forms of violet tungsten oxide. Through the reduction test, it was found that the tungsten powder obtained by using the needle-shaped crystal violet tungsten oxide was finer, and the tungsten powder obtained by the rod-shaped crystal violet tungsten oxide was relatively coarse.
In addition, studies have shown that if the furnace temperature is too high or the feed amount is too small and the residence time of the material in the furnace is too long, the WO2 phase content in the violet tungsten oxide product may be high; otherwise, the APT is not completely decomposed into W18O49. Therefore, the modulation of the three directly determines the phase composition of the violet tungsten oxide.
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