The researchers proposed a preparation method of ammonium paratungstate (APT) using tungsten-contained soft waste material. And the obtained APT can be directly used in the production of tungsten alloys or be applied as additives for chemical products.
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A Preparation Method of Ammonium Paratungstate Using Tungsten-contained Soft Waste Material
Put 900g of AMT leaching residue (WO3 content of 89.5%) in the reaction kettle and add 3600mL of 6wt% diluted ammonia water (molar ratio NH3: WO3=3.9), reacted at 130 °C and 0.35Mpa pressure for 2.5h. Vacuum suction filtration to obtain 3660mL of ammonium tungstate solution (containing P: 0.002g/L, SiO2: 0.01g/L, Fe: 0.01g/L, WO3: 220g/L, free ammonia 28.3g/L), residual slag amount 1.0g; send the obtained ammonium tungstate solution into an evaporator, evaporated and crystallized at a temperature of 80 °C until the density of the mother liquor was 1.05g/mL, and vacuum filtration to obtain 846.5g of APT crystals.
