Tungstic Acid Method to Prepare Ammonium Metatungstate
Tungstic acid method to prepare ammonium metatungstate is dissolving tungstic acid (H2WO4) in aqueous ammonia (NH4?OH), adding into boiled deionized water, and heating with stirring to remove ammonia until pH value going to 8; then, adding acetic acid when the solution is boiling, and then adjust the pH value to 2 to 4 by dilute nitric acid, going on heating until the solution is concentrated to the relative density of 1.5 to 2:00, stopping heating, cooling and filtering. After adding ethanol into the filtrate and thoroughly stirring, then after settling filter, drying the crystal at 80℃ and grinding to obtain AMT product.
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