White Tungstic Acid (White Tungstic Acid) is an inorganic compound composed of tungsten, oxygen and hydrogen elements. It is a tungstic acid composed of tungsten trioxide (WO3) and water in different proportions. A hydrated tungsten oxide, generally a mixture of monomeric tungstic acid and polytungstic acid, the molecular formula is mWO3•nH2O (n:m>1. When the monomeric tungstic acid is completely converted into polytungstic acid, the appearance is colloid , its activity is similar to that of yellow tungstic acid.
From the perspective of physical and chemical properties, the appearance of white tungstic acid is microcrystalline white powder or white colloid, soluble in ammonia water, phosphoric acid solution, niobium/potassium tantalate solution, has certain acidity, high chemical activity, weak It has the characteristics of thermal stability, strong photosensitivity (blue when seeing light) and remarkable exchange performance. The weak thermal stability of white tungstic acid is mainly manifested in: it is easy to remove part of the water by heating, but if the ratio of n:m is still greater than 1.3, it is still active; it is easy to convert into yellow tungstic acid when heated in dilute hydrochloric acid, losing active. Its properties are quite different from yellow tungstic acid, which is not only non-acidic, but also does not react with phosphoric acid solution and niobium/potassium tantalate solution.
From the point of view of the production method, the preparation steps of white tungstic acid are: drop 0.3-0.85mol/L sodium tungstate (Na2WO4) solution under strong stirring into 2mol/L sulfuric acid or nitric acid solution at a rate of 0.1ml/min, Until the pH value is 1.0; after standing still, filter in layers, and the filtered precipitate can be washed with water (if necessary, washed with ethanol or ether), and then dried to obtain the desired product. Note: Although the effect of precipitating white tungstic acid with nitric acid solution is much better than that of sulfuric acid, the filtrate cannot be discharged when nitric acid is used as precipitant.
From the point of view of use, compared with yellow tungstic acid, white tungstic acid is more suitable for the production of ammonium metatungstate, sodium metatungstate, ammonium paratungstate and tungstophosphoric heteropoly acid. Not only the yield can reach 100%, but also the reaction is mild. , rapid and easy purification.
More details of tungstate product, please visit website: tungstate.net
Please contact CHINATUNGSTEN for inquiry and order of tungstate:
Email: sales@chinatungsten.com
Tel.: 86 592 5129595
