Ammonium metatungstate (AMT) is white or slightly yellow crystals, have good water solubility, solubility is 303.99/loogH:O when 20℃, aqueous fairly stable. No harmful components, slightly acidic. AMT is commonly used as efficient catalysts in tungsten for the petrochemical and have been widely used in the electronics industry, nuclear industry, metal finishing and chemical reagents. It is China's rapid development in recent years, export volume increased year by year. There are many method of preparation ammonium metatungstate, each method is different from the process preceding the main difference ammonium metatungstate solution . And preparation method can be summed up into two categories: one for solid phase transformation, the most typical process is using paratungstate thermal dissociation to preparation ammonium metatungstate, the advantage is high product purity, but the heat from the solution is difficult to control the conversion rate and higher power consumption; another is liquid phase transformation, mostly use ammonium tungstate solution as raw material, different methods to reduce the pH value within a suitable range to obtain a solution of ammonium metatungstate, the disadvantage is difficult to obtain a high purity ammonium metatungstate product.
Ammonium metatungstate (AMT) is an important intermediate compounds of tungsten hydrometallurgical process. Because of its excellent features and a wide range of uses, it take more and more people's attention. With the development of science and technology, AMT has become increasingly widespread and important use in the petroleum, chemical, machinery, electronics, defense, aviation, metallurgy, corrosion, fire and so on. Acid neutralization method is an industrial method for preparing partial ammonium tungstate. And the acid that neutralization method used can be an organic acid (formic acid, acetic acid, citric acid, lactic acid, etc.), can also be an inorganic acid (acid, nitric acid, etc.). Organic acid is ease and easy to operate, but the price is more expensive, the cost is one major drawback. In inorganic acid, nitric acid has the advantage of easily available raw materials and cheap prices.