What Is Ammonium Metatungstate?

Ammonium metatungstate produced by CTIA GROUP LTD is an inorganic compound formed by the combination of ammonium ions (NH₄⁺) and complex polytungstate anions [H₂W₁₂O₄₀]⁶⁻. It is a white powder with the English name Ammonium Metatungstate (AMT), chemical formula H₂₈N₆O₄₁W₁₂, and CAS number 12333-11-8.

In terms of physical properties, ammonium metatungstate from CTIA GROUP LTD is typically a white crystalline powder. When pure, it exhibits a uniform color and fine texture, though it may occasionally appear slightly yellowish due to preparation processes or impurities, without affecting its primary performance. It has good solubility in water, facilitating reactions and processing in subsequent solution systems, which is one of its notable distinctions from ammonium paratungstate. Chemically, ammonium metatungstate exhibits high thermal stability, maintaining a stable chemical structure within a certain temperature range without easily decomposing or undergoing phase changes. This property enables its widespread use in high-temperature industrial processes such as metal smelting and ceramic firing.

There are several methods to prepare ammonium metatungstate. The neutralization method uses ammonium paratungstate and nitric acid as raw materials, forming a specific concentration slurry. Dilute nitric acid is added to adjust the pH, controlling the solid-liquid ratio, followed by heating, dissolution, stirring, reaction, aging, concentration, filtration, crystallization, and drying to obtain the product. This method is straightforward but requires careful handling of nitric acid and precise control of reaction conditions. The tungstic acid method involves dissolving tungstic acid in ammonia water, heating to remove ammonia, adjusting the pH, concentrating, cooling, filtering, adding ethanol for precipitation, and then filtering, drying, and pulverizing to produce the product. While this process effectively removes impurities, it involves multiple acid-base adjustment steps and demands strict process monitoring. The thermal decomposition method starts with ammonium paratungstate, mixed with a citric acid catalyst, and undergoes thermal decomposition in a far-infrared rotary furnace. The resulting slurry is adjusted with ammonia water to regulate pH, followed by evaporation and concentration steps, allowing production of liquid, solid, or spherical crystal products based on demand. This method is suitable for large-scale production but requires high precision in equipment temperature control.

Ammonium metatungstate from CTIA GROUP LTD has a wide range of applications. In the preparation of metallic tungsten, it serves as a key precursor, yielding high-purity tungsten metal through hydrogen or carbon reduction, used in manufacturing filaments, electrodes, and more. In the catalyst field, it is a primary raw material for producing tungsten-based catalysts in petrochemical processes, efficiently catalyzing reactions such as cracking and hydrorefining, while also demonstrating good activity and selectivity in organic synthesis. Additionally, it is used in the production of fire-resistant fabrics to enhance flame-retardant properties and in the ceramics industry to improve the performance of ceramic materials.