Preparation of High Grade Ammonium Metatungstate (AMT) as Precursor for Industrial Tungsten Catalyst

• Published in: Rare Metal Technology 2021 pp. 73 - 78
• Main Authors: Baba, Alafara A., Girigisu, Sadisu, Raji, Mustapha A., Ibrahim, Abdullah S., Ayinla, Kuranga I., Adeyemi, Christianah O., Abdulkareem, Aishat Y., Abdul, Mohammed J., Alabi, Abdul G. F.
• Format: Book Chapter
• Language: English
• Published: Cham Springer International Publishing
• Series: The Minerals, Metals & Materials Series
• Subjects: Ammonium metatungstate (AMT); Industrial applications; Leaching; Wolframite
• ISBN: 3030654885; 9783030654887
• ISSN: 2367-1181; 2367-1696
• DOI: 10.1007/978-3-030-65489-4_9

The increasing demand for pure tungsten and its compounds due to their high tensile strength makes them a versatile materialMaterials in catalyst, heavy alloy, cemented carbide, among others. This exceptional property makes it to be of high interest by industrialists for use in the engineering and manufacturing industries. Thus, preparation of ammonium metatungstate (AMT)Ammonium Metatungstate (AMT) from a Nigerian wolframiteWolframite ore by hydrometallurgical technique was examined in sulphuric and phosphoric acid. During leachingLeaching, parameters such as leachant concentration, reaction temperature, and particle size on ore dissolution were examined. At optimal conditions (2.0M H2SO4H2SO4+ 0.15M H3PO4H3PO4, 75 °C, −63 µm), 93.7% of the ore dissolved within 120 min. The calculated activation energy of 6.93 kJ/mol supported the proposed diffusion mechanism. The leachate at optimal conditions was treated to obtain a pure tungstate solution. The purified solution was beneficiated to prepare a high grade AMTAmmonium Metatungstate (AMT) ((NH4)6[H2W12O40]·4H2O: 96-901-3322, m.p.: 98.7 °C, density: 2.16 g/cm3), which serves as an intermediate for some defined industries.