Ammonium metatungstate (AMT) can be produced by neutralization, which is used ammonium paratungstate (APT) as raw material.
This production method is using APT and nitric acid, adding de-ionized water and citric acid, after stirring, it contains 12%~30WO3. Heat the fluid and make its density 1.18~1.20g/cm3. Stirring, sedimentation, filtration, cooling, crystallization are the following steps to produce AMT. Drying is the last step. After drying, the AMT is produced.