The detailed steps for the preparation of ammonium metatungstate by neutralization method are as follows.
- Pre-preparation
Preparation of raw materials
Prepare ammonium paratungstate and nitric acid as raw materials, as well as deionized water and ammonium citrate as auxiliary solvents.
Preparation of slurry
Add ammonium paratungstate to deionized water and ammonium citrate to form a slurry containing WO₃ 12% to 30% concentration.
- Neutralization reaction
Nitric acid addition
Add 3%～5% dilute nitric acid to ammonium paratungstate slurry according to the ratio of ammonium paratungstate:nitric acid=1:20.
Control conditions
Control the solid-liquid ratio of 1: (3 ~ 4), Ph value of 2 ~ 4, heating to dissolve, so that the relative density of the solution to 1.18 ~ 1.20.
Stirring and heating
Under the appropriate stirring speed, heating to 80 ~ 90 ℃, constant temperature and volume control Ph value, stirring reaction for 4 hours.
- Aging and filtration
Aging
Age for several hours to allow the substances in solution to fully react and precipitate.
Filtration
Through the filtration equipment, remove the insoluble substances in the solution to get a clear ammonium metatungstate solution.
- Concentration and crystallization
Concentration
Concentrate the clear solution until the WO3 content is about 50%.
Cooling and crystallization
The concentrated solution is cooled, so that the ammonium metatungstate crystals are precipitated.
- Drying and crushing
Drying
The crystallized ammonium metatungstate is dried at 80°C to remove excess water.
Crushing
Crush the dried ammonium metatungstate to get the final ammonium metatungstate product.
- Batch combination, inspection and packaging
During the whole process, special attention must be paid to controlling the parameters such as temperature, pH value, stirring speed, etc. to ensure the activity of the reactants during the production process, so as to guarantee the quality of the final product and ensure the quality stability. Besides, the operators need to have enough experience and strict quality management system to ensure the quality of Ammonium Metatungstate meets the requirements.
More details of ammonium metatungstate product, please visit website: http://ammonium-metatungstate.com/
Please contact CHINATUNGSTEN for inquiry and order of ammonium metatungstate:
Email: sales@chinatungsten.com
Tel.: 86 592 5129595
