The process of preparing ammonium metatungstate hydrate using ion exchange method can be divided into the following steps, and the following are the detailed step-by-step instructions:
- Preparation of raw materials
Main raw materials
Ammonium paratungstate solution or ammonium tungstate solution.
- Ion exchange process
Ion exchange resin
Use strong acid or weak acid H+ type cation resin, such as D354 weak base macroporous ion exchange resin.
pH adjustment
Adjust the pH value of ammonium tungstate solution or ammonium sec-tungstate solution to the range suitable for ion exchange, generally around pH 3.5.
Ion exchange
Utilizing the H+ in the resin to exchange ions with the NH4+ in the solution, the H+ enters the solution while the NH4+ is adsorbed by the resin.
- Cooking and conversion
Cooking
Boil solution at 98°C for 5 hours to convert ammonium tungstate to a stable ammonium metatungstate solution.
Conversion
After boiling, ammonium tungstate solution is converted to ammonium metatungstate solution.
- Evaporation, concentration and crystallization
Evaporation and concentration
The ammonium metatungstate solution is concentrated by evaporation to increase the concentration of ammonium metatungstate in the solution.
Crystallization
Ammonium metatungstate is precipitated from the solution by cooling crystallization or spray drying to form ammonium metatungstate hydrate crystals.
- Filtration and drying
Filtration
The crystallized ammonium metatungstate hydrate is separated from the mother liquor by using filtration equipment.
Drying
The ammonium metatungstate hydrate obtained by filtration is dried to remove the residual water, and the dried ammonium metatungstate hydrate is obtained as a finished product.
Precautions
Resin treatment
The resin saturated by NH4+ can be regenerated by hydrochloric acid solution for recycling.
Operating conditions
Strictly control the operating conditions, such as pH, temperature and time, to ensure the quality and stability of the product.
Safety
Pay attention to safety during operation, avoid contact with skin and eyes, and ensure good ventilation.
Ion exchange method is an effective method to prepare ammonium metatungstate hydrate. High quality ammonium metatungstate hydrate can be efficiently prepared by adjusting the pH value, using suitable ion exchange resin and strict steps of boiling, evaporation and crystallization.
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
