The process of preparing ammonium metatungstate hydrate by ion exchange method can be summarized as follows:
Preparation of raw materials
Ammonium paratungstate is used as raw material to ensure that the purity and quantity of raw material meet the production requirements.
Heating and conversion
Heat the ammonium paratungstate at a temperature of 130-140°C for a duration of about 1-8 hours.
The heated product is made into a slurry for subsequent reaction.
Boiling
The product, which was blended into a slurry, was boiled at a temperature of 80 to 100°C for a duration of about 2 to 6 hours.
The purpose of this step is to promote the reaction to generate the ammonium metatungstate solution.
Control of acidity of effluent solution
The acidity of the effluent needs to be controlled at a pH of about 3.5, this is to ensure that the subsequent reaction is carried out under appropriate acid-base conditions.
Cooking
The ammonium metatungstate solution was boiled at a temperature of 98°C for a duration of about 5 hours.
The purpose of this step is to convert the ammonium tungstate into a stable ammonium metatungstate solution.
Evaporation and concentration
The boiled ammonium metatungstate solution is concentrated by evaporation to remove excess water and increase the concentration of ammonium metatungstate in the solution.
Cooling crystallization or spray drying:
According to the production demand, the method of cooling crystallization or spray drying can be chosen to transform the concentrated ammonium metatungstate solution into solid form.
Cooling crystallization is to make the ammonium metatungstate in the solution precipitate into crystals by lowering the temperature; while spray drying is to spray the solution into fine droplets, which are quickly dried into powder under high temperature.
Filtration Separation and Drying
If the method of cooling crystallization is used, the crystals need to be filtered and separated to remove the impurities in the solution, and then dried.
If the method of spray drying is adopted, the dried ammonium metatungstate powder is obtained directly.
Product Inspection and Packing
The quality inspection of the produced ammonium metatungstate hydrate is carried out to ensure that it meets the relevant standards and requirements.
After passing the inspection, the product is packed for storage and transportation.
Above is the detailed process of preparing ammonium metatungstate hydrate by ion exchange method. This method has the advantages of simple process, convenient control, can avoid the formation of APT, will not bring in new pollutants and so on, so it has been widely used in the actual production.
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
