Ion exchange method is used to prepare ammonium paratungstate. That is because this method has advantages of a short process flow, simple equipment and high tungsten recovery rate. Also, it can simultaneously complete the two tasks of impurity removal and transformation. In addition, it can significantly increase the concentration of tungsten trioxide in the pre-delivery solution and reduce the generation of wastewater.
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Preparation of ammonium paratungstate by ion exchange method
Step One: Tungsten concentrate is treated with alkali to get alkaline sodium tungstate;
Step Two: Add acidic substances into the alkaline solution with heating for neutralization treatment to get sodium tungstate;
Step Three: Dilute the sodium tungstate to get pre-exchange solution;
Step Four: Use weakly basic anion exchange resin to adsorb the tungsten in pre-exchange solution;
Step Five: Use desorbent to desorb the weakly basic anion exchange resin with tungsten, and get the desorption;
Step Six: Remove impurities in the desorption;
Step Seven: Evaporate and crystallize the solution to obtain ammonium paratungstate.
