REMOVAL OF Na FROM THE AMMONIUM TUNGSTATE SOLUTION BY Nal+xAlxTi2-x(PO4)3

摘要

In tungsten ion-exchange process, excessive sodium impurity enters into ammonium tungstate solution. However, the Na content of the final ammonium paratungstate (APT) product must be strictly controlled. Consequently, it is necessary to remove Na from the ammonium tungstate solution during processing in order to obtain the required purity of APT. In this study, porous Na specific absorbent, Nal+xAlxTi2-x(PO4)3, is used to remove Na from the ammonium tungstate solution. Through experiments, the effect of reagent concentration of Nal+xAlxTi2-x(PO4)3, reaction time, reaction temperature and Na concentration on the Na removal were investigated. The results showed that under optimal reaction conditions of reagent amount of NATP 1.0 times of theoretical amount, reaction temperature 25°C and reaction time 15 min, the Na removal from commercial (NH4)2WO4 solution can reach 98%. Nal+xAlxTi2-x(PO4)3 has a good applicability to different Na+ concentrations. The obtained APT product reaches the national standard purity of zero level.