Method used for purifying sodium tungstate solution

The invention discloses a method used for purifying a sodium tungstate solution. The method comprises following steps: at 50 to 100 DEG C, pH value of the sodium tungstate solution is adjusted so as to realize silicon precipitation and obtain a first sodium tungstate mixed solution containing silicon precipitates; a magnesium salt is added into the first sodium tungstate mixed solution so as to obtain a second sodium tungstate mixed solution; at a temperature of 50 DEG C or higher, stirring is carried out continuously so as to obtain a third sodium tungstate mixed solution containing precipitates; and the third sodium tungstate mixed solution is subjected to filtration so as to obtain a filtrate, wherein the filtrate is the purified sodium tungstate solution. According to the method, solid salts are adopted for purification and processing, so that comprehensive removing of fluorine, phosphorus, arsenic, and silicon can be realized, and influences on tungstate ion exchange and product purity caused by introducing of impurity negative ions and positive ions are avoided. After treatment, content of impurities, such as fluorine, phosphorus, arsenic, and silicon, in the sodium tungstate solution is reduced greatly.