Purification process for purifying sodium tungstate solution

Abstract

The invention discloses a purification process for purifying a sodium tungstate solution, comprising the following steps: S1: acid neutralization of the sodium tungstate solution, wherein acid used for acid neutralization is inorganic diluted acid, preferably dilute sulphuric acid; S2: adding of a magnesium salt solution, wherein the calculation formula of the magnesium salt adding amount according to according to the molar ratio of P, As and Si in the sodium tungstate solution is n(Mg)=X*n(P)+Y*n(As)+Z*n(Si), the scope of X value is 1-30, the scope of Y value is 1-30, and the scope of the Z value is 1-20; S3: heating and preserving heat, wherein the heating temperature of the sodium tungstate solution is 40-100 DEG C, preferably 70-80 DEG C; S4: cooling and filtering, namely cooling and filtering the sodium tungstate solution after heating and heat preservation. According to the purification process for purifying a sodium tungstate solution, in the sodium tungstate solution purified by adopting the method, P is less than or equal to 0.007g/L, As is less than or equal to 0.01g/L, and SiO2 is less than or equal to 0.1g/L, and ammonium tungstate is prepared by adopting an extractionmethod, wherein P is less than or equal to 5ppm, As is less than or equal to 5ppm, and Si is less than or equal to 5ppm, and therefore, not only is the impurity removal effect good due to adding of insoluble magnesium salt, but also the price of the reagent is low, and cost is saved.

Description

technical field [0001] The invention relates to the technical field of hydrometallurgy, in particular to a purification process for purifying sodium tungstate solution. Background technique [0002] Tungsten is a refractory non-ferrous metal and an important strategic resource. It is widely used because of its excellent properties such as high melting point, high hardness, strong ductility, wear resistance and corrosion resistance. With the development of tungsten products towards high purity With the development of the direction, the requirements for impurity removal in the smelting process are getting higher and higher. [0003] Generally, the impurity removal of sodium tungstate adopts the classic magnesium salt precipitation method. Generally, soluble MgCl2 or MgSO4 is used to precipitate P, As, Si and other impurity elements in the sodium tungstate solution. Using this chemical precipitation method to treat sodium tungstate solution with high impurity content has a po...

AI Technical Summary

Problems solved by technology

Using this chemical precipitation method to treat sodium tungstate solution with high impurity content has a poor overall impurity removal effect, and a large number of anions (such as chloride ions, sulfate ions, nitrate ions, etc.) will be introduced. At the same time, with P, As, Precipitation of impurity elements such as Si, a large amount of tungsten will also be absorbed into the slag, the loss of tungsten is large, and the direct metal recovery rate is low