Method used for purifying sodium tungstate solution

Abstract

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.

Description

technical field [0001] The invention relates to the field of metallurgy, in particular to a method for purifying sodium tungstate solution. Background technique [0002] Tungsten concentrates are usually treated with acid or alkali. At present, domestic tungsten smelting enterprises mainly use NaOH decomposition process. During the decomposition process, impurities such as phosphorus, arsenic, silicon, tin, fluorine and other impurities in the raw materials will be decomposed and enter the sodium tungstate feed solution. For example, when a factory in my country conducts high-pressure leaching of wolframite concentrate at 135°C, the leaching rates of phosphorus, arsenic and silicon in the raw materials are 30%-40%, 35%-42% and 20%-25%, respectively. Up to 1g / L, in addition to other impurities such as tin. It can be seen that the sodium tungstate feed solution obtained by decomposition contains a large amount of impurities. These impurity components will hinder the treatmen...

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Problems solved by technology

This method may have poor comprehensive impurity removal effect, or may introduce a large amount of anions (such as chloride ions, sulfate ions, nitrate ions, etc.), which will seriously affect the adsorption capacity of tungsten in the subsequent ion exchange process. Impurity cations can easily cause ammonium paratungstate cation elements to exceed the standard

[0005] Therefore, in the hydrometallurgical process of tungsten, the method of purifying the sodium tungstate liquid with high impurity content needs to be improved

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