阅读说明：本技术 一种钨酸的制备方法 (Preparation method of tungstic acid ) 是由 谢建干 庄世明 蓝永祥 于 2021-07-23 设计创作，主要内容包括：本发明公开一种钨酸制备方法,采用萃取法替代了传统工艺中的沉淀人造白钨、酸分解人造白钨等多重工序。工业钨酸钠溶液用经典沉淀法除砷、磷、硅、等杂质后,再调整钨酸钠溶液酸度至pH为2-3,然后将已经酸化的有机相与钨酸钠溶液混合后萃取,分相后,钨被萃入有机相中,有机相用双氧水和柠檬酸反萃,得到反萃液,将反萃液加热煮沸至无小气泡,冷却,静置沉淀、过滤,得到钨酸,本发明制得的符合钨酸《YS/T692-2009》H-(2)WO-(4)-0级产品要求。(The invention discloses a preparation method of tungstic acid, which adopts an extraction method to replace multiple procedures of precipitating artificial scheelite, decomposing artificial scheelite by acid and the like in the traditional process. Removing arsenic, phosphorus, silicon and other impurities from an industrial sodium tungstate solution by a classical precipitation method, adjusting the acidity of the sodium tungstate solution to pH 2-3, mixing an acidified organic phase with the sodium tungstate solution, extracting tungsten into the organic phase after phase separation, back-extracting the organic phase by hydrogen peroxide and citric acid to obtain a back-extraction solution, heating and boiling the back-extraction solution until no small bubbles exist, cooling, standing for precipitation and filtering to obtain the tungstic acid 2 WO 4 -a product requirement of grade 0.)

1. A preparation method of tungstic acid is characterized by comprising the following steps:

(1) acid adjustment: taking the industrial sodium tungstate solution after impurity removal treatment, and adjusting the pH of the sodium tungstate solution to 2-3 by using sulfuric acid or hydrochloric acid;

(2) and (3) extraction: mixing the sodium tungstate solution after pH adjustment with an organic phase solution consisting of acidified isooctyl alcohol and sulfonated kerosene, performing ten-stage countercurrent extraction, and standing for phase splitting;

(3) back extraction: after standing and phase splitting, performing ten-stage counter-current back extraction on the tungsten-loaded organic phase by using a back extractant consisting of hydrogen peroxide and citric acid to obtain a back extraction solution;

(4) heating and boiling the stripping solution obtained in the step (3) until no small bubbles exist, cooling, standing for precipitation, and filtering to obtain the tungstic acid.

2. A process for producing a tungstic acid as claimed in claim 1 characterised in that before or after the sodium tungstate solution is adjusted with sulfuric acid or hydrochloric acid in step (1), the concentration of tungsten trioxide in the solution is not more than 250 g/L.

3. The process for producing tungstic acid according to claim 1 wherein in step (2) the mass fraction of isooctanol is 50% and the volume ratio of isooctanol to sulfonated kerosene is 1: 1.

4. A process for preparing tungstic acid according to claim 1 characterised in that when the organic phase is extracted against the sodium tungstate solution in step (2), the oil phase to water phase ratio is 1: 1.

5. The preparation method of tungstic acid according to claim 1, characterized in that the mass fraction of hydrogen peroxide and the mass fraction of citric acid in the stripping agent of step (2) are respectively 5% and 1% -2%.

6. The process for producing a tungstic acid according to claim 1 wherein in step (2) the negative tungsten organic phase is extracted at a phase ratio of oil phase to aqueous phase of 3/1.

Technical Field

The invention relates to a preparation method of tungstic acid, belonging to the field of wet tungsten metallurgy.

Background

The tungstic acid is an oxide of tungsten, is yellow powder at normal temperature, and has a molecular formula as follows: h₂WO₄. Tungstic acid is an important basic chemical raw material, and the application of the tungstic acid is very wide. Tungstic acid is used as a mordant in the industries of pigments, dyes and printing ink; the ceramic glaze pigment is introduced as a cosolvent to play roles in reducing the firing temperature and supplementing color; as a fabric weighting agent and a fabric auxiliary agent, a mixture composed of tungstic acid, ammonium sulfate, ammonium phosphate and the like is used for the fire prevention and the water prevention of the fiber to manufacture the fire-proof rayon and the artificial cotton; the inorganic non-metallic material can be applied to the petroleum industry and the manufacture of aviation and aerospace materials.

The traditional tungstic acid is prepared by reacting sodium tungstate solution and calcium chloride solution to generate calcium tungstate (artificial white tungsten) precipitate,the reaction formula is as follows: na (Na)₂WO₄+CaCl₂＝CaWO₄↓ +2 NaCl; then, calcium tungstate is decomposed by hot concentrated hydrochloric acid to generate yellow tungstic acid precipitate, impurities such as calcium ions, iron ions and the like in the artificial white tungsten form soluble chlorides, and the soluble chlorides are filtered to be removed along with residual acid, wherein the quality of the prepared tungstic acid can be ensured only by preferentially performing molybdenum removal treatment on a sodium tungstate solution, but the molybdenum removal process is complicated and time-consuming. With the wide application of tungstic acid in the fields of aerospace, analytical science, catalysts and the like, the purity and the grain size of tungstic acid and the preparation efficiency, energy consumption, environmental protection and the like which influence the industrial development are all required to be higher, so that an industrial preparation method which has high efficiency and low cost and can prepare high-quality tungstic acid is urgently needed.

The patent with publication number CN104386755A discloses a preparation method of high-purity tungstic acid, and particularly discloses a method for preparing tungstic acid with the purity of more than 99.999 percent by using tungstic acid with the content of 99.95 percent as a raw material and utilizing the superiority of acid solvent washing and ultrasonic cavitation effect to efficiently remove impurities of the raw material without chemical reaction.

Disclosure of Invention

In order to solve the problems in the prior art, the invention provides a preparation method of tungstic acid, which solves the problems of low efficiency and high cost of the decomposition of artificial white tungstic acid in the traditional tungstic acid preparation, and is very suitable for industrial production.

The technical scheme of the invention is as follows:

the invention discloses a preparation method of tungstic acid, which comprises the following steps:

(1) acid adjustment: taking the industrial sodium tungstate solution after impurity removal treatment, and adjusting the pH of the sodium tungstate solution to 2-3 by using sulfuric acid or hydrochloric acid;

(2) and (3) extraction: mixing the sodium tungstate solution after pH adjustment with an organic phase solution consisting of acidified isooctyl alcohol and sulfonated kerosene, performing ten-stage countercurrent extraction, and standing for phase splitting;

(3) back extraction: after standing and phase splitting, performing ten-stage counter-current back extraction on the tungsten-loaded organic phase by using a back extractant consisting of hydrogen peroxide and citric acid to obtain a back extraction solution;

(4) heating and boiling the stripping solution obtained in the step (3) until no small bubbles exist, cooling, standing for precipitation, and filtering to obtain the tungstic acid.

Further, after the sodium tungstate solution is adjusted by sulfuric acid or hydrochloric acid in the step (1), the concentration of tungsten trioxide in the solution is not more than 250 g/L.

Further, in the step (2), the mass fraction of isooctyl alcohol is 50%, and the volume ratio of isooctyl alcohol to sulfonated kerosene is 1:1

Further, when the organic phase is extracted from the sodium tungstate solution in the step (2), the ratio of the oil phase to the water phase is 1: 1.

Further, the mass fraction of the hydrogen peroxide and the mass fraction of the citric acid in the stripping agent in the step (2) are respectively 5% and 1% -2%.

Further, when the negative tungsten organic phase is extracted in the step (2), the ratio of the oil phase to the water phase is 3/1.

Compared with the prior art, the invention has the beneficial effects that:

1. the invention provides a preparation method of tungstic acid, which adopts an extraction method, abandons the multiple procedures of precipitating artificial white tungsten, decomposing the artificial white tungsten by acid and the like in the traditional tungstic acid preparation process, shortens the whole technological process for preparing the tungstic acid, starts with the processes of acid adjustment, organic phase configuration, back extractant configuration and the like, carries out innovative improvement process, solves the problems of low efficiency and high cost of the artificial white tungstic acid decomposition in the traditional tungstic acid preparation process, and is suitable for industrial production.

2. In the preparation method of the tungstic acid provided by the invention, the acidity of the industrial sodium tungstate solution used as a raw material is adjusted, isooctanol is used as an extracting agent, sulfonated kerosene is used as a diluting agent to form an organic phase for extraction, and when the pH is less than or equal to 3, molybdenum in the sodium tungstate solution is MoO₂ ²⁺The form of cation exists in the solution, tungsten still exists in the form of anion, isooctanol belongs to weak neutral extractant, molybdenum is not easy to be extracted, and the difference can be used for removing molybdenum and other impurities of potassium, sodium, magnesium,Iron, calcium, manganese, arsenic, sulfur, phosphorus and the like are not extracted, so the method has high selectivity for extracting tungsten and has good molybdenum removal effect, and complex molybdenum removal treatment of a raw material sodium tungstate solution is omitted; in the back extraction process, the back extraction agent consisting of hydrogen peroxide and citric acid is adopted, the tungstic acid is oxidized by the hydrogen peroxide to form soluble peroxytungstic acid, the citric acid can be used for complexing with the peroxytungstic acid to realize back extraction of the tungstic acid, and the back extraction efficiency is higher than that of pure water.

3. The size of the tungstic acid crystal grains prepared by the method provided by the invention is smaller than that prepared by the traditional method, a stripping agent consisting of hydrogen peroxide and citric acid is used in the stripping process, and the tungstic acid crystal grains can be dispersed after the citric acid has a complexing effect and is dried, so that the tungstic acid crystal grains are smaller in size and high in preparation efficiency.

Detailed Description

The following examples are intended to illustrate the invention but are not intended to limit the scope of the invention. The examples do not show the specific techniques or conditions, according to the technical or conditions described in the literature in the field, or according to the product specifications. The reagents or instruments used are conventional products available from regular distributors, not indicated by the manufacturer.

Example 1

A preparation method of tungstic acid comprises the following steps:

(1) taking an industrial sodium tungstate solution, wherein the concentration of tungsten trioxide is 250g/L, the content of other impurity elements in the sodium tungstate solution is shown in table 1, and adjusting the pH value of the sodium tungstate solution to 2.5 by hydrochloric acid; wherein, the industrial sodium tungstate solution is precipitated in advance to remove impurities such as arsenic, phosphorus, silicon and the like;

(2) taking 50% isooctyl alcohol as an extracting agent and a diluting agent as sulfonated kerosene to form an organic extraction phase, acidifying the organic phase, performing ten-stage countercurrent extraction on the sodium tungstate solution with the organic phase subjected to acid adjustment, wherein the ratio of O/A (oil phase/water phase) is 1:1, and standing for phase separation;

(3) after extraction, performing ten-stage counter-current back extraction on the tungsten-negative organic phase by using a back extractant consisting of 5% by mass of hydrogen peroxide and 1% by mass of citric acid, wherein the ratio of O/A (oil phase/water phase) is 3:1, and obtaining a back extraction solution;

(4) heating and boiling the stripping solution until no small bubbles exist, cooling, standing for precipitation, filtering, and drying to obtain the tungstic acid.

Example 2

A preparation method of tungstic acid comprises the following steps:

(1) taking an industrial sodium tungstate solution, wherein the concentration of tungsten trioxide is 231g/L, the content of other impurity elements in the sodium tungstate solution is shown in table 1, and adjusting the pH value of the sodium tungstate solution to 2.0 by hydrochloric acid; wherein, the industrial sodium tungstate solution is precipitated in advance to remove impurities such as arsenic, phosphorus, silicon and the like;

(2) taking 50% isooctyl alcohol as an extracting agent and a diluting agent as sulfonated kerosene to form an organic extraction phase, acidifying the organic phase, performing ten-stage countercurrent extraction on the sodium tungstate solution with the organic phase subjected to acid adjustment, wherein the ratio of O/A (oil phase/water phase) is 1:1, and standing for phase separation;

(3) after extraction, performing ten-stage counter-current back extraction on the tungsten-negative organic phase by using a back extractant consisting of 5% by mass of hydrogen peroxide and 2% by mass of citric acid, wherein the ratio of O/A (oil phase/water phase) is 3:1, and obtaining a back extraction solution;

(4) heating and boiling the stripping solution until no small bubbles exist, cooling, standing for precipitation, filtering, and drying to obtain the tungstic acid.

Example 3

Example 3 differs from example 1 in that:

in the acid adjusting process, the concentration of tungsten trioxide in the sodium tungstate solution is 240g/L, and the pH value of the sodium tungstate solution is adjusted to 3.0.

The contents of other impurity elements in the industrial sodium tungstate solutions according to examples 1 to 3 are shown in table 1 below;

table 1 chemical analysis of raw industrial sodium tungstate solution (aqueous phase): g/L

The properties of tungstic acid products prepared according to the methods described in examples 1-3 were tested as follows;

table 2 target product tungstic acid spectral analysis results: ug/g

Table 3 results of the freund's particle size detection of the target product: um

As can be seen from tables 1, 2 and 3, the tungstic acid prepared by the method provided by the invention has the advantages of greatly simplified process flow, low energy consumption, low cost and high purity compared with the traditional tungstic acid preparation method, and the crystal grain size of the prepared tungstic acid is smaller than that prepared by the traditional method; the obtained target tungstic acid sample is detected by chemical analysis and is all attached with tungstic acid YS/T692-2009H₂WO₄-a product requirement of grade 0.

The above examples of the present invention are merely examples provided for clearly illustrating the present invention and are not intended to limit the embodiments of the present invention. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. Not all embodiments are exhaustive. All obvious changes and modifications of the present invention are within the scope of the present invention.