Method for producing high-purity ammonium metavanadate from vanadium-containing purified liquid

Abstract

The invention discloses a method for producing high-purity ammonium metavanadate from vanadium-containing purified liquid. The method specifically comprises the following steps: adjusting the pH value of the vanadium-containing purified liquid to 5-6, and adding ammonium salt at normal temperature for vanadium precipitation to obtain a sodium ammonium vanadate solid; dissolving the sodium ammonium vanadate solid in pure water at 80-100 DEG C, adjusting the pH value to 8-10 by using ammonia gas, preserving heat and filtering to obtain a purified solution; and controlling the temperature of the purified solution, cooling, adding ammonium metavanadate seed crystals at 50-60 DEG C, and filtering at normal temperature to obtain large-particle high-purity ammonium metavanadate solids. The method is wide in raw material source, simple in process, low in cost and few in product impurity, and has good economic benefits and application prospects.

Description

Technical Field

[0001] The invention belongs to the technical field of vanadium chemical industry, and in particular relates to a method for producing high-purity ammonium metavanadate from vanadium-containing purified liquid. Background Art

[0002] Ammonium metavanadate is an important intermediate product in the vanadium chemical industry. It can be used to produce vanadium pentoxide by oxidation calcination, or to produce vanadium trioxide by reduction calcination. Due to its complete crystal structure and large particle size, it can produce a series of high-purity vanadium products. With the adjustment of my country's industrial structure and the upgrading of products, the demand for high-purity series products in the aerospace field, vanadium-aluminum alloys, vanadium catalysts, vanadium battery electrolytes and other industries is increasing.

[0003] At present, the industry mostly adopts the method of directly adding acid / alkali to the vanadium-containing purified liquid to adjust the pH, and then adding ammonium salt to produce ammonium metavanadate. This method has a simple process, but there are problems such as low product grade, high impurities, and small particles, and it is difficult to produce high-purity vanadium oxide series products. Patent CN106241872A discloses a method for preparing large-particle ammonium metavanadate. By adjusting the factors affecting the grain size such as the concentration of sodium metavanadate solution, the concentration of ammonium salt solution, the addition method of the two solutions and the reaction time, an ammonium metavanadate product with a large average particle size and a narrow particle size distribution is prepared. This method solves the problem of small ammonium metavanadate particles, but does not improve the purity of the product. Patent CN107117653A discloses a method for preparing high-purity ammonium polyvanadate, wherein ammonia gas is introduced into the vanadium-containing purified leachate, the pH value is adjusted to 4.0-7.0, sodium ammonium vanadate is obtained after stirring and filtering, and then the sodium ammonium vanadate is heated and dissolved after adding water, and an ammonium salt is added and the pH value is adjusted to 2.0-3.0 to obtain high-purity ammonium polyvanadate. This method has the advantages of simple process, low cost, and easy operation, but the prepared ammonium polyvanadate crystal particles are small and the water content is high, resulting in a high impurity content. Summary of the invention

[0004] The invention provides a method for producing high-purity ammonium metavanadate from vanadium-containing purified liquid. The method uses the vanadium-containing purified liquid based on the traditional vanadium industry as a raw material, adopts a method of weak acid ammonium precipitation-hot water re-dissolution-weak alkali impurity removal-temperature controlled cooling crystallization, and focuses on solving the industry problems of low purity and small particle size in conventional methods, so as to provide raw materials for the subsequent production of high-purity series vanadium oxide.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention includes: a method for producing high-purity ammonium metavanadate from a vanadium-containing purified liquid, the method comprising the following steps: a. Adjusting the pH value of the vanadium-containing purified liquid to 5-6, adding ammonium salt to precipitate vanadium at room temperature to obtain sodium ammonium vanadate solid; b. Dissolve the sodium ammonium vanadate solid in 80-100°C pure water, adjust the pH to 8-10 with ammonia gas, and filter at the temperature to obtain a purified solution; c. Cool the purified solution under controlled temperature, add ammonium metavanadate seeds at 50-60°C, cool to room temperature under stirring, and filter to obtain large-particle high-purity ammonium metavanadate solid.

[0006] In step a of the present invention, the vanadium-containing purification liquid is a sodium salt solution of the traditional vanadium industry, with a vanadium concentration of 15-40 g / L, a chromium concentration of ≤2.0 g / L, a phosphorus content of ≤0.1 g / L, and a silicon content of ≤0.30 g / L.

[0007] In step a of the present invention, the pH regulator is one of sulfuric acid or hydrochloric acid; the ammonium salt is one of ammonium sulfate or ammonium chloride; the mass ratio of the ammonium salt (in terms of NH4+) to the vanadium in the solution is 0.2-0.4:1.

[0008] In step b of the present invention, the vanadium concentration of the solution obtained by dissolving sodium ammonium vanadate in water is 15-40 g / L; and the heat preservation and filtration temperature is not lower than 80°C.

[0009] In step b of the present invention, the conductivity of pure water is ≤2μS / cm; the ammonia gas is a high-grade liquid anhydrous ammonia, and the pressure after gasification is 0.1-0.16MPa.

[0010] In step c of the present invention, the purified solution is temperature controlled and crystallized, and the cooling rate is 0.1-1°C / min.

[0011] In step c of the present invention, the amount of ammonium metavanadate seed added is 1 / 10 to 1 / 20 of the mass of the ammonium metavanadate obtained by the reaction.

[0012] In step c of the present invention, the stirring rate is 100 to 350 r / min.

[0013] The purity of the ammonium metavanadate obtained by the method of the present invention is ≥99.9%.

[0014] The beneficial effects of the above technical scheme are: 1. The present invention first uses weakly acidic vanadium precipitation to prepare sodium ammonium vanadate, which can effectively remove a large amount of impurities such as potassium, sodium, chromium, and phosphorus; then the sodium ammonium vanadate is heated and dissolved in pure water, and the pH is adjusted with ammonia, and the solution is filtered to further remove impurities such as iron, aluminum, and silicon. The use of pure water and ammonia as auxiliary materials can ensure that no new impurities are introduced; finally, the temperature is controlled and cooled for crystallization, and crystal seeds are added at the same time. The supersaturation of ammonium metavanadate is reduced by adding crystal seeds, and the growth of crystals is promoted by combining temperature control and cooling crystallization, ensuring the integrity of the crystal structure, thereby comprehensively improving the purity and particle size of the product. 2. The process of the present invention is simple, easy to operate, and has low production cost. The process solution can be returned to the traditional vanadium industry for continued use. The purity of the prepared ammonium metavanadate reaches more than 99.9%, which has good social benefits and application prospects. DETAILED DESCRIPTION

[0015] The present invention will be further described in detail below with reference to specific embodiments. Example 1

[0016] A method for producing high-purity ammonium metavanadate from a vanadium-containing purified liquid comprises the following steps: a. The vanadium-containing purified liquid is a sodium salt solution obtained after vanadium slag is oxidized and roasted, filtered by water, and removed from aluminum salts, wherein the vanadium concentration is 28.4 g / L, the chromium concentration is 1.2 g / L, the phosphorus content is 15 mg / L, and the silicon content is 153 mg / L; the pH value of the vanadium-containing purified liquid is adjusted to 5.4 with sulfuric acid, and ammonium sulfate is added at 25°C, the mass ratio of ammonium sulfate to vanadium in the solution is 0.27:1, and white sodium ammonium vanadate is obtained by filtration; b. Dissolve sodium ammonium vanadate in 90℃ pure water (conductivity 1.2μS / cm), vanadium concentration 25g / L, adjust pH value to 8.5 with ammonia (ammonia is liquid anhydrous ammonia premium grade, pressure 0.14MPa after gasification), keep warm and filter at above 85℃ to obtain purified liquid; c. The purified solution was cooled under controlled temperature at a rate of 0.3°C / min. When the temperature reached 55°C, 1 / 20 of the mass of the obtained ammonium metavanadate was added as ammonium metavanadate seeds. The stirring rate during the crystallization process was 200r / min. After the temperature dropped to 25°C, large-particle high-purity ammonium metavanadate was obtained by filtration. The purity of the ammonium metavanadate reached 99.96%. Example 2

[0017] A method for producing high-purity ammonium metavanadate from a vanadium-containing purified liquid comprises the following steps: a. The vanadium-containing purified liquid is a sodium salt solution obtained after vanadium slag is oxidized and roasted, filtered by water, and removed by aluminum salt, wherein the vanadium concentration is 40.0 g / L, the chromium concentration is 1.8 g / L, the phosphorus content is 35 mg / L, and the silicon content is 253 mg / L; the pH value of the vanadium-containing purified liquid is adjusted to 5.0 with sulfuric acid, and ammonium sulfate is added at 30°C, the mass ratio of ammonium sulfate to vanadium in the solution is 0.4:1, and white sodium ammonium vanadate is obtained by filtration; b. Dissolve sodium ammonium vanadate in 95℃ pure water (conductivity 1.2μS / cm), vanadium concentration 40g / L, adjust pH value to 10.0 with ammonia (ammonia is liquid anhydrous ammonia premium grade, pressure 0.14MPa after gasification), keep warm and filter at above 90℃ to obtain purified liquid; c. The purified solution was cooled under controlled temperature at a rate of 0.1°C / min. When the temperature reached 60°C, 1 / 10 of the mass of the obtained ammonium metavanadate was added as ammonium metavanadate seeds. The stirring rate during the crystallization process was 100r / min. After the temperature dropped to 25°C, large-particle high-purity ammonium metavanadate was obtained by filtration. The purity of the ammonium metavanadate reached 99.92%. Example 3

[0018] A method for producing high-purity ammonium metavanadate from a vanadium-containing purified liquid comprises the following steps: a. The vanadium-containing purified liquid is a sodium salt solution obtained after vanadium slag is oxidized and roasted, water-leached and filtered, and aluminum salt is removed, wherein the vanadium concentration is 15 g / L, the chromium concentration is 0.9 g / L, the phosphorus content is 8 mg / L, and the silicon content is 128 mg / L; the pH value of the vanadium-containing purified liquid is adjusted to 5.7 with sulfuric acid, and ammonium sulfate is added at 25°C, the mass ratio of ammonium sulfate to vanadium in the solution is 0.2:1, and white sodium ammonium vanadate is obtained by filtration; b. Dissolve sodium ammonium vanadate in 85℃ pure water (conductivity 1.2μS / cm), vanadium concentration 15g / L, adjust pH value to 8.0 with ammonia (ammonia is liquid anhydrous ammonia premium grade, pressure 0.16MPa after gasification), keep warm and filter at above 80℃ to obtain purified liquid; c. The purified solution was cooled at a temperature control rate of 1.0°C / min. When the temperature reached 50°C, 1 / 15 of the mass of the obtained ammonium metavanadate was added as ammonium metavanadate seeds. The stirring rate during the crystallization process was 350r / min. After the temperature dropped to 25°C, large-particle high-purity ammonium metavanadate was obtained by filtration. The purity of the ammonium metavanadate reached 99.98%. Example 4

[0019] A method for producing high-purity ammonium metavanadate from a vanadium-containing purified liquid comprises the following steps: a. The vanadium-containing purified liquid is a sodium salt solution obtained after vanadium slag is oxidized and roasted, water-leached and filtered, and aluminum salt is removed, wherein the vanadium concentration is 16 g / L, the chromium concentration is 2.0 g / L, the phosphorus content is 8 mg / L, and the silicon content is 128 mg / L; the pH value of the vanadium-containing purified liquid is adjusted to 5.0 with sulfuric acid, and ammonium sulfate is added at 25°C, the mass ratio of ammonium sulfate to vanadium in the solution is 0.22:1, and white sodium ammonium vanadate is obtained by filtration; b. Dissolve sodium ammonium vanadate in 85℃ pure water (conductivity 1.2μS / cm), vanadium concentration 20g / L, adjust pH value to 8.8 with ammonia (ammonia is liquid anhydrous ammonia premium grade, pressure 0.1MPa after gasification), keep warm and filter at above 80℃ to obtain purified liquid; c. The purified solution was cooled under controlled temperature at a cooling rate of 0.8°C / min. When the temperature reached 50°C, 1 / 15 of the mass of the obtained ammonium metavanadate was added as ammonium metavanadate seeds. The stirring rate during the crystallization process was 250r / min. After the temperature dropped to 25°C, large-particle high-purity ammonium metavanadate was obtained by filtration. The purity of the ammonium metavanadate reached 99.94%. Example 5

[0020] A method for producing high-purity ammonium metavanadate from a vanadium-containing purified liquid comprises the following steps: a. The vanadium-containing purified liquid is a sodium salt solution obtained after vanadium slag is oxidized and roasted, filtered by water, and removed from aluminum salts, wherein the vanadium concentration is 35 g / L, the chromium concentration is 1.2 g / L, the phosphorus content is 24 mg / L, and the silicon content is 230 mg / L; the pH value of the vanadium-containing purified liquid is adjusted to 5.2 with sulfuric acid, and ammonium sulfate is added at 25°C, the mass ratio of ammonium sulfate to vanadium in the solution is 0.35:1, and white sodium ammonium vanadate is obtained by filtration; b. Dissolve sodium ammonium vanadate in 90℃ pure water (conductivity 2.0μS / cm), vanadium concentration is 32g / L, adjust pH value to 9.2 with ammonia (ammonia is liquid anhydrous ammonia premium grade, pressure after gasification is 0.14MPa), keep warm and filter at above 85℃ to obtain purified liquid; c. The purified solution was cooled at a rate of 0.3°C / min. When the temperature reached 55°C, 1 / 20 of the mass of the obtained ammonium metavanadate was added as ammonium metavanadate seeds. The stirring rate during the crystallization process was 300r / min. After the temperature dropped to 25°C, large-particle high-purity ammonium metavanadate was obtained by filtration. The purity of the ammonium metavanadate reached 99.95%.

[0021] The above embodiments are only used to illustrate rather than limit the technical solutions of the present invention. Although the present invention is described in detail with reference to the above embodiments, those skilled in the art should understand that the present invention can still be modified or replaced by equivalents. Any modification or partial replacement that does not depart from the spirit and scope of the present invention should be included in the scope of the claims of the present invention.

Claims

1. A method for producing high-purity ammonium metavanadate from a vanadium-containing purified liquid, characterized in that: The method comprises the following steps: a. Adjusting the pH value of the vanadium-containing purified liquid to 5-6, adding ammonium salt to precipitate vanadium at room temperature to obtain sodium ammonium vanadate solid; b. Dissolve the sodium ammonium vanadate solid in 80-100°C pure water, adjust the pH to 8-10 with ammonia gas, and filter at the temperature to obtain a purified solution; c. Cool the purified solution under controlled temperature, add ammonium metavanadate seeds at 50-60°C, cool to room temperature under stirring, and filter to obtain large-particle high-purity ammonium metavanadate solid.

2. A method for producing high-purity ammonium metavanadate from a vanadium-containing purified liquid according to claim 1, characterized in that: In step a, the vanadium-containing purified liquid is a sodium salt solution of the traditional vanadium industry, with a vanadium concentration of 15-40 g / L, a chromium concentration of ≤2.0 g / L, a phosphorus content of ≤0.1 g / L, and a silicon content of ≤0.30 g / L.

3. The method for producing high-purity ammonium metavanadate from a vanadium-containing purified liquid according to claim 1, characterized in that: In step a, the pH adjuster is one of sulfuric acid or hydrochloric acid; the ammonium salt is one of ammonium sulfate or ammonium chloride; the ammonium salt (NH 4+ The mass ratio of vanadium in the solution is 0.2-0.4:

1.

4. A method for producing high-purity ammonium metavanadate from a vanadium-containing purified liquid according to any one of claims 1 to 3, characterized in that: In the step b, sodium ammonium vanadate is dissolved in water to obtain a solution with a vanadium concentration of 15 to 40 g / L; and the heat preservation and filtration temperature is not lower than 80°C.

5. A method for producing high-purity ammonium metavanadate from a vanadium-containing purified liquid according to any one of claims 1 to 3, characterized in that: In the step b, the conductivity of pure water is ≤2 μS / cm; the ammonia gas is a high-grade liquid anhydrous ammonia, and the pressure after gasification is 0.1 to 0.16 MPa.

6. A method for producing high-purity ammonium metavanadate from a vanadium-containing purified liquid according to any one of claims 1 to 3, characterized in that: In the step c, the purified solution is temperature controlled and crystallized, and the cooling rate is 0.1-1°C / min.

7. A method for producing high-purity ammonium metavanadate from a vanadium-containing purified liquid according to any one of claims 1 to 3, characterized in that: In the step c, the amount of ammonium metavanadate seed added is 1 / 10 to 1 / 20 of the mass of the ammonium metavanadate obtained by the reaction.

8. A method for producing high-purity ammonium metavanadate from a vanadium-containing purified liquid according to any one of claims 1 to 3, characterized in that: In the step c, the stirring rate is 100 to 350 r / min.

9. A method for producing high-purity ammonium metavanadate from a vanadium-containing purified liquid according to any one of claims 1 to 3, characterized in that: The purity of the ammonium metavanadate obtained by the method is ≥99.9%.