A method for precipitating vanadium from sodium vanadium solution

Abstract

This invention belongs to the field of vanadium chemical industry, and particularly relates to a method for vanadium precipitation from sodium vanadium chloride solution, comprising the following steps: a) adjusting the pH of the sodium vanadium chloride solution to 6-7 with sulfuric acid and stirring to obtain a pre-adjusted vanadium solution; b) adjusting the pH of the pre-adjusted vanadium solution to 3.5-5.5 with vanadium pentoxide and stirring to obtain a further adjusted vanadium solution; c) mixing the further adjusted vanadium solution with ammonium salt and carrying out a vanadium precipitation reaction at 45-60°C; then raising the temperature of the reaction system to above 92°C to continue vanadium precipitation, obtaining a vanadium precipitate. The method provided by this invention can reduce the amount of sulfuric acid used for vanadium precipitation, and has good economic and environmental benefits.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of vanadium chemical industry, and particularly relates to a vanadium precipitation method for sodium vanadate solution. BACKGROUND

[0002] In the process of vanadium extraction from vanadium slag by sodiumization, vanadium slag is subjected to roasting, water immersion and impurity removal to obtain qualified sodium vanadate solution, and then the acid ammonium salt vanadium precipitation process is used to obtain ammonium polyvanadate (APV).

[0003] At present, the conventional acid ammonium salt vanadium precipitation process uses ammonium sulfate as a precipitant, controls the pH value of precipitation to be less than or equal to 2.0, and obtains ammonium polyvanadate under the condition of boiling. This vanadium precipitation process has a large acid consumption, and the sulfate ion in the waste water is much, which needs a large amount of alkali for neutralization, and brings huge economic pressure and equipment corrosion pressure for waste water treatment. SUMMARY

[0004] Therefore, the purpose of the present application is to provide a vanadium precipitation method for sodium vanadate solution, which can reduce the sulfuric acid consumption for vanadium precipitation and has good economic and environmental benefits.

[0005] The present application provides a vanadium precipitation method for sodium vanadate solution, which comprises the following steps:

[0006] a) adjusting the pH value of the sodium vanadate solution to 6-7 with sulfuric acid, and stirring to obtain a preliminary adjusted vanadium solution;

[0007] b) adjusting the pH value of the preliminary adjusted vanadium solution to 3.5-5.5 with vanadium pentoxide, and stirring to obtain a re-adjusted vanadium solution;

[0008] c) mixing the re-adjusted vanadium solution with an ammonium salt, and performing a vanadium precipitation reaction at 45-60℃; then increasing the temperature of the reaction system to above 92℃, and continuing the vanadium precipitation to obtain a vanadium precipitate.

[0009] Preferably, in step a), the V content of the sodium vanadate solution is 20-65 g / L; and the Na content of the sodium vanadate solution is 20-60 g / L.

[0010] Preferably, in step a), the stirring temperature is 10-40℃; and the stirring time is greater than or equal to 20 min.

[0011] Preferably, in step b), the mass ratio of vanadium in the vanadium pentoxide to vanadium in the preliminary adjusted vanadium solution is (0.5-1.5):2.

[0012] Preferably, in step b), the stirring temperature is 10-40℃; and the stirring time is 30-60 min.

[0013] Preferably, in step c), the ammonium salt is ammonium sulfate; the mass ratio of the ammonium sulfate to vanadium provided by the sodium vanadium solution in the re-adjusted vanadium solution is (0.7-1):1.

[0014] Preferably, in step c), the time for the vanadium precipitation reaction is 40-60 min.

[0015] Preferably, in step c), the time for the continued vanadium precipitation is 20-40 min.

[0016] Preferably, in step c), after the continued vanadium precipitation, the vanadium precipitate is obtained by sequentially performing standing, filtering and drying.

[0017] Preferably, the standing time is 10-20 min.

[0018] Compared with the prior art, the present application provides a vanadium precipitation method for a sodium vanadium solution, comprising the following steps: a) adjusting the pH value of the sodium vanadium solution to 6-7 by using sulfuric acid, and stirring to obtain a primary-adjusted vanadium solution; b) adjusting the pH value of the primary-adjusted vanadium solution to 3.5-5.5 by using vanadium pentoxide, and stirring to obtain a re-adjusted vanadium solution; c) mixing the re-adjusted vanadium solution with an ammonium salt, and performing a vanadium precipitation reaction at 45-60°C; and then increasing the temperature of the reaction system to above 92°C, and continuing the vanadium precipitation to obtain a vanadium precipitate. 10 O 28 ) in the sodium vanadium solution; then adjusting the pH value of the above vanadium solution system to 3.5-5.5 by using vanadium pentoxide, and changing the aggregation state of the vanadium pentoxide and the six-sodium decavanadate protons in the system containing the sulfuric acid aqueous solution to form a four-sodium decavanadate (Na4H2V 10 O 28 ) salt; then adding an ammonium salt into the above vanadium solution system, combining the decavanadate ions in the vanadium solution system with the ammonium ions to form a vanadium precipitate to be precipitated out, ionizing hydrogen ions in the process, combining with the sulfate ions to increase the acidity, which is beneficial to the precipitation, and does not need to use sulfuric acid for secondary acid adjustment, and the precipitation reaction is relatively complete. The method provided by the present application can reduce the sulfuric acid consumption for the vanadium precipitation, and has good economic and environmental benefits. DETAILED DESCRIPTION

[0019] The technical solutions in the embodiments of the present application will be described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the present application.

[0020] The application provides a vanadium precipitation method of sodium vanadium solution, comprising the following steps:

[0021] a) adjusting the pH value of the sodium vanadium solution to 6-7 by sulfuric acid, and stirring to obtain a primary adjusted vanadium solution;

[0022] b) adjusting the pH value of the primary adjusted vanadium solution to 3.5-5.5 by vanadium pentoxide, and stirring to obtain a secondary adjusted vanadium solution;

[0023] c) mixing the secondary adjusted vanadium solution with an ammonium salt, and performing a vanadium precipitation reaction at 45-60 DEG C; then increasing the temperature of the reaction system to above 92 DEG C, and continuing the vanadium precipitation to obtain a vanadium precipitate.

[0024] In the vanadium precipitation method provided by the application, in step a), the main component of the sodium vanadium solution is sodium vanadate, and a small amount of impurities such as sulfate, silicon, chromium and phosphorus may also be contained. In the application, the V content of the sodium vanadium solution is preferably 20-65 g / L, and specifically can be 20 g / L, 25 g / L, 30 g / L, 35 g / L, 40 g / L, 45 g / L, 50 g / L, 55 g / L, 60 g / L or 65 g / L; the Na content of the sodium vanadium solution is preferably 20-60 g / L, and specifically can be 20 g / L, 23 g / L, 24 g / L, 25 g / L, 30 g / L, 32 g / L, 33 g / L, 35 g / L, 40 g / L, 45 g / L, 50 g / L, 53 g / L, 54 g / L, 55 g / L or 60 g / L; the Cr content of the sodium vanadium solution is preferably 1-5 g / L, and specifically can be 1 g / L, 1.5 g / L, 2 g / L, 2.3 g / L, 2.5 g / L, 2.8 g / L, 3 g / L, 3.5 g / L, 4 g / L, 4.5 g / L or 5 g / L; the P content of the sodium vanadium solution is preferably 0.01-0.05 g / L, and specifically can be 0.01 g / L, 0.014 g / L, 0.015 g / L, 0.02 g / L, 0.024 g / L, 0.025 g / L, 0.03 g / L, 0.035 g / L, 0.04 g / L, 0.045 g / L or 0.05 g / L; and the Si content of the sodium vanadium solution is preferably 0.2-2 g / L, and specifically can be 0.2 g / L, 0.3 g / L, 0.4 g / L, 0.46 g / L, 0.5 g / L, 0.6 g / L, 0.7 g / L, 0.8 g / L, 0.89 g / L, 0.9 g / L, 1 g / L, 1.2 g / L, 1.45 g / L, 1.5 g / L, 1.7 g / L or 2 g / L.

[0025] In the vanadium precipitation method provided by the present application, in step a), the initial pH value of the sodium vanadate solution is preferably 10-12, and can be specifically 10, 10.1, 10.2, 10.3, 10.4, 10.45, 10.5, 10.6, 10.7, 10.8, 10.9, 11, 11.1, 11.2, 11.3, 11.4, 11.45, 11.5, 11.6, 11.7, 11.8, 11.9 or 12.

[0026] In the vanadium precipitation method provided by the present application, in step a), the pH value of the sodium vanadate solution can be specifically adjusted to 6, 6.1, 6.2, 6.3, 6.4, 6.5, 6.6, 6.7, 6.8, 6.9 or 7 by using the sulfuric acid.

[0027] In the vanadium precipitation method provided by the present application, in step a), the temperature of the stirring is preferably 10-40℃, and can be specifically 10℃, 15℃, 20℃, 25℃ (room temperature), 30℃, 35℃ or 40℃; and the time of the stirring is preferably ≥20 min, and more preferably 20-150 min, and can be specifically 20 min, 30 min, 40 min, 50 min, 60 min, 70 min, 80 min, 90 min, 100 min, 110 min, 120 min, 130 min, 140 min or 150 min.

[0028] In the vanadium precipitation method provided by the present application, in step b), the pH value of the primary adjusted vanadium solution can be specifically adjusted to 3.5, 3.7, 4, 4.2, 4.5, 4.7, 5, 5.2 or 5.5 by using the vanadium pentoxide.

[0029] In the vanadium precipitation method provided by the present application, in step b), the mass ratio of vanadium in the vanadium pentoxide to vanadium in the primary adjusted vanadium solution is preferably (0.5-1.5):2, and can be specifically 0.5:2, 0.6:2, 0.7:2, 0.8:2, 0.9:2, 1:2, 1.1:2, 1.2:2, 1.3:2, 1.4:2 or 1.5:2.

[0030] In the vanadium precipitation method provided by the present application, in step b), the temperature of the stirring is preferably 10-40℃, and can be specifically 10℃, 15℃, 20℃, 25℃ (room temperature), 30℃, 35℃ or 40℃; and the time of the stirring is preferably 30-60 min, and can be specifically 30 min, 35 min, 40 min, 45 min, 50 min, 55 min or 60 min.

[0031] In the vanadium precipitation method provided by the present application, in step c), the ammonium salt is preferably ammonium sulfate; the mass ratio of the ammonium sulfate to vanadium provided by the sodium vanadium solution in the re-adjusted vanadium solution is preferably (0.7-1):1, and more preferably (0.78-0.85):1. In the present application, the mass ratio of the ammonium sulfate to vanadium provided by the sodium vanadium solution in the re-adjusted vanadium solution can be specifically 0.7:1, 0.71:1, 0.72:1, 0.73:1, 0.74:1, 0.75:1, 0.76:1, 0.77:1, 0.78:1, 0.79:1, 0.8:1, 0.81:1, 0.82:1, 0.83:1, 0.84:1, 0.85:1, 0.86:1, 0.87:1, 0.88:1, 0.89:1, 0.9:1, 0.91:1, 0.92:1, 0.93:1, 0.94:1, 0.95:1, 0.96:1, 0.97:1, 0.98:1, 0.99:1 or 1:1.

[0032] In the vanadium precipitation method provided by the present application, in step c), the temperature of the vanadium precipitation reaction can be specifically 45℃, 46℃, 47℃, 48℃, 49℃, 50℃, 51℃, 52℃, 53℃, 54℃, 55℃, 56℃, 57℃, 58℃, 59℃ or 60℃; and the time of the vanadium precipitation reaction is preferably 40-60 min, and can be specifically 40 min, 42 min, 45 min, 47 min, 50 min, 52 min, 55 min, 57 min or 60 min.

[0033] In the vanadium precipitation method provided by the present application, in step c), the temperature of the continued vanadium precipitation is 92℃-boiling temperature, and can be specifically 92℃, 93℃, 94℃, 95℃, 96℃, 97℃, 98℃, 99℃ or boiling temperature; and the time of the continued vanadium precipitation is preferably 20-40 min, and can be specifically 20 min, 23 min, 25 min, 27 min, 30 min, 32 min, 35 min, 37 min or 40 min.

[0034] In the vanadium precipitation method provided by the present application, in step c), after the continued vanadium precipitation, preferably, standing, filtration and drying are sequentially performed to obtain vanadium precipitate. The standing time is preferably 10-20 min, and can be specifically 10 min, 11 min, 12 min, 13 min, 14 min, 15 min, 16 min, 17 min, 18 min, 19 min or 20 min.

[0035] The vanadium precipitation method provided by the present application first adjusts the pH value of the sodium vanadium solution to 6-7 by using sulfuric acid, so that sodium and vanadium in the sodium vanadium solution form sodium decavanadate (Na6V 10 O 28); then the above vanadium liquid system is adjusted to pH 3.5-5.5 by using vanadium pentoxide, and the aggregation state of the ten vanadate with four sodium (Na4H2V 10 O 28 ); then ammonium salt is added into the above vanadium liquid system, the ten vanadate ions in the vanadium liquid system combine with the ammonium ions to form vanadium precipitate, hydrogen ions are ionized in the process and combine with the sulfate ions to increase the acidity, which is beneficial to the precipitation and the precipitation reaction is relatively complete. The method provided by the application can reduce the consumption of sulfuric acid for vanadium precipitation, and has good economic and environmental benefits.

[0036] For a clearer understanding, the following examples and comparative examples are described in detail.

[0037] In the following examples and comparative examples of the application, the composition information of the treated sodium vanadium liquid is shown in Table 1:

[0038] Table 1 Composition table of sodium vanadium liquid (unit: g / L)

[0039]

[0040] In Table 1, the original pH value of vanadium 1 is 10.45, the original pH value of vanadium 2 is 10.8, and the original pH value of vanadium 3 is 11.45.

[0041] In the following examples and comparative examples of the application, the vanadium precipitation rate = (the mass of vanadium in the vanadium precipitate - the mass of vanadium in the added V2O5) / the mass of vanadium in the sodium vanadium liquid × 100%.

[0042] Example 1

[0043] 800 mL of sodium vanadium liquid 1 is adjusted to pH 6.0 by using 27.7 mL of sulfuric acid, stirred at room temperature for 20 min; then 7.13 g of vanadium pentoxide is added to adjust the pH value to 5.5, and stirred at room temperature for 30 min; then 11.2 g of ammonium sulfate is added, and reacted at 45℃ for 40 min; then the temperature is increased to 92℃, and the vanadium precipitation is performed for 40 min; after standing for 20 min, filtration and drying are performed to obtain 40.20 g of vanadium precipitate.

[0044] The vanadium precipitate obtained in this example is subjected to XRD analysis, and the main component is (NH4)4H2V 10 O 28 ; the vanadium precipitation rate is calculated, and the result is 99.35%.

[0045] Comparative Example 1

[0046] 800 mL of sodium vanadate solution 1, add 11.2 g of ammonium sulfate, adjust to pH = 2 with 41.6 mL of sulfuric acid, and then heat to 92°C. Vanadium precipitation is carried out for 40 min. After standing for 20 min, filtration and drying, 32.14 g of vanadium precipitate is obtained.

[0047] The vanadium precipitate obtained in the present comparative example is subjected to XRD analysis, and the main component is (NH4)4H2V 10 O 28 The vanadium precipitation rate is calculated, and the result is 99.28%.

[0048] By comparing Example 1 and Comparative Example 1, it can be seen that the acid consumption of Example 1 is saved by 33.41% compared with Comparative Example 1.

[0049] Example 2

[0050] 300 mL of sodium vanadate solution 2, adjust the pH value to 6.5 with 10.4 mL of sulfuric acid, and stir at room temperature for 60 min. Then add 9.5 g of vanadium pentoxide to adjust the pH value to 4, and stir at room temperature for 50 min. Then add 8.544 g of ammonium sulfate, and react at 50°C for 50 min. Then heat to 95°C, and precipitate vanadium for 30 min. After standing for 15 min, filtration and drying, 32.23 g of vanadium precipitate is obtained.

[0051] The vanadium precipitate obtained in the present example is subjected to XRD analysis, and the main component is (NH4)4H2V 10 O 28 The vanadium precipitation rate is calculated, and the result is 99.45%.

[0052] Comparative Example 2

[0053] 300 mL of sodium vanadate solution 2, add 8.544 g of ammonium sulfate, adjust to pH = 2 with 15.9 mL of sulfuric acid, and then heat to 95°C. Vanadium precipitation is carried out for 30 min. After standing for 15 min, filtration and drying, 21.82 g of vanadium precipitate is obtained.

[0054] The vanadium precipitate obtained in the present comparative example is subjected to XRD analysis, and the main component is (NH4)4H2V 10 O 28 The vanadium precipitation rate is calculated, and the result is 99.30%.

[0055] By comparing Example 2 and Comparative Example 2, it can be seen that the acid consumption of Example 2 is saved by 34.59% compared with Comparative Example 2.

[0056] Example 3

[0057] 1000 mL of sodium vanadate solution 3, adjust pH to 7.0 with sulfuric acid 30 mL, stir at room temperature for 120 min; then add vanadium pentoxide 87 g, adjust pH to 3.5, stir at room temperature for 60 min; then add ammonium sulfate 65 g, react at 60 °C for 60 min; then warm up to boiling, precipitate vanadium for 20 min; stand for 15 min, filter, dry to obtain vanadium precipitate 224.81 g.

[0058] The vanadium precipitate obtained in this example is subjected to XRD analysis, the main components are (NH4)4H2V 10 O 28 and V2O5; the vanadium precipitation rate is calculated, the result is 99.25%.

[0059] Comparative Example 3

[0060] 1000 mL of sodium vanadate solution 3, add ammonium sulfate 65 g, adjust pH to 2 with sulfuric acid 50 mL, then warm up to boiling, precipitate vanadium for 20 min; stand for 15 min, filter, dry to obtain vanadium precipitate 130.52 g.

[0061] The vanadium precipitate obtained in this example is subjected to XRD analysis, the main components are (NH4)4H2V 10 O 28 ; the vanadium precipitation rate is calculated, the result is 99.23%.

[0062] By comparing Example 3 and Comparative Example 3, it can be seen that the acid consumption of Example 3 is saved by 40% compared with Comparative Example 2.

[0063] The above only describes the preferred embodiments of the present application, it should be noted that for those skilled in the art, without departing from the principles of the present application, can make several improvements and refinements, these improvements and refinements should also be considered as the protection scope of the present application.

Claims

1. A method for vanadium precipitation from a sodium vanadate solution, characterized by, The method comprises the following steps: a) adjusting the pH value of a sodium vanadate solution to 6-7 with sulfuric acid, and stirring to obtain a primary adjusted vanadium solution; b) adjusting the pH value of the primary adjusted vanadium solution to 3.5-5.5 with vanadium pentoxide, and stirring to obtain a secondary adjusted vanadium solution; c) mixing the secondary adjusted vanadium solution with an ammonium salt, and performing a vanadium precipitation reaction at 45-60°C; then increasing the temperature of the reaction system to above 92°C, and continuing the vanadium precipitation to obtain a vanadium precipitate.

2. The vanadium precipitation method according to claim 1, characterized in that, In step a), the V content of the sodium vanadate solution is 20-65 g / L; and the Na content of the sodium vanadate solution is 20-60 g / L.

3. The vanadium precipitation method according to claim 1, characterized in that, In step a), the stirring temperature is 10-40°C; and the stirring time is ≥20 min.

4. The vanadium precipitation method according to claim 1, characterized in that, In step b), the mass ratio of vanadium in the vanadium pentoxide to vanadium in the primary adjusted vanadium solution is (0.5-1.5):

2.

5. The vanadium precipitation method according to claim 1, characterized in that, In step b), the stirring temperature is 10-40°C; and the stirring time is 30-60 min.

6. The vanadium precipitation method according to claim 1, characterized in that, In step c), the ammonium salt is ammonium sulfate; and the mass ratio of the ammonium sulfate to vanadium provided by the sodium vanadate solution in the secondary adjusted vanadium solution is (0.7-1):

1.

7. The vanadium precipitation method according to claim 1, characterized in that, In step c), the vanadium precipitation reaction time is 40-60 min.

8. The vanadium precipitation method according to claim 1, characterized in that, In step c), the continued vanadium precipitation time is 20-40 min.

9. The vanadium precipitation method according to claim 1, characterized in that, In step c), after the continued vanadium precipitation, the following steps are performed in sequence: standing, filtering, and drying, to obtain a vanadium precipitate.

10. The vanadium precipitation method according to claim 9, characterized in that, The standing time is 10-20 min.

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