Method for preparing high-purity vanadium pentoxide from vanadium-chromium solution without ammonium

A technology for vanadium pentoxide and vanadium oxide is applied in the field of preparing high-purity vanadium pentoxide without ammonium from a vanadium-chromium solution, and can solve the problems of intractability, inapplicability, complicated process and the like of a production system

Pending Publication Date: 2022-05-27

四川省绵阳市华意达化工有限公司 +1

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AI-Extracted Technical Summary

Problems solved by technology

[0003] Thus, the Chinese patent CN109750169A uses a reducing agent to reduce vanadium and chromium to tetravalent vanadium and trivalent chromium respectively, adds a complexing agent to complex the tetravalent vanadium, adds alkali to precipitate the trivalent chromium, separates the trivalent chromium and then separates the tetravalent chromium. The valence vanadium is oxidized to pentavalent vanadium, and the vanadium is extracted by the traditional ammonium method. Although the present invention realizes the separation of vanadium and chromium, the vanadium is first reduced and complexed, and then the ammonium salt is oxidized to...

Method used

In the present embodiment, in described step 2, when calcium vanadate precipitation is added water and sulfuric acid to stir, adopt ultrasonic dispersion method to stir, utilize the cavitation effect that ultrasonic generation produces, make calcium vanadate precipitation fully dissolving, in solution The material reaction is more thorough. Compared with Example 1, the purity of vanadium pentoxide generated in step 3 is higher.

In the present embodiment, in described step one, calcium sulfate is added in the vanadium-chromium solution, after adjusting pH and heated and stirred, adopt dual-frequency ultrasonic to process simultaneously, utilize the sonic effect that dual-frequency ultrasonic produces, make calcium sulfate and The vanadium precipitation reaction of the vanadium chromium solution is more sufficient. In the second step...

Abstract

The invention discloses an ammonium-free method for preparing high-purity vanadium pentoxide from a vanadium-chromium solution, which comprises the following steps: adding calcium sulfate into the vanadium-chromium solution, adjusting the pH value, heating and stirring to obtain calcium vanadate precipitate and vanadium-free chromium-containing filtrate; washing the calcium vanadate precipitate, and mixing the washed calcium vanadate precipitate with water and a sulfuric acid solution to obtain vanadium-containing leachate and calcium sulfate precipitate; adding a sulfuric acid solution into the vanadium-containing leachate, heating and stirring to obtain hydrated vanadium oxide; mixing the hydrated vanadium oxide with water and an oxalic acid solution, heating and stirring to obtain a vanadyl oxalate solution and a calcium oxalate precipitate; adding an oxalic acid solution into the vanadyl oxalate solution to adjust the pH value, heating and stirring to obtain vanadium dioxide; calcining the vanadium dioxide to obtain vanadium pentoxide; stirring the calcium oxalate precipitate with water and a sulfuric acid solution to obtain an oxalic acid solution and a calcium sulfate precipitate; according to the method, ammonium salt is not used, ammonium-containing wastewater is not generated, waste residues are not discharged, and the purity of the prepared vanadium pentoxide is more than 99.5%; the calcium sulfate precipitate generated in the preparation process can be recycled.

Application Domain

Vanadium oxidesProcess efficiency improvement

Technology Topic

OXALIC ACID DIHYDRATEVanadium dioxide +9

Examples

Experimental program(7)

Example Embodiment

[0023]

[0024] A method for preparing high-purity vanadium pentoxide from a vanadium-chromium solution without ammonium, comprising the following steps:

[0025] Step 1. Add 91.5g calcium sulfate to 1L vanadium-chromium solution with a vanadium concentration of 35g/L and a chromium concentration of 100g/L, adjust the pH to 8, heat at 80°C and stir for 30min, and separate solid-liquid to obtain calcium vanadate precipitation And vanadium-free and chromium-containing filtrate, vanadium-free and chromium-containing filtrate is used to produce chromium-based chemical products;

[0026] Step 2: After washing the calcium vanadate precipitate, add 10 times its mass of water to stir, then add a 50% sulfuric acid solution, adjust the pH to 4, and separate the solid-liquid to obtain a vanadium-containing leachate and calcium sulfate precipitation; Add 50% sulfuric acid to the vanadium leaching solution, adjust the pH to 1.5, heat at 80 °C and stir for 60 minutes, and separate the solid and liquid to obtain hydrated vanadium oxide;

[0027] Step 3: Add the hydrated vanadium oxide to 10 times its mass of water and stir, then add 50 mL of a 50% oxalic acid solution, heat at 80°C and stir until the hydrated vanadium oxide dissolves, continue stirring for 30min, and separate the solid from the liquid to obtain the vanadyl oxalate. The solution and calcium oxalate are precipitated; to the vanadyl oxalate solution, continue to add 50% oxalic acid solution to adjust the pH to 3, heat at 150 ° C and stir for 120 min, and solid-liquid separation to obtain vanadium dioxide; vanadium dioxide is calcined at 600 ° C for 2 hours to obtain Vanadium pentoxide, the purity is 99.7%, and impurities such as silicon, iron, potassium, sodium and calcium are all less than 0.01%;

[0028] Step 4: Add 10 times the mass of calcium oxalate precipitation to water and stir, add 50 mL of 50% sulfuric acid solution, stir for 30 minutes, and separate solid and liquid to obtain oxalic acid solution and calcium sulfate precipitation.

Example Embodiment

[0029]

[0030] A method for preparing high-purity vanadium pentoxide from a vanadium-chromium solution without ammonium, comprising the following steps:

[0031] Step 1. Add 72g calcium sulfate to 1L vanadium-chromium solution with a vanadium concentration of 35g/L and a chromium concentration of 100g/L, adjust the pH value to 6.8, heat at 80°C and stir for 100min, and separate solid-liquid to obtain calcium vanadate precipitation and Vanadium-free and chromium-containing filtrate, vanadium-free and chromium-containing filtrate is used to produce chromium-based chemical products;

[0032] Step 2: After washing the calcium vanadate precipitate, add 10 times its mass of water to stir, then add a 60% sulfuric acid solution, adjust the pH to 2, and separate the solid-liquid to obtain a vanadium-containing leachate and calcium sulfate precipitation; Add 60% sulfuric acid to the vanadium leaching solution, adjust the pH to 2.3, heat at 80°C and stir for 90 minutes, and separate the solid and liquid to obtain hydrated vanadium oxide;

[0033] Step 3: Add the hydrated vanadium oxide to 10 times its mass of water and stir, then add 60 mL of a 40% oxalic acid solution, heat at 80 ° C and stir until the hydrated vanadium oxide dissolves, continue stirring for 50min, and separate the solid-liquid to obtain the vanadyl oxalate The solution and calcium oxalate are precipitated; to the vanadyl oxalate solution, continue to add 40% oxalic acid solution to adjust the pH to 2.3, heat at 250 °C and stir for 60 minutes, and separate the solid-liquid to obtain vanadium dioxide; the vanadium dioxide is calcined at 900 °C for 2 hours to obtain Vanadium pentoxide, the purity is 99.81%, and impurities such as silicon, iron, potassium, sodium and calcium are all less than 0.01%;

[0034] Step 4: Add calcium oxalate into 10 times the mass of water and stir, add 60 mL of a 60% sulfuric acid solution by mass, stir for 30 min, and separate solid and liquid to obtain oxalic acid solution and calcium sulfate precipitation.

Example Embodiment

[0035]

[0036] A method for preparing high-purity vanadium pentoxide from a vanadium-chromium solution without ammonium, comprising the following steps:

[0037] Step 1. Add 138g calcium sulfate to 1L vanadium-chromium solution with a vanadium concentration of 35g/L and a chromium concentration of 100g/L, adjust the pH value to 10.5, heat at 80°C and stir for 30min, and separate solid-liquid to obtain calcium vanadate precipitation and Vanadium-free and chromium-containing filtrate, vanadium-free and chromium-containing filtrate is used to produce chromium-based chemical products;

[0038]Step 2: After washing the calcium vanadate precipitate, add 10 times its mass of water to stir, then add a 60% sulfuric acid solution, adjust the pH to 3, and separate the solid-liquid to obtain a vanadium-containing leachate and calcium sulfate precipitation; Add 60% sulfuric acid to the vanadium leaching solution, adjust the pH to 0.5, heat at 80 °C and stir for 60 min, and separate the solid and liquid to obtain hydrated vanadium oxide;

[0039] Step 3: Add the hydrated vanadium oxide to 10 times its mass of water and stir, then add 120 mL of a 20% oxalic acid solution, heat at 80°C and stir until the hydrated vanadyl oxide dissolves, continue stirring for 45 minutes, and separate the solid and liquid to obtain vanadyl oxalate. The solution and calcium oxalate are precipitated; to the vanadyl oxalate solution, continue to add 20% oxalic acid solution to adjust the pH to 2.1, heat at 220 °C and stir for 100 min, and separate the solid and liquid to obtain vanadium dioxide; the vanadium dioxide is calcined at 900 °C for 2 hours to obtain Vanadium pentoxide, the purity is 99.78%, and impurities such as silicon, iron, potassium, sodium and calcium are all less than 0.01%;

[0040] Step 4: Add calcium oxalate into 10 times the mass of water and stir, add 80 mL of a 30% sulfuric acid solution by mass, stir for 30 min, and separate solid and liquid to obtain oxalic acid solution and calcium sulfate precipitation.

PUM

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