Method for preparing vanadium pentoxide from carbonation leachate

Abstract

The invention provides a method for preparing vanadium pentoxide from carbonation leachate. The method comprises the following steps: S1) carrying out silicon removal on the carbonation leachate, and carrying out solid-liquid separation to obtain silicon-removed slag and silicon-removed liquid; s2) carrying out a reaction on the silicon-removed liquid in an oxygen-containing atmosphere, and then adding diethanol amine; s3) introducing carbon dioxide into the solution obtained in the step S2), standing, and performing solid-liquid separation to obtain filtrate; s4) carrying out vanadium precipitation on the filtrate, and carrying out solid-liquid separation to obtain ammonium metavanadate and vanadium precipitation wastewater; and S5) oxidizing and calcining the ammonium metavanadate to obtain vanadium pentoxide. According to the method for preparing vanadium pentoxide, Fe < 2 + > in the carbonation leachate is oxidized through oxygen, then the pH of the solution is adjusted through carbon dioxide and diethanol amine, Fe < 3 + > is precipitated and separated out, the problem that the iron content of a vanadium product is high when vanadium is directly precipitated through the carbonation leachate is solved, meanwhile, impurity ions are not introduced, and the method is suitable for industrial production. And the advantage that the clinker is directly and circularly leached from the vanadium precipitation wastewater is reserved.

Description

Technical Field

[0001] The invention relates to the technical field of vanadium extraction and metallurgy, and in particular to a method for preparing vanadium pentoxide by carbonating leaching solution. Background Art

[0002] Vanadium slag is the main raw material for the production of vanadium oxide, and the traditional industrial process is sodium roasting-water leaching to extract vanadium. This process uses a large amount of sodium carbonate as a roasting additive and has high water treatment costs, resulting in high production costs for vanadium oxide; at the same time, a large amount of difficult-to-treat solid wastes such as vanadium chromium filter cakes and sodium sulfate will be produced during the treatment of vanadium precipitation wastewater, posing a high environmental risk. In order to solve the problems of high production costs and high environmental risks in existing vanadium oxide, a process idea of ​​vanadium slag calcination roasting-carbonation leaching to extract vanadium was proposed: During the carbonation leaching process of vanadium-containing clinker, a small amount of iron dissolves into the leachate and exists stably, so that vanadium products that meet the needs of the steel industry can be prepared, but vanadium products with low iron content cannot be directly prepared, which affects the application of vanadium products in non-steel fields.

[0003] In view of the problem of iron removal from carbonated leaching solution, Chinese patent No. CN116555591A provides a method for iron removal from carbonated vanadium leaching solution, which is to adjust the pH of the leaching solution to 10-12, and then add soluble nickel salts such as nickel sulfate, nickel chloride, and nickel nitrate to remove iron at 90-100°C; Chinese patent No. CN116656949A discloses a method for impurity removal from carbonated vanadium leaching solution, which is to adjust the pH of the leaching solution to 10.5-12.5, and add soluble zinc salts such as zinc sulfate, zinc chloride, and zinc nitrate to remove iron at 90-100°C. In the above patents, the above iron remover introduces sulfate, chloride, nitrate and other ions into the solution system, which cannot meet the technical requirements for recycling process water in the vanadium slag calcination roasting-carbonation leaching vanadium extraction process. The Chinese patent with publication number CN117488061A provides a method for removing iron from a carbonated leaching solution, which achieves the purpose of reducing the iron concentration of the solution by adding a strong oxidant, sodium percarbonate, to oxidize and precipitate iron. However, for a solution system leached only with ammonium carbonate or ammonium bicarbonate, sodium ions are introduced.

[0004] On the basis of the above, the technical problem of how to use carbonated leaching solution to prepare vanadium pentoxide with low iron content without affecting the recycling of process water so that it can meet the application index requirements in the non-steel field needs to be further optimized and improved. Summary of the invention

[0005] The technical problem solved by the present invention is to provide a method for preparing vanadium pentoxide from a carbonated leaching solution. The method provided in the present application can prepare vanadium pentoxide with a low iron content, and further retains the advantage of directly recycling leaching clinker from vanadium precipitation wastewater.

[0006] In view of this, the present application provides a method for preparing vanadium pentoxide by carbonating a leaching solution, comprising the following steps:

[0007] S1) desiliconizing the carbonated leaching solution, and obtaining desiliconized slag and desiliconized liquid after solid-liquid separation;

[0008] S2) reacting the desiliconized liquid in an atmosphere containing oxygen, and then adding diethanolamine;

[0009] S3) introducing carbon dioxide into the solution obtained in step S2) to adjust the pH to 6.5-7.5, allowing to stand for solid-liquid separation to obtain a filtrate;

[0010] S4) subjecting the filtrate to vanadium precipitation, and obtaining ammonium metavanadate and vanadium precipitation wastewater after solid-liquid separation;

[0011] S5) oxidizing and calcining the ammonium metavanadate to obtain vanadium pentoxide.

[0012] Preferably, the carbonated leaching solution is obtained by leaching vanadium slag blank or calcified roasted clinker through one or more of sodium carbonate, sodium bicarbonate, ammonium carbonate and ammonium bicarbonate.

[0013] Preferably, in step S1), the desiliconizing agent is sodium aluminate, and the amount of sodium aluminate added is according to the Al / Si molar ratio (0.8-1.0):1; the temperature of the desiliconizing reaction is 50-70°C, and the time is 0.5-2h.

[0014] Preferably, in step S2), the atmosphere containing oxygen includes air; the reaction temperature is 50-70° C., and the reaction time is 2-5 hours.

[0015] Preferably, in step S2), the diethanolamine is added in an amount according to a diethanolamine concentration of 10 to 15 g / L in the solution.

[0016] Preferably, in step S3), the temperature of the solution whose pH is adjusted to 6.5-7.5 is 40-60° C.; and the standing time is 5-15 hours.

[0017] Preferably, in step S4), the vanadium precipitation reagent is an ammonium salt, and the ammonium salt is selected from one or more of ammonia water, ammonium carbonate and ammonium bicarbonate, and the amount of the ammonium salt is based on the NH4 + / V molar ratio is 2.6-3.5:1.

[0018] Preferably, in step S4), the pH of the vanadium precipitation is 9.0-9.5, and the temperature of the vanadium precipitation is 15-30°C.

[0019] Preferably, the temperature of the oxidative calcination is 500-600° C., and the time is 3-5 hours.

[0020] Preferably, step S5) further includes:

[0021] The vanadium precipitation wastewater is supplemented with a leaching agent and then recycled for leaching clinker;

[0022] The leaching agent includes one or more of sodium carbonate, sodium bicarbonate, ammonium carbonate and ammonium bicarbonate.

[0023] The present application provides a method for preparing vanadium pentoxide from a carbonated leaching solution, which first removes silicon from the carbonated leaching solution to remove silicon in the carbonated leaching solution, and then reacts the desiliconized solution in an atmosphere containing oxygen to oxidize Fe in the carbonated leaching solution. 2+ Then, diethanolamine and carbon dioxide were introduced to adjust the pH of the solution so that Fe 3 + The precipitation effectively reduces the iron content in the vanadium product. Finally, vanadium precipitation and calcination are performed to obtain vanadium pentoxide with low iron content, which solves the problem of high iron content in vanadium products caused by direct vanadium precipitation from carbonated leaching solution. At the same time, no impurity ions are introduced, so that the vanadium precipitation wastewater can be directly recycled for leaching clinker. DETAILED DESCRIPTION

[0024] In order to further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, rather than limiting the claims of the present invention.

[0025] In view of the problem that the low iron content of vanadium pentoxide prepared by carbonated leaching solution in the prior art and the recycling of waste liquid cannot be taken into account at the same time, the present application provides a method for preparing vanadium pentoxide by carbonated leaching solution, which uses the leaching solution obtained by the process of low-calcium roasting of vanadium slag-carbonation leaching and vanadium extraction as raw material, and reduces the colloidal stability of iron hydroxide by adjusting the pH of the leaching solution, so as to achieve the purpose of reducing the iron concentration of the solution, and finally obtains vanadium pentoxide with low iron content; and the process is simple, easy to implement, and low in cost, which is one of the methods for preparing vanadium pentoxide by carbonated leaching solution. Specifically, the embodiment of the present invention discloses a method for preparing vanadium pentoxide by carbonated leaching solution, comprising the following steps:

[0026] S1) desiliconizing the carbonated leaching solution, and obtaining desiliconized slag and desiliconized liquid after solid-liquid separation;

[0027] S2) reacting the desiliconized liquid in an atmosphere containing oxygen, and then adding diethanolamine;

[0028] S3) introducing carbon dioxide into the solution obtained in step S2) to adjust the pH to 6.5-7.5, allowing to stand for solid-liquid separation to obtain a filtrate;

[0029] S4) subjecting the filtrate to vanadium precipitation, and obtaining ammonium metavanadate and vanadium precipitation wastewater after solid-liquid separation;

[0030] S5) oxidizing and calcining the ammonium metavanadate to obtain vanadium pentoxide.

[0031] In the method for preparing vanadium pentoxide from a carbonated leaching solution, the present application first removes silicon from the carbonated leaching solution, and obtains silicon-free slag and silicon-free liquid after solid-liquid separation; in this process, the carbonated leaching solution is obtained by leaching blank vanadium slag or calcified roasted clinker through one or more of sodium carbonate, sodium bicarbonate, ammonium carbonate and ammonium bicarbonate, wherein the vanadium slag is obtained by oxidative blowing of vanadium-containing molten iron, that is, the vanadium slag is vanadium slag well known to those skilled in the art, and the present application does not impose any special restrictions on this; in a specific embodiment, the carbonated leaching solution includes: V 30-50 g / L, Si 0.10-1.00 g / L, Fe 0.05-0.30 g / L; specifically, the carbonated leaching solution includes: V 32-45 g / L, Si 0.20-0.50 g / L, Fe 0.10-0.20 g / L. The carbonated leaching solution is alkaline, and the main impurities include silicon, iron and phosphorus, and the concentration of other impurity elements is relatively low; under alkaline conditions, phosphorus does not affect the quality of vanadium products in alkaline ammonium salt vanadium precipitation, and does not need to be specially removed, and it will not be enriched during the process water circulation process. The desiliconizing agent for desiliconization is selected from sodium aluminate, and the amount of sodium aluminate is added according to the molar ratio of Al / Si of (0.8 to 1.0): 1; the temperature of desiliconization is 50 to 70°C, and the time is 0.5 to 2h; specifically, the temperature of desiliconization is 50 to 60°C, and the time is 1 to 1.5h; the reaction is carried out under water bath conditions.

[0032] According to the present invention, the desiliconized liquid is reacted in an atmosphere containing oxygen to remove Fe 2+ Under alkaline conditions, it is oxidized by oxygen to Fe 3+ ; The atmosphere containing oxygen includes air. In a specific embodiment, the atmosphere containing oxygen is air; the reaction temperature is 50-70°C and the reaction time is 2-5h; specifically, the reaction temperature is 55-65°C and the reaction time is 3-4h. Diethanolamine is added after the reaction to increase the absorption rate and absorption amount of the subsequent carbon dioxide, which is beneficial to the reduction of the solution pH; the solution containing diethanolamine will be regenerated during the cyclic leaching of clinker to achieve the reuse of diethanolamine. The amount of diethanolamine is added according to the diethanolamine concentration of 10-15g / L in the solution; specifically, the amount of diethanolamine is added according to the diethanolamine concentration of 12-14g / L in the solution.

[0033] The present application then introduces carbon dioxide into the solution into which diethanolamine is introduced and adjusts the pH to 6.5-7.5, and after standing, solid-liquid separation is performed to obtain a filtrate; in this process, the iron in the solution exists in the form of iron hydroxide colloid, and the isoelectric point pH of iron hydroxide colloid is ≈ 5.2. The closer the solution pH is to the isoelectric point pH value, the worse the stability of the iron hydroxide colloid is, that is, the easier it is to precipitate out as iron hydroxide. In this process, carbon dioxide is introduced to adjust the solution pH to 6.5-7.5 to reduce the stability of the iron hydroxide colloid, so that the iron is precipitated out in the form of iron hydroxide precipitation, and the use of carbon dioxide to adjust the pH does not introduce impurity ions, and does not affect the circulation of process water to leaching clinker. The temperature of the solution adjusted to pH 6.5-7.5 is 40-60°C, and the standing time is 5-15h; specifically, the standing time is 10-12h.

[0034] According to the present invention, the filtrate is then subjected to vanadium precipitation to obtain ammonium metavanadate and vanadium precipitation wastewater; in the above process, the vanadium precipitation also includes: cooling the reaction liquid to 15-30°C, specifically, cooling to 20-25°C. The reagent for vanadium precipitation is selected from one or more of ammonia water, ammonium carbonate and ammonium bicarbonate, and the amount of the reagent for vanadium precipitation is determined according to the amount of NH4 + / V is added at a molar ratio of 2.6 to 3.5:1; the pH of the vanadium precipitation is 9.0 to 9.5; specifically, the amount of the vanadium precipitation reagent is based on the NH4 + The molar ratio of V / V is 2.8 to 3.2:1; the pH of the vanadium precipitation is 9.2 to 9.4.

[0035] Finally, the ammonium metavanadate is subjected to oxidation calcination to obtain high-purity vanadium pentoxide; the oxidation calcination temperature is 500-600° C. and the time is 3-5.

[0036] Furthermore, the present application also recycles the above-mentioned vanadium precipitation wastewater after supplementing the leaching reagent to be used for leaching clinker; the leaching reagent is selected from one or more of sodium carbonate, sodium bicarbonate, ammonium carbonate and ammonium bicarbonate.

[0037] In order to further understand the present invention, the method for preparing vanadium pentoxide from carbonation leaching solution provided by the present invention is described in detail below in conjunction with examples, and the protection scope of the present invention is not limited by the following examples.

[0038] The reagents used in the following examples are all known products and were purchased.

[0039] Example 1

[0040] Take 500mL of carbonated leaching solution (V 34.28g / L, Si 0.24g / L and Fe 0.12g / L), heat it to 70°C in a water bath, add 0.31g of sodium aluminate and stir to react for 1h, after the desiliconization reaction is completed, separate the solid and liquid to obtain desiliconized slag and desiliconized liquid (Si<0.01g / L); pass air through the desiliconized liquid and heat it in a water bath to maintain the solution temperature at 50°C for 4h, then add 5.5g of diethanolamine; pass carbon dioxide into the obtained solution to adjust the solution pH to 7.42, let it stand for 15h, separate the solid and liquid and wash the filter residue to obtain 492mL of filtrate (Fe 0.014g / L); cool the filtrate to 25°C, add 56g of ammonium carbonate and stir to react for 3h, after the vanadium precipitation reaction is completed, separate the solid and liquid to obtain ammonium metavanadate and vanadium precipitation wastewater (V 5.32 g / L); calcining ammonium metavanadate in a muffle furnace at 550° C. for 4 h to obtain 25.85 g of powdered vanadium pentoxide, of which V2O5 was 99.79%, Si was 0.012% and Fe was 0.018%.

[0041] Comparative Example 1 (no air oxidation and no carbon dioxide pH adjustment)

[0042] 500mL of carbonated leaching solution (V 34.28g / L, Si 0.24g / L and Fe 0.12g / L) was taken and heated to 70°C in a water bath, 0.31g of sodium aluminate was added and stirred for reaction for 1h, and after the desiliconization reaction, the solid-liquid separation was carried out to obtain desiliconization slag and desiliconization liquid (Si<0.01g / L); the desiliconization liquid was cooled to 25°C, 56g of ammonium carbonate was added and stirred for reaction for 3h, and after the vanadium precipitation reaction was completed, the solid-liquid separation was carried out to obtain ammonium metavanadate and vanadium precipitation wastewater (V 4.33g / L); the ammonium metavanadate was calcined at a constant temperature of 550°C for 4h in a muffle furnace to obtain 26.65g of powdered vanadium pentoxide, wherein V2O5 was 99.71%, Si was 0.014% and Fe was 0.086%. Compared with the embodiment, the iron content in the vanadium pentoxide product prepared in this comparative example was increased.

[0043] Example 2

[0044] Take 500mL of carbonated leaching solution (V 40.36g / L, Si 0.26g / L and Fe 0.14g / L), heat it to 60°C in a water bath, add 0.34g of sodium aluminate and stir to react for 2h, after the desiliconization reaction is completed, separate the solid and liquid to obtain desiliconized slag and desiliconized liquid (Si<0.01g / L); pass air into the desiliconized liquid and heat it in a water bath to maintain the solution temperature at 70°C for 2h, then add 7g of diethanolamine; pass carbon dioxide into the obtained solution to adjust the solution pH to 7.12, let it stand for 12h, separate the solid and liquid and wash the filter residue to obtain 497mL of filtrate (Fe 0.012g / L); cool the filtrate to 20°C, add 42mL of 28% ammonia water and 50g of ammonium bicarbonate and stir to react for 3h, after the vanadium precipitation reaction is completed, separate the solid and liquid to obtain ammonium metavanadate and vanadium precipitation wastewater (V 5.27g / L); calcining ammonium metavanadate at 500°C for 5h in a muffle furnace to obtain 30.85g of powdered vanadium pentoxide, of which V2O5 was 99.81%, Si was 0.013% and Fe was 0.014%.

[0045] Comparative Example 2 (no air oxidation and no carbon dioxide pH adjustment)

[0046] 500 mL of carbonated leaching solution (V 40.36 g / L, Si 0.26 g / L and Fe 0.14 g / L) was taken and heated to 60°C in a water bath, 0.34 g of sodium aluminate was added and stirred for reaction for 2 h, and after the desiliconization reaction, the solid-liquid separation was carried out to obtain desiliconized slag and desiliconized liquid (Si<0.01 g / L); the desiliconized liquid was cooled to 20°C, 42 mL of 27% ammonia water and 50 g of ammonium bicarbonate were added and stirred for reaction for 3 h, and after the vanadium precipitation reaction, the solid-liquid separation was carried out to obtain ammonium metavanadate and vanadium precipitation wastewater (V 4.52 g / L); the ammonium metavanadate was calcined at a constant temperature of 500°C for 5 h in a muffle furnace to obtain 31.59 g of powdered vanadium pentoxide, of which V2O5 was 99.67%, Si was 0.012% and Fe was 0.01%; 0.095%. Compared with the example, the iron content in the vanadium pentoxide product prepared in this comparative example is increased.

[0047] Example 3

[0048] Take 500mL of carbonated leaching solution (V 38.84g / L, Si 0.23g / L and Fe 0.12g / L), heat it in a water bath to 50°C, add 0.28g of sodium aluminate and stir to react for 1.5h, after the desiliconization reaction is completed, separate the solid and liquid to obtain desiliconized slag and desiliconized liquid (Si<0.01g / L); pass air through the desiliconized liquid and heat it in a water bath to maintain the solution temperature at 60°C for 3h, then add 7.5g of diethanolamine; pass carbon dioxide into the solution obtained above to adjust the solution pH to 6.72, let it stand for 10h, separate the solid and liquid and wash the filter residue to obtain 508mL of filtrate (Fe 0.009g / L); cool the filtrate to 15°C, add 62mL of 28% ammonia water and 25g of ammonium bicarbonate and stir to react for 3h, after the vanadium precipitation reaction is completed, separate the solid and liquid to obtain ammonium metavanadate and vanadium precipitation wastewater (V 4.24 g / L); calcining ammonium metavanadate at 550° C. for 4 h in a muffle furnace to obtain 30.25 g of powdered vanadium pentoxide, of which V2O5 was 99.82%, Si was 0.013% and Fe was 0.012%.

[0049] Comparative Example 3 (no air oxidation and no carbon dioxide pH adjustment)

[0050] 500 mL of carbonated leaching solution (V 38.84 g / L, Si 0.23 g / L and Fe 0.12 g / L) was taken and heated to 50°C in a water bath, 0.28 g of sodium aluminate was added and stirred for reaction for 1.5 h, and after the desiliconization reaction was completed, the solid-liquid separation was carried out to obtain desiliconized slag and desiliconized liquid (Si<0.01 g / L); the desiliconized liquid was cooled to 15°C, 62 mL of 28% ammonia water and 25 g of ammonium bicarbonate were added and stirred for reaction for 3 h, and after the vanadium precipitation reaction was completed, the solid-liquid separation was carried out to obtain ammonium metavanadate and vanadium precipitation wastewater (V 3.67 g / L); the ammonium metavanadate was calcined at a constant temperature of 550°C for 4 h in a muffle furnace to obtain 30.91 g of powdered vanadium pentoxide, of which V2O5 was 99.73%, Si was 0.012% and Fe was 0.01%. 0.089%. Compared with the example, the iron content in the vanadium pentoxide product prepared in this comparative example is increased.

[0051] In summary, the method for preparing vanadium pentoxide from a carbonated leaching solution of the present invention utilizes air to oxidize Fe in the carbonated leaching solution. 2+ The pH value of the solution is adjusted with carbon dioxide and diethanolamine to precipitate iron, thereby reducing the iron content of the vanadium product and creating conditions for the application of vanadium products in non-steel fields. At the same time, no impurity ions are introduced, thus retaining the advantage of directly recycling the vanadium precipitation wastewater to leach clinker.

[0052] The above embodiments are only used to help understand the method and core idea of ​​the present invention. It should be noted that, for those skilled in the art, several improvements and modifications can be made to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

[0053] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing vanadium pentoxide by carbonating a leaching solution, comprising the following steps: S1) desiliconizing the carbonated leaching solution, and obtaining desiliconized slag and desiliconized liquid after solid-liquid separation; S2) reacting the desiliconized liquid in an atmosphere containing oxygen, and then adding diethanolamine; S3) introducing carbon dioxide into the solution obtained in step S2) to adjust the pH to 6.5-7.5, allowing to stand for solid-liquid separation to obtain a filtrate; S4) subjecting the filtrate to vanadium precipitation, and obtaining ammonium metavanadate and vanadium precipitation wastewater after solid-liquid separation; S5) oxidizing and calcining the ammonium metavanadate to obtain vanadium pentoxide.

2. The method according to claim 1, characterized in that The carbonation leaching solution is obtained by leaching vanadium slag blank or calcified roasted clinker through one or more of sodium carbonate, sodium bicarbonate, ammonium carbonate and ammonium bicarbonate.

3. The method according to claim 1, characterized in that In step S1), the desiliconizing agent is sodium aluminate, and the amount of sodium aluminate added is according to the Al / Si molar ratio (0.8-1.0):1; the temperature of the desiliconizing reaction is 50-70°C, and the time is 0.5-2h.

4. The method according to claim 1, characterized in that: In step S2), the atmosphere containing oxygen includes air; the reaction temperature is 50-70° C., and the reaction time is 2-5 hours.

5. The method according to claim 1, characterized in that In step S2), the diethanolamine is added in an amount according to the diethanolamine concentration in the solution of 10 to 15 g / L.

6. The method according to claim 1, characterized in that In step S3), the temperature of the solution whose pH is adjusted to 6.5-7.5 is 40-60° C.; and the standing time is 5-15 hours.

7. The method according to claim 1, characterized in that In step S4), the reagent for vanadium precipitation is an ammonium salt, which is selected from one or more of ammonia water, ammonium carbonate and ammonium bicarbonate, and the amount of the ammonium salt is based on the amount of NH4 + / V molar ratio is 2.6-3.5:

1.

8. The method according to claim 1, characterized in that In step S4), the pH of the vanadium precipitation is 9.0-9.5, and the temperature of the vanadium precipitation is 15-30°C.

9. The method according to claim 1, characterized in that: The oxidation calcination temperature is 500-600° C. and the time is 3-5 hours.

10. The method according to any one of claims 1 to 9, characterized in that: Step S5) also includes: The vanadium precipitation wastewater is supplemented with a leaching agent and then recycled for leaching clinker; The leaching agent includes one or more of sodium carbonate, sodium bicarbonate, ammonium carbonate and ammonium bicarbonate.