Method for preparing vanadium pentoxide from iron-containing ammonium metavanadate

Abstract

The invention provides a method for preparing vanadium pentoxide from iron-containing ammonium metavanadate, which comprises the following steps: S1) mixing iron-containing ammonium metavanadate with water to obtain ammonium metavanadate slurry; s2) mixing the ammonium metavanadate slurry with a complexing agent, adjusting the pH value to 1.5-2.5, carrying out iron dissolving reaction, and carrying out solid-liquid separation to obtain ammonium polyvanadate; 3, ammonium polyvanadate is calcined, and vanadium pentoxide is obtained.According to the method for preparing vanadium pentoxide from iron-containing ammonium metavanadate, the technical thought of acid dissolution-complexing iron removal is provided, the content of iron in vanadium pentoxide is effectively reduced, the process is simple, and the process cost is low.

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 from iron-containing ammonium metavanadate. Background Art

[0002] Vanadium slag is the main raw material for the production of vanadium oxide. The traditional industrial process is sodium roasting-water leaching to extract vanadium. The sodium roasting of this process consumes a large amount of sodium carbonate, and the process cost is relatively high; the sodium oxide content of the vanadium extraction tailings is about 6%, which is difficult to reuse; a large amount of solid waste vanadium chromium reduction filter cake and sodium sulfate will be produced during the water treatment process, which poses a great environmental hazard. In order to reduce the production cost of vanadium oxide and eliminate environmental hazards, a new process of vanadium slag blank or calcification roasting-carbonation leaching to extract vanadium is proposed, that is, vanadium slag roasting clinker is leached with sodium carbonate, sodium bicarbonate, ammonium carbonate or ammonium bicarbonate to extract vanadium. The iron content of ammonium metavanadate prepared by this process is generally less than 0.2%, and the prepared vanadium pentoxide meets the requirements of the YB / T 5304-2017 quality standard. The product can be used as a raw material for smelting ferrovanadium and vanadium-nitrogen alloy. However, due to the relatively high iron content of vanadium pentoxide, its application in non-steel fields such as vanadium-aluminum alloy and high-purity vanadium oxide is affected.

[0003] In order to remove iron from ammonium metavanadate, ammonium polyvanadate or vanadium pentoxide, Li Mingming et al. used a 7.5% sodium hydroxide solution at 90°C for 2 hours with stirring, and the iron removal rate was about 92%; Ni Hangxing et al. used a 7.5% sodium hydroxide solution at 90°C for 2 hours with stirring, and the iron was removed in the form of iron hydroxide. The vanadium pentoxide prepared by the purified solution had an iron content of 0.008%. The above-mentioned sodium hydroxide dissolution method can separate most of the iron, but the price of sodium hydroxide reagent is high, and the amount of ammonium salt reagent used in the weak alkaline ammonium salt precipitation of vanadium is large, resulting in high cost of the dissolution and iron removal process. A Chinese patent with publication number CN117625961A provides a method for selectively removing iron, aluminum, titanium and molybdenum from an acidic vanadium solution. The method uses an acidic leaching solution or an acidic return solution of a vanadium product as a raw material, and removes iron, aluminum and titanium by adding at least one of aminotri (methylene phosphonic acid), diethylenetriamine penta (methylene phosphonic acid), ethylenediaminetetra (methylene phosphonic acid), hexamethylenediaminetetra (methylene phosphonic acid) and bis (1,6-hexamethylenetriaminepenta (methylene phosphonic acid). The iron concentration of the purified liquid is 0.01-0.02 g / L. However, the method has the problem of large vanadium loss.

[0004] Although there are public technologies for iron removal and purification of ammonium metavanadate, there are still problems such as high iron removal cost and large vanadium loss. The technical problems of low-cost iron removal and purification need to be solved. At present, there are no relevant technical reports that can effectively solve the above problems and have prospects for industrial application. Summary of the invention

[0005] The technical problem solved by the present invention is to provide a method for preparing vanadium pentoxide from iron-containing ammonium metavanadate. The method provided by the present application can reduce the loss of vanadium and reduce the cost of iron removal.

[0006] In view of this, the present application provides a method for preparing vanadium pentoxide from ammonium metavanadate containing iron, comprising the following steps:

[0007] S1) mixing iron-containing ammonium metavanadate and water to obtain ammonium metavanadate slurry;

[0008] S2) mixing the ammonium metavanadate slurry and the complexing agent, adjusting the pH to 1.5-2.5, performing an iron dissolving reaction, and performing solid-liquid separation to obtain ammonium polyvanadate; the complexing agent is selected from one or more of tartaric acid, ethylenediaminetetraacetic acid, disodium ethylenediaminetetraacetate, and tetrasodium ethylenediaminetetraacetate;

[0009] S3) calcining the ammonium polyvanadate to obtain vanadium pentoxide.

[0010] Preferably, the iron-containing ammonium metavanadate is prepared by sequentially carrying out the process of blank or calcification roasting-carbonation leaching-alkaline ammonium salt vanadium precipitation on vanadium slag.

[0011] Preferably, the iron content in the iron-containing ammonium metavanadate is less than 0.2 wt %.

[0012] Preferably, the solid-to-liquid ratio of the iron-containing ammonium metavanadate and water is 1 g: (3-10) mL.

[0013] Preferably, when the complexing agent is selected from tartaric acid, the complexing agent is added in a molar ratio of C4H6O6:Fe=1.3~2.0:1.

[0014] Preferably, when the complexing agent is selected from ethylenediaminetetraacetic acid, disodium ethylenediaminetetraacetate or tetrasodium ethylenediaminetetraacetate, the complexing agent is added in a molar ratio of EDTA:Fe=1.2~1.5:1.

[0015] Preferably, the temperature of the iron dissolving reaction is 50-70° C. and the time is 0.5-2 h.

[0016] Preferably, the reagent used to adjust the pH is sulfuric acid, and the pH is 1.5-2.2.

[0017] Preferably, the calcination temperature is 500-600° C. and the calcination time is 3-5 hours.

[0018] The present application provides a method for preparing vanadium pentoxide from ammonium metavanadate containing iron, which first mixes ammonium metavanadate containing iron with water, then adds a complexing agent to the obtained ammonium metavanadate slurry, and then uses sulfuric acid to adjust the slurry pH to 1.5~2.5, so that the iron in the ammonium metavanadate is fully dissolved and combined with the complexing agent, and exists in the solution in the form of ions, and at the same time, the ammonium metavanadate is converted into ammonium polyvanadate, and finally the obtained ammonium polyvanadate is calcined to obtain a vanadium pentoxide product. In the method for preparing vanadium pentoxide from ammonium metavanadate containing iron provided in the present application, the iron in the ammonium metavanadate containing iron exists in the solution in the form of stable complex ions after acid dissolution, and the loss of vanadium is small. At the same time, the ammonium metavanadate uses acid to adjust the pH to dissolve the iron, and no ammonium salt needs to be added. The purification process is simple and the cost is low. The iron content in the vanadium pentoxide finally prepared by the present application is low, which can meet the application technical requirements of non-steel fields such as vanadium aluminum alloy and high-purity vanadium oxide. DETAILED DESCRIPTION

[0019] 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.

[0020] In view of the problems of high iron removal and purification cost and large vanadium loss in the prior art of iron-containing ammonium metavanadate, the present application provides a method for preparing vanadium pentoxide from iron-containing ammonium metavanadate, which reduces the loss of vanadium by dissolving the iron in the ammonium metavanadate in the form of a stable complex ion, and only dissolves the iron by adjusting the pH with an acid, without adding additional reagents, thereby reducing the cost. Therefore, the method for preparing vanadium pentoxide from iron-containing ammonium metavanadate provided by the present application has low vanadium loss and low cost. Specifically, an embodiment of the present invention discloses a method for preparing vanadium pentoxide from iron-containing ammonium metavanadate, comprising the following steps:

[0021] S1) mixing iron-containing ammonium metavanadate and water to obtain ammonium metavanadate slurry;

[0022] S2) mixing the ammonium metavanadate slurry and the complexing agent, adjusting the pH to 1.5-2.5, performing an iron dissolving reaction, and performing solid-liquid separation to obtain ammonium polyvanadate; the complexing agent is selected from one or more of tartaric acid, ethylenediaminetetraacetic acid, disodium ethylenediaminetetraacetate, and tetrasodium ethylenediaminetetraacetate;

[0023] S3) calcining the ammonium polyvanadate to obtain vanadium pentoxide.

[0024] In the process of preparing vanadium pentoxide from ammonium metavanadate containing iron provided in the present application, the present application first mixes ammonium metavanadate containing iron with water to obtain ammonium metavanadate slurry; in the process, the ammonium metavanadate containing iron is obtained by sequentially carrying out blank or calcification roasting-carbonation leaching-alkaline ammonium salt vanadium precipitation process of vanadium slag, and the above process is a process well known to those skilled in the art, and the present application does not impose any special restrictions on this, and the vanadium slag is also a raw material well known to those skilled in the art, and the source thereof is not particularly restricted in the present application. The content of iron in the ammonium metavanadate is less than 0.2wt%, and further, the content of iron in the ammonium metavanadate is 0.05~0.15wt%, and more specifically, the content of iron in the ammonium metavanadate is 0.08~0.14wt%; the iron in the ammonium metavanadate mainly exists in the form of ferric hydroxide. The iron-containing ammonium metavanadate and water are mixed and slurried at a solid-liquid ratio of 1g: (3-10) mL to control the iron concentration in the solution; specifically, the solid-liquid ratio of the iron-containing ammonium metavanadate and water is 1g: (3-8) mL, more specifically, the solid-liquid ratio of the iron-containing ammonium metavanadate and water is 1g: (3.5-6.5) mL; more specifically, the solid-liquid ratio of the iron-containing ammonium metavanadate and water is 1g: (4-5) mL.

[0025] The present application then mixes the ammonium metavanadate slurry and the complexing agent, and then adjusts the pH to 1.5-2.5, and separates the solid and liquid after the iron dissolving reaction to obtain ammonium polyvanadate. In the above process, the complexing agent is selected from one or more of tartaric acid, ethylenediaminetetraacetic acid, disodium ethylenediaminetetraacetic acid and tetrasodium ethylenediaminetetraacetic acid; specifically, when the complexing agent is selected from tartaric acid, the amount of the complexing agent is calculated according to the molar ratio of C4H6O6:Fe=1.3-2.0:1, and for example, the amount of the complexing agent is calculated according to the molar ratio of C4H6O6:Fe=1.3:1, 1.4:1, 1.5:1, 1.6:1, 1.7:1, 1.8:1, 1.9:1 or 2.0:1; the complexing agent is selected from one or more of tartaric acid, ethylenediaminetetraacetic acid, disodium ethylenediaminetetraacetic acid and tetrasodium ethylenediaminetetraacetic acid; specifically, when the complexing agent is selected from tartaric acid, the amount of the complexing agent is calculated according to the molar ratio of C4H6O6:Fe=1.3:1, 1.4:1, 1.5:1, 1.6:1, 1.7:1, 1.8:1, 1.9:1 or 2.0:1; When the mixture is selected from ethylenediaminetetraacetic acid, disodium ethylenediaminetetraacetate or tetrasodium ethylenediaminetetraacetate, the amount of the complexing agent is calculated according to the molar ratio of EDTA:Fe=1.2~1.5:1. For example, the amount of the complexing agent is calculated according to the molar ratio of EDTA:Fe=1.2:1, 1.3:1, 1.4:1, 1.5:1. The excessive addition of the complexing agent allows the iron in the ammonium metavanadate to be fully complexed and exist in the form of soluble ions, avoiding the combination of iron and vanadate to form insoluble iron vanadate, resulting in an increase in the iron content in vanadium pentoxide. The pH is adjusted so that the iron hydroxide in the ammonium metavanadate dissolves and promptly forms a stable soluble complex ion with the complexing agent, thereby reducing the Fe in the slurry. 3+ion concentration, promote the dissolution of iron hydroxide; the pH is adjusted to 1.5-2.5 to fully dissolve the iron hydroxide and reduce the iron content in the vanadium precipitate; in the present application, sulfuric acid is used to adjust the pH to 1.5-2.2, more specifically, sulfuric acid is used to adjust the pH to 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1 or 2.2. The temperature of the iron dissolving reaction is 50-70°C, and the time is 0.5-2h; specifically, the temperature of the iron dissolving reaction is 55-65°C, 1.0-1.5h. The control of the temperature of the iron dissolving reaction accelerates the dissolution rate of iron hydroxide, while avoiding excessive temperature causing the stability of iron-containing complex ions to deteriorate, and iron is precipitated in the form of iron hydroxide. Since the ammonia content in ammonium metavanadate is higher than that in ammonium polyvanadate, ammonium salt does not need to be added when ammonium metavanadate is converted into ammonium polyvanadate. After the above-mentioned iron dissolving reaction, solid-liquid separation is performed to obtain filtrate and ammonium polyvanadate, and the ammonium polyvanadate is washed with water to obtain ammonium polyvanadate.

[0026] In the present application, ammonium polyvanadate is finally calcined to obtain vanadium pentoxide. The calcination temperature is 500-600°C and the time is 3-5 hours; specifically, the calcination temperature is 520-580°C, more specifically, the calcination temperature is 550-570°C and the time is 3-4 hours.

[0027] The present application provides a method for preparing vanadium pentoxide from iron-containing ammonium metavanadate, which comprises first preparing the iron-containing ammonium metavanadate into ammonium metavanadate slurry, and then adjusting the pH of the ammonium metavanadate slurry with sulfuric acid to dissolve the iron, without adding ammonium salt, and the purification process is simple and low in cost; the iron in the ammonium metavanadate is dissolved in acid and exists in the solution in the form of stable complex ions, and the loss of vanadium is small; therefore, the vanadium pentoxide prepared by the method provided in the present application has a low iron content and meets the application technical requirements of non-steel fields such as vanadium-aluminum alloys and high-purity vanadium oxide.

[0028] In order to further understand the present invention, the method for preparing vanadium pentoxide from ammonium metavanadate containing iron 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.

[0029] The reagents used in the following examples are all known products and are commercially available.

[0030] Example 1

[0031] Take 100g of iron-containing ammonium metavanadate (V2O5 77.27%, Fe 0.095%), add it to 350mL of water, stir and slurry and heat it in a water bath to 55°C; add 0.46g of tartaric acid to the ammonium metavanadate slurry, then adjust the slurry pH to 1.5-1.6 with sulfuric acid, and perform iron dissolving reaction for 0.5h; after the iron dissolving reaction is completed, solid-liquid separation is performed to obtain filtrate (V 1.02g / L) and ammonium polyvanadate, and the ammonium polyvanadate is washed with 300mL of water;

[0032] The washed ammonium polyvanadate was calcined at 550°C for 4 hours in a muffle furnace to obtain 76.75 g of powdered vanadium pentoxide product; wherein the V2O5 content was 99.85%, and the vanadium loss during the iron removal and purification process was 0.82%; the Fe content was 0.007%, and the iron removal rate was 94.34%.

[0033] Example 2

[0034] Take 100g of iron-containing ammonium metavanadate (V2O5 77.07%, Fe 0.142%), add it to 500mL of water, stir and slurry and heat it to 60°C in a water bath; add 1.11g of disodium ethylenediaminetetraacetate to the ammonium metavanadate slurry, then adjust the slurry pH to 1.8-2.0 with sulfuric acid, and dissolve the iron for 1h; after the iron dissolving reaction is completed, separate the solid and liquid to obtain the filtrate (V 0.52g / L) and ammonium polyvanadate, and wash the ammonium polyvanadate with 300mL of water;

[0035] The washed ammonium polyvanadate was calcined at 550°C for 4 hours in a muffle furnace to obtain 76.74 g of powdered vanadium pentoxide product; wherein the V2O5 content was 99.83%, and the vanadium loss during the iron removal and purification process was 0.60%; the Fe content was 0.009%, and the iron removal rate was 95.14%.

[0036] Example 3

[0037] Take 100g of iron-containing ammonium metavanadate (V2O5 77.15%, Fe 0.104%), add it to 650mL of water, stir and slurry and heat it in a water bath to 65°C; add 1.00g of tetrasodium ethylenediaminetetraacetate to the ammonium metavanadate slurry, then adjust the slurry pH to 1.9-2.1 with sulfuric acid, and dissolve the iron for 1.5h; after the iron dissolving reaction is completed, separate the solid and liquid to obtain the filtrate (V 0.49g / L) and ammonium polyvanadate, and wash the ammonium polyvanadate with 300mL of water;

[0038] The washed ammonium polyvanadate was calcined at 500°C for 5h in a muffle furnace to obtain 76.72g of powdered vanadium pentoxide product; wherein the V2O5 content was 99.82%, and the vanadium loss during the iron removal and purification process was 0.74%; the Fe content was 0.009%, and the iron removal rate was 93.36%.

[0039] Example 4

[0040] Take 100g of iron-containing ammonium metavanadate (V2O5 77.24%, Fe 0.087%), add it to 800mL of water, stir and slurry and heat it to 70°C in a water bath; add 0.68g of ethylenediaminetetraacetic acid to the ammonium metavanadate slurry, then adjust the slurry pH to 2.0-2.2 with sulfuric acid, and dissolve the iron for 2h; after the iron dissolving reaction is completed, separate the solid and liquid to obtain the filtrate (V 0.55g / L) and ammonium polyvanadate, and wash the ammonium polyvanadate with 300mL of water;

[0041] The washed ammonium polyvanadate was calcined at 600°C for 3 h in a muffle furnace to obtain 76.61 g of powdered vanadium pentoxide product; wherein the V2O5 content was 99.79%, and the vanadium loss during the iron removal purification process was 1.02%; the Fe content was 0.011%, and the iron removal rate was 90.31%.

[0042] Comparative Example 1

[0043] Take 100g of iron-containing ammonium metavanadate (V2O5 77.07%, Fe 0.142%), add it to 500mL of water, stir and slurry and heat it to 60℃ in a water bath; then adjust the slurry pH to 1.8-2.0 with sulfuric acid, and dissolve the iron for 1h; after the iron dissolving reaction, separate the solid and liquid to obtain the filtrate (V 0.50g / L) and ammonium polyvanadate, and wash the ammonium polyvanadate with 300mL of water;

[0044] The washed ammonium polyvanadate was calcined at 550°C for 4 hours in a muffle furnace to obtain 76.88 g of powdered vanadium pentoxide product; wherein the V2O5 content was 99.67%, and the vanadium loss during the iron removal and purification process was 0.58%; the Fe content was 0.127%, and the iron removal rate was 31.24%.

[0045] In summary, the method for preparing low-iron vanadium pentoxide from iron-containing ammonium metavanadate provided by the present invention adopts acid dissolution and complexation to dissolve the iron in the ammonium metavanadate and exist in the solution in the form of soluble ions, thereby avoiding the secondary reaction of iron ions with vanadate ions to enter the vanadium product, significantly reducing the iron content of the vanadium product, and providing support for the application of vanadium products in non-steel fields such as vanadium-aluminum alloys and high-purity vanadium oxide.

[0046] 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.

[0047] 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 from ammonium metavanadate containing iron, comprising the following steps: S1) mixing iron-containing ammonium metavanadate and water to obtain ammonium metavanadate slurry; S2) mixing the ammonium metavanadate slurry and the complexing agent, adjusting the pH to 1.5-2.5, performing an iron dissolving reaction, and performing solid-liquid separation to obtain ammonium polyvanadate; the complexing agent is selected from one or more of tartaric acid, ethylenediaminetetraacetic acid, disodium ethylenediaminetetraacetate, and tetrasodium ethylenediaminetetraacetate; S3) calcining the ammonium polyvanadate to obtain vanadium pentoxide.

2. The method according to claim 1, characterized in that: The iron-containing ammonium metavanadate is prepared by sequentially carrying out the process of blank or calcification roasting-carbonation leaching-alkaline ammonium salt vanadium precipitation on vanadium slag.

3. The method according to claim 1 or 2, characterized in that: The iron content in the iron-containing ammonium metavanadate is less than 0.2 wt %.

4. The method according to claim 1, characterized in that The solid-to-liquid ratio of the iron-containing ammonium metavanadate and water is 1 g: (3-10) mL.

5. The method according to claim 1, characterized in that When the complexing agent is selected from tartaric acid, the complexing agent is added according to a molar ratio of C4H6O6:Fe=1.3~2.0:

1.

6. The method according to claim 1, characterized in that When the complexing agent is selected from ethylenediaminetetraacetic acid, disodium ethylenediaminetetraacetate or tetrasodium ethylenediaminetetraacetate, the complexing agent is added according to a molar ratio of EDTA:Fe=1.2~1.5:

1.

7. The method according to claim 1, characterized in that The temperature of the iron dissolving reaction is 50-70° C. and the time is 0.5-2 h.

8. The method according to claim 1, characterized in that The reagent used for adjusting the pH is sulfuric acid, and the pH is 1.5-2.

2.

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