A method for short-process preparation of high-purity vanadium pentoxide

Abstract

The application discloses a method for preparing high-purity vanadium pentoxide in a short process, and belongs to the technical field of non-ferrous hydrometallurgy. The method comprises the following steps: firstly, after pretreatment of vanadium-containing leaching solution, sodium sulfide and na-methylmercury sulfonate are added, aging is carried out, impurities are removed, hydrogen peroxide is added and heated, pH is adjusted, attapulgite is added, aluminum sulfate is added, aging and impurity removal are carried out; secondly, vanadium precipitation treatment is carried out, ammonium polyvanadate is washed, dried and calcined, and high-purity vanadium pentoxide with a grade of greater than or equal to 99.5% is obtained. In the application, the vanadium-containing leaching solution is used to produce high-purity vanadium pentoxide, the impurity removal process is advanced, high-purity vanadium pentoxide with a grade of greater than or equal to 99.5% can be prepared, and the vanadium recovery rate can reach 98%. The preparation process is greatly simplified, the production efficiency is high, the cost is reduced, the treatment time is short, energy saving and emission reduction and green production are beneficial, the production cost is reduced by 3000-5000 yuan / ton, the vanadium recovery rate can be increased by about 3%, the process is more environmentally friendly, the vanadium recovery rate is higher, and the production efficiency is also higher. The application is suitable for preparing high-purity vanadium pentoxide in a short process.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of non-ferrous hydrometallurgy, and particularly relates to a method for preparing high-purity vanadium pentoxide through a short process. BACKGROUND

[0002] Vanadium pentoxide is widely used in the fields of chemical industry, metallurgy, aerospace, aviation and the like, and plays an important role in the national economy, production and daily life. With the successful development of vanadium batteries, the safety, capacity and power of the flow battery are increasingly highlighted, and therefore the demand for vanadium pentoxide is gradually increasing. In order to avoid the impurities in vanadium pentoxide from blocking the exchange membrane, causing battery polarization and reducing battery performance, the market increasingly requires high purity of vanadium pentoxide.

[0003] Most of the existing production methods of high-purity vanadium pentoxide use ammonium polyvanadate produced by a vanadium factory as a raw material, and adopt a traditional back-solubilization impurity removal method to reduce impurity elements and improve product purity. However, compared with directly using the leaching solution of sodium vanadium slag for production, the cost of using ammonium polyvanadate as a raw material is about 3000-5000 yuan / t higher. The extraction process has the problem of environmental pollution, and the ion exchange method has the problems of low vanadium recovery rate and low production efficiency. Therefore, it is urgent to develop an energy-saving and environment-friendly, high-efficiency and low-cost preparation method of high-purity vanadium pentoxide. SUMMARY

[0004] The application aims to solve the problems of long process flow, low efficiency and high cost in the existing preparation of high-purity vanadium pentoxide, and provides a method for preparing high-purity vanadium pentoxide through a short process.

[0005] A method for preparing high-purity vanadium pentoxide through a short process, which is implemented according to the following steps:

[0006] I. A vanadium-containing leaching solution is pretreated to obtain a leaching solution, then sodium sulfide is added, fully stirred, then sodium formaldehyde is added and aged, the first impurity removal product is filtered, then hydrogen peroxide is added and heated, the pH is adjusted to 8-8.5, then attapulgite is added, fully stirred, then aluminum sulfate is added, fully stirred and aged, and the second impurity removal product is filtered to obtain a purified leaching solution;

[0007] II. The above-mentioned purified leaching solution is subjected to vanadium precipitation treatment to obtain ammonium polyvanadate precipitate, which is washed, dried and calcined to obtain vanadium pentoxide with a grade of ≥99.5%, i.e. the short-process preparation method is completed;

[0008] In step I, the vanadium-containing leaching solution is pretreated by one-time filtration, and the filtration standard is that there is no visible solid impurity, the solution is clear and transparent, the solution pH value is 8.5-9.7, and the vanadium concentration is ≥30 g / L.

[0009] Further, the standing time in step one is 120 min.

[0010] Further, the amount of sodium sulfide in step one is controlled to make the pH value of the leaching solution reach 10-10.5.

[0011] Further, the amount of sodium dimethyldithiocarbamate in step one is controlled to make the mass ratio of sodium dimethyldithiocarbamate to impurity metal elements in the leaching solution be 1:1.

[0012] Further, the amount of hydrogen peroxide in step one is controlled to make the leaching solution become yellow after the heating reaction is completed; the heating reaction temperature is 70-80℃.

[0013] Further, the amount of attapulgite in step one is controlled to make the mass ratio of vanadium to attapulgite in per liter of leaching solution be 40:1.

[0014] Further, the amount of aluminum sulfate in step one is 0.4-0.6 g / L of leaching solution.

[0015] Further, the vanadium precipitation treatment in step two is an acid ammonium salt vanadium precipitation method, in which the purified leaching solution is heated to boiling state, the pH value is adjusted to 5-5.5, ammonium sulfate is added according to an ammonium coefficient of 0.9-1.2, the ammonium sulfate grade is required to be superior grade or above, the pH value is adjusted to 2-2.5 again, and the stirring reaction is continued for 1 h to obtain polyvanadic acid ammonium precipitate.

[0016] Further, the washing in step two is once; the washing water is required to be grade three water or above, and solid ammonium sulfate is required to be added in the washing water to adjust to 2% ammonium sulfate solution, and the volume ratio of washing water to polyvanadic acid ammonium precipitate is 3:1.

[0017] Further, the drying and calcination in step two are drying at 100℃ for 120 min, and then calcination at 500-550℃ for 150 min.

[0018] The high-purity vanadium pentoxide is produced by using the vanadium-containing leaching solution in the application, the original solution concentration is not reduced, the impurity removal process is advanced, and the influence of the impurities in the leaching solution on the product purity is avoided, the method can produce high-purity vanadium pentoxide with a grade of more than 99.5%, and the vanadium recovery rate can reach 98%. The preparation process is greatly simplified, the production efficiency is high, the cost is reduced, the treatment time is short, and the method is beneficial to energy saving, emission reduction and green production; compared with the traditional back-solubilization impurity removal method, the production cost is reduced by 3000-5000 yuan / ton, the vanadium recovery rate is increased by about 3%, the method is more environmentally friendly than the extraction method, and compared with the ion exchange method, the vanadium recovery rate is higher, and the production efficiency is also higher; if relying on existing vanadium sheet production enterprises, the impurity removal product can be realized to be re-roasted, and the production wastewater can be reused to produce metallurgical grade vanadium pentoxide, so that green environmental protection and sustainable production are realized.

[0019] The application is suitable for short-process preparation of high-purity vanadium pentoxide. DETAILED DESCRIPTION

[0020] Specific embodiment one: a method for short-process preparation of high-purity vanadium pentoxide, which is realized according to the following steps:

[0021] I. The vanadium-containing leaching solution is pretreated to obtain a leaching solution, then sodium sulfide is added, after fully stirring, sodium acetamiprid is added and is placed for aging, the first impurity removal product is filtered, then hydrogen peroxide is added and is heated to react, the pH is adjusted to 8-8.5, then attapulgite is added, after fully stirring, aluminum sulfate is added, after fully stirring, it is placed for aging, the second impurity removal product is filtered, and the purified leaching solution is obtained;

[0022] II. The above-mentioned purified leaching solution is subjected to vanadium precipitation treatment to obtain ammonium polyvanadate precipitate, after washing, drying and calcination, vanadium pentoxide with a grade of ≥99.5% is obtained, and the short-process preparation method is completed;

[0023] In step one, the vanadium-containing leaching solution is pretreated by using one-time filtration, the filtration standard is that there is no visible solid impurity, the solution is clear and transparent, the solution pH value is 8.5-9.7, and the vanadium concentration is ≥30 g / L.

[0024] In the embodiment, the vanadium-containing leaching solution comes from the vanadium-containing leaching solution produced by the leaching section of Heilongjiang Jianlong Vanadium Industry Co., Ltd.

[0025] In the embodiment, the addition of sodium sulfide is carried out in a fume hood under normal temperature and pressure.

[0026] In the embodiment, the sodium sulfide, as a reducing agent, can reduce high-valence iron, chromium, manganese and other elements in the leaching solution, so that the combination of the metal collector is easier; and the alkali metal salt can play a role in adjusting the pH value, the solubility of part of the metal is greatly reduced when the pH value is above 10; in addition, part of the heavy metals can be precipitated in the form of sulfide.

[0027] In this embodiment, sodium thiram is a highly affinity adsorbent that can adsorb heavy metal ions in water. The adsorption principle of sodium thiram is achieved through electrostatic interaction and chemisorption. Heavy metal ions exist in an ionic state in water, and the surface of sodium thiram carries a positive charge. Therefore, heavy metal ions are attracted to the positive charge on the sodium thiram surface and are thus adsorbed onto it. Furthermore, the sodium thiram surface also possesses several chemical functional groups that can react chemically with heavy metal ions to form chemical bonds, thereby more firmly fixing the heavy metal ions to the sodium thiram surface.

[0028] In this embodiment, the attapulgite soil is fibrous attapulgite, which has high porosity, large specific surface area, and active sites and cation exchange properties on its surface, enabling it to effectively adsorb heavy metal pollutants.

[0029] The impurity removal products in this embodiment are all organic complexes and stable inorganic substances, which can be returned to the roasting process of vanadium flake production enterprises to achieve green and environmentally friendly production.

[0030] Specific Implementation Method Two: This implementation method differs from Specific Implementation Method One in that the settling and aging time in step one is 120 minutes. Other steps and parameters are the same as in Specific Implementation Method One.

[0031] Specific Implementation Method Three: This implementation method differs from Specific Implementation Method One in that the amount of sodium sulfide used in step one is controlled based on pH value, with the addition endpoint being when the pH value of the leachate reaches 10-10.5. Other steps and parameters are the same as in Specific Implementation Method One.

[0032] Specific Implementation Method Four: This implementation method differs from Specific Implementation Method One in that the amount of sodium thiram used in step one is: the mass ratio of sodium thiram to the impurity metal elements in the leachate is 1:1. Other steps and parameters are the same as in Specific Implementation Method One.

[0033] Specific Implementation Method Five: This implementation method differs from Specific Implementation Method One in that, in step one, hydrogen peroxide is added and a heating reaction is carried out: the amount of hydrogen peroxide used is based on the color of the leachate after the heating reaction is complete, and the addition is controlled to the endpoint when the leachate turns yellow; the heating reaction temperature is 70-80℃. Other steps and parameters are the same as in Specific Implementation Method One.

[0034] Specific Implementation Method Six: This implementation method differs from Specific Implementation Method One in that the amount of attapulgite used in step one is: the mass ratio of vanadium to attapulgite in each liter of leachate is 40:1. Other steps and parameters are the same as in Specific Implementation Method One.

[0035] Specific Implementation Method Seven: This implementation method differs from Specific Implementation Method One in that the amount of aluminum sulfate used in step one is 0.4–0.6 g / L of leachate. All other steps and parameters are the same as in Specific Implementation Method One.

[0036] Specific Implementation Method Eight: This implementation method differs from Specific Implementation Method One in that the vanadium precipitation treatment in step two is as follows: The vanadium precipitation method using acidic ammonium salts is employed. The purified leachate is heated to boiling, the pH is adjusted to 5-5.5, and ammonium sulfate is added at an ammonium addition coefficient of 0.9-1.2. The ammonium sulfate grade must be superior purity or higher. The pH is then adjusted again to 2-2.5, and the reaction is continuously stirred for 1 hour to obtain ammonium polyvanadate precipitate. Other steps and parameters are the same as in Specific Implementation Method One.

[0037] Specific Implementation Method Nine: This implementation method differs from Specific Implementation Method One in that, in step two, the washing process involves one wash; the washing water must be of grade III or higher, and solid ammonium sulfate must be added to the washing water to adjust it into a 2% ammonium sulfate solution. The volume ratio of washing water to ammonium polyvanadate precipitate is 3:1. Other steps and parameters are the same as in Specific Implementation Method One.

[0038] Specific Implementation Method Ten: This implementation method differs from Specific Implementation Method One in that the drying and calcination in step two are performed as follows: drying at 100°C for 120 minutes, followed by calcination at 500–550°C for 150 minutes. Other steps and parameters are the same as in Specific Implementation Method One.

[0039] The beneficial effects of the present invention are verified through the following embodiments:

[0040] Example:

[0041] A short-process method for preparing high-purity vanadium pentoxide, comprising the following steps:

[0042] I. The vanadium-containing leachate is pretreated to obtain leachate, then sodium sulfide is added, stirred thoroughly, then sodium formaldehyde sulfoxylate is added and allowed to stand for aging, the first impurity removal product is filtered, then hydrogen peroxide is added and heated to react, the pH is adjusted to 8, then attapulgite is added, stirred thoroughly, then aluminum sulfate is added, stirred thoroughly, allowed to stand for aging, the second impurity removal product is filtered, and the purified leachate is obtained.

[0043] 2. The purified leachate is subjected to vanadium precipitation treatment to obtain ammonium polyvanadate precipitate. After washing, drying and calcination, vanadium pentoxide with a grade ≥99.5% is obtained, thus completing the short process preparation method described above.

[0044] The vanadium-containing leachate in step one is pretreated by a single filtration process. The filtration standard is that there are no visible solid impurities, the solution is clear and transparent, the solution pH is 9, and the vanadium concentration is ≥30g / L.

[0045] In this embodiment, the settling and aging time in step one is 120 minutes.

[0046] The amount of sodium sulfide used in step one of this embodiment is controlled based on the pH value, with the endpoint being the pH value of the leachate reaching 10.

[0047] The amount of sodium thiram used in step one of this embodiment is: the mass ratio of sodium thiram to the impurity metal elements in the leachate is 1:1.

[0048] In step one of this embodiment, hydrogen peroxide is added and heated to react: the amount of hydrogen peroxide used is based on the color of the leachate after the heating reaction is complete, and the addition is controlled to the point where the leachate turns yellow; the heating reaction temperature is 75℃; in this embodiment, the amount of hydrogen peroxide used is 30g / L of leachate.

[0049] The amount of attapulgite used in step one of this embodiment is: the mass ratio of vanadium to attapulgite in each liter of leachate is 40:1.

[0050] The amount of aluminum sulfate used in step one of this embodiment is 0.5 g / L of leachate.

[0051] The vanadium precipitation process described in step two of this embodiment is as follows: using the acidic ammonium salt precipitation method, the purified leachate is heated to boiling, the pH value is adjusted to 5-5.5, ammonium sulfate is added according to the ammonium addition coefficient of 0.9-1.2, the ammonium sulfate grade is required to be superior grade or above, the pH value is adjusted again to 2-2.5, and the reaction is continuously stirred for 1 hour to obtain ammonium polyvanadate precipitate.

[0052] The washing process described in step two of this embodiment involves one wash; the washing water must be of grade three or higher, and solid ammonium sulfate must be added to the washing water to adjust it into a 2% ammonium sulfate solution. The volume ratio of washing water to ammonium polyvanadate precipitate is 3:1.

[0053] The drying and calcination described in step two of this embodiment are as follows: drying at 100°C for 120 min, and then calcining at 500°C for 150 min.

[0054] In this embodiment, the vanadium-containing leaching solution comes from the leaching section of Heilongjiang Jianlong Vanadium Industry Co., Ltd.

[0055] The method in this embodiment can produce vanadium pentoxide with a purity of 99.5% and a vanadium recovery rate of 98%.

Claims

1. A short-process method for preparing high-purity vanadium pentoxide, characterized in that... It is implemented in the following steps: I. The vanadium-containing leachate is pretreated to obtain leachate, then sodium sulfide is added, stirred thoroughly, then sodium formaldehyde sulfoxylate is added and allowed to stand for aging, the first impurity removal product is filtered, then hydrogen peroxide is added and heated to react, the pH is adjusted to 8-8.5, then attapulgite is added, stirred thoroughly, then aluminum sulfate is added, stirred thoroughly, allowed to stand for aging, the second impurity removal product is filtered, and the purified leachate is obtained.

2. The purified leachate is subjected to vanadium precipitation treatment to obtain ammonium polyvanadate precipitate. After washing, drying and calcination, vanadium pentoxide with a grade ≥99.5% is obtained, thus completing the short process preparation method described above. The vanadium-containing leachate in step one is pretreated by a single filtration process, with the filtration standard being the absence of visible solid impurities, a clear and transparent solution, a pH value of 8.5–9.7, and a vanadium concentration ≥30 g / L. The settling and aging time mentioned in step one is 120 minutes; The amount of sodium sulfide used in step one: based on the pH value, the addition endpoint is controlled so that the pH value of the leachate reaches 10 to 10.5; The amount of sodium thiram used in step one: the mass ratio of sodium thiram to the impurity metal elements in the leachate is 1:1; In step one, hydrogen peroxide is added and a heating reaction is carried out: the amount of hydrogen peroxide used is based on the color of the leachate after the heating reaction is complete, and the addition is controlled to the point where the leachate turns yellow; the heating reaction temperature is 70-80℃. The amount of attapulgite used in step one: the mass ratio of vanadium to attapulgite in each liter of leachate is 40:1; The amount of aluminum sulfate used in step one is 0.4–0.6 g / L of leachate; The vanadium precipitation treatment described in step two is as follows: using the acidic ammonium salt precipitation method, the purified leachate is heated to boiling, the pH value is adjusted to 5-5.5, ammonium sulfate is added according to the ammonium addition coefficient of 0.9-1.2, the ammonium sulfate grade is required to be superior grade or above, the pH value is adjusted again to 2-2.5, and the reaction is continuously stirred for 1 hour to obtain ammonium polyvanadate precipitate. The washing process described in step two involves one wash; the washing water must be of grade three or higher, and solid ammonium sulfate must be added to the washing water to adjust it into a 2% ammonium sulfate solution. The volume ratio of washing water to ammonium polyvanadate precipitate is 3:

1. The drying and calcination described in step two are as follows: dry at 100°C for 120 min, and then calcine at 500-550°C for 150 min.