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CN-121983625-A - Method for separating ferrovanadium in high-iron vanadium electrolyte

CN121983625ACN 121983625 ACN121983625 ACN 121983625ACN-121983625-A

Abstract

The invention discloses a method for separating vanadium from vanadium in a high-iron vanadium electrolyte, which comprises pH regulation, iron removal, vanadium extraction and vanadium back extraction, wherein iron ion targeting complexing agent and solid phase adsorbent are added into the high-iron vanadium electrolyte after pH adjustment, the low-iron vanadium electrolyte and the solid phase are obtained by direct filtration after reaction for 10-15min under stirring, the vanadium extraction is carried out, the vanadium in the low-iron vanadium electrolyte is extracted by adopting a pretreated mixed solvent of P204, TBP and sulfonated kerosene, so as to obtain vanadium-containing organic solution, and the vanadium back extraction is carried out, namely the vanadium-containing organic solution is back extracted by a sulfuric acid solution with the concentration of 2.0-5.0 mol/L, so as to obtain the vanadium electrolyte. The method can be used for treating iron ions in all valence states, particularly ferric ions which are easier to extract than vanadium ions, and can directly obtain qualified vanadium electrolyte with the iron ion concentration meeting the industry standard after back extraction, and the complexing agent and the adsorbent can be recycled.

Inventors

  • WANG BAOHUA
  • LV YEQING
  • WANG ZHENJIE
  • DU HAO
  • QI JIAN
  • MA RUIFENG
  • ZHAO LIANG
  • ZHANG XU

Assignees

  • 承德钒钛新材料有限公司
  • 承德钢铁集团有限公司
  • 河钢股份有限公司承德分公司

Dates

Publication Date
20260505
Application Date
20251231

Claims (10)

  1. 1. A method for separating vanadium and iron in a high-iron vanadium electrolyte is characterized by comprising the steps of pH regulation, iron removal, vanadium extraction and vanadium back extraction, wherein iron ion targeting complexing agent and solid-phase adsorbent are added into the high-iron vanadium electrolyte after pH regulation, the low-iron vanadium electrolyte and the solid-phase adsorbent are obtained by direct filtration after reaction for 10-15min under stirring, and the vanadium extraction is carried out, and vanadium in the low-iron vanadium electrolyte is extracted by adopting a pretreated mixed solvent of P204, TBP and sulfonated kerosene, so that a vanadium-containing organic solution is obtained.
  2. 2. The method for separating vanadium from iron and vanadium in high-iron vanadium electrolyte according to claim 1, wherein the pH value is adjusted to 1.5-4 by adding sodium hydroxide or potassium hydroxide into the high-iron vanadium electrolyte.
  3. 3. The method for separating ferrovanadium in a high-iron vanadium electrolyte according to claim 1, wherein the iron ion targeting complexing agent is a combination of 1 or 2 or more of ethylenediamine tetraacetic acid, tetraethylenediamine tetraacetic acid, 5-sulfosalicylic acid, malonic acid, citric acid and 1, 10-benzyl dipyrazole.
  4. 4. The method for separating ferrovanadium from high-iron vanadium electrolyte according to claim 1, wherein the solid-phase adsorbent is activated carbon or zeolite.
  5. 5. The method for separating ferrovanadium in a high-iron vanadium electrolyte according to claim 1, wherein the P204, TBP and sulfonated kerosene are pretreated by saponification.
  6. 6. The method for separating ferrovanadium in the high-iron vanadium electrolyte according to claim 5, wherein the saponification agent used in the saponification reaction comprises sodium hydroxide with the concentration of 0.1-1.0 mol/L, and the reaction time of the saponification reaction is 5-15 min.
  7. 7. The method for separating ferrovanadium in the high-iron vanadium electrolyte according to claim 1, wherein the volume ratio of P204 to TBP to sulfonated kerosene is 15-40:1-5:55-84.
  8. 8. The method for separating ferrovanadium in the high-iron vanadium electrolyte according to claim 1, wherein the extraction time is 20-60 min, and the extraction stage number is 3-6.
  9. 9. The method for separating vanadium and iron in the high-iron vanadium electrolyte according to claim 1, wherein the vanadium back extraction is carried out by subjecting a vanadium-containing organic solution to sulfuric acid solution with the concentration of 2.0-5.0 mol/L to obtain the vanadium electrolyte.
  10. 10. The method for separating vanadium from iron in high-iron vanadium electrolyte according to claim 1, wherein the solid phase obtained after iron removal and separation can be regenerated and recycled after washing with sulfuric acid solution.

Description

Method for separating ferrovanadium in high-iron vanadium electrolyte Technical Field The invention belongs to the technical field of vanadium chemical metallurgy, and particularly relates to a method for separating vanadium and iron in a high-iron vanadium electrolyte. Background All-vanadium redox flow batteries become the most potential energy storage mode in electrochemical energy storage due to the advantages of long service life, large capacity, high safety performance and the like. The energy storage and conversion core of the all-vanadium redox flow battery is vanadium electrolyte, and the all-vanadium redox flow battery comprises positive electrolyte and negative electrolyte, wherein the positive electrolyte is a solution containing tetravalent and pentavalent vanadium compounds, the negative electrolyte is a solution containing divalent and trivalent vanadium compounds, and in the operation process of the all-vanadium redox flow battery, the energy storage and conversion are realized through the conversion between vanadium in different valence states. However, in the production process or the long-term operation process of the vanadium electrolyte, as the concentration of sulfuric acid in the vanadium electrolyte is relatively high, the long-term contact with the iron pipe or the stirring paddle can cause the iron ions in the electrolyte to be obviously out of standard, so that the high-iron vanadium electrolyte is formed. According to NB/T42133-2017 technical conditions of electrolyte for all-vanadium redox flow batteries, the concentration of iron ions in the vanadium electrolyte is required to be less than or equal to 100 mg/L. Aiming at the separation of ferrovanadium in the high-iron vanadium electrolyte, the existing separation method mainly adopts an extraction technology, and the adopted extractant mainly is P204 or P507. For the vanadium electrolyte containing Fe 3+, because Fe 3+ is easier to extract than vanadium ions, the extraction and separation of Fe 3+ and vanadium ions are difficult to realize, and a reducing agent is required to be added to reduce Fe 3+ into Fe 2+. This is mainly because Fe 2+ is more difficult to extract than vanadium ions, but part of Fe 2+ is still extracted to an organic phase together with vanadium ions during the extraction process, and thus one-time reduction of the iron ion concentration to below 100 mg/L cannot be achieved. Therefore, a method for separating vanadium and iron in a high-iron vanadium electrolyte with high speed and low cost is needed, the high-iron vanadium electrolyte is processed into a qualified vanadium electrolyte at one time, and the method is applicable to both Fe 2+ and Fe 3+, and provides technical support for the high-efficiency separation of vanadium and iron in the preparation process of the vanadium electrolyte. Disclosure of Invention The invention aims to provide a method for separating ferrovanadium in a high-iron vanadium electrolyte, which is simple in method, easy to operate and suitable for popularization and application. In order to achieve the above purpose, the present invention adopts the following technical scheme: A method for separating vanadium and iron in a high-iron vanadium electrolyte comprises pH regulation, iron removal, vanadium extraction and vanadium back extraction, wherein iron ion targeting complexing agent and solid-phase adsorbent are added into the high-iron vanadium electrolyte after pH regulation, the low-iron vanadium electrolyte and the solid-phase are obtained by direct filtration after reaction for 10-15min under stirring, and the vanadium extraction is carried out by adopting a pretreated mixed solvent of P204, TBP and sulfonated kerosene to extract vanadium in the low-iron vanadium electrolyte, so as to obtain a vanadium-containing organic solution. Further, the concentration of iron ions in the high-iron vanadium electrolyte of the present invention is not less than 1g/L, for example, 1, 5, 10, 15, 20 or 25, but is not limited to the values listed. Further, the pH value of the high-iron vanadium electrolyte is adjusted to 1.5-4 by adding sodium hydroxide or potassium hydroxide, for example, 1.5, 1.8, 2.0, 2.2, 2.5, 2.8, 3.0, 3.2, 3.5, 3.8 or 4.0, but the invention is not limited to the listed values. Further, the iron ion targeting complexing agent is a combination of 1 or more than 2 of ethylenediamine tetraacetic acid, tetraethylenediamine tetraacetic acid, 5-sulfosalicylic acid, malonic acid, citric acid and 1, 10-benzyl dipyrazole. Further, the addition amount of the iron ion targeting complexing agent is 0.5-1.5 times, preferably 0.6-1.0 times, of the theoretical requirement amount of iron in the electrolyte, for example, 0.5 times, 0.6 times, 0.7 times, 0.8 times, 0.9 times, 1.0 times, 1.1 times, 1.2 times, 1.3 times, 1.4 times or 1.5 times, but the iron ion targeting complexing agent is not limited to the listed values. Further, the solid-phase adsorbent is one of adsorbents with