Method for preparing vanadyl sulfate solution from stone coal

Abstract

The invention belongs to the technical field of vanadium resource treatment, and particularly relates to a method for preparing a vanadyl sulfate solution from stone coal. The method comprises the following steps: grinding stone coal to a certain particle size, adding concentrated sulfuric acid into the ground stone coal powder, uniformly stirring, and roasting to obtain a roasted stone coal material; adding phosphate into the stone coal roasting material, uniformly mixing, adding deionized water, adjusting the pH value, and performing water leaching to obtain a vanadyl sulfate solution; the method has the advantages of being simple and easy to implement, short in production period, low in cost and the like. Particularly, phosphate ions can react with ferric ions in a solution to generate iron phosphate precipitates, and iron phosphate has the characteristics of low solubility, high precipitation rate, good crystallization property, less adsorption of cations and the like. Therefore, the ferric ions in the solution can be effectively removed by adding the phosphate for water leaching, the adverse effect of the ferric ions on extraction in the subsequent extraction and reverse extraction process is remarkably eliminated, and the obtained vanadyl sulfate solution can be directly subjected to extraction operation.

Description

Technical Field

[0001] The invention belongs to the technical field of vanadium resource processing, and specifically relates to a method for preparing a vanadyl sulfate solution by utilizing stone coal. Background Art

[0002] Vanadyl sulfate is mainly used in all-vanadium flow batteries, which are large-scale energy storage systems with great application prospects. They have the advantages of fast charging and discharging speed, safety and high efficiency. At present, vanadyl sulfate is mainly prepared by dissolving high-purity vanadium pentoxide in sulfuric acid and chemically reducing it. The process of preparing high-purity vanadium pentoxide includes "roasting-leaching-impurity removal-vanadium precipitation-calcination" of vanadium minerals. This process is complicated and costly. In the process of impurity removal, the solvent extraction method can effectively enrich the vanadium in the leachate, but since the trivalent iron ions will be extracted first during the extraction process, the purity of the vanadyl sulfate solution is affected. The traditional method is to reduce the trivalent iron ions to divalent iron after obtaining the leachate using a reducing agent such as sodium sulfite and then extract it, but this process will produce polluting gases and the operation is complicated. In addition, the grade of stone coal vanadium ore is low, most of which do not meet the industrial recycling standards, and its occurrence state and mineral composition are relatively complex, so it has not been fully utilized. Therefore, it is urgent to develop new methods to prepare high-purity vanadium oxysulfate solution using stone coal. Summary of the invention

[0003] In order to solve the problems existing in the prior art, the main purpose of the present invention is to provide a method for preparing a vanadyl sulfate solution using stone coal.

[0004] To solve the above technical problems, according to one aspect of the present invention, the present invention provides the following technical solutions: A method for preparing a vanadyl sulfate solution using stone coal comprises the following steps: S1. Grind the stone coal ore to a certain particle size, add concentrated sulfuric acid to the ground stone coal ore powder and stir evenly, and then roast to obtain stone coal roasting material; S2. Add phosphate to the stone coal roasting material and mix evenly, add deionized water and adjust the pH value, then soak in water to obtain a vanadyl sulfate solution.

[0005] As a preferred embodiment of the method for preparing vanadyl sulfate solution using stone coal according to the present invention, in step S1, the particle size of the ground stone coal powder is ≤200 mesh.

[0006] As a preferred embodiment of the method for preparing vanadyl sulfate solution using stone coal according to the present invention, wherein: in the step S1, the liquid-to-solid ratio of concentrated sulfuric acid to ground stone coal powder is (0.1-0.3) mL:1 g.

[0007] As a preferred embodiment of the method for preparing vanadyl sulfate solution using stone coal described in the present invention, wherein: in the step S1, the roasting temperature is 200-260° C. and the time is 1-4 hours.

[0008] As a preferred embodiment of the method for preparing vanadyl sulfate solution using stone coal according to the present invention, wherein: in step S1, the concentration of concentrated sulfuric acid is 95-98wt%.

[0009] As a preferred embodiment of the method for preparing vanadyl sulfate solution using stone coal described in the present invention, wherein: in step S2, the phosphate is at least one of sodium phosphate and potassium phosphate.

[0010] As a preferred embodiment of the method for preparing vanadyl sulfate solution using stone coal according to the present invention, wherein: in step S2, the mass ratio of phosphate to stone coal roasting material is (0.03-0.16):1.

[0011] As a preferred embodiment of the method for preparing vanadyl sulfate solution using stone coal described in the present invention, wherein: in the step S2, the liquid-to-solid ratio during water immersion is (1-3) mL:1 g, and the pH value is 0.5-2.5.

[0012] As a preferred embodiment of the method for preparing vanadyl sulfate solution using stone coal described in the present invention, wherein: in the step S2, the water immersion temperature is 70-100°C and the time is 1-4 hours.

[0013] To solve the above technical problem, according to another aspect of the present invention, the present invention provides the following technical solution: A vanadyl sulfate solution is prepared by the above method for preparing the vanadyl sulfate solution by using stone coal. The iron content of the vanadyl sulfate solution is ≤2g / L, and the iron extraction rate after extraction with an extractant is ≤7%.

[0014] The beneficial effects of the present invention are as follows: The present invention proposes a method for preparing a vanadium sulfate solution using stone coal, wherein the stone coal ore is ground to a certain particle size, concentrated sulfuric acid is added to the ground stone coal ore powder and stirred evenly, and then roasted to obtain a stone coal roasted material; phosphate is added to the stone coal roasted material and mixed evenly, deionized water is added and the pH value is adjusted, and then water leaching is performed to obtain a vanadium sulfate solution. The method of the present invention has the advantages of being simple and easy to implement, a short production cycle and low cost. In particular, phosphate ions can react with trivalent iron ions in the solution to generate iron phosphate precipitates, and iron phosphate has the characteristics of low solubility, fast precipitation rate, good crystallization performance and little adsorption of cations. Therefore, by adding phosphate for water leaching, the trivalent iron ions in the solution can be effectively removed, and the adverse effects of the trivalent iron ions on the extraction in the subsequent extraction and stripping processes can be significantly eliminated, and the obtained vanadium sulfate solution can be directly subjected to extraction operations. DETAILED DESCRIPTION

[0015] The following will be described clearly and completely in conjunction with the technical solutions in the embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0016] The present invention proposes a method for preparing a vanadyl sulfate solution using stone coal, wherein phosphate ions can react with trivalent iron ions in the solution to generate iron phosphate precipitates, and the iron phosphate has the characteristics of low solubility, fast precipitation rate, good crystallization performance, and little adsorption of cations. The present invention has the following advantages: 1) The method described in the present invention is simple and has a short process, and can effectively remove trivalent iron ions in the solution.

[0017] 2) Compared with the traditional method of adding a reducing agent to reduce trivalent iron to divalent iron before extraction, the present invention uses phosphate ions to react with trivalent iron ions in the solution to generate iron phosphate precipitates, which can omit the filtration step and reduce vanadium loss. At the same time, it is pollution-free and environmentally friendly.

[0018] According to one aspect of the present invention, the present invention provides the following technical solution: A method for preparing a vanadyl sulfate solution using stone coal comprises the following steps: S1. Grind the stone coal ore to a certain particle size, add concentrated sulfuric acid to the ground stone coal ore powder and stir evenly, and then roast to obtain stone coal roasting material; S2. Add phosphate to the stone coal roasting material and mix evenly, add deionized water and adjust the pH value, then soak in water to obtain a vanadyl sulfate solution.

[0019] Preferably, in step S1, the particle size of the ground stone coal powder is ≤200 mesh.

[0020] Preferably, in step S1, the liquid-to-solid ratio of concentrated sulfuric acid to ground stone coal powder is (0.1-0.3) mL:1 g.

[0021] Preferably, in step S1, the calcination temperature is 200-260° C. and the calcination time is 1-4 hours.

[0022] Preferably, in step S1, the concentration of concentrated sulfuric acid is 95-98wt%.

[0023] Preferably, in step S2, the phosphate is at least one of sodium phosphate and potassium phosphate.

[0024] Preferably, in step S2, the mass ratio of phosphate to stone coal roasting material is (0.03~0.16):1.

[0025] Preferably, in step S2, the liquid-to-solid ratio during water immersion is (1-3) mL:1 g, and the pH value is 0.5-2.5.

[0026] Preferably, in step S2, the water immersion temperature is 70-100° C. and the time is 1-4 hours.

[0027] According to another aspect of the present invention, the present invention provides the following technical solution: A vanadium sulfate solution is prepared by the above method for preparing a vanadium sulfate solution by using stone coal. The iron content of the vanadium sulfate solution is ≤3g / L, and the iron extraction rate thereof after extraction with an extractant is ≤7%.

[0028] The technical solution of the present invention is further described below in conjunction with specific embodiments.

[0029] Example 1 A method for preparing a vanadyl sulfate solution using stone coal comprises the following steps: S1. Grind the stone coal ore to a particle size of ≤200 mesh, take 10g of the ground stone coal ore powder, add 2mL of 95wt% concentrated sulfuric acid and the ground stone coal ore powder and stir evenly, and roast at 260°C for 2h to obtain stone coal roasting material; S2. Add 1g of sodium phosphate to the roasted stone coal material and mix evenly. Then add 30mL of deionized water and adjust the pH value to 0.7 with ammonia water. Soak in water at 90°C for 2h to obtain a vanadium sulfate solution. The vanadium content is 1.29g / L and the iron content is 1.58g / L after testing.

[0030] Example 2 S1. Grind the stone coal ore to a particle size of ≤200 mesh, take 5g of the ground stone coal ore powder, add 1mL of 95wt% concentrated sulfuric acid and the ground stone coal ore powder and stir evenly, and roast at 220°C for 3h to obtain stone coal roasting material; S2. Add 0.16 g of sodium phosphate to the stone coal roasting material and mix evenly. Then add 15 mL of deionized water and adjust the pH value to 2.5 with ammonia water. Soak in water at 90°C for 2 h to obtain a vanadium sulfate solution. The vanadium content is 1.05 g / L and the iron content is 1.99 g / L after testing.

[0031] Example 3 S1. Grind the stone coal ore to a particle size of ≤200 mesh, take 5g of the ground stone coal ore powder, add 1mL of 95wt% concentrated sulfuric acid and the ground stone coal ore powder and stir evenly, and roast at 220°C for 3h to obtain stone coal roasting material; S2. Add 0.32g sodium phosphate to the stone coal roasting material and mix evenly. Then add 15mL deionized water and adjust the pH value to 2.5 with ammonia water. Soak in water at 90°C for 2h to obtain a vanadium sulfate solution. The vanadium content is 1.01g / L and the iron content is 1.76g / L after testing.

[0032] Example 4 S1. Grind the stone coal ore to a particle size of ≤200 mesh, take 5g of the ground stone coal ore powder, add 1mL of 95wt% concentrated sulfuric acid and the ground stone coal ore powder and stir evenly, and roast at 220°C for 3h to obtain stone coal roasting material; S2, stone coal roasting material added 0.24g sodium phosphate and mixed evenly, then added 15mL deionized water, ammonia water adjusted pH = 2.5, soaked in water at 90℃ for 2h, obtained vanadium sulfate solution, the vanadium content was 0.97g / L, and the iron content was 1.82g / L. The vanadium sulfate solution was treated with an extractant, the extractant was 10 vol% P204+10 vol% TBP (tributyl phosphate) + 80 vol% sulfonated kerosene, the extraction conditions were: oil-water ratio of 1:2, mixing speed of 400r / min, time of 8min, extraction level of one, and the vanadium extraction rate was 95.87% and the iron extraction rate was 5.87%.

[0033] Comparative Example 1 The difference from Example 1 is that sodium phosphate is not added in step S2.

[0034] The vanadyl sulfate solution prepared in this comparative example was tested to have a vanadium content of 1.35 g / L and an iron content of 3.51 g / L.

[0035] Comparative Example 2 The difference from Example 4 is that sodium phosphate is not added in step S2.

[0036] After the comparative example was extracted and impurities were removed by an extractant, the vanadium extraction rate was 69.16% and the iron extraction rate was 18.94%.

[0037] The present invention grinds stone coal ore to a certain particle size, adds concentrated sulfuric acid to the ground stone coal ore powder and stirs evenly, then roasts to obtain stone coal roasting material; adds phosphate to the stone coal roasting material and mixes evenly, adds deionized water and adjusts the pH value, then water-leaches to obtain a vanadium sulfate solution. The method of the present invention has the advantages of being simple and easy to implement, short production cycle and low cost. In particular, phosphate ions can react with trivalent iron ions in the solution to generate iron phosphate precipitates, and iron phosphate has the characteristics of low solubility, fast precipitation rate, good crystallization performance and little adsorption of cations. Therefore, by adding phosphate for water leaching, the trivalent iron ions in the solution can be effectively removed, and the adverse effects of the trivalent iron ions on the extraction in the subsequent extraction and stripping processes can be significantly eliminated, and the obtained vanadium sulfate solution can be directly subjected to extraction operations.

[0038] The above description is only a preferred embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification under the inventive concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A method for preparing a vanadyl sulfate solution using stone coal, characterized in that: The steps include: S1. Grind the stone coal ore to a certain particle size, add concentrated sulfuric acid to the ground stone coal ore powder and stir evenly, and then roast to obtain stone coal roasting material; S2. Add phosphate to the stone coal roasting material and mix evenly, add deionized water and adjust the pH value, then soak in water to obtain a vanadyl sulfate solution.

2. The method for preparing vanadyl sulfate solution using stone coal according to claim 1, characterized in that: In the step S1, the particle size of the ground stone coal powder is ≤200 mesh.

3. The method for preparing vanadyl sulfate solution using stone coal according to claim 1, characterized in that: In the step S1, the liquid-to-solid ratio of concentrated sulfuric acid to the ground stone coal powder is (0.1-0.3) mL:1 g.

4. The method for preparing vanadyl sulfate solution using stone coal according to claim 1, characterized in that: In the step S1, the calcination temperature is 200-260° C. and the calcination time is 1-4 hours.

5. The method for preparing vanadyl sulfate solution using stone coal according to claim 1, characterized in that: In step S1, the concentration of concentrated sulfuric acid is 95-98 wt %.

6. The method for preparing vanadyl sulfate solution using stone coal according to claim 1, characterized in that: In step S2, the phosphate is at least one of sodium phosphate and potassium phosphate.

7. The method for preparing vanadyl sulfate solution using stone coal according to claim 1, characterized in that: In step S2, the mass ratio of phosphate to stone coal roasting material is (0.03-0.16):

1.

8. The method for preparing vanadyl sulfate solution using stone coal according to claim 1, characterized in that: In the step S2, the liquid-to-solid ratio during water immersion is (1-3) mL:1 g, and the pH value is 0.5-2.

5.

9. The method for preparing vanadyl sulfate solution using stone coal according to claim 1, characterized in that: In step S2, the water immersion temperature is 70-100° C. and the time is 1-4 hours.

10. A vanadyl sulfate solution, characterized in that: The vanadium sulfate solution is prepared by the method for preparing vanadium sulfate solution using stone coal as described in any one of claims 1 to 9, wherein the iron content of the vanadium sulfate solution is ≤2g / L, and the iron extraction rate thereof after extraction with an extractant is ≤7%.