CN111020233A - Method for preparing vanadium pentoxide by ammonium-free vanadium precipitation - Google Patents
Method for preparing vanadium pentoxide by ammonium-free vanadium precipitation Download PDFInfo
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- CN111020233A CN111020233A CN202010039116.1A CN202010039116A CN111020233A CN 111020233 A CN111020233 A CN 111020233A CN 202010039116 A CN202010039116 A CN 202010039116A CN 111020233 A CN111020233 A CN 111020233A
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B34/00—Obtaining refractory metals
- C22B34/20—Obtaining niobium, tantalum or vanadium
- C22B34/22—Obtaining vanadium
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B3/00—Extraction of metal compounds from ores or concentrates by wet processes
- C22B3/20—Treatment or purification of solutions, e.g. obtained by leaching
- C22B3/44—Treatment or purification of solutions, e.g. obtained by leaching by chemical processes
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Abstract
The invention discloses a method for preparing vanadium pentoxide by ammonium-free vanadium precipitation, which comprises the following steps: reducing the vanadium-containing pickle liquor by using a reducing agent, and adjusting the pH of the solution by using ammonia water; extracting by adopting a cation extracting agent to obtain an organic phase loaded with vanadium oxide cations and raffinate; hydrogen peroxide and sulfuric acid are used as stripping agents for stripping to obtain vanadium stripping liquid; after the stripping solution is placed for a period of time, peroxypolyvanadate is unstable, polyvanadate generated by decomposition is gradually separated out from a water phase, and then a vanadium pentoxide product is obtained by calcining. The method for preparing vanadium pentoxide by ammonium-free vanadium precipitation greatly simplifies the vanadium smelting process, thoroughly solves the problems of large consumption of sulfuric acid and ammonia water and large output of ammonia nitrogen wastewater in the back extraction process, has the technical characteristics of short process, environmental friendliness and high efficiency, and is easy for industrial popularization.
Description
Technical Field
The invention relates to the technical field of nonferrous metallurgy, in particular to a method for preparing vanadium pentoxide by ammonium-free vanadium precipitation.
Background
Vanadium is an important strategic metal, and is widely used as a grain refiner and a deoxidizer in the field of producing high-quality alloys, such as production of various iron alloys and titanium alloys, due to the properties of grain refinement and oxygen affinity; in recent years, vanadium oxide is added to a novel material, and electromagnetic properties thereof can be expected, so that production of vanadium compounds is attracting attention.
In China, stone coal is an important vanadium storage resource, and accounts for 87% of the total vanadium storage. In recent years, the direct acid leaching method has the advantages of high leaching rate, no air pollution and the like and gradually becomes the leading method for extracting vanadium from stone coal, but the stone coal as a complex mineral resource contains about 60 metals and nonmetal elements, and the non-selective direct acid leaching can leach a large amount of impurities such as iron, aluminum, molybdenum, sodium, potassium, silicon and the like together with the vanadium.
The solvent extraction method can selectively extract vanadium from complex leachate, and the P204+ TBP synergistic extraction system can effectively extract vanadyl oxide, but the current P204+ TBP extraction process has the following problems: (1) the back extraction vanadium extraction process is long, and comprises the following steps: 1.5mol/L sulfuric acid 5-stage countercurrent back extraction → V (IV) to V (V) in oxidation back extraction liquid → ammonia water is added to adjust the pH value of the solution to about 2.0 → ammonium polyvanadate (red vanadium) is obtained by hydrolyzing vanadium precipitation → V2O5 product is obtained by calcining the red vanadium; (2) the consumption of sulfuric acid and ammonia water is large, and about 1.01mol/L of free sulfuric acid remained in the stripping solution needs to be neutralized until the pH value of the solution is 2; (3) a large amount of ammonia nitrogen wastewater is generated.
In general, the existing vanadium metallurgy process has the problems of large consumption of sulfuric acid and ammonia water, complex process flow and the like which are urgently needed to be solved. In the face of these problems, a new clean and efficient vanadium metallurgy process needs to be developed through theoretical innovation.
Disclosure of Invention
The invention aims to provide a method for preparing vanadium pentoxide by ammonium-free vanadium precipitation, which aims to solve the problem of high consumption of sulfuric acid and ammonia water in the existing vanadium metallurgy process.
In order to achieve the aim, the invention provides a short-process vanadium extraction method, which comprises the following steps:
1) reducing the vanadium-containing pickle liquor by using a reducing agent, and adjusting the pH of the solution by using ammonia water;
2) extracting vanadium in the leachate obtained in the step 1) by adopting a cationic extractant to obtain an organic phase loaded with vanadium oxygen cations and a raffinate, wherein the cationic extractant is one or more of P204 and Cyanex 272;
3) taking a mixed solution of hydrogen peroxide and sulfuric acid as a stripping agent, and mixing the stripping agent with an organic phase loaded with vanadium oxide cations to obtain vanadium stripping solution;
4) standing the back extraction solution for a period of time, wherein under a strong acid condition, peroxypolyvanadate is unstable and decomposed to generate polyvanadate which is gradually separated out from a water phase;
5) calcining the red-black solid precipitated in the step 4) to obtain V2O5And (5) producing the product.
Preferably, in the step 3), the mass concentration of the hydrogen peroxide is 3-6%, and the concentration of the sulfuric acid is 1-1.5 mol/L.
Preferably, in the step 3), hydrogen peroxide is adopted for two-stage cross-flow back extraction of the same organic phase, and then sulfuric acid is adopted for one-stage cross-flow back extraction, wherein the ratio is 5: 1-10: 1.
Preferably, in step 4), the three back extracts are mixed together and kept still at room temperature for 1 day or more, so that the peroxypolyvanadate in the back extracts is decomposed to generate polyvanadate, and the polyvanadate is precipitated from the water phase.
Preferably, in the step 5), the red-black solid obtained in the step 4) is calcined in a muffle furnace for 4-6 hours at 545-555 ℃.
Wherein, the step 1) and the step 2) are the preparation process of the raw material liquid and the preparation process of the loaded organic phase, which are not the key points of the invention but the precondition of the implementation of the invention, and the key parameters are listed as follows:
in the step 1), the potential of the solution is reduced to-150 mV to-160 mV, and the reducing agent is sodium sulfite or scrap iron.
In the step 1), the pH value of the ammonia water adjusting solution is 2.5-3.0, and the mass fraction of the ammonia water is 25-28%.
And (3) supplementing inorganic acid consumed in the leaching process with the raffinate obtained in the step 2), circulating the raffinate to the step 1) for use, and circularly enriching and recovering vanadium for multiple times.
In the step 2), compared with the O/A ratio of 3: 1-1: 1, multi-stage countercurrent extraction is adopted, the number of extraction stages is 3-5, dilute sulfuric acid is used for washing a loaded organic phase, the concentration of the sulfuric acid is 0.15-0.20 mol/L, and washing liquid is used for supplementing inorganic acid consumed in the leaching process.
The technical conception and the principle of the invention are as follows:
vanadium is used as a variable valence metal, and shows different states at different pH values, different potentials and different concentrations. According to the invention, by utilizing the properties of vanadium and reasonably controlling the potential, vanadium (IV) in a loaded organic phase is oxidized to vanadium (V), and the concentration of vanadium ions is controlled by a back extraction phase; the sulfuric acid stripping further improves the stripping rate and simultaneously provides enough acidity for mixing with the stripping solution of the first two times, and high-concentration vanadium (V) is converted into H2V10O28 5-The existence of anion forms creates conditions. Generation of H2V10O28 5-The peroxopolyvanadate complex formed by anions and hydrogen peroxide is unstable under strong acid condition, is easy to decompose and gradually separates out red-black solid particles, and is directly calcined to obtain V2O5And (5) producing the product.
The invention is superior to the traditional nest mortar for vanadium metallurgy ammonium salt vanadium precipitation, provides a new short-flow metallurgy process route of one-step oxidation stripping and direct vanadium precipitation, greatly simplifies the process flow of vanadium metallurgy, effectively solves the problems of high consumption of sulfuric acid and ammonia water and output of ammonia nitrogen wastewater in the stripping process, has the technical characteristics of short flow, cleanness and high efficiency, and is easy for industrial popularization.
Detailed Description
The technical solution of the present invention is further illustrated by the following specific examples. It will be appreciated by those skilled in the art that the examples are only for illustrating the present invention and are not intended to limit the scope of the present invention.
In the examples, the technical means used are conventional in the art and are not specifically described.
In the embodiment, raw material liquid is prepared, sodium sulfite is added into a vanadium-containing raw material to reduce the potential to-150 mV to-160 mV, 25 to 28 percent of ammonia water is added to adjust the pH value of the solution to 2.5 to 3.0, and the vanadium-containing raw material liquid is one or more of stone coal acid leaching solution, vanadium-containing waste catalyst acid leaching solution and vanadium-titanium magnetite slag leaching solution.
EXAMPLES preparation of loaded organic phase, the prepared raw material liquid was extracted by 6-stage countercurrent extraction using 10% P204+ 5% TBP + 85% sulfonated kerosene as extractant under the condition that the extraction ratio O: A is 1.2:1 to obtain loaded organic phase (containing V2O5Counting: 6.44g/L) and a raffinate, wherein the loaded organic phase is stripped and the raffinate is supplemented with sulfuric acid consumed in the leaching process.
Example 1
(1) The prepared loaded organic phase is used as a raw material, and hydrogen peroxide with the mass concentration of 3% and sulfuric acid with the mass concentration of 1.5mol/L are used as stripping agents for stripping.
(2) The resulting loaded organic phase was stripped under conditions where the O/a ratio was 5: 1: performing cross-flow back extraction by two stages of hydrogen peroxide, and performing single-stage back extraction by using sulfuric acid; the back extraction time is 3min, and the phase separation is carried out within 30 s; after 3 times of cross-flow back extraction, the total back extraction rate is above 97.77%.
(3) And mixing the back extraction solution obtained in the third extraction for 24 hours, and separating out poly-vanadic acid generated along with the decomposition of the peroxovanadium complex from the solution, wherein the crystallization rate is more than 85%. Calcining the red black solid in a muffle furnace for 4 hours at 555 ℃ to obtain red V2O5And (5) producing the product.
Example 2
(1) The prepared loaded organic phase is used as a raw material, and hydrogen peroxide with the mass concentration of 4% and sulfuric acid with the mass concentration of 1.3mol/L are used as stripping agents for stripping.
(2) The resulting loaded organic phase was stripped under conditions where the O/a ratio was 8: 1: performing three-stage cross-flow back extraction by using hydrogen peroxide, and performing single-stage back extraction by using sulfuric acid; the back extraction time is 3min, and the phase separation is carried out within 30 s; after 4 times of cross-flow back extraction, the total back extraction rate is more than 85.43 percent.
(3) Mixing the back extraction solution obtained in the third extraction for 30 hours, and separating out poly-vanadic acid generated along with the decomposition of the peroxovanadium complex from the solution, wherein the crystallization rate is more than 92%. Calcining the red-black solid in a muffle furnace for 5 hours at the calcining temperatureThe temperature was 550 ℃ to give a red color V2O5And (5) producing the product.
Example 3
(1) And (3) carrying out back extraction by using the prepared loaded organic phase as a raw material and using hydrogen peroxide with the mass concentration of 6% and 1mol/L sulfuric acid as a back extractant.
(2) The resulting loaded organic phase was stripped under conditions where the O/a ratio was 10: 1: performing three-stage cross-flow back extraction by using hydrogen peroxide, and performing single-stage back extraction by using sulfuric acid; the back extraction time is 2.5min, and the phase separation is carried out within 30 s; after 4 times of cross-flow back extraction, the total back extraction rate is more than 92.25 percent.
(3) Mixing the back extraction solution obtained in the third extraction for 28h, and separating out poly-vanadic acid generated along with the decomposition of the peroxovanadium complex from the solution, wherein the crystallization rate is more than 94.3%. Calcining the red black solid in a muffle furnace for 6h at 545 ℃ to obtain red V2O5And (5) producing the product.
Claims (9)
1. A method for preparing vanadium pentoxide by ammonium-free vanadium precipitation is characterized by comprising the following steps:
1) reducing the vanadium-containing pickle liquor by using a reducing agent, and adjusting the pH of the solution by using ammonia water;
2) extracting vanadium in the leachate obtained in the step 1) by adopting a cationic extractant to obtain an organic phase loaded with vanadium oxygen cations and a raffinate, wherein the cationic extractant is one or more of P204 and Cyanex 272;
3) taking a mixed solution of hydrogen peroxide and sulfuric acid as a stripping agent, and mixing the stripping agent with an organic phase loaded with vanadium oxide cations to obtain vanadium stripping solution;
4) standing the back extraction solution for a period of time, wherein under a strong acid condition, peroxypolyvanadate is unstable and decomposed to generate polyvanadate which is gradually separated out from a water phase;
5) calcining the red-black solid precipitated in the step 4) to obtain V2O5And (5) producing the product.
2. The method for preparing vanadium pentoxide by ammonium-free vanadium precipitation according to claim 1, wherein in the step 3), the mass concentration of hydrogen peroxide is 3% -6%, and the concentration of sulfuric acid is 1-1.5 mol/L.
3. The method for preparing vanadium pentoxide by ammonium-free vanadium precipitation according to claim 1, wherein in the step 3), hydrogen peroxide is adopted for two-stage cross-flow back extraction of the same organic phase, and then sulfuric acid is adopted for one-stage cross-flow back extraction, wherein the ratio is 5: 1-10: 1.
4. The method for preparing vanadium pentoxide by ammonium-free vanadium precipitation according to claim 3, wherein in the step 4), the three back-extraction solutions are mixed together and allowed to stand at room temperature for 1 day or more, so that the peroxypolyvanadate is decomposed to generate polyvanadate, and the polyvanadate is separated out from the aqueous phase.
5. The method for preparing vanadium pentoxide by ammonium-free vanadium precipitation according to claim 1, wherein in the step 5), the red-black solid obtained in the step 4) is calcined in a muffle furnace for 4-6 h at 545-555 ℃.
6. A short-run vanadium extraction process according to any one of claims 1 to 5, characterized in that in step 1), the potential of the solution is reduced to-150 mV to-160 mV, the reducing agent being sodium sulfite or iron filings.
7. The short-process vanadium extraction method according to any one of claims 1 to 5, wherein in the step 1), the pH of the solution is adjusted to 2.5-3.0 by ammonia water, and the mass fraction of the ammonia water is 25-28%.
8. The short-process vanadium extraction method according to any one of claims 1 to 5, wherein the raffinate obtained in step 2) is recycled to step 1) after supplementing the inorganic acid consumed in the leaching process, and the vanadium is enriched and recovered through multiple cycles.
9. The short-flow vanadium extraction method according to any one of claims 1 to 5, characterized in that in the step 2), multi-stage countercurrent extraction is adopted compared with O/A (ratio of oxygen to acetic acid) of 3: 1-1: 1, the extraction stage number is 3-5, the loaded organic phase is washed by dilute sulfuric acid, the concentration of the sulfuric acid is 0.15-0.20 mol/L, and the washing liquid supplements the inorganic acid consumed in the leaching process.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN114672668A (en) * | 2022-04-06 | 2022-06-28 | 中南大学 | Method for preparing vanadium pentoxide by reducing precipitated vanadium, vanadium pentoxide and application |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN114672668A (en) * | 2022-04-06 | 2022-06-28 | 中南大学 | Method for preparing vanadium pentoxide by reducing precipitated vanadium, vanadium pentoxide and application |
| CN114672668B (en) * | 2022-04-06 | 2023-09-08 | 中南大学 | Method for preparing vanadium pentoxide by reducing precipitated vanadium and vanadium pentoxide and application |
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