Method for recovering metal ions from vanadium-containing leachate and preparing high-purity vanadium pentoxide

Abstract

The invention relates to a method for recovering metal ions from vanadium-containing leachate and preparing high-purity vanadium pentoxide, and belongs to the technical field of chemical metallurgy. The technical problem to be solved by the invention is to provide the method for recovering the metal ions from the vanadium-containing leachate and preparing the high-purity vanadium pentoxide, which is simple in process. The method comprises an extraction process, a washing process, a reverse extraction process, an associated resource recovery process, a vanadium precipitation-calcination process and a regeneration process, while vanadium is recovered to prepare high-purity vanadium pentoxide, associated resources such as manganese, magnesium, iron and the like in the vanadium-containing leachate are recovered, and the maximum benefit of the resources is realized. The extraction agent, the washing agent, the stripping agent and the like can be recycled, no waste water is generated, the influence on the environment is avoided, and the green development concept is met. The process is simple, the production efficiency can be effectively improved, the cost and the energy consumption are reduced, the yield and the purity of vanadium are improved, the purity of the obtained vanadium pentoxide product reaches 99.8%, and the vanadium pentoxide product has better market competitiveness.

Description

Technical Field

[0001] The invention relates to a method for recovering metal ions from a vanadium-containing leaching solution and preparing high-purity vanadium pentoxide, belonging to the technical field of chemical metallurgy. Background Art

[0002] Vanadium is a strategically important metal resource, widely used in steel alloys, aerospace, chemical catalysts, and the emerging field of vanadium flow batteries. In recent years, with the rapid development of the energy storage and new energy industries, market demand for high-purity vanadium products, particularly high-purity vanadium pentoxide (V2O5, purity >99.5%), has grown significantly, becoming a key area of ​​vanadium resource utilization.

[0003] Currently, vanadium resources primarily come from vanadium-titanium magnetite, vanadium-containing petroleum coke, spent catalysts, by-product vanadium-containing industrial wastewater, and vanadium-containing solid waste. Vanadium-titanium magnetite, the primary source of vanadium, is typically recovered through a multi-step process, including blast furnace smelting, vanadium slag extraction, acid leaching, extraction, and roasting. Petroleum coke and heavy oil residue produced during petroleum refining are also rich in vanadium and can be recovered through incineration, acid leaching, and roasting, but these processes are generally complex and polluting. Vanadium-containing catalysts used in sulfuric acid and petrochemicals, after deactivation, are rich in vanadium pentoxide and can be recovered and reused through acid leaching. Furthermore, metallurgical waste slag and industrial by-product liquids also contain a certain amount of vanadium. Although low in content and high in impurities, recovery is difficult, their large volume presents significant potential. With the development of vanadium flow batteries, the utilization of vanadium resources after electrolyte upgrades also deserves special attention.

[0004] Although vanadium resources are plentiful, they also face numerous challenges. Current vanadium recovery processes are generally plagued by lengthy processes, high energy consumption, significant environmental pollution, and severe co-extraction of impurities. This is particularly true during the preparation of high-purity V2O5. Impurities such as manganese, magnesium, iron, and chromium in the vanadium solution are often difficult to remove, significantly impacting product purity and added value. For example, the acid leaching solution of vanadium-titanium magnetite contains high levels of valuable impurities such as manganese and magnesium. Conventional impurity removal processes are complex, multi-step, and costly, making them a major constraint on the industrialization of high-purity vanadium products.

[0005] Therefore, there is an urgent need to develop a new process for vanadium recovery and purification that is simple, environmentally friendly, and low-cost, especially for the efficient separation of vanadium and impurities in vanadium-containing leachate, and the preparation of high-purity vanadium pentoxide.

[0006] Patent CN119461481A discloses a method for preparing high-purity vanadium pentoxide from an acidic calcified vanadium solution. This method involves adding ammonia to the acidic calcified vanadium solution to adjust the pH to 6-8. After the reaction, the solution is allowed to settle to obtain a vanadium-containing precipitate. The vanadium-containing precipitate is washed once and then re-dissolved to remove impurities. This solution is then treated with calcium salts for impurity removal and decalcification to obtain a purified vanadium solution. Finally, the solution is cooled and precipitated to obtain sodium metavanadate, which is then calcined to produce a high-purity vanadium pentoxide product. While the vanadium pentoxide obtained by this method meets the required purity, the cost is high, the continuous re-dissolution and impurity removal produces a large amount of wastewater, and other associated resources are not effectively utilized, resulting in a waste of resources.

[0007] Patent CN119287177A discloses a method for preparing high-purity vanadium oxide from vanadium slag, comprising: calcining and calcining the vanadium slag, followed by acid leaching to obtain an acidic vanadium-containing solution; adding an excess of an impurity removal agent to the acidic vanadium-containing solution to remove impurity ions; adding a reducing agent to the acidic vanadium-containing solution to reduce pentavalent vanadium to tetravalent vanadium; extracting the acidic vanadium-containing solution with an extraction solvent to obtain a vanadium-negative organic phase; washing the vanadium-negative organic phase; stripping the washed vanadium-negative organic phase with a stripping agent to obtain a stripping raffinate and a blank organic phase, which is recycled as the extraction solvent; precipitating the stripping raffinate, drying it, and calcining it to obtain vanadium pentoxide. Although this method can recover most of the vanadium as vanadium pentoxide, the product purity is low, and the impurity removal process not only increases production costs but also inevitably causes vanadium loss. Furthermore, a reduction step is required, which introduces new impurity ions, affecting product purity.

[0008] Patent CN119082507A discloses a method for efficiently separating metal elements from manganese-containing salt solutions. The method involves extracting high-manganese and vanadium-containing wastewater, then stripping the manganese, and then stripping the vanadium. The core of the method is to separate the manganese through a multi-step stripping and extraction process, ultimately recovering some vanadium. However, this method suffers from complex procedures, multiple washing steps, a limited number of recovered metals, and high vanadium losses during the washing process.

[0009] In summary, the existing technology for recovering vanadium from vanadium-containing leachate and preparing high-purity vanadium pentoxide has problems such as high production cost, complex process, large fluctuation of impurities, low product purity and low vanadium yield. Summary of the Invention

[0010] In view of the above drawbacks, the technical problem solved by the present invention is to provide a method for recovering metal ions from a vanadium-containing leachate with a simple process and preparing high-purity vanadium pentoxide.

[0011] The method for recovering metal ions from a vanadium-containing leachate and preparing high-purity vanadium pentoxide comprises the following steps:

[0012] A. Extraction process: mixing the vanadium-containing leachate with an extractant to carry out an extraction reaction, and then separating the phases to obtain an organic phase 1 and an aqueous phase 1;

[0013] B. Washing process: the organic phase 1 is mixed and stirred with a detergent, and then separated into an organic phase 2 and an aqueous phase 2; wherein the detergent is a mixed solution of sulfuric acid, ammonium sulfate and pentavalent vanadium ions;

[0014] C. Stripping process: the organic phase 2 is mixed with the stripping agent and stirred, and then phase-separated to obtain the aqueous phase 3 and the organic phase 3;

[0015] D. Recovery of associated resources: cooling and crystallization of aqueous phase 2, followed by solid-liquid separation to obtain a double salt product;

[0016] E. Vanadium precipitation-calcination step: Ammonia water is introduced into the aqueous phase 3, and after precipitation, solid-liquid separation is performed to obtain ammonium metavanadate, which is then calcined at 560°C for 2 hours to obtain high-purity vanadium pentoxide;

[0017] F. Regeneration process: The organic phase 3 is mixed and stirred with the sulfuric acid solution, and then separated to obtain a clean organic phase, which is returned to process A for recycling as an extractant.

[0018] In some embodiments of the present invention, the extractant in step A includes at least one of an organophosphorus extractant, an organophosphine extractant, an organic sulfonic acid extractant, an organic carboxylic acid extractant, and a tertiary carbonic acid extractant; preferably, the extractant includes at least one of di(2-ethylhexyl) phosphate, 2-ethylhexyl phosphate 2-ethylhexyl ester, di(2,4,4-trimethylpentyl) hypophosphorous acid, 2-ethylhexyl phosphonic acid mono(2-ethylhexyl) ester, N,NN-n-octylamino dimethylenephenylphosphonic acid, N,NN-n-hexylamino dimethylenephenylphosphonic acid, toluenesulfonic acid, p-toluenesulfonic acid, benzenesulfonic acid, xylenesulfonic acid, dodecylbenzenesulfonic acid, dinonylnaphthalenesulfonic acid, cinnamic acid, fatty acid, lauric acid, and cycloalkanecarboxylic acid.

[0019] In a specific embodiment, the vanadium-containing leachate is prepared by the following method: mixing a vanadium-containing raw material with an acid for leaching, filtering, and obtaining a vanadium-containing leachate; the vanadium-containing raw material is at least one of stone coal, vanadium slag, vanadium-containing waste slag generated by chemical production, and deactivated vanadium-containing catalyst.

[0020] In some specific embodiments, in step A, the volume ratio of the vanadium-containing leachate to the extractant is 1:4 to 4:1, the extraction time is 1 to 90 minutes, and the extraction temperature is 30 to 90° C. In a preferred embodiment, the volume ratio of the vanadium-containing leachate to the organic phase is 1:3 to 1:1.

[0021] In some embodiments of the present invention, in the detergent of step B, the concentration of sulfuric acid is 8-50 wt.%, the concentration of ammonium sulfate is 10-40 wt.%, and the concentration of vanadium ions is 0.1-1.0 wt.%.

[0022] In some preferred embodiments, in the detergent of step B, the concentration of sulfuric acid is 20-30 wt.%, the concentration of ammonium sulfate is 15-25 wt.%, and the concentration of vanadium ions is 0.1-1.0 wt.%.

[0023] In some preferred embodiments, in step B, the volume ratio of the organic phase 1 to the detergent is 1:8 to 8:1, the washing time is 1 to 90 minutes, and the washing temperature is 20 to 90°C.

[0024] In one embodiment of the present invention, in step C, the stripping agent is an ammonium oxalate solution. Preferably, the concentration of the ammonium oxalate solution is 5 to 13 wt.%, more preferably 8 to 10 wt.%.

[0025] In one embodiment of the present invention, in step C, the volume ratio of the stripping agent to the organic phase 2 is 1:3 to 3:1, the stripping time is 1 to 90 minutes, and the stripping temperature is 20 to 90°C; preferably, the volume ratio of the stripping agent to the organic phase 2 is 1:2 to 1:1; in step D, the cooling crystallization temperature is -10 to 30°C, and the crystallization time is 1 to 3 hours; in step E, ammonia water is added to adjust the pH to 7.6 to 8.0, and the precipitation reaction time is 1 to 4 hours; in step F, the volume ratio of the sulfuric acid solution to the organic phase 3 is 1:4 to 4:1, countercurrent regeneration is adopted, the countercurrent stage is 1 to 3, and the reaction time is 1 to 90 minutes.

[0026] In one embodiment of the present invention, in step F, the concentration of the sulfuric acid solution is 6 to 50 wt.%, preferably 8 to 10 wt.%.

[0027] In one embodiment of the present invention, the aqueous phase 1 obtained in step A is returned to the acid leaching step for recycling as acid; the crystallization supernatant after crystallization in step D is returned to step B for recycling as detergent; and the vanadium precipitation supernatant after vanadium precipitation in step E is returned to step C for recycling as stripping agent after adjusting the pH.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] 1. The present invention recovers associated resources such as manganese, magnesium, and iron in the vanadium-containing leaching solution while recovering vanadium to prepare high-purity vanadium pentoxide, thereby achieving maximum utilization of resources.

[0030] 2. The extractant, detergent and stripping agent used in the present invention can be recycled, no wastewater is generated, and the impact on the environment is avoided. It is in line with the concept of green development, and there is no loss of various metal elements in theory.

[0031] 3. The process of the present invention is simple, can effectively improve production efficiency, and reduce costs and energy consumption.

[0032] 4. Compared with the currently commonly used dilute sulfuric acid solution, the stripping agent used in the present invention is more selective for vanadium, can further reduce the impurity content in the vanadium precipitation mother liquor, improve the purity of vanadium pentoxide, and can effectively separate vanadium from other metal ions, realizing multi-metal co-recovery.

[0033] 5. The present invention adds a washing process in the extraction-stripping process, effectively separating vanadium and impurity ions. At the same time, a quantitative amount of vanadium ions is added to the washing liquid to suppress the washing loss of vanadium, thereby ensuring the yield of vanadium.

[0034] 6. The purity of the vanadium pentoxide product obtained by the present invention reaches 99.8%, which is more competitive in the market. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is a process flow chart for recovering metal ions from a vanadium-containing leachate and preparing high-purity vanadium pentoxide in Example 1 of the present invention. DETAILED DESCRIPTION

[0036] The method for recovering metal ions from a vanadium-containing leachate and preparing high-purity vanadium pentoxide comprises the following steps:

[0037] A. Extraction process: The vanadium-containing leachate is mixed with an extractant to undergo extraction reaction, and then phase separation is performed to obtain an organic phase 1 and an aqueous phase 1; the organic phase 1 at this time is the organic phase loaded with metal ions; the aqueous phase 1 is the raffinate;

[0038] B. Washing process: The organic phase 1 is mixed and stirred with a detergent, and then separated into an organic phase 2 and an aqueous phase 2; wherein the detergent is a mixed solution of sulfuric acid, ammonium sulfate and pentavalent vanadium ions; the organic phase 2 is an organic phase loaded with vanadium ions, and the aqueous phase 2 is a washing solution containing impure metal ions;

[0039] C. Stripping process: the organic phase 2 is mixed and stirred with a stripping agent, and then separated into an aqueous phase 3 and an organic phase 3. The organic phase 3 is the organic phase after vanadium removal, i.e., the lean organic phase; the aqueous phase 3 is the vanadium-containing stripping solution;

[0040] D. Recovery of associated resources: cooling and crystallization of aqueous phase 2, followed by solid-liquid separation to obtain a double salt product;

[0041] E. Vanadium precipitation-calcination step: Ammonia water is introduced into the aqueous phase 3, and after precipitation, solid-liquid separation is performed to obtain ammonium metavanadate, which is then calcined at 560°C for 2 hours to obtain high-purity vanadium pentoxide;

[0042] F. Regeneration process: The organic phase 3 is mixed and stirred with the sulfuric acid solution, and then separated to obtain a clean organic phase, which is returned to process A for recycling as an extractant.

[0043] The method of the present invention recovers manganese, magnesium, iron and other associated resources in the vanadium-containing leachate while recovering vanadium to prepare high-purity vanadium pentoxide, thus achieving maximum resource utilization. By adopting a specific washing process, vanadium and impurity ions (such as Fe 2 O 2 ) can be effectively separated in one washing process. 3+ 、Al3+、Mg 2+ This eliminates the need for complex, multiple washing steps, simplifies the process, and reduces energy consumption and costs. Furthermore, adding a fixed amount of vanadium ions to the washing solution reduces vanadium losses during washing, ensuring vanadium yield and improving product purity and yield. Impurity ions in the washing solution can be directly recovered as valuable products through crystallization, enabling multi-metal co-recovery and increasing economic value.

[0044] The present invention is further described in detail below in steps.

[0045] Process A is an extraction process, in which the vanadium-containing leachate is mixed with an extractant to undergo an extraction reaction, and then phase separation is performed to obtain an organic phase 1 and an aqueous phase 1; at this time, the organic phase 1 is the organic phase loaded with metal ions; and the aqueous phase 1 is the raffinate.

[0046] The extractants commonly used in the art are applicable to the present invention. In some specific embodiments, the extractant in step A includes at least one of an organophosphorus extractant, an organophosphine extractant, an organic sulfonic acid extractant, an organic carboxylic acid extractant, and a tertiary carbonic acid extractant. In some more specific embodiments, the extractant includes at least one of di(2-ethylhexyl) phosphate, 2-ethylhexyl phosphate 2-ethylhexyl ester, di(2,4,4-trimethylpentyl) hypophosphorous acid, 2-ethylhexyl phosphonic acid mono(2-ethylhexyl) ester, N,NN-n-octylamino dimethylenephenylphosphonic acid, N,NN-n-hexylamino dimethylenephenylphosphonic acid, toluenesulfonic acid, p-toluenesulfonic acid, benzenesulfonic acid, xylenesulfonic acid, dodecylbenzenesulfonic acid, dinonylnaphthalenesulfonic acid, cinnamic acid, fatty acid, lauric acid, and cyclohexanecarboxylic acid.

[0047] The raw material used in the present invention is a vanadium-containing leachate, which can be any of the common vanadium-containing leachates in the art. In one specific embodiment, the vanadium-containing leachate is prepared by mixing a vanadium-containing raw material with an acid for leaching, and filtering to obtain the vanadium-containing leachate; the vanadium-containing raw material is at least one of stone coal, vanadium slag, vanadium-containing waste slag from chemical production, and a deactivated vanadium-containing catalyst.

[0048] In some specific embodiments, in step A, the volume ratio of the vanadium-containing leachate to the extractant is 1:4 to 4:1, the extraction time is 1 to 90 minutes, and the extraction temperature is 30 to 90° C. In a preferred embodiment, the volume ratio of the vanadium-containing leachate to the organic phase is 1:3 to 1:1.

[0049] In some specific embodiments, the aqueous phase 1 obtained in step A is returned to the acid leaching step for recycling as acid, thereby saving costs.

[0050] Step B is the key step of the present invention, wherein a specific detergent is used to wash the organic phase 1, and then phase separation is performed to obtain an organic phase 2 and an aqueous phase 2, wherein the organic phase 2 is an organic phase loaded with vanadium ions, and the aqueous phase 2 is a washing liquid containing impure metal ions.

[0051] The detergent is crucial for step B. The detergent used in the present invention is a mixed solution of sulfuric acid, ammonium sulfate, and pentavalent vanadium ions. In some embodiments of the present invention, the detergent in step B has a sulfuric acid concentration of 8-50 wt.%, an ammonium sulfate concentration of 10-40 wt.%, and a vanadium ion concentration of 0.1-1.0 wt.%.

[0052] The present invention introduces high concentration sulfuric acid into the detergent, which can effectively remove impurity ions (such as Fe 3+ 、Al3+、Mg 2+ This avoids the complex process of multiple washes, significantly simplifies the process, and reduces energy consumption and costs. Adding an appropriate concentration of vanadium ions to the detergent inhibits vanadium loss, ensuring the subsequent preparation of high-purity vanadium pentoxide and improving product purity and yield.

[0053] In some preferred embodiments, in the detergent of step B, the concentration of sulfuric acid is 20-30 wt.%, the concentration of ammonium sulfate is 15-25 wt.%, and the concentration of vanadium ions is 0.1-1.0 wt.%.

[0054] The washing method can be conventional methods in the art. In some preferred embodiments, in step B, the volume ratio of the organic phase 1 to the detergent is 1:8 to 8:1, the washing time is 1 to 90 minutes, and the washing temperature is 20 to 90°C.

[0055] Step C is stripping, mixing and stirring the washed organic phase 2 with the stripping agent, and then separating the phases to obtain aqueous phase 3 and organic phase 3. The organic phase 3 is the organic phase after vanadium removal, that is, the lean organic phase; the aqueous phase 3 is the vanadium-containing stripping liquid.

[0056] In one embodiment of the present invention, in step C, the stripping agent is an ammonium oxalate solution. Preferably, the concentration of the ammonium oxalate solution is 5 to 13 wt.%, more preferably 8 to 10 wt.%.

[0057] In one embodiment of the present invention, in step C, the volume ratio of the stripping agent to the organic phase 2 is 1:3 to 3:1, the stripping time is 1 to 90 minutes, and the stripping temperature is 20 to 90°C; preferably, the volume ratio of the stripping agent to the organic phase 2 is 1:2 to 1:1.

[0058] Step D is to recover associated resources. The aqueous phase 2 obtained after washing in step B is cooled and crystallized, and then the solid-liquid separation is performed to obtain a double salt product.

[0059] In the present invention, there is no time sequence for process C and process D. After processes A and B, process C can be performed first and then process D, or process D can be performed first and then process C, or processes C and D can be performed simultaneously.

[0060] In one embodiment of the present invention, in step D, the cooling crystallization temperature is -10 to 30° C., and the crystallization time is 1 to 3 hours. A double salt product can be obtained by cooling crystallization.

[0061] In one embodiment of the present invention, the crystallization supernatant after the crystallization in step D is returned to step B for recycling as a detergent.

[0062] Step E is vanadium precipitation-calcination. Ammonia water is introduced into aqueous phase 3, and after precipitation, solid-liquid separation is performed to obtain ammonium metavanadate. The obtained ammonium metavanadate is calcined at 560°C for 2 hours to obtain high-purity vanadium pentoxide. The high-purity vanadium pentoxide mentioned in this invention refers to vanadium pentoxide with a purity of 99.5% or above.

[0063] In one embodiment of the present invention, in step E, aqueous ammonia is introduced to adjust the pH to 7.6-8.0, and the precipitation reaction time is 1-4 hours.

[0064] In one embodiment of the present invention, the supernatant of vanadium precipitation after vanadium precipitation in step E is pH-adjusted and then returned to step C for recycling as a stripping agent.

[0065] Step F is the regeneration of the extractant. The organic phase 3 is mixed and stirred with the sulfuric acid solution, and then the phases are separated to obtain a clean organic phase, which is returned to step A for recycling as the extractant.

[0066] In one embodiment of the present invention, in step F, the volume ratio of the sulfuric acid solution to the organic phase 3 is 1:4 to 4:1, countercurrent regeneration is adopted, the number of countercurrent stages is 1 to 3, and the reaction time is 1 to 90 min.

[0067] In one embodiment of the present invention, in step F, the concentration of the sulfuric acid solution is 6 to 50 wt.%, preferably 8 to 10 wt.%.

[0068] The specific embodiments of the present invention are further described below in conjunction with examples, but the present invention is not limited to the scope of the examples.

[0069] Example 1

[0070] (1) Extraction: 1565.80 g of vanadium-containing leachate was subjected to an extraction reaction with 2526.10 g of extractant P-15 at 60 °C. The extraction temperature was 60 °C, the extraction time was 30 min, and the stirring intensity was 400 rpm. After the reaction, 2551.41 g of an organic phase loaded with metal ions and 1502.81 g of a raffinate phase were obtained.

[0071] (2) Washing: 1551.6 g of a mixed solution having a sulfuric acid concentration of 10 wt.%, an ammonium sulfate concentration of 20 wt.%, and a vanadium ion concentration of 0.47 wt.% was prepared as a washing agent, and the washing agent was mixed and stirred with 2551.41 g of the organic phase loaded with metal ions in (1) to wash the manganese and magnesium in the organic phase. The stirring intensity was 400 rpm, the reaction temperature was 50° C., and the reaction time was 30 min. Then, the mixture was separated by a separatory funnel to obtain 2520.32 g of the organic phase loaded with vanadium and 1553.23 g of a washing solution.

[0072] (3) Stripping: 2520.32 g of the vanadium-loaded organic phase obtained in (2) was mixed and stirred with 1520.07 g of a 10 wt.% ammonium oxalate solution to carry out a stripping reaction at a stirring intensity of 400 rpm, a stripping temperature of 50° C., and a stripping time of 30 min. The mixture was then separated by a separatory funnel to obtain 2515.42 g of a lean organic phase and 1474.34 g of a vanadium-containing ammonium oxalate solution.

[0073] (4) Vanadium precipitation: dilute ammonia water was slowly introduced into the ammonium oxalate solution obtained in (3) using a peristaltic pump to adjust the pH of the solution at an ammonia flow rate of 3 mL / min. The pH was adjusted to 7.99, and then the solution was reacted at 60°C for 4 h under low-speed stirring. The solution was then filtered using a circulating water vacuum pump, and the obtained ammonium metavanadate was calcined at 580°C for 3 h to finally obtain the product vanadium pentoxide.

[0074] (5) Crystallization: The washing solution obtained in step (2) is placed in a constant temperature water bath at 5±0.5°C for low temperature crystallization for 2 hours, and then cold filtered using a Buchner funnel in conjunction with a circulating water vacuum pump to finally obtain a mixed crystal product of magnesium ammonium sulfate hexahydrate and manganese ammonium sulfate hexahydrate.

[0075] (6) Regeneration: 2496.78 g of the lean organic phase obtained in step (3) was stirred and mixed with 2590.34 g of 8 wt.% sulfuric acid solution at a stirring intensity of 500 rpm, a reaction temperature of 30° C., and a reaction time of 30 min. The mixture was then allowed to stand for phase separation to obtain 2491.98 g of fresh extractant and 2593.23 g of regenerated washing liquid.

[0076] The results are shown in Tables 1 and 2.

[0077] Table 1 Experimental data of Example 1

[0078]

[0079] Table 2 Product quality of vanadium pentoxide in Example 1

[0080] <![CDATA[V2O5]]> <![CDATA[Na2O+K2O]]> Si Fe P S As National Standard ≥99 ≤1 ≤0.15 ≤0.2 ≤0.03 ≤0.01 ≤0.01 product 99.99 ≤0.001 ≤0.001 0.017 0.001 0.006 ≤0.001

[0081] Note: The determination method for vanadium pentoxide is to oxidize all vanadium to pentavalent vanadium and then determine it by titration. The impurity content is measured using inductively coupled plasma.

[0082] As shown in Table 1, after the first-stage extraction, the extraction rates of vanadium, manganese, and magnesium were 94.38%, 63.60%, and 30.97%, respectively. Most of the vanadium was recovered through extraction, and the remaining vanadium in the raffinate could be returned to the acid leaching process for recovery in the next cycle. The results indicate that the extraction rates of manganese and magnesium in the first-stage extraction are relatively low, suggesting that increasing the number of extraction stages can improve the recovery rate of metal ions in the vanadium-containing leachate. The addition of 0.47 wt.% vanadium ions to the detergent ensures a 74.92% and 63.29% extraction rate for manganese and magnesium, respectively, without any vanadium loss. The majority of manganese and magnesium impurities were removed, facilitating the subsequent precipitation of high-purity vanadium pentoxide. After removing most of the impurities, stripping with 10 wt.% ammonium oxalate solution as a stripping agent resulted in a vanadium stripping rate of 88.66%, with little stripping effect on manganese and magnesium. This further optimized the vanadium purity, increasing the vanadium impurity ratio in the stripping solution and facilitating the subsequent precipitation of high-purity vanadium pentoxide. As shown in Table 2, the vanadium pentoxide obtained by calcination has a purity of 99.99%, and its impurity content is far less than the national standard requirement of 99V2O5. Through extraction-washing-strip extraction-vanadium precipitation, metallic impurities in the vanadium-containing leachate are effectively removed while simultaneously recovering and producing high-purity vanadium pentoxide. This process is simple and produces a high-value-added product.

[0083] Example 2

[0084] (1) Extraction: 1467.71 g of the vanadium-containing leachate was subjected to a secondary countercurrent extraction reaction with 24692.3 g of P-15 extractant at 60°C. The feed rate of the vanadium-containing leachate was 10 ml / min, and the feed rate of the P-15 extractant was 20 ml / min. After the reaction, 2504.23 g of an organic phase loaded with metal ions and 1403.8 g of a raffinate were obtained.

[0085] (2) Washing: A mixed solution containing 20 wt.% sulfuric acid, 25 wt.% ammonium sulfate, and 0.85 wt.% vanadium ions was prepared as a washing agent. 2504.23 g of the metal ion-loaded organic phase obtained in (1) was mixed and stirred with 1494.42 g of the washing agent to wash the manganese and magnesium from the organic phase. The washing temperature was 50°C, the washing time was 30 min, and the stirring intensity was 400 rpm. The phases were then separated using a separatory funnel to obtain 2498.99 g of the vanadium-loaded organic phase and 1487.86 g of the washing solution.

[0086] (3) Stripping: 2498.99 g of the vanadium-loaded organic phase obtained in (2) was mixed and stirred with 1521.34 g of a 10 wt.% ammonium oxalate solution at a stirring intensity of 400 rpm, a stripping temperature of 40° C., and a stripping time of 30 min. After the reaction was completed, 2496.78 g of a lean organic phase and 1521.67 g of a vanadium-containing stripping solution were obtained by phase separation using a separatory funnel.

[0087] (4) dilute ammonia water is slowly introduced into the ammonium oxalate stripping solution obtained in step (3) using a peristaltic pump to adjust the pH of the solution, the ammonia flow rate is 5 ml / min, the pH is adjusted to 8.00, and then the reaction is carried out under low-speed stirring at 60° C. for 2 h, and then filtered by a circulating water vacuum pump, and the obtained ammonium metavanadate is calcined at 580° C. for 3 h to finally obtain the product vanadium pentoxide.

[0088] (5) Crystallization: The washing solution obtained in step (2) is placed in a constant temperature water bath at 5±0.5°C for low temperature crystallization for 2 hours, and then cold filtered using a Buchner funnel in conjunction with a circulating water vacuum pump to finally obtain a mixed crystal product of magnesium ammonium sulfate hexahydrate and manganese ammonium sulfate hexahydrate.

[0089] (6) Regeneration: 2496.78 g of the lean organic phase obtained in step (3) was stirred and mixed with 2590.34 g of 8 wt.% sulfuric acid solution at a stirring intensity of 500 rpm, a reaction temperature of 30° C., and a reaction time of 30 min. The mixture was then allowed to stand for phase separation to obtain 2491.98 g of fresh extractant and 2593.23 g of regenerated washing liquid.

[0090] The experimental results are shown in Tables 3 and 4.

[0091] Table 3 Experimental data of Example 2

[0092]

[0093] Table 4 Product quality of vanadium pentoxide in Example 2

[0094] <![CDATA[V2O5]]> <![CDATA[Na2O+K2O]]> Si Fe P S As National Standard ≥99 ≤1 ≤0.15 ≤0.2 ≤0.03 ≤0.01 ≤0.01 product 99.87 ≤0.001 ≤0.001 0.02 0.003 0.009 ≤0.001

[0095] As shown in Table 3, after two-stage countercurrent extraction, the extraction rates of vanadium, manganese, and magnesium reached 97.63%, 90.80%, and 77.78%, respectively. These extraction rates were significantly improved compared to single-stage extraction, achieving efficient recovery of all metal ions in the vanadium-containing leachate. Increasing the sulfuric acid concentration in the wash solution to 20 wt.% significantly improved the washing efficiency of manganese and magnesium, achieving washing rates exceeding 90%, effectively removing most manganese and magnesium impurities. Furthermore, increasing the sulfuric acid concentration suggests that the vanadium concentration in the detergent should be increased to minimize vanadium losses. The vanadium content in the stripping solution reached 1.99 wt.%, while both manganese and magnesium levels were below the detection limit, demonstrating high selectivity for vanadium in the stripping step and providing an excellent foundation for the subsequent preparation of high-purity vanadium pentoxide. The supernatant after vanadium precipitation contained only 0.09 wt.% vanadium ions, with a vanadium precipitation rate exceeding 95%. Furthermore, the supernatant from the vanadium precipitation process can be directly recycled as a stripping agent for the next cycle. Through material balance, the vanadium recovery rate of this process in a single cycle can reach more than 90%, and the obtained product meets the national standard of 99% V2O5.

[0096] Example 3 Effect of Stripping Phase Ratio on Stripping Rate

[0097] Referring to the method of Example 1, vanadium was stripped using 6 wt.% ammonium oxalate solution under different stripping ratios. The experimental results are shown in Table 5.

[0098] The experimental conditions for stripping vanadium were as follows: stripping temperature of 50°C, stripping time of 30 min, sufficient stirring, ammonium oxalate solution concentration of 6 wt.%, and the loading amounts of vanadium, manganese and magnesium in organic phase 2 were 9.17 mg / g, 0.73 mg / g and 0.12 mg / g, respectively. The stripping phase O / A ratio varied in the range of 0.5 to 3.

[0099] Table 5 Experimental data of comparative example 1

[0100]

[0101] The calculation method of stripping rate is:

[0102] As can be seen from the table, when the ratio is greater than 1, the separation of vanadium from other impurity metal ions is very effective, with the stripping rates of manganese and magnesium both less than 10%. As the ratio increases, the stripping rates of vanadium and impurity ions decrease simultaneously, resulting in an excessively low vanadium ion concentration in the stripping solution, which is not conducive to the subsequent precipitation of ammonium metavanadate. Therefore, it is not advisable to select an excessively large ratio when controlling the stripping of impurity ions. At the same time, if the ratio is too small, although the vanadium ion concentration increases, the impurity ions are stripped out simultaneously, affecting the purity of vanadium pentoxide. Therefore, the ratio should be selected moderately, with the preferred volume ratio of the organic phase to the aqueous phase being 1:1 to 2:1.

[0103] Example 4 Selection of sulfuric acid concentration in detergent

[0104] The initial concentrations of vanadium, manganese and magnesium in the vanadium-containing leachate are 1.55 wt.%, 0.52 wt.% and 0.17 wt.%, respectively.

[0105] (1) Extraction: 1222.80 g of vanadium-containing leachate was subjected to an extraction reaction with 2600.34 g of extractant P-15 at 60°C. The extraction temperature was 60°C, the extraction time was 30 min, and the stirring intensity was 400 rpm. After the reaction, 2605.80 g of an organic phase loaded with metal ions and 1198.2 g of a raffinate phase were obtained.

[0106] (2) The organic phase obtained in step (1) was divided into six equal parts. Under the same experimental conditions, the organic phases were washed with mixed solutions of sulfuric acid and ammonium sulfate containing different concentrations of sulfuric acid. The experimental results are shown in Table 6.

[0107] Experimental conditions: washing phase ratio O / A=2, washing time 30 min, washing temperature 60°C, stirring intensity 400 rpm, vanadium ion concentration 0 wt.%, ammonium sulfate concentration 25 wt.%.

[0108] The calculation method of washing rate is:

[0109] Table 6 Experimental data of Example 4

[0110]

[0111] As can be seen from the table, sulfuric acid has a very good cleaning effect on manganese and magnesium. At a sulfuric acid concentration of 3 wt.%, the manganese cleaning rate exceeds 90%. As the sulfuric acid concentration increases, the manganese cleaning effect gradually increases, but at the same time, the vanadium washing loss also gradually increases. Therefore, when choosing a high sulfuric acid concentration, the vanadium ion concentration in the washing solution should also be increased. Because the vanadium ion concentration in the acid leaching vanadium solution fluctuates, a sulfuric acid concentration of 20-30 wt.% is preferred to remove the majority of manganese and magnesium impurities.

[0112] Example 5 Selection of detergent

[0113] The initial concentrations of vanadium, manganese and magnesium in the vanadium-containing leachate are 1.55 wt.%, 0.52 wt.% and 0.17 wt.%, respectively.

[0114] (1) Extraction: 1222.80 g of vanadium-containing leachate was subjected to an extraction reaction with 2600.34 g of extractant P-15 at 60°C. The extraction temperature was 60°C, the extraction time was 30 min, and the stirring intensity was 400 rpm. After the reaction, 2605.80 g of an organic phase loaded with metal ions and 1198.2 g of a raffinate phase were obtained.

[0115] (2) The organic phase obtained in step (1) was divided into three equal parts. Under the same experimental conditions, the organic phases were washed with mixed solutions of sulfuric acid and ammonium sulfate containing different concentrations of sulfuric acid. The experimental results are shown in Table 7.

[0116] Experimental conditions: washing phase ratio O / A=2, washing time 30 min, washing temperature 60°C, stirring intensity 400 rpm.

[0117] Table 7

[0118]

[0119] Referring to the method of Example 1, only the type of detergent was changed to prepare high-purity vanadium pentoxide. The purity and yield of vanadium pentoxide are shown in Table 8.

[0120] Table 8

[0121]

[0122] It can be seen that only by adopting the detergent composition of the present invention can the purity and yield of vanadium pentoxide be improved at the same time.

[0123] In summary, the method of the present invention not only recovers vanadium to prepare high-purity vanadium pentoxide, but also recovers associated resources such as manganese, magnesium, and iron in the vanadium-containing leachate, thereby achieving maximum resource utilization. The purity of the obtained vanadium pentoxide product reaches 99.8%, and the yield is as high as 91.1%, making it more competitive in the market.

Claims

1. A method for recovering metal ions from a vanadium-containing leachate and preparing high-purity vanadium pentoxide, characterized in that: The following steps are involved: A. Extraction process: mixing the vanadium-containing leachate with an extractant to carry out an extraction reaction, and then separating the phases to obtain an organic phase 1 and an aqueous phase 1; B. Washing process: the organic phase 1 is mixed and stirred with a detergent, and then separated into an organic phase 2 and an aqueous phase 2; wherein the detergent is a mixed solution of sulfuric acid, ammonium sulfate and pentavalent vanadium ions; C. Stripping process: the organic phase 2 is mixed and stirred with the stripping agent, and then separated into aqueous phase 3 and organic phase 3; D. Recovery of associated resources: cooling and crystallization of aqueous phase 2, followed by solid-liquid separation to obtain a double salt product; E. Vanadium precipitation-calcination step: Ammonia water is introduced into the aqueous phase 3, and after precipitation, solid-liquid separation is performed to obtain ammonium metavanadate, which is then calcined at 560°C for 2 hours to obtain high-purity vanadium pentoxide; F. Regeneration process: The organic phase 3 is mixed and stirred with the sulfuric acid solution, and then separated to obtain a clean organic phase, which is returned to process A for recycling as an extractant.

2. The method for recovering metal ions from a vanadium-containing leachate and preparing high-purity vanadium pentoxide according to claim 1, characterized in that: The extractant in step A includes at least one of an organophosphorus extractant, an organophosphine extractant, an organic sulfonic acid extractant, an organic carboxylic acid extractant, and a tertiary carbonic acid extractant; preferably, the extractant includes at least one of di(2-ethylhexyl) phosphate, 2-ethylhexyl phosphate 2-ethylhexyl ester, di(2,4,4-trimethylpentyl) hypophosphorous acid, 2-ethylhexyl phosphonic acid mono(2-ethylhexyl) ester, N,NN-n-octylamino dimethylenephenylphosphonic acid, N,NN-n-hexylamino dimethylenephenylphosphonic acid, toluenesulfonic acid, p-toluenesulfonic acid, benzenesulfonic acid, xylenesulfonic acid, dodecylbenzenesulfonic acid, dinonylnaphthalenesulfonic acid, cinnamic acid, fatty acid, lauric acid, and cyclohexanecarboxylic acid.

3. The method for recovering metal ions from a vanadium-containing leachate and preparing high-purity vanadium pentoxide according to claim 1, characterized in that: The vanadium-containing leachate is prepared by the following method: mixing a vanadium-containing raw material with an acid for leaching, filtering, and obtaining the vanadium-containing leachate; the vanadium-containing raw material is at least one of stone coal, vanadium slag, vanadium-containing waste slag produced by chemical production, and deactivated vanadium-containing catalyst.

4. The method for recovering metal ions from a vanadium-containing leachate and preparing high-purity vanadium pentoxide according to claim 1, characterized in that: In step A, the volume ratio of the vanadium-containing leachate to the extractant is 1:4 to 4:1, the extraction time is 1 to 90 minutes, and the extraction temperature is 30 to 90° C.; preferably, the volume ratio of the vanadium-containing leachate to the organic phase is 1:3 to 1:

1.

5. The method for recovering metal ions from a vanadium-containing leachate and preparing high-purity vanadium pentoxide according to claim 1, characterized in that: In the detergent of step B, the concentration of sulfuric acid is 8-50 wt.%, the concentration of ammonium sulfate is 10-40 wt.%, and the concentration of vanadium ions is 0.1-1.0 wt.%; preferably, the concentration of sulfuric acid is 20-30 wt.%, and the concentration of ammonium sulfate is 15-25 wt.%.

6. The method for recovering metal ions from a vanadium-containing leachate and preparing high-purity vanadium pentoxide according to claim 1, characterized in that: In step B, the volume ratio of the organic phase 1 to the detergent is 1:8 to 8:1, the washing time is 1 to 90 minutes, and the washing temperature is 20 to 90°C.

7. The method for recovering metal ions from a vanadium-containing leachate and preparing high-purity vanadium pentoxide according to claim 1, characterized in that: In step C, the stripping agent is an ammonium oxalate solution, and the concentration of the ammonium oxalate solution is preferably 5 to 13 wt.%, and more preferably 8 to 10 wt.%.

8. The method for recovering metal ions from a vanadium-containing leachate and preparing high-purity vanadium pentoxide according to claim 1, characterized in that: In step C, the volume ratio of the stripping agent to the organic phase 2 is 1:3 to 3:1, the stripping time is 1 to 90 minutes, and the stripping temperature is 20 to 90° C.; preferably, the volume ratio of the stripping agent to the organic phase 2 is 1:2 to 1:1; In step D, the cooling crystallization temperature is -10 to 30°C, and the crystallization time is 1 to 3 hours; In step E, ammonia water is introduced to adjust the pH to 7.6-8.0, and the precipitation reaction time is 1-4 hours; In step F, the volume ratio of the sulfuric acid solution to the organic phase 3 is 1:4 to 4:1, countercurrent regeneration is adopted, the number of countercurrent stages is 1 to 3, and the reaction time is 1 to 90 minutes.

9. The method for recovering metal ions from a vanadium-containing leachate and preparing high-purity vanadium pentoxide according to claim 1, characterized in that: In step F, the concentration of the sulfuric acid solution is 6 to 50 wt.%, preferably 8 to 10 wt.%.

10. The method for recovering metal ions from a vanadium-containing leachate and preparing high-purity vanadium pentoxide according to claim 1, characterized in that: The aqueous phase 1 obtained in step A is returned to the acid leaching step for recycling as acid; the crystallization supernatant after crystallization in step D is returned to step B for recycling as detergent; the vanadium precipitation supernatant after vanadium precipitation in step E is adjusted in pH and returned to step C for recycling as stripping agent.

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