Vanadium slag calcification vanadium extraction process
By employing a three-stage low-temperature dynamic roasting process and optimizing the vanadium slag calcification vanadium extraction process, the problems of low vanadium leaching rate and high cost have been solved, achieving efficient and green vanadium extraction with a significant improvement in product purity and recovery rate.
Patent Information
- Application Number
- CN202511777798.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-28
- Publication Date
- 2026-02-27
AI Technical Summary
Traditional calcification vanadium extraction processes have low vanadium leaching rates, high costs, and the introduction of complexing agents increases process complexity and environmental pressure.
A three-stage low-temperature dynamic roasting process is adopted, which combines pretreatment, magnetic separation, roasting, grinding, acid leaching and vanadium precipitation. By controlling the roasting temperature and time, impurities are separated, the use of complexing agents is avoided, and the vanadium leaching rate is improved.
It achieves efficient vanadium extraction, with a green and environmentally friendly production process, reduced equipment and operating costs, increased vanadium leaching rate to over 95.9%, and product purity to over 98%.
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Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of calcium vanadium extraction technology, in particular to a vanadium slag calcification vanadium extraction process. BACKGROUND
[0002] Vanadium is an important metal widely used in steel, chemical industry, aerospace and energy storage fields. Vanadium pentoxide (V2O5) is one of the main industrial products of vanadium, and its purity directly affects the performance of downstream materials. Currently, the process for extracting vanadium pentoxide from vanadium slag mainly includes sodium calcination roasting method, calcium calcination roasting method and direct acid leaching method, etc. Among them, the calcium vanadium extraction process is the most widely used due to its environmental friendliness and strong raw material adaptability.
[0003] However, the traditional calcium vanadium extraction process faces many challenges in actual operation. Vanadium slag often contains various impurity elements such as silicon, aluminum, phosphorus and iron, which are easy to form complex silicates and aluminates during roasting and leaching, seriously affecting the leaching efficiency of vanadium and leading to excessive impurity content in the final product. Currently, complexing agents or other chemical additives are often added to remove impurities, which not only increases the complexity of the process, but also significantly increases the construction cost, equipment maintenance cost and additive usage cost. At the same time, the introduction of complexing agents and additives may also bring difficulties to the subsequent wastewater and residue treatment, increasing the environmental pressure.
[0004] Therefore, it is of great significance to develop a vanadium slag calcification vanadium extraction process that can improve the vanadium leaching rate without adding complexing agents, and obtain vanadium pentoxide with stable product purity to meet people's needs. SUMMARY
[0005] The present application provides a vanadium slag calcification vanadium extraction process, which solves the problems of low vanadium leaching rate and high vanadium extraction process cost in the related art.
[0006] The technical scheme of the present application is as follows: The present application provides a vanadium slag calcification vanadium extraction process, which includes the following steps: S1, mixing pretreated vanadium slag with limestone powder, roasting to obtain clinker vanadium slag; S2, slurry the clinker vanadium slag, perform first acid leaching, separate to obtain first leaching liquid and first tailings, slurry the first tailings, perform second acid leaching, separate to obtain second leaching liquid and second tailings; S3, add ammonium sulfate to the first leaching liquid, perform vanadium precipitation treatment, filter to obtain supernatant and precipitate, dry and calcine the precipitate to obtain vanadium pentoxide powder; The roasting is divided into first-stage roasting, second-stage roasting and third-stage roasting; The first segment is baked at a temperature of 580-600 DEG C, and the holding time is 120-150 min; The second segment is baked at a temperature of 850-900 DEG C, and the holding time is 90-120 min; The third segment is baked at a temperature of 350-450 DEG C, and the holding time is 60-90 min.
[0007] As a further technical solution, the first segment baking and the second baking, the heating rate is independently 5-15 DEG C / min; The third segment is baked at a temperature of 350-450 DEG C, and the holding time is 60-90 min.
[0008] As a further technical solution, the first segment baking and the second baking, the heating rate is independently 5-15 DEG C / min;
[0009] In the application, by optimizing the heating rate of the first segment baking and the second baking, when the heating rate of the first segment baking is greater than the heating rate of the second baking, the vanadium leaching rate can be further improved.
[0010] As a further technical solution, in step S1, the specific process of the pretreatment is: after crushing, iron removal, grinding, and screening, the pretreated vanadium slag is obtained.
[0011] As a further technical solution, in step S1, the limestone powder is a limestone powder after grinding and screening.
[0012] As a further technical solution, during the grinding and screening, the powder is ground to 60-85% of the powder under a 120-mesh sieve.
[0013] As a further technical solution, in step S2, when the clinker vanadium slag is slurried, deionized water is added to the clinker vanadium slag, and the mass volume of the clinker vanadium slag and the deionized water is 1g:3mL; When the first tailings are slurried, deionized water is added to the first tailings, and the mass volume of the first tailings and the deionized water is 1g:3mL.
[0014] As a further technical solution, the first acid leaching is divided into a first stage acid leaching, a second stage acid leaching, and a third stage acid leaching; The first stage acid leaching is carried out at a leaching pH value of 3.5-4.0, and the leaching time is 10-15 min; The second stage acid leaching is carried out at a leaching pH value of 2.5-2.8, and the leaching time is 30-40 min; The third stage acid leaching is stable at pH 2.5-2.8.
[0015] In the application, the first stage acid leaching is at pH 3.5-4.0, the iron ions in the vanadium slag significantly hydrolyze and form colloids, 95%-99% of the iron ions can be removed, the manganese ions have been precipitated when the pH is greater than 7, 90% of the chromium ions can be precipitated when the pH is greater than 4, the titanium ions can be completely precipitated when the pH is reduced to 3.5-4, and the first stage acid leaching can realize the preliminary separation of impurities in the vanadium slag; the second stage acid leaching is at pH 2.5-2.8 for 30-40 min, which can further remove iron, chromium, titanium, silicon and other impurities; and the third stage acid leaching is stable at pH 2.5-2.8, and the pH is not raised to achieve the effect of complete leaching.
[0016] As a further technical solution, the first stage acid leaching is at a speed of 4-12 mL / min. The second stage acid leaching is at a speed of 1-3 mL / min.
[0017] In the application, the first stage acid leaching is at a speed of 4-12 mL / min, which can quickly reduce the pH to 3.5-4.0, and avoid the slow reduction of pH value to cause the vanadium to be wrapped by colloids, thereby causing the loss of vanadium; the second stage acid leaching is at a speed of 1-3 mL / min, which slowly reduces the pH to 2.5-2.8, and the reasonable speed of 1-3 mL / min can avoid the excessive local acid solution, thereby reducing the vanadium leaching rate.
[0018] As a further technical solution, the second stage acid leaching is at pH 1.5-1.7. The second stage acid leaching is at a speed of 0.7-2 mL / min. In the application, the second stage acid leaching is at a speed of 0.7-2 mL / min and pH 1.5-1.7, the slow acid addition ensures that the acid uniformly penetrates into the tailings, effectively destroys the possible wrapping structure of vanadium in the first stage acid leaching, and further improves the vanadium leaching rate.
[0019] In the application, by reasonably regulating the leaching reaction pH, leaching time and the addition speed of the acid solution in the first and second stage acid leaching, the pH, reaction time and reaction degree are used to differentially affect the dissolution kinetics of multi-metal particles, and the contents of Fe, P, S, Si, Mg and other impurities are reduced to below the standard requirements.
[0020] As a further technical solution, the adding speed of the acidic solution in the second acid leaching is < the adding speed of the acidic solution in the second stage acid leaching.
[0021] In the present application, when the adding speed of the acidic solution in the second acid leaching is < the adding speed of the acidic solution in the second stage acid leaching, the vanadium leaching rate can be further improved, and the vanadium leaching rate can be improved to 95.9% or more.
[0022] As a further technical solution, in the first acid leaching, the solid-liquid ratio of the clinker vanadium slag and the acidic solution is 1g:2.5~3mL; In the second acid leaching, the solid-liquid ratio of the first tailings and the acidic solution is 1g:2.5~3mL.
[0023] As a further technical solution, in step S1, when mixing, the calcium-vanadium ratio is 0.3~0.6; In the roasting, the oxygen content of the flue gas is 10%~18%.
[0024] As a further technical solution, the acidic solution is a sulfuric acid solution, and the mass fraction of the sulfuric acid solution is 50%~98%.
[0025] The working principle and beneficial effects of the present application are as follows: In the vanadium slag calcification vanadium extraction process of the present application, through pretreatment, magnetic separation, roasting, grinding, acid leaching, vanadium precipitation, and wastewater reuse of the vanadium slag raw material, the production process does not need to add complexing agents for impurity removal or other impurity removal processes, the vanadium leaching rate in the vanadium slag can be effectively improved, the interference of impurities in the vanadium leaching process is reduced, and vanadium pentoxide powder with a purity of >98% is obtained. In the roasting process, it is divided into first-stage roasting, second-stage roasting, and third-stage roasting, the temperature and roasting time of each stage are reasonably adjusted, in the first-stage roasting, the temperature is 580~630℃, and the holding time is 120~150min, in the second-stage roasting, the temperature is 850~900℃, and the holding time is 90~120min, in the third-stage roasting, the temperature is 350~450℃, and the holding time is 60~90min, through the reasonable cooperation of three-stage low-temperature dynamic roasting, the vanadium slag and limestone powder can be fully decomposed and oxidized, and the generation of silicate solution is effectively cut off at the same time, which avoids the excessive generation of impurities such as Si, Al, and P, reduces the silicon and manganese leaching rate, improves the vanadium leaching rate, and finally improves the comprehensive recovery rate of vanadium.
[0026] The process flow of the present application is short, the investment in equipment and facilities is small, there is no consumption of impurity removal reagents, and the operation cost is low. The production process is green and efficient, and through production practice, it is proved to be suitable for industrialized production of vanadium extraction from steel plant vanadium slag, vanadium extraction from stone coal, and vanadium recovery from copper slag. DETAILED DESCRIPTION
[0027] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments of the present application, all the other embodiments obtained by a person of ordinary skill in the art without creative effort are within the scope of the present application.
[0028] Embodiment 1 A vanadium slag calcification vanadium extraction process, comprising the following steps: S1, after the vanadium slag is crushed, iron is removed, and the powder is ground to 80% of the powder under a 120 mesh sieve, the pretreated vanadium slag is obtained, 200g of the pretreated vanadium slag is mixed with 14g of limestone powder (calcium oxide content 48.45%) ground to 80% under a 120 mesh sieve (calcium vanadium ratio 0.49), the temperature is raised to 580℃ at a temperature raising speed of 3℃ / min, and after the heat preservation roasting treatment of 120min, the temperature is raised from 580℃ to 850℃ at a temperature raising speed of 3℃ / min, and after the heat preservation roasting treatment of 90min, the temperature is lowered from 850℃ to 350℃ at a temperature lowering speed of 6℃ / min, and after the heat preservation roasting treatment of 90min, the temperature is naturally cooled to room temperature, and the clinker vanadium slag is obtained; wherein, the oxygen content of the flue gas is 10% during the roasting process; S2, deionized water is added to the clinker vanadium slag (the mass volume of the clinker vanadium slag and the deionized water is 1g:3mL), after pulping, sulfuric acid solution (mass fraction 60%) is first added at an adding speed of 2mL / min, the leaching pH value is adjusted to 3.5, the leaching time is 10min, then sulfuric acid solution (mass fraction 60%) is added at an adding speed of 0.7mL / min, the leaching pH value is adjusted to 2.5, the leaching time is 30min, then the leaching pH value is kept at 2.5, and the keeping time is 10min, then separation is performed, and the first leaching liquid and the first tailings are obtained, deionized water is added to the first tailings (the mass volume of the first tailings and the deionized water is 1g:3mL), after pulping, sulfuric acid solution (mass fraction 60%) is added at an adding speed of 0.7mL / min, the leaching pH value is adjusted to 1.5, and after the pH value does not rise back, separation is performed, and the second leaching liquid and the second tailings are obtained; S3, ammonium sulfate is added to the first leaching liquid (ammonium vanadium ratio 1.2), vanadium precipitation treatment is performed, and filtration is performed, and the supernatant and ammonium vanadate precipitate are obtained, the ammonium vanadate precipitate is dried and calcined, and vanadium pentoxide powder is obtained.
[0029] Embodiment 2 A vanadium slag calcification vanadium extraction process, comprising the following steps: S1, the vanadium slag is crushed, iron is removed, and the powder is ground to 80% of the powder under a 120 mesh sieve to obtain pretreated vanadium slag. 200g of the pretreated vanadium slag is mixed with 14g of limestone powder (calcium oxide content 48.45%) ground to 80% under a 120 mesh sieve (calcium vanadium ratio 0.49), heated to 600℃ at a heating rate of 3℃ / min, and kept at 600℃ for 150min. Then, the temperature is raised to 900℃ at a heating rate of 3℃ / min, and kept at 900℃ for 120min. Then, the temperature is lowered to 450℃ at a cooling rate of 10℃ / min, and kept at 450℃ for 60min. Then, the temperature is naturally cooled to room temperature to obtain clinker vanadium slag. During the calcination process, the oxygen content of the flue gas is 18%. S2, deionized water is added to the clinker vanadium slag (mass volume of clinker vanadium slag and deionized water 1g:3mL). After pulping, sulfuric acid solution (mass fraction 60%) is added at a rate of 3mL / min to adjust the leaching pH value to 4.0, and the leaching time is 15min. Then, sulfuric acid solution (mass fraction 60%) is added at a rate of 0.7mL / min to adjust the leaching pH value to 2.8, and the leaching time is 40min. Then, the leaching pH value is kept at 2.8 for 20min. Then, the first leaching liquid and the first tailings are separated. Deionized water is added to the first tailings (mass volume of first tailings and deionized water 1g:3mL). After pulping, sulfuric acid solution (mass fraction 60%) is added at a rate of 0.7mL / min to adjust the leaching pH value to 1.7. After the pH value does not rise, the second leaching liquid and the second tailings are separated. S3, ammonium sulfate is added to the first leaching liquid (ammonium vanadium ratio 1.3) to perform vanadium precipitation treatment. After filtration, the supernatant and ammonium vanadate precipitate are obtained. The ammonium vanadate precipitate is dried and calcined to obtain vanadium pentoxide powder.
[0030] Example 3 The difference between this example and Example 2 is only that the step S1 in the vanadium extraction process of the vanadium slag in this example is different, which is specifically as follows: S1, the vanadium slag is crushed, iron is removed, and the powder is ground to 80% of the powder under a 120 mesh sieve to obtain pretreated vanadium slag. 200g of the pretreated vanadium slag is mixed with 14g of limestone powder (calcium oxide content 48.45%) ground to 80% under a 120 mesh sieve (calcium vanadium ratio 0.49), heated to 600℃ at a heating rate of 3℃ / min, and kept at 600℃ for 150min. Then, the temperature is raised to 900℃ at a heating rate of 3℃ / min, and kept at 900℃ for 120min. Then, the temperature is lowered to 450℃ at a cooling rate of 10℃ / min, and kept at 450℃ for 60min. Then, the temperature is naturally cooled to room temperature to obtain clinker vanadium slag. During the calcination process, the oxygen content of the flue gas is 18%.
[0031] Example 4 The difference between this example and Example 2 is only that, in the vanadium extraction process of the vanadium slag calcification in this example, step S1 is different, specifically: S1, after the vanadium slag is crushed, iron is removed, and the powder is ground to 80% of the powder under the 120 mesh sieve, the pretreated vanadium slag is obtained, 200g of the pretreated vanadium slag is mixed with 14g of the ground lime stone powder (calcium oxide content 48.45%) to 80% under the 120 mesh sieve (calcium vanadium ratio is 0.49), the temperature is raised to 600℃ at a temperature raising speed of 5℃ / min, after the heat preservation roasting treatment for 150min, the temperature is raised from 600℃ to 900℃ at a temperature raising speed of 15℃ / min, after the heat preservation roasting treatment for 120min, the temperature is lowered from 900℃ to 450℃ at a temperature lowering speed of 10℃ / min, after the heat preservation roasting treatment for 60min, the temperature is naturally cooled to room temperature, and the clinker vanadium slag is obtained.
[0032] Example 5 The difference between this example and Example 2 is only that, in the vanadium extraction process of the vanadium slag calcification in this example, step S1 is different, specifically: S1, after the vanadium slag is crushed, iron is removed, and the powder is ground to 80% of the powder under the 120 mesh sieve, the pretreated vanadium slag is obtained, 200g of the pretreated vanadium slag is mixed with 14g of the ground lime stone powder (calcium oxide content 48.45%) to 80% under the 120 mesh sieve (calcium vanadium ratio is 0.49), the temperature is raised to 600℃ at a temperature raising speed of 15℃ / min, after the heat preservation treatment for 150min, the temperature is raised from 600℃ to 900℃ at a temperature raising speed of 5℃ / min, after the heat preservation treatment for 120min, the temperature is lowered from 900℃ to 450℃ at a temperature lowering speed of 10℃ / min, after the heat preservation treatment for 60min, the temperature is naturally cooled to room temperature, and the clinker vanadium slag is obtained.
[0033] Example 6 The difference between this example and Example 5 is only that, in the vanadium extraction process of the vanadium slag calcification in this example, step S2 is different, specifically: S2, deionized water is added to the clinker vanadium slag (the mass and volume of the clinker vanadium slag and the deionized water is 1 g:3 mL), after pulping, sulfuric acid solution (mass fraction is 60%) is added at a rate of 15 mL / min, the leaching pH value is adjusted to 4.0, the leaching time is 15 min, then sulfuric acid solution (mass fraction is 60%) is added at a rate of 3.5 mL / min, the leaching pH value is adjusted to 2.8, the leaching time is 40 min, then the leaching pH value is kept at 2.8 for 20 min, and then separated to obtain the first leaching liquid and the first tailings, deionized water is added to the first tailings (the mass and volume of the first tailings and the deionized water is 1 g:3 mL), after pulping, sulfuric acid solution (mass fraction is 60%) is added at a rate of 3.5 mL / min, the leaching pH value is adjusted to 1.7, and then separated after the pH value does not rise.
[0034] Example 7 The difference between this example and Example 5 is only that, in the vanadium extraction process of the calcification of vanadium slag in this example, step S2 is different, specifically: S2, deionized water is added to the clinker vanadium slag (the mass and volume of the clinker vanadium slag and the deionized water is 1 g:3 mL), after pulping, sulfuric acid solution (mass fraction is 60%) is added at a rate of 15 mL / min, the leaching pH value is adjusted to 4.0, the leaching time is 15 min, then sulfuric acid solution (mass fraction is 60%) is added at a rate of 3.5 mL / min, the leaching pH value is adjusted to 2.8, the leaching time is 40 min, then the leaching pH value is kept at 2.8 for 20 min, and then separated to obtain the first leaching liquid and the first tailings, deionized water is added to the first tailings (the mass and volume of the first tailings and the deionized water is 1 g:3 mL), after pulping, sulfuric acid solution (mass fraction is 60%) is added at a rate of 3.5 mL / min, the leaching pH value is adjusted to 1.7, and then separated after the pH value does not rise.
[0035] Example 8 The difference between this example and Example 5 is only that, in the vanadium extraction process of the calcification of vanadium slag in this example, step S2 is different, specifically: S2. Add deionized water to the vanadium clinker slag (mass-volume ratio of vanadium clinker slag to deionized water is 1 g: 3 mL). After pulping, first add sulfuric acid solution (mass fraction of 60%) at a rate of 12 mL / min to adjust the leaching pH to 4.0 and the leaching time to 15 min. Then add sulfuric acid solution (mass fraction of 60%) at a rate of 3 mL / min to adjust the leaching pH to 2.8 and the leaching time to 40 min. Then maintain the leaching pH at 2.8 for 20 min and separate to obtain the first leachate and the first tailings. Add deionized water to the first tailings (mass-volume ratio of the first tailings to deionized water is 1 g: 3 mL). After pulping, add sulfuric acid solution (mass fraction of 60%) at a rate of 2 mL / min to adjust the leaching pH to 1.7. After the pH does not rise again, separate to obtain the second leachate and the second tailings.
[0036] Example 9 The only difference between this embodiment and Embodiment 5 is that step S2 in the vanadium slag calcification and vanadium extraction process is different in this embodiment, specifically: S2. Add deionized water to the vanadium clinker slag (mass-volume ratio of 1g:3mL for vanadium clinker slag and deionized water). After pulping, first add sulfuric acid solution (mass fraction 60%) at a rate of 12mL / min to adjust the leaching pH to 4.0 and the leaching time to 15min. Then add sulfuric acid solution (mass fraction 60%) at a rate of 3mL / min to adjust the leaching pH to 2.8 and the leaching time to 40min. Then maintain the leaching pH at 2.8 for 20min. After separation, obtain the first leachate and the first tailings. Add deionized water to the first tailings (mass-volume ratio of 1g:3mL for the first tailings). After pulping, add sulfuric acid solution (mass fraction 60%) at a rate of 0.7mL / min to adjust the leaching pH to 1.7. After the pH does not rise again, separate to obtain the second leachate and the second tailings.
[0037] Example 10 The only difference between this embodiment and Embodiment 5 is that step S2 in the vanadium slag calcification and vanadium extraction process is different in this embodiment, specifically: S2, deionized water is added to the clinker vanadium slag (the mass and volume of the clinker vanadium slag and the deionized water are 1 g:3 mL), after slurry preparation, sulfuric acid solution (mass fraction of 60%) is added at a rate of 12 mL / min, the leaching pH value is adjusted to 4.0, the leaching time is 15 min, then sulfuric acid solution (mass fraction of 60%) is added at a rate of 1 mL / min, the leaching pH value is adjusted to 2.8, the leaching time is 40 min, then the leaching pH value is kept at 2.8 for 20 min, and then separated to obtain the first leaching liquid and the first tailings, deionized water is added to the first tailings (the mass and volume of the first tailings and the deionized water are 1 g:3 mL), after slurry preparation, sulfuric acid solution (mass fraction of 60%) is added at a rate of 2 mL / min, the leaching pH value is adjusted to 1.7, and then separated after the pH value does not rise, to obtain the second leaching liquid and the second tailings.
[0038] Comparative Example 1 The difference between the present comparative example and Example 2 is only that, in the vanadium extraction process by calcification of the vanadium slag in the present comparative example, step S1 is different, specifically: S1, after the vanadium slag is crushed, de-ironed and ground to 80% of the powder below the 120 mesh sieve, the pretreated vanadium slag is obtained, 200 g of the pretreated vanadium slag is mixed with 14 g of limestone powder (calcium oxide content of 48.45%) ground to 80% of the powder below the 120 mesh sieve (calcium-vanadium ratio of 0.49), heated to 900℃ at a heating rate of 3℃ / min, and kept for 120 min, then cooled to 450℃ at a cooling rate of 10℃ / min from 900℃, and kept for 60 min, and then naturally cooled to room temperature to obtain the clinker vanadium slag.
[0039] Comparative Example 2 The difference between the present comparative example and Example 2 is only that, in the vanadium extraction process by calcification of the vanadium slag in the present comparative example, step S1 is different, specifically: S1, after the vanadium slag is crushed, de-ironed and ground to 80% of the powder below the 120 mesh sieve, the pretreated vanadium slag is obtained, 200 g of the pretreated vanadium slag is mixed with 14 g of limestone powder (calcium oxide content of 48.45%) ground to 80% of the powder below the 120 mesh sieve, heated to 600℃ at a heating rate of 3℃ / min, and kept for 150 min, then heated to 900℃ at a heating rate of 3℃ / min, and kept for 90 min, and then naturally cooled to room temperature to obtain the clinker vanadium slag.
[0040] Comparative Example 3 The difference between the present comparative example and Example 2 is only that, in the vanadium extraction process by calcification of the vanadium slag in the present comparative example, step S1 is different, specifically: S1, the vanadium slag is crushed, iron is removed, and the powder is ground to 80% of the powder under 120 mesh sieve, then the pretreated vanadium slag is obtained, 200g of the pretreated vanadium slag is mixed with 14g of limestone powder ground to 80% under 120 mesh sieve, the temperature is raised to 600℃ at a temperature raising rate of 3℃ / min, and then the calcination treatment is carried out for 150min, then the temperature is lowered from 600℃ to 450℃ at a temperature lowering rate of 10℃ / min, and then the calcination treatment is carried out for 60min, and then the natural cooling is carried out to room temperature, and then the clinker vanadium slag is obtained.
[0041] The component content of the pretreated vanadium slag in the vanadium extraction process of the vanadium slag calcification of examples 1~10 and comparative examples 1~3 is shown in table 1: Table 1 Component content of pretreated vanadium slag in examples 1~10 and comparative examples 1~3
[0042] The component content of the second tailings in the vanadium extraction process of the vanadium slag calcification of examples 1~10 and comparative examples 1~3 is shown in table 2: Table 2 Component content of the second tailings in examples 1~10 and comparative examples 1~3
[0043] The component content of the ammonium vanadate precipitation in the vanadium extraction process of the vanadium slag calcification of examples 1~10 and comparative examples 1~3 is shown in table 3: Table 3 Component content of ammonium vanadate precipitation in examples 1~10 and comparative examples 1~3
[0044] The vanadium leaching rate and the purity of the final vanadium pentoxide powder in the vanadium extraction process of the vanadium slag calcification of examples 1~10 and comparative examples 1~3 is shown in table 4: Table 4 Vanadium leaching rate and purity of vanadium pentoxide powder in examples 1~10 and comparative examples 1~3
[0045] As can be seen from Tables 1-3, compared with Comparative Examples 1-3, in the vanadium slag calcification vanadium extraction process of Examples 1-10, the V2O5 content in the second tailing is significantly reduced and can be reduced to below 0.86%, the V2O5 content in the obtained ammonium vanadate precipitate is significantly increased and can reach above 89.32%, the vanadium leaching rate is significantly increased and reaches above 93.5%, indicating that in the roasting process, the temperature and roasting time of the first-stage roasting, the second-stage roasting and the third-stage roasting are reasonably adjusted, the temperature is 580-630 ℃, the holding time is 120-150 min in the first-stage roasting, the temperature is 850-900 ℃, the holding time is 90-120 min in the second-stage roasting, the temperature is 350-450 ℃, the holding time is 60-90 min in the third-stage roasting, which can increase the vanadium leaching rate, increase the comprehensive recovery rate of vanadium and obtain vanadium pentoxide powder with a purity of >98.5%.
[0046] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. within the spirit and principle of the present application shall be included in the protection scope of the present application.
Claims
1. A vanadium extraction process by calcification of vanadium slag, characterized in that, Includes the following steps: S1. Mix the pretreated vanadium slag with limestone powder and calcine to obtain clinker vanadium slag. S2. After the clinker vanadium slag is pulped, it is subjected to a first acid leaching and separation to obtain a first leachate and a first tailings. After the first tailings is pulped, it is subjected to a second acid leaching and separation to obtain a second leachate and a second tailings. S3. Add ammonium sulfate to the first leachate for vanadium precipitation treatment, filter to obtain supernatant and precipitate, dry and calcine the precipitate to obtain vanadium pentoxide powder. The roasting process is divided into three stages: a first stage of roasting, a second stage of roasting, and a third stage of roasting. During the first stage of roasting, the temperature is 580~600℃ and the holding time is 120~150min; During the second stage of roasting, the temperature is 850~900℃ and the holding time is 90~120min; During the third stage of roasting, the temperature is 350~450℃ and the holding time is 60~90min.
2. The vanadium slag calcification and vanadium extraction process according to claim 1, characterized in that, During the first stage of roasting and the second stage of roasting, the heating rate is independently 5~15℃ / min; During the third stage of roasting, the temperature is reduced from 850-900℃ to 350-450℃ at a rate of 6-10℃ / min, and after roasting for 60-90 minutes, it is naturally cooled to room temperature.
3. The vanadium slag calcification and vanadium extraction process according to claim 2, characterized in that, The heating rate of the first stage of roasting is greater than the heating rate of the second stage of roasting.
4. The vanadium extraction process by calcification of vanadium slag according to claim 1, characterized in that, The first acid leaching process is divided into a first-stage acid leaching, a second-stage acid leaching, and a third-stage acid leaching. During the first stage of acid leaching, the leaching pH value is 3.5~4.0, and the leaching time is 10~15 minutes; During the second stage of acid leaching, the leaching pH value is 2.5~2.8, and the leaching time is 30~40 minutes; During the third stage of acid leaching, the leaching pH value is stabilized at 2.5~2.
8.
5. The vanadium slag calcification and vanadium extraction process according to claim 4, characterized in that, During the first stage of acid leaching, the acid solution is added at a rate of 4~12 mL / min; During the second stage of acid leaching, the acid solution is added at a rate of 1-3 mL / min.
6. The vanadium slag calcification and vanadium extraction process according to claim 1, characterized in that, During the second acid leaching, the leaching pH value is 1.5~1.7; During the second acid leaching, the acid solution is added at a rate of 0.7~2 mL / min.
7. The vanadium slag calcification and vanadium extraction process according to claim 6, characterized in that, The rate at which the acidic solution is added during the second acid leaching is less than the rate at which the acidic solution is added during the second stage acid leaching.
8. The vanadium slag calcification and vanadium extraction process according to claim 1, characterized in that, During the first acid leaching, the solid-liquid ratio of the vanadium slag and the acidic solution is 1g:2.5~3mL; During the second acid leaching, the solid-liquid ratio of the first tailings and the acidic solution is 1g:2.5~3mL.
9. The vanadium slag calcification and vanadium extraction process according to claim 1, characterized in that, In step S1, the oxygen content of the flue gas during roasting is 10%~18%.
10. A vanadium slag calcification and vanadium extraction process according to claim 5, characterized in that, The acidic solution is a sulfuric acid solution, and the mass fraction of the sulfuric acid solution is 50%~98%.