A method for preparing V2O5 from vanadium slag

Abstract

The present application belongs to the technical field of metallurgy, and particularly relates to a method for preparing V2O5 by using vanadium slag. After the molten vanadium slag is subjected to quenching and tempering treatment, the temperature is controlled to induce vanadium in the molten vanadium slag to precipitate as vanadium spinel solid phase, and the quenching and tempering treatment inhibits the precipitation of silicate. With the aid of supergravity separation technology, the separation of the vanadium spinel solid phase and the silicate liquid phase is realized, and the inhibition of vanadium extraction by silicate wrapping vanadium is eliminated. The separated vanadium spinel solid phase is used to prepare V2O5 product, realizing efficient extraction of vanadium resources. The separated silicate liquid phase can be used as blast furnace raw material after cooling, thereby realizing harmless utilization of vanadium slag.

Description

Technical Field

[0001] This invention belongs to the field of metallurgical technology, specifically a method for preparing V2O5 using vanadium slag. Background Technology

[0002] Vanadium is an important transition metal element, listed as a critical metal resource by major economies worldwide, and widely used in important fields such as steel, chemicals, energy, optics, electronics, environmental protection, medicine, and nuclear energy. As the largest producer of vanadium products, approximately 88% of my country's vanadium production comes from vanadium slag. With the increasing consumption of vanadium slag, large amounts of vanadium extraction tailings are piling up, not only wasting vanadium resources but also containing toxic high-valence vanadium ions (V₂O₃). 5+ Vanadium slag poses a serious threat to the environment. Therefore, achieving efficient extraction of vanadium resources from vanadium slag is urgently needed.

[0003] Currently, several processes for the efficient extraction of vanadium resources from vanadium slag have been disclosed. Among them, the sodium vanadium extraction process is mainly used to prepare V₂O₅ from vanadium slag. Firstly, low-valent vanadium (V₂O₅) in vanadium slag... 3+ After sodium roasting, it is transformed into a high-valence state (V). 5+ The process involves obtaining soluble sodium vanadate; then, vanadium is extracted from the sodium-roasted vanadium slag by leaching to obtain a vanadium-containing leachate; subsequently, vanadium is precipitated from the vanadium-containing leachate using ammonium salts to obtain ammonium polyvanadate; finally, the ammonium polyvanadate is calcined to prepare the product V₂O₅. This process is mature and has low production costs. However, the main vanadium-rich phase in the vanadium slag is tightly encapsulated by the silicate phase, which severely inhibits the oxidation and leaching of vanadium during the extraction process, resulting in a low vanadium recovery rate from the vanadium slag. On the other hand, the use of strong acid and strong alkali reagents leads to the leaching of a large amount of other elements from the vanadium slag, thus affecting the purity of the final V₂O₅ product. Summary of the Invention

[0004] To address the aforementioned problems, this invention provides a method for preparing V₂O₅ using vanadium slag. By adjusting the alkalinity of the molten vanadium slag, the precipitation of silicates is suppressed; by controlling the temperature, vanadium is induced to fully precipitate from the vanadium slag, resulting in a vanadium spinel solid phase and a silicate liquid phase. These two phases are then separated using centrifugal force, thus solving the problem of silicate encapsulation inhibiting vanadium leaching during extraction. Furthermore, V₂O₅ with a purity higher than 99.5 wt% is prepared using the separated vanadium spinel solid phase.

[0005] A method for preparing V2O5 using vanadium slag according to the present invention includes the following steps: S1. The molten vanadium slag is subjected to conditioning treatment to obtain a first mixture, wherein the conditioning treatment specifically involves adjusting the basicity of the vanadium slag to 0.5~0.8; S2. Cool the first mixture to obtain a second mixture, wherein the second mixture contains a vanadium spinel solid phase and a silicate liquid phase; S3. The second mixture is subjected to centrifugal separation to obtain the vanadium spinel solid phase and the silicate liquid phase; S4. Purify the vanadium spinel solid phase to obtain V2O5 product.

[0006] In the above technical solution, in step S1, the precipitation of silicates is suppressed by conditioning the molten vanadium slag; in step S2, vanadium in the vanadium slag is induced to fully precipitate in the state of vanadium spinel by lowering the temperature, thereby obtaining a vanadium spinel solid phase; in step S3, the separation of the vanadium spinel solid phase and the silicate liquid phase is achieved by using high gravity separation technology, thereby solving the problem of inhibiting vanadium leaching during the extraction process due to silicate encapsulation.

[0007] As a preferred embodiment of the method for preparing V2O5 using vanadium slag according to the present invention, in step S1, the vanadium slag is converter vanadium slag or electric furnace vanadium slag, wherein the V2O3 content in the vanadium slag is 5wt%~20wt%.

[0008] As a preferred embodiment of the method for preparing V2O5 using vanadium slag according to the present invention, in step S1, the temperature of the molten vanadium slag is 1350~1400℃.

[0009] As a preferred embodiment of the method for preparing V2O5 using vanadium slag according to the present invention, in step S1, lime is used to condition the molten vanadium slag.

[0010] In the above technical solution, lime is added to increase alkalinity, so that silicate can be stably retained in the liquid phase in liquid form.

[0011] In a preferred embodiment of the method for preparing V2O5 using vanadium slag according to the present invention, in step S2, the cooling rate is 0.5~5℃ / min.

[0012] As a preferred embodiment of the method for preparing V2O5 using vanadium slag according to the present invention, in step S2, the temperature of the second mixture is 1100~1200℃. In the above technical solution, controlling the temperature of the second mixture to be 1100~1200℃ can promote the precipitation of vanadium in the state of vanadium spinel.

[0013] As a preferred embodiment of the method for preparing V2O5 using vanadium slag according to the present invention, in step S3, the gravity coefficient of the hypergravity separation is 200~800.

[0014] As a preferred embodiment of the method for preparing V2O5 using vanadium slag according to the present invention, in step S3, the separation time of the supergravity separation is 5~15 min.

[0015] As a preferred embodiment of the method for preparing V2O5 using vanadium slag according to the present invention, in step S3, the content of V2O3 in the vanadium spinel solid phase is higher than 29.5 wt%, and the vanadium recovery rate is higher than 90%.

[0016] As a preferred embodiment of the method for preparing V2O5 using vanadium slag according to the present invention, step S4 further includes: cooling the silicate liquid phase to obtain a silicate solid phase.

[0017] As a preferred embodiment of the method for preparing V2O5 using vanadium slag according to the present invention, in step S4, the purification adopts a sodium vanadium extraction process.

[0018] As a preferred embodiment of the method for preparing V2O5 using vanadium slag according to the present invention, in step S4, the purity of the V2O5 product is higher than 98.8 wt%, and the vanadium recovery rate is higher than 96%.

[0019] This invention proposes a method for preparing V₂O₅ from vanadium slag, which yields the following beneficial effects: Pre-treatment of molten vanadium slag with lime inhibits silicate precipitation; pre-treatment of the molten vanadium slag with cooling induces vanadium precipitation as a vanadium spinel solid phase; and centrifugation of the molten vanadium slag strengthens the separation of the vanadium spinel solid phase and the silicate liquid phase, avoiding the inhibition of vanadium leaching by the silicate phase during subsequent V₂O₅ preparation, thus preventing a decrease in vanadium recovery rate. This conditioning-cooling-separation method not only improves the vanadium recovery rate from vanadium slag to over 90%, but also produces V₂O₅ with a purity exceeding 99.5 wt%. The obtained silicate solid phase can be used as a blast furnace feedstock, achieving the harmless utilization of vanadium slag. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0021] Figure 1 The images show the SEM images and elemental composition of the vanadium spinel solid phase and the silicate solid phase in Example 1. Figure 2The images show the SEM and EDS spectra of the vanadium spinel solid phase and the silicate solid phase in Example 2. The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0022] The technical solutions described below in conjunction with the embodiments will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] This invention provides the following technical solution: A method for preparing V2O5 using vanadium slag includes the following steps: S1. The molten vanadium slag is subjected to conditioning treatment to obtain a first mixture, wherein the conditioning treatment specifically involves adjusting the basicity of the vanadium slag to 0.5~0.8; Preferably, lime is used to condition the molten vanadium slag; the V2O3 content in the vanadium slag is 5wt%~20wt%; and the temperature of the molten vanadium slag is 1350~1400℃. Specifically, the V2O3 content in the vanadium slag can be any one or any two of 5wt%, 8wt%, 11wt%, 14wt%, 17wt%, and 20wt%; the temperature of the molten vanadium slag can be any one or any two of 1350℃, 1360℃, 1370℃, 1380℃, 1390℃, and 1400℃.

[0024] S2. Cool the first mixture to obtain a second mixture, wherein the second mixture contains a vanadium spinel solid phase and a silicate liquid phase; Preferably, the cooling rate is 0.5~5℃ / min; the temperature of the second mixture is 1100~1200℃; Specifically, the cooling rate can be any one or a range between any two of 0.5℃ / min, 1℃ / min, 1.5℃ / min, 2℃ / min, 2.5℃ / min, 3℃ / min, 3.5℃ / min, 4℃ / min, 4.5℃ / min, and 5℃ / min; the temperature of the second mixture can be any one or a range between any two of 1100℃, 1120℃, 1140℃, 1160℃, 1180℃, and 1200℃.

[0025] S3. The second mixture is subjected to centrifugal separation to obtain the vanadium spinel solid phase and the silicate liquid phase; Preferably, the gravity coefficient of the hypergravity separation is 200-800; the separation time of the hypergravity separation is 5-15 min; the V2O3 content in the vanadium spinel solid phase is higher than 29.5 wt%, and the vanadium recovery rate is higher than 90%. Specifically, the gravity coefficient for the hypergravity separation can be any one of 200, 300, 400, 500, 600, 700, 800 or any two of these values; the separation time for the hypergravity separation can be any one of 5 min, 6 min, 7 min, 8 min, 9 min, 10 min, 11 min, 12 min, 13 min, 14 min, 15 min or any two of these values.

[0026] S4. Purify the vanadium spinel solid phase to obtain V2O5 product; Preferably, the silicate liquid phase is cooled to obtain a silicate solid phase; the purification adopts a sodium vanadium extraction process; the purity of the V2O5 product is higher than 98.8 wt%, and the vanadium recovery rate is higher than 96%.

[0027] The technical solution of the present invention will be further described below with reference to specific embodiments.

[0028] The main components of the vanadium slag used in Examples 1-5 and Comparative Examples 1-3 are shown in Table 1: Table 1

[0029] The main components of the vanadium slag used in Example 6 are shown in Table 2: Table 2

[0030] Example 1

[0031] A method for preparing V2O5 using vanadium slag includes the following steps: S1. The molten vanadium slag is subjected to conditioning treatment to obtain a first mixture, wherein the conditioning treatment specifically involves adjusting the alkalinity of the vanadium slag to 0.5 using lime; S2. Cool the first mixture to obtain a second mixture, wherein the second mixture contains a vanadium spinel solid phase and a silicate liquid phase, wherein the cooling rate is 0.5℃ / min and the temperature of the second mixture is 1200℃; S3. The second mixture is subjected to centrifugal separation to obtain the vanadium spinel solid phase and the silicate liquid phase, wherein the gravity coefficient of the centrifugal separation is 200 and the separation time is 5 min; S4. The vanadium spinel solid phase is subjected to a vanadium extraction process using sodium vanadium treatment to obtain V2O5 product. The silicate liquid phase is then cooled to obtain a silicate solid phase. The microstructure and elemental composition of the vanadium spinel solid phase and the silicate solid phase are characterized, and the results are as follows: Figure 1 As shown, the separated vanadium spinel solid phase is an equiaxed crystal, with Fe, V, Ti, Mn, and O as its main constituent elements, while the silicate solid phase is a glassy phase, with Fe, Si, O, Mn, and Ca as its main constituent elements. The V₂O₃ content in the vanadium spinel solid phase is 34.28 wt%, and the vanadium recovery rate is 94.24%. Further analysis of the prepared V₂O₅ product revealed a purity of 99.80 wt% and a vanadium recovery rate of 98.69%.

[0032] Example 2

[0033] A method for preparing V2O5 using vanadium slag includes the following steps: S1. The molten vanadium slag is subjected to conditioning treatment to obtain a first mixture, wherein the conditioning treatment specifically involves adjusting the alkalinity of the vanadium slag to 0.8 using lime; S2. Cool the first mixture to obtain a second mixture, wherein the second mixture contains a vanadium spinel solid phase and a silicate liquid phase, wherein the cooling rate is 0.5℃ / min and the temperature of the second mixture is 1200℃; S3. The second mixture is subjected to centrifugal separation to obtain the vanadium spinel solid phase and the silicate liquid phase, wherein the gravity coefficient of the centrifugal separation is 200 and the separation time is 5 min; S4. The vanadium spinel solid phase is subjected to a sodium vanadium extraction process to obtain V2O5 product. The silicate liquid phase is cooled to obtain the silicate solid phase. The V2O3 content in the vanadium spinel solid phase is 29.59 wt%, and the vanadium recovery rate is 91.47%. Further testing of the prepared V2O5 product shows that the purity of the V2O5 product is 98.87 wt%, and the vanadium recovery rate is 96.17%. Compared with Example 1, when the basicity is increased, it promotes the extraction of V2O3 in the slag. 3+ The oxidation of Fe inhibits the precipitation of vanadium spinel; on the other hand, it also promotes the precipitation of Fe. 2+ Oxidation of ions to Fe 3+ This leads to more iron ions dissolving into the spinel phase, resulting in a decrease in vanadium recovery and a decrease in V2O3 content in the vanadium spinel solid phase.

[0034] Example 3

[0035] A method for preparing V2O5 using vanadium slag includes the following steps: S1. The molten vanadium slag is subjected to conditioning treatment to obtain a first mixture, wherein the conditioning treatment specifically involves adjusting the alkalinity of the vanadium slag to 0.5 using lime; S2. Cool the first mixture to obtain a second mixture, wherein the second mixture contains a vanadium spinel solid phase and a silicate liquid phase, wherein the cooling rate is 0.5℃ / min and the temperature of the second mixture is 1100℃; S3. The second mixture is subjected to centrifugal separation to obtain the vanadium spinel solid phase and the silicate liquid phase, wherein the gravity coefficient of the centrifugal separation is 200 and the separation time is 5 min; S4. The vanadium spinel solid phase is subjected to a vanadium extraction process using sodium vanadium treatment to obtain V2O5 product. The silicate liquid phase is then cooled to obtain the silicate solid phase. The V2O3 content in the vanadium spinel solid phase is 33.18 wt%, and the vanadium recovery rate is 92.54%. Further testing of the prepared V2O5 product reveals a purity of 99.74 wt% and a vanadium recovery rate of 99.18%.

[0036] Example 4

[0037] A method for preparing V2O5 using vanadium slag includes the following steps: S1. The molten vanadium slag is subjected to conditioning treatment to obtain a first mixture, wherein the conditioning treatment specifically involves adjusting the alkalinity of the vanadium slag to 0.5 using lime; S2. Cool the first mixture to obtain a second mixture, wherein the second mixture contains a vanadium spinel solid phase and a silicate liquid phase, wherein the cooling rate is 0.5℃ / min and the temperature of the second mixture is 1200℃; S3. The second mixture is subjected to hypergravity separation to obtain the vanadium spinel solid phase and the silicate liquid phase, wherein the gravity coefficient of the hypergravity separation is 200 and the separation time is 15 min; S4. The vanadium spinel solid phase is subjected to a vanadium extraction process using sodium vanadium extraction to obtain V2O5 product. The silicate liquid phase is then cooled to obtain the silicate solid phase. The V2O3 content in the vanadium spinel solid phase is 33.25 wt%, and the vanadium recovery rate is 95.61%. Further testing of the prepared V2O5 product reveals a purity of 99.75 wt% and a vanadium recovery rate of 98.84%.

[0038] Example 5

[0039] A method for preparing V2O5 using vanadium slag includes the following steps: S1. The molten vanadium slag is subjected to conditioning treatment to obtain a first mixture, wherein the conditioning treatment specifically involves adjusting the alkalinity of the vanadium slag to 0.5 using lime; S2. Cool the first mixture to obtain a second mixture, wherein the second mixture contains a vanadium spinel solid phase and a silicate liquid phase, wherein the cooling rate is 0.5℃ / min and the temperature of the second mixture is 1200℃; S3. The second mixture is subjected to centrifugal separation to obtain the vanadium spinel solid phase and the silicate liquid phase, wherein the gravity coefficient of the centrifugal separation is 800 and the separation time is 5 min; S4. The vanadium spinel solid phase is subjected to a vanadium extraction process using sodium vanadium extraction to obtain V2O5 product. The silicate liquid phase is then cooled to obtain the silicate solid phase. The V2O3 content in the vanadium spinel solid phase is 33.25 wt%, and the vanadium recovery rate is 94.03%. Further testing of the prepared V2O5 product reveals a purity of 99.87 wt% and a vanadium recovery rate of 98.61%.

[0040] Example 6

[0041] A method for preparing V2O5 using vanadium slag includes the following steps: S1. The molten vanadium slag is subjected to conditioning treatment to obtain a first mixture, wherein the conditioning treatment specifically involves adjusting the alkalinity of the vanadium slag to 0.5 using lime; S2. Cool the first mixture to obtain a second mixture, wherein the second mixture contains a vanadium spinel solid phase and a silicate liquid phase, wherein the cooling rate is 0.5℃ / min and the temperature of the second mixture is 1200℃; S3. The second mixture is subjected to centrifugal separation to obtain the vanadium spinel solid phase and the silicate liquid phase, wherein the gravity coefficient of the centrifugal separation is 200 and the separation time is 5 min; S4. The vanadium spinel solid phase is subjected to a vanadium extraction process using sodium vanadium treatment to obtain V2O5 product. The silicate liquid phase is then cooled to obtain the silicate solid phase. The microstructure and elemental composition of the vanadium spinel solid phase and the silicate solid phase are characterized, and the results are as follows: Figure 2 As shown, the separated vanadium spinel solid phase is an equiaxed crystal, with Fe, V, Ti, Mn, and O as its main constituent elements, while the silicate solid phase is a glassy phase, with Fe, Si, O, Mn, and Ca as its main constituent elements. The V₂O₃ content in the vanadium spinel solid phase is 33.35 wt%, and the vanadium recovery rate is 93.87%. Further analysis of the prepared V₂O₅ product revealed a purity of 99.28 wt% and a vanadium recovery rate of 96.94%.

[0042] Comparative Example 1 The difference from Example 1 is that, in step S1, the basicity of the vanadium slag is adjusted to 0.2. The V2O3 content in the vanadium spinel solid phase is 38.51 wt%, and the vanadium recovery rate is 74.29%. Furthermore, the prepared V2O5 product is tested, and the purity of the V2O5 product is 97.64 wt%, and the vanadium recovery rate is 91.57%.

[0043] Comparative Example 2 The difference from Example 1 is that, in step S1, the basicity of the vanadium slag is adjusted to 1.2. The V2O3 content in the vanadium spinel solid phase is 26.14 wt%, and the vanadium recovery rate is 71.54%. Furthermore, the prepared V2O5 product is tested, and the purity of the V2O5 product is 98.21 wt%, and the vanadium recovery rate is 96.46%.

[0044] Comparative Example 3 The difference from Example 1 is that in step S3, the second mixture is subjected to sedimentation separation for 60 minutes. The V2O3 content in the vanadium spinel solid phase is 25.82 wt%, and the vanadium recovery rate is 72.00%. Furthermore, the prepared V2O5 product is tested, and the purity of the V2O5 product is 88.20 wt%, with a vanadium recovery rate of 78.40%.

[0045] The above description is merely a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A method for preparing V₂O₅ using vanadium slag, characterized in that, Includes the following steps: S1. The molten vanadium slag is subjected to conditioning treatment to obtain a first mixture, wherein the conditioning treatment specifically involves adjusting the basicity of the vanadium slag to 0.5~0.8; S2. Cool the first mixture to obtain a second mixture, wherein the second mixture contains a vanadium spinel solid phase and a silicate liquid phase; S3. The second mixture is subjected to centrifugal separation to obtain the vanadium spinel solid phase and the silicate liquid phase; S4. Purify the vanadium spinel solid phase to obtain V2O5 product.

2. The method for preparing V₂O₅ using vanadium slag according to claim 1, characterized in that, In step S1, the vanadium slag is converter vanadium slag or electric furnace vanadium slag, wherein the V2O3 content in the vanadium slag is 5wt%~20wt%.

3. The method for preparing V₂O₅ using vanadium slag according to claim 1, characterized in that, In step S1, the temperature of the molten vanadium slag is 1350~1400℃.

4. The method for preparing V₂O₅ using vanadium slag according to claim 1, characterized in that, In step S2, the cooling rate is 0.5~5℃ / min.

5. The method for preparing V₂O₅ using vanadium slag according to claim 1, characterized in that, In step S2, the temperature of the second mixture is 1100~1200℃.

6. The method for preparing V₂O₅ using vanadium slag according to claim 1, characterized in that, In step S3, the gravity coefficient of the hypergravity separation is 200~800.

7. The method for preparing V₂O₅ using vanadium slag according to claim 1, characterized in that, In step S3, the separation time for the hypergravity separation is 5-15 minutes.

8. The method for preparing V₂O₅ using vanadium slag according to claim 1, characterized in that, In step S3, the V2O3 content in the vanadium spinel solid phase is higher than 29.5 wt%, and the vanadium recovery rate is higher than 90%.

9. The method for preparing V₂O₅ using vanadium slag according to claim 1, characterized in that, In step S4, the purification process employs sodium vanadium extraction.

10. A method for preparing V₂O₅ from vanadium slag according to claim 1, characterized in that, In step S4, the purity of the V2O5 product is higher than 98.8 wt%, and the vanadium recovery rate is higher than 96%.

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