Na 2co 3 / nao 2 additive and method for improving vanadium leaching rate

Abstract

A Na2CO3 / NaO2 additive and a method for improving the vanadium leaching rate. In the present invention, Na2CO3 and NaO2 are used as additives for extracting vanadium by means of vanadium slag roasting, wherein NaO2 is strongly basic, and is decomposed to generate oxygen during the roasting process, such that the air permeability of the block sample is improved, so that trivalent vanadium can be oxidized into pentavalent vanadium without an overhigh roasting temperature and is then finally converted into a soluble vanadate; in addition, vanadium in the vanadium slag can be almost completely oxidized into sodium vanadate, thereby improving the vanadium leaching rate; and the price of Na2CO3 is relatively low, and by adding Na2CO3, the amount of NaO2 is greatly reduced, thereby reducing the cost; in addition, the amount of Na2CO3 and NaO2 is controlled, thereby ensuring the vanadium leaching rate. Moreover, compared with a single addition of Na2CO3, the vanadium leaching rate is increased by 7.39%, the roasting temperature is reduced by 90ºC, and the energy consumption is reduced.

Description

A Na2CO3 / NaO2 additive and a method for improving vanadium leaching rate Technical Field

[0001] The present invention relates to the technical field of vanadium slag extraction, in particular to a Na2CO3 / NaO2 additive and a method for improving vanadium leaching rate. Background Art

[0002] To extract vanadium from vanadium slag, various roasting methods have been developed. Depending on the additives used, roasting processes for vanadium extraction can be categorized as sodium roasting, calcium roasting, salt-free roasting, magnesium roasting, and composite salt roasting. Sodium roasting is currently the most widely used vanadium extraction process. Commonly used sodium salts for sodium roasting include NaCl, Na2SO4, Na2CO3, Na2O2, and NaOH. However, in actual production, large amounts of NaCl and Na2SO4 are added, which decompose during the roasting process to produce large amounts of toxic gases such as Cl2 and SO2, causing significant environmental pollution. If Na2CO3 is used exclusively as an additive, the vanadium leaching rate is relatively low.

[0003] In a February 2022 article titled "Exploration of Vanadium Extraction Technology by Roasting Vanadium Slag with Na2O2," Yue Hongrui et al. from Northeastern University in China investigated the use of Na2O2 as an additive. However, this method only achieved a vanadium leaching rate of 95.57% at a sodium-to-vanadium ratio of 3:1, and the cost of using Na2O2 alone as an additive is high. NaO2 can also be used as a roasting additive, but its price is also relatively high, making its use as a standalone additive unsuitable for industrial production. Therefore, developing a simple, economical additive that can achieve a high vanadium leaching rate has become a pressing technical challenge in this field.

[0004] Summary of the Invention

[0005] The object of the present invention is to provide a Na2CO3 / NaO2 additive and a method for improving the vanadium leaching rate. When the Na2CO3 / NaO2 additive provided by the present invention is used for roasting and extracting vanadium, the vanadium leaching rate is improved, the cost and roasting temperature are reduced, and the energy consumption is reduced. The Na2CO3 / NaO2 additive is suitable for industrial production and promotes the development of the vanadium extraction industry.

[0006] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0007] The present invention provides a Na2CO3 / NaO2 additive, which comprises Na2CO3 and NaO2; the molar ratio of the Na2CO3 to NaO2 is 1:(0.2-0.8):(0.15-0.6).

[0008] Preferably, the molar ratio of Na2CO3 and NaO2 is 1:(0.2-0.4):(0.15-0.4).

[0009] The present invention provides a method for improving vanadium leaching rate, comprising the following steps:

[0010] (1) mixing vanadium slag and the Na2CO3 / NaO2 additive described in the above technical solution to obtain a mixed material;

[0011] (2) The mixture obtained in step (1) is sequentially roasted, leached and filtered to obtain a vanadium-containing solution and leached residue.

[0012] Preferably, the molar ratio of V2O5 in the vanadium slag to Na2CO3 in the additive is 1:(0.2-0.8).

[0013] Preferably, the molar ratio of V2O5 in the vanadium slag to Na2CO3 in the additive is 1:(0.2-0.4).

[0014] Preferably, the vanadium slag in step (1) comprises converter vanadium slag.

[0015] Preferably, the calcination temperature in step (2) is 550-950°C.

[0016] Preferably, the calcination temperature in step (2) is 600-850°C.

[0017] Preferably, the calcination time in step (2) is 30 to 120 minutes.

[0018] Preferably, the calcination time in step (2) is 60 to 100 minutes.

[0019] Preferably, the leaching temperature in step (2) is 25-95°C.

[0020] Preferably, the leaching temperature in step (2) is 70-90°C.

[0021] Preferably, the liquid-to-solid ratio of the leaching in step (2) is 6 to 14 mL / g.

[0022] Preferably, the liquid-to-solid ratio of the leaching in step (2) is 8 to 10 mL / g.

[0023] Preferably, the leaching time in step (2) is 15 to 60 minutes.

[0024] Preferably, the stirring rate during leaching in step (2) is 100 to 500 r / min.

[0025] Preferably, the leaching agent used in step (2) is water.

[0026] The present invention provides a Na2CO3 / NaO2 additive, comprising Na2CO3 and NaO2; the molar ratio of Na2CO3 to NaO2 is (0.2-0.8):(0.15-0.6). The present invention uses Na2CO3 and NaO2 as additives for vanadium extraction from vanadium slag roasting. NaO2 has strong alkalinity and decomposes to produce oxygen during the roasting process, improving the permeability of the block sample. Therefore, trivalent vanadium can be oxidized to pentavalent vanadium without using excessively high roasting temperatures, ultimately converting it into soluble vanadate. Simultaneously, almost all of the vanadium in the vanadium slag can be oxidized to sodium vanadate, thereby increasing the vanadium leaching rate. Na2CO3 is relatively inexpensive, and by adding it, the amount of NaO2 used is significantly reduced, thereby lowering costs. Simultaneously, the amounts of Na2CO3 and NaO2 used are controlled to ensure the vanadium leaching rate. Compared with adding Na2CO3 alone, the vanadium leaching rate is increased by 7.39%, and the roasting temperature is reduced by 90°C, reducing energy consumption. Experimental results show that when the Na2CO3 / NaO2 additive provided by the present invention is used for sodium roasting of vanadium slag to extract vanadium, the vanadium leaching rate is 97.36%. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] FIG1 is a schematic diagram of a process flow of a method for improving vanadium leaching rate provided by the present invention;

[0028] FIG2 is a technical roadmap of the method for improving vanadium leaching rate provided by the present invention. DETAILED DESCRIPTION

[0029] The present invention provides a Na2CO3 / NaO2 additive, which comprises Na2CO3 and NaO2; the molar ratio of the Na2CO3 to the NaO2 is (0.2-0.8): (0.15-0.6).

[0030] Unless otherwise specified, the raw materials used in the present invention are all commercially available products.

[0031] The Na2CO3 / NaO2 additive provided by the present invention includes Na2CO3 and NaO2. The present invention uses Na2CO3 and NaO2 as additives for vanadium extraction by roasting vanadium slag. NaO2 has strong alkalinity and decomposes to produce oxygen during the roasting process, which improves the permeability of the block sample. Therefore, trivalent vanadium can be oxidized to pentavalent vanadium without using an excessively high roasting temperature, and ultimately converted into soluble vanadate. At the same time, almost all of the vanadium in the vanadium slag can be oxidized to sodium vanadate, thereby improving the vanadium leaching rate. Compared with adding Na2CO3 alone, the vanadium leaching rate is increased by 7.39%, while the roasting temperature is also reduced by 90°C. Na2CO3 is relatively cheap, and by adding Na2CO3, the amount of NaO2 used is significantly reduced, thereby reducing costs. At the same time, the amount of Na2CO3 and NaO2 used is controlled to ensure the vanadium leaching rate.

[0032] In the present invention, the molar ratio of Na2CO3 to NaO2 is (0.2-0.8): (0.15-0.6), preferably (0.2-0.4): (0.15-0.4). By controlling the amount of Na2CO3 and NaO2, the present invention ensures the vanadium leaching rate and reduces the cost.

[0033] The present invention provides a method for improving vanadium leaching rate, comprising the following steps:

[0034] (1) mixing vanadium slag and the Na2CO3 / NaO2 additive described in the above technical solution to obtain a mixed material;

[0035] (2) The mixture obtained in step (1) is sequentially roasted, leached and filtered to obtain a vanadium-containing solution and leached residue.

[0036] The present invention mixes vanadium slag and Na2CO3 / NaO2 additives to obtain a mixed material.

[0037] In the present invention, the vanadium slag preferably includes converter vanadium slag; the converter vanadium slag preferably comes from Chengde Iron and Steel Plant in Hebei Province.

[0038] In the present invention, the particle size of the vanadium slag is preferably less than 200 meshes; when the particle size of the vanadium slag is not within the above range, the present invention preferably sequentially crushes and ball-mills the vanadium slag.

[0039] In the present invention, the molar ratio of V2O5 in the vanadium slag to Na2CO3 in the additive is preferably 1:(0.2-0.8), more preferably (0.2-0.4).

[0040] After obtaining the mixed material, the present invention sequentially roasts, leaches, and filters the mixed material to obtain a vanadium-containing solution and leached residue. The present invention destroys the original vanadium-containing mineral structure through roasting and oxidizes it to obtain pentavalent vanadium oxide, which is then combined with an additive to produce water-soluble sodium vanadate.

[0041] In the present invention, the calcination temperature is preferably 550-950° C., more preferably 600-850° C.; the calcination time is preferably 30-120 min, more preferably 60-100 min.

[0042] After the roasting is completed, the roasted product is preferably ball-milled to obtain roasted clinker. In the present invention, the particle size of the roasted clinker is preferably less than 200 mesh.

[0043] In the present invention, the leaching temperature is preferably 25-95° C., more preferably 70-90° C. The present invention can further improve the vanadium leaching rate by controlling the leaching temperature. The vanadium leaching rate increases with increasing leaching temperature, but the influence trend gradually slows down.

[0044] In the present invention, the liquid-to-solid ratio of the leaching is preferably 6 to 14 mL / g, more preferably 8 to 10 mL / g. In the present invention, if the liquid-to-solid ratio of the leaching is small, the viscosity of the leachate is high, resulting in high resistance to the outward diffusion of soluble vanadium, which cannot fully disperse the roasted slag and is not conducive to the smooth progress of leaching. If the liquid-to-solid ratio of the leaching is too large, the alkalinity of the leachate is reduced, which is also not conducive to the smooth progress of leaching.

[0045] In the present invention, the leaching time is preferably 15 to 60 minutes, more preferably 30 to 50 minutes.

[0046] In the present invention, the stirring rate during the leaching is preferably 100 to 500 r / min, more preferably 300 to 400 r / min.

[0047] In the present invention, the leaching agent is preferably water; and the water is preferably deionized water.

[0048] The present invention has no special limitation on the filtering operation, and any filtering technical solution well known to those skilled in the art may be used.

[0049] The method provided by the invention reduces extraction costs and can achieve a higher vanadium leaching rate at a lower temperature.

[0050] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions of the present invention. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0051] Example 1

[0052] A Na2CO3 / NaO2 additive, consisting of Na2CO3 and NaO2, wherein the molar ratio of Na2CO3 to NaO2 is 0.52:0.33;

[0053] A method for improving vanadium leaching rate:

[0054] (1) Crushing and ball-milling the converter vanadium slag to a particle size of less than 200 mesh, taking 40 g of the ball-milled converter vanadium slag, and then mixing the converter vanadium slag, Na2CO3, and NaO2 to obtain a mixed material; wherein the V content in the converter vanadium slag is 10 wt%; and the molar ratio of V2O5 to Na2CO3 in the converter vanadium slag is 1:0.52;

[0055] (2) placing the mixture obtained in step (1) in a muffle furnace at 780° C. for 90 min, and then ball-milling the mixture to a particle size of less than 200 mesh to obtain a calcined clinker;

[0056] (3) Leaching the roasted clinker obtained in step (2) with 90° C. deionized water at a liquid-to-solid ratio of 10 mL / g and a stirring rate of 400 r / min for 30 min to obtain a leachate; filtering the leachate to obtain a vanadium-containing solution and a leaching residue; and measuring a vanadium leaching rate of 97.36%.

[0057] Example 2

[0058] A Na2CO3 / NaO2 additive, consisting of Na2CO3 and NaO2, wherein the molar ratio of Na2CO3 to NaO2 is 0.4:0.4;

[0059] A method for improving vanadium leaching rate:

[0060] (1) Crushing and ball-milling the converter vanadium slag in sequence to a particle size of less than 200 mesh, and then mixing the converter vanadium slag, Na2CO3, and NaO2 to obtain a mixed material; wherein the V content in the converter vanadium slag is 10 wt%; and the molar ratio of V2O5 to Na2CO3 in the converter vanadium slag is 1:0.4;

[0061] (2) placing the mixture obtained in step (1) in a muffle furnace at 750° C. for 120 min, and then ball-milling the mixture to a particle size of less than 200 mesh to obtain a calcined clinker;

[0062] (3) Leaching the roasted clinker obtained in step (2) with 95° C. deionized water at a liquid-to-solid ratio of 8 mL / g and a stirring rate of 400 r / min for 30 min to obtain a leachate; filtering the leachate to obtain a vanadium-containing solution and a leach residue; and measuring a vanadium leaching rate of 94.43%.

[0063] Example 3

[0064] A Na2CO3 / NaO2 additive, consisting of Na2CO3 and NaO2, wherein the molar ratio of Na2CO3 to NaO2 is 0.3:0.55;

[0065] A method for improving vanadium leaching rate:

[0066] (1) Crushing and ball-milling the converter vanadium slag in sequence to a particle size of less than 200 mesh, and then mixing the converter vanadium slag, Na2CO3, and NaO2 to obtain a mixed material; wherein the V content in the converter vanadium slag is 10 wt%; and the molar ratio of V2O5 to Na2CO3 in the converter vanadium slag is 1:0.3;

[0067] (2) placing the mixed material obtained in step (1) in a muffle furnace at 850° C. for 60 min, and then ball-milling to a particle size of less than 200 mesh to obtain a calcined clinker;

[0068] (3) Leaching the roasted clinker obtained in step (2) with 80° C. deionized water at a liquid-to-solid ratio of 12 mL / g and a stirring rate of 400 r / min for 30 min to obtain a leachate; filtering the leachate to obtain a vanadium-containing solution and a leaching residue; and measuring a vanadium leaching rate of 93.03%.

[0069] Example 4

[0070] A Na2CO3 / NaO2 additive, consisting of Na2CO3 and NaO2, wherein the molar ratio of Na2CO3 to NaO2 is 0.6:0.26;

[0071] A method for improving vanadium leaching rate:

[0072] (1) Crushing and ball-milling the converter vanadium slag in sequence to a particle size of less than 200 mesh, and then mixing the converter vanadium slag, Na2CO3, and NaO2 to obtain a mixed material; wherein the V content in the converter vanadium slag is 10 wt%; and the molar ratio of V2O5 to Na2CO3 in the converter vanadium slag is 1:0.6;

[0073] (2) placing the mixed material obtained in step (1) in a muffle furnace at 900° C. for 90 min, and then ball-milling to a particle size of less than 200 mesh to obtain a roasted clinker;

[0074] (3) Leaching the roasted clinker obtained in step (2) with 60° C. deionized water at a liquid-to-solid ratio of 6 mL / g and a stirring rate of 400 r / min for 30 min to obtain a leachate; filtering the leachate to obtain a vanadium-containing solution and a leach residue; and measuring a vanadium leaching rate of 92.12%.

[0075] Example 5

[0076] The difference from Example 1 is that the molar ratio of Na2CO3 to NaO2 is 0.7:0.2; and the vanadium leaching rate is 91.27%.

[0077] Example 6

[0078] The difference from Example 1 is that the molar ratio of Na2CO3 to NaO2 is 0.8:0.15; and the vanadium leaching rate is 90.46%.

[0079] Comparative Example 1

[0080] The difference from Example 1 is that the molar ratio of V2O5 to Na2CO3 in the converter vanadium slag is 1:1.5, the roasting temperature in step (3) is 870°C, and the vanadium leaching rate is 89.97%.

[0081] The description of the above embodiments is only intended to help understand the method of the present invention and its core concept. It should be noted that for those skilled in the art, without departing from the principles of the present invention, several improvements and modifications may be made to the present invention, and these improvements and modifications also fall within the scope of protection of the claims of the present invention. Various modifications to these embodiments are obvious to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A Na2CO3 / NaO2 additive, comprising Na2CO3 and NaO2; the molar ratio of the Na2CO3 and NaO2 is (0.2-0.8): (0.15-0.6).

2. The Na2CO3 / NaO2 additive according to claim 1, characterized in that The molar ratio of the Na2CO3 and NaO2 is (0.2-0.4):(0.15-0.4).

3. A method for improving vanadium leaching rate, comprising the following steps: (1) mixing vanadium slag and the Na2CO3 / NaO2 additive according to any one of claims 1 to 2 to obtain a mixed material; (2) The mixed material obtained in step (1) is sequentially roasted, leached and filtered to obtain a vanadium-containing solution and leached slag.

4. The method according to claim 3, characterized in that In the step (1), the molar ratio of V2O5 in the vanadium slag to Na2CO3 in the additive is 1:(0.2-0.8).

5. The method according to claim 4, characterized in that In the step (1), the molar ratio of V2O5 in the vanadium slag to Na2CO3 in the additive is 1:(0.2-0.4).

6. The method according to claim 3, characterized in that: The vanadium slag in step (1) comprises converter vanadium slag.

7. The method according to claim 3, characterized in that The calcination temperature in step (2) is 550-950°C.

8. The method according to claim 7, characterized in that The calcination temperature in the step (2) is 600-850°C.

9. The method according to claim 3, characterized in that: The calcination time in step (2) is 30 to 120 minutes.

10. The method according to claim 9, characterized in that The calcination time in step (2) is 60 to 100 minutes.

11. The method according to claim 3, characterized in that The leaching temperature in step (2) is 25-95°C.

12. The method according to claim 11, characterized in that The leaching temperature in step (2) is 70-90°C.

13. The method according to claim 3, characterized in that The liquid-to-solid ratio of the leaching in step (2) is 6 to 14 mL / g.

14. The method according to claim 13, characterized in that The liquid-to-solid ratio of the leaching in step (2) is 8 to 10 mL / g.

15. The method according to claim 3, characterized in that The leaching time in step (2) is 15 to 60 minutes.

16. The method according to claim 3, characterized in that The stirring rate during leaching in step (2) is 100 to 500 r / min.

17. The method according to claim 3, characterized in that The leaching agent used in step (2) is water.

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