Vanadium extraction process

Abstract

The invention provides a vanadium extraction process. The vanadium extraction process comprises the following steps: S1, carrying out decarburization treatment on vanadium-containing stone coal and oxygen-enriched air in a fluidized bed furnace to obtain a decarburized intermediate; s2, the decarburized intermediate, chlorine and air are subjected to chlorination vanadium extraction treatment in a fluidized bed furnace, and chlorinated gas is obtained; and S3, the chlorinated gas is subjected to fractional condensation treatment, and vanadium oxytrichloride is obtained. The decarburization intermediate, chlorine and air are subjected to chlorination vanadium extraction treatment in a fluidized bed furnace, and vanadium, chlorine and air in the decarburization intermediate react to form chlorinated gas. And performing fractional condensation treatment according to different condensation points of different substances in the chlorinated gas to obtain vanadium oxytrichloride with relatively high purity. According to the vanadium extraction process, the use of chemical reagents is reduced, and particularly, the consumption of a large amount of acid or alkali is avoided, so that the potential pollution to the environment is reduced. Compared with a traditional vanadium extraction process, the vanadium extraction process is simpler, and the vanadium recovery rate is higher.

Description

Technical Field

[0001] The invention relates to the technical field of metal recovery, and in particular to a vanadium extraction process. Background Art

[0002] Vanadium-containing stone coal is a low-grade polymetallic ore, in which vanadium is an important strategic material. However, the existing technology for extracting vanadium from stone coal resources has the problems of low thermal utilization rate and low recovery rate. For example, the sodium roasting process has the problem that a large amount of alkaline leaching residue will be produced during the test, which pollutes the environment and requires further treatment. The calcium roasting process has the problem that a large amount of acid leaching residue will be produced during the test, which pollutes the environment and requires further treatment, and a large amount of calcium additives will be added, etc., and the process cost is relatively high. The sulfuric acid aging process has the problem of large consumption of sulfuric acid, high production cost of the process, high pressure on equipment operation and maintenance, and a large amount of waste liquid and leaching residue will be produced, causing environmental pollution.

[0003] The Chinese patent with the patent authorization announcement number CN108754125B discloses a treatment method for sodium roasting of stone coal. Stone coal and sodium chloride are mixed evenly, then roasted and water-leached, calcium chloride is added to the water-leaching liquid to precipitate and enrich vanadium, and the calcium vanadate filter cake and the vanadium precipitation liquid are filtered. The total leaching rate of vanadium in the roasted sand reaches 80-95%. However, a large amount of alkaline leaching residue will be produced in the above-mentioned treatment process, which pollutes the environment and needs further treatment. The Chinese patent application with the patent application publication number CN117127028A discloses a treatment method for calcification roasting of stone coal. Stone coal and calcium additives (at least one of Ca(OH)2, CaO, and CaCO3) are mixed evenly, then oxidative roasting and decarbonization are carried out, and the roasted product is ball milled (the ball milling aid is potassium permanganate, potassium dichromate, sodium perchlorate, sodium chlorate, etc.) and acid leached, and the vanadium leaching rate reaches 87.5%. However, a large amount of acid leaching residue will be produced in the above-mentioned treatment process, which pollutes the environment and needs further treatment. In addition, a large amount of calcium additives and ball milling aids need to be added in the above-mentioned treatment method, and the process cost is relatively high. The Chinese patent application with the patent application publication number CN115354173A discloses a stone coal concentrated acid two-stage ripening vanadium extraction process, which uses sulfuric acid two-stage ripening to treat stone coal. First, dilute sulfuric acid is added to the crushed stone coal and allowed to stand, and then the mixture is heated at 150-300°C for 1-6 hours, and finally water leaching is performed to extract vanadium, and the leaching rate of vanadium reaches up to 86.85%. However, the consumption of sulfuric acid in the above-mentioned sulfuric acid heating process is large, resulting in high production costs of the process, high pressure on the operation and maintenance of the equipment, and the sulfuric acid heating vanadium extraction process will produce a large amount of waste liquid and leaching residue, which pollutes the environment. The Chinese patent with the patent authorization announcement number CN102766762B discloses a stone coal roasting vanadium extraction process, which uses a separate decarbonization device and a vanadium conversion container to extract vanadium from stone coal. The decarbonization process is carried out at 650°C, and the vanadium conversion process is carried out at 800-980°C. After the vanadium conversion, leaching is performed. After the vanadium conversion is completed in the above process, leaching is required to obtain the vanadium-containing product, and the process cost is relatively high. Summary of the invention

[0004] The main purpose of the present invention is to provide a vanadium extraction process to solve the problems of complex process, high cost and low yield in the prior art vanadium extraction process.

[0005] In order to achieve the above-mentioned purpose, according to one aspect of the present invention, a vanadium extraction process is provided, which comprises the following steps: step S1, decarburizing vanadium-containing stone coal and oxygen-enriched air in a boiling furnace to obtain a decarburized intermediate; step S2, subjecting the decarburized intermediate, chlorine and air to a chlorination vanadium extraction process in a boiling furnace to obtain a chlorinated gas; step S3, subjecting the chlorinated gas to a graded condensation process to obtain vanadium oxychloride.

[0006] Furthermore, in the above step S2, the ratio of the mass of the decarbonized intermediate, the volume of chlorine gas and the volume of air is (50-150 g): (4-10 Nm 3 ):(50~80Nm 3 ); Preferably, the mass content of vanadium in the vanadium-containing stone coal is 0.2% to 1%.

[0007] Further, in the above step S2, the temperature of the vanadium extraction by chlorination is 700-1100°C; and / or, the time of the vanadium extraction by chlorination is 1-3h; preferably, the vanadium extraction by chlorination includes a first vanadium extraction by chlorination and a second vanadium extraction by chlorination sequentially; the temperature of the first vanadium extraction by chlorination is 700-900°C; and / or, the time of the first vanadium extraction by chlorination is 0.5-2h; and / or, the temperature of the second vanadium extraction by chlorination is 950-1100°C; and / or, the time of the second vanadium extraction by chlorination is 0.5-1h.

[0008] Furthermore, in the above step S2, the flow rate of chlorine gas is 4-10 Nm 3 / h; and / or, the air flow rate is 50-80Nm 3 / h.

[0009] Furthermore, in the above step S3, the graded condensation treatment includes sequentially performing a first-stage condensation treatment, a second-stage condensation treatment and a third-stage condensation treatment; preferably, the temperature of the first-stage condensation treatment is 200-300°C; and / or, the time of the first-stage condensation treatment is 0.5h-1h; and / or, the temperature of the second-stage condensation treatment is 100-200°C; and / or, the time of the second-stage condensation treatment is 0.5h-1h; and / or, the temperature of the third-stage condensation treatment is 50-100°C; and / or, the time of the third-stage condensation treatment is 0.5h-1h.

[0010] Furthermore, in the above step S3, the chlorinated gas is introduced into a fractional condenser for fractional condensation treatment; preferably, the flow rate of the chlorinated gas is 50 to 100 Nm 3 / h.

[0011] Furthermore, in the above step S1, the ratio of the mass of vanadium-containing stone coal to the volume of oxygen-enriched air is (50-150 g): (60-100 Nm 3 ).

[0012] Furthermore, in the above step S1, the temperature of the decarburization treatment is 700-1000°C; and / or the time of the decarburization treatment is 0.5h-2h; preferably, the decarburization treatment includes a first decarburization treatment and a second decarburization treatment performed sequentially; the temperature of the first decarburization treatment is 700-800°C; and / or the time of the first decarburization treatment is 0.25-1h; and / or the temperature of the second decarburization treatment is 850-1000°C; and / or the time of the second decarburization treatment is 0.25-1h.

[0013] Furthermore, in the above step S1, the flow rate of oxygen-enriched air is 60-100 Nm 3 / h; and / or, the oxygen content in the oxygen-enriched air is 60-80%.

[0014] Furthermore, in the above step S1, the average particle size of the vanadium-containing stone coal is 0.1-1 mm.

[0015] Applying the technical solution of the present invention, in step S1, vanadium-containing stone coal and oxygen-enriched air are decarbonized in a fluidized bed furnace, and the oxygen-enriched air has a high oxygen content, which helps to fully remove the carbon in the vanadium-containing stone coal, thereby helping to reduce the content of impurities in vanadium oxychloride. In step S2, the decarbonized intermediate, chlorine and air are subjected to chlorination vanadium extraction in a fluidized bed furnace, and the vanadium, chlorine and air in the decarbonized intermediate react to form chlorinated gas. In step S3, graded condensation treatment is performed according to the different condensation points of different substances in the chlorinated gas to obtain vanadium oxychloride with higher purity. The vanadium extraction process of the present application reduces the use of chemical reagents, especially avoids the consumption of a large amount of acid or alkali, thereby reducing potential pollution to the environment. Compared with the traditional vanadium extraction process, the vanadium extraction process of the present application is simpler and has a higher vanadium recovery rate. DETAILED DESCRIPTION

[0016] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail with reference to the embodiments below.

[0017] As analyzed in the background technology of this application, the vanadium extraction process in the prior art has the problems of complex process, high cost and low yield. In order to solve the above problems, this application provides a vanadium extraction process.

[0018] In a typical embodiment of the present application, a vanadium extraction process is provided, which comprises the following steps: step S1, decarburizing vanadium-containing stone coal and oxygen-enriched air in a boiling furnace to obtain a decarburized intermediate; step S2, subjecting the decarburized intermediate, chlorine and air to a chlorination vanadium extraction treatment in a boiling furnace to obtain a chlorinated gas; step S3, subjecting the chlorinated gas to a graded condensation treatment to obtain vanadium oxychloride.

[0019] In step S1, vanadium-containing stone coal and oxygen-enriched air are decarbonized in a fluidized bed furnace. The oxygen-enriched air has a high oxygen content, which helps to fully remove the carbon in the vanadium-containing stone coal, thereby helping to reduce the content of impurities in vanadium oxychloride. In step S2, the decarbonized intermediate, chlorine and air are subjected to chlorination vanadium extraction in a fluidized bed furnace. The vanadium, chlorine and air in the decarbonized intermediate react to form chlorinated gas. In step S3, graded condensation treatment is performed according to the different condensation points of different substances in the chlorinated gas to obtain vanadium oxychloride with higher purity. The vanadium extraction process of the present application reduces the use of chemical reagents, especially avoids the consumption of a large amount of acid or alkali, thereby reducing potential pollution to the environment. Compared with the traditional vanadium extraction process, the vanadium extraction process of the present application is simpler and has a higher vanadium recovery rate.

[0020] In one embodiment of the present application, in the above step S2, the ratio of the mass of the decarbonized intermediate, the volume of chlorine gas and the volume of air is (50-150 g): (4-10 Nm 3 ):(50~80Nm 3 ); Preferably, the mass content of vanadium in the vanadium-containing stone coal is 0.2% to 1%.

[0021] Controlling the mass of the decarburization intermediate and the ratio of the volume of chlorine to the volume of air within the above ranges helps to ensure sufficient contact between the decarburization intermediate, chlorine and air, reduces the occurrence of side reactions, and thus helps to improve the yield and purity of vanadium oxychloride.

[0022] In one embodiment of the present application, in the above step S2, the temperature of the vanadium extraction by chlorination is 700-1100°C; and / or, the time of the vanadium extraction by chlorination is 1-3h; preferably, the vanadium extraction by chlorination includes a first vanadium extraction by chlorination and a second vanadium extraction by chlorination sequentially; the temperature of the first vanadium extraction by chlorination is 700-900°C; and / or, the time of the first vanadium extraction by chlorination is 0.5-2h; and / or, the temperature of the second vanadium extraction by chlorination is 950-1100°C; and / or, the time of the second vanadium extraction by chlorination is 0.5-1h.

[0023] If the temperature and time of vanadium extraction by chlorination are too low and too short, it is not conducive to the full progress of the reaction. If the temperature and time of vanadium extraction by chlorination are too high and too long, it is easy to produce side reactions. Controlling the temperature and time of vanadium extraction by chlorination within the above range is helpful to improve the yield and purity of vanadium oxychloride. Increasing the temperature of vanadium extraction by chlorination step by step is helpful to promote the full contact between decarburization intermediates, chlorine and air, thereby helping to improve the efficiency of vanadium extraction and further help to improve the yield of vanadium.

[0024] In order to improve the efficiency of vanadium extraction by chlorination, in one embodiment of the present application, it is preferred that in the above step S2, the flow rate of chlorine gas is 4-10 Nm 3 / h; and / or, the air flow rate is 50-80Nm 3 / h.

[0025] In order to improve the utilization rate of heat, in one embodiment of the present application, in the above step S2, the heat generated during the vanadium extraction by chlorination is used to produce steam.

[0026] In one embodiment of the present application, in the above-mentioned step S3, the graded condensation treatment includes sequentially performing a first-stage condensation treatment, a second-stage condensation treatment and a third-stage condensation treatment; preferably, the temperature of the first-stage condensation treatment is 200-300°C; and / or, the time of the first-stage condensation treatment is 0.5h-1h; and / or, the temperature of the second-stage condensation treatment is 100-200°C; and / or, the time of the second-stage condensation treatment is 0.5h-1h; and / or, the temperature of the third-stage condensation treatment is 50-100°C; and / or, the time of the third-stage condensation treatment is 0.5h-1h.

[0027] Chlorinated gas contains vanadium oxychloride, ferric chloride, aluminum chloride, etc. The present application helps to separate vanadium oxychloride from chlorinated gas by subjecting the chlorinated gas to a first-stage condensation treatment, a second-stage condensation treatment, and a third-stage condensation treatment. Controlling the temperature and time of the first-stage condensation treatment within the above range helps to separate ferric chloride, etc.; controlling the temperature and time of the second-stage condensation treatment within the above range helps to separate aluminum chloride, etc.; controlling the temperature and time of the third-stage condensation treatment within the above range helps to separate vanadium oxychloride.

[0028] In order to further improve the separation efficiency, thereby improving the yield and purity of vanadium oxychloride, in one embodiment of the present application, preferably in the above step S3, the chlorinated gas is passed into a fractional condenser for fractional condensation treatment; preferably, the flow rate of the chlorinated gas is 50 to 100 Nm 3 / h.

[0029] In one embodiment of the present application, in the above step S1, the ratio of the mass of vanadium-containing stone coal to the volume of oxygen-enriched air is (50-150 g): (60-100 Nm 3 ).

[0030] If the volume of oxygen-enriched air is too low, it will be difficult to fully remove carbon from vanadium-containing stone coal. If the volume of oxygen-enriched air is too high, it will easily cause side reactions. Controlling the ratio of the mass of vanadium-containing stone coal to the volume of oxygen-enriched air within the above range will help improve the efficiency of decarbonization treatment.

[0031] In one embodiment of the present application, in the above-mentioned step S1, the temperature of the decarburization treatment is 700-1000°C; and / or, the time of the decarburization treatment is 0.5h-2h; preferably, the decarburization treatment includes a first decarburization treatment and a second decarburization treatment performed sequentially; the temperature of the first decarburization treatment is 700-800°C; and / or, the time of the first decarburization treatment is 0.25-1h; and / or, the temperature of the second decarburization treatment is 850-1000°C; and / or, the time of the second decarburization treatment is 0.25-1h.

[0032] If the temperature of decarburization treatment is too low or the time is too short, it is not conducive to the removal of carbon. If the temperature of decarburization treatment is too high or the time is too long, it is not conducive to reducing the generation of side reactions. Controlling the temperature and time of decarburization treatment within the above range is conducive to reducing the carbon content of the decarburization intermediate, thereby helping to improve the yield and purity of vanadium oxychloride. Decarburization treatment by step-by-step temperature increase is conducive to improving the efficiency of decarburization treatment, thereby helping to improve the purity of vanadium oxychloride.

[0033] In order to further improve the efficiency of decarburization treatment and reduce process costs, in one embodiment of the present application, it is preferred that in the above step S1, the flow rate of oxygen-enriched air is 60-100 Nm 3 / h; and / or, the oxygen content in the oxygen-enriched air is 60-80%.

[0034] In one embodiment of the present application, in the above step S1, the average particle size of the vanadium-containing stone coal is 0.1-1 mm.

[0035] If the average particle size of vanadium-containing stone coal is too low, the vanadium-containing stone coal particles are prone to agglomeration. If the average particle size of vanadium-containing stone coal is too high, it is not conducive to increasing the contact area between the vanadium-containing stone coal and oxygen-enriched air. Controlling the average particle size of vanadium-containing stone coal within the above range helps to ensure sufficient contact between the vanadium-containing stone coal and oxygen-enriched air, thereby helping to increase the carbon removal rate in the vanadium-containing stone coal.

[0036] In one embodiment of the present application, in the above step S1, the vanadium-containing stone coal is crushed and then decarbonized in a boiling furnace with oxygen-enriched air to obtain a decarbonized intermediate.

[0037] The beneficial effects of the present application will be further illustrated below in conjunction with embodiments.

[0038] Example 1

[0039] The vanadium-containing stone coal with a vanadium content of 0.5% was crushed to an average particle size of 0.5 mm and sent to a boiling furnace. 70 Nm 3 / h of oxygen-enriched air for decarbonization, the oxygen content in the oxygen-enriched air is 60%, and the ratio of the mass of stone coal to the volume of oxygen-enriched air is 150g:~60Nm 3During the decarburization process, the temperature is first raised to 700°C and kept for 1 hour, then raised to 850°C and kept for 1 hour to obtain a decarburized intermediate. The heat generated in this stage is used to produce steam. The decarburized intermediate is discharged into a boiling furnace and 5Nm 3 / h chlorine and 70Nm 3 / h of air for chlorination vanadium extraction, the mass of decarburization intermediates, the volume of chlorine and the volume of air are 150g:4Nm 3 :50Nm 3 In the chlorination treatment, the temperature is first raised to 700℃ and kept for 2h, then raised to 950℃ and kept for 1h to obtain chlorinated gas. The chlorinated gas is heated at 70Nm 3 / h flow rate is passed into a three-stage condenser for graded condensation treatment, the temperature of the first stage condensation treatment is 200°C, the time of the first stage condensation treatment is 1h, the temperature of the second stage condensation treatment is 100°C, the time of the second stage condensation treatment is 1h, the temperature of the third stage condensation treatment is 50°C, the time of the third stage condensation treatment is 1h, and vanadium trichloride is obtained.

[0040] Example 2

[0041] The difference from Example 1 is that the vanadium-containing stone coal with a vanadium content of 0.2% by mass is crushed to an average particle size of 1 mm and then sent to a boiling furnace, into which 100 Nm 3 / h of oxygen-enriched air for decarbonization, the oxygen content in the oxygen-enriched air is 60%, and the ratio of the mass of stone coal to the volume of oxygen-enriched air is 150g:~60Nm 3 During the decarburization process, the temperature is first raised to 700°C and kept for 1 hour, then raised to 850°C and kept for 1 hour to obtain a decarburized intermediate. The heat generated in this stage is used to produce steam. The decarburized intermediate is discharged into a boiling furnace and 4Nm 3 / h chlorine and 80Nm 3 / h of air for chlorination vanadium extraction, the mass of decarburization intermediates, the volume of chlorine and the volume of air are 150g:4Nm 3 :50Nm 3 In the chlorination treatment, the temperature is first raised to 700℃ and kept for 2h, then raised to 950℃ and kept for 1h to obtain chlorinated gas. The chlorinated gas is heated at 70Nm 3 / h flow rate is passed into a three-stage condenser for graded condensation treatment, the temperature of the first stage condensation treatment is 200°C, the time of the first stage condensation treatment is 1h, the temperature of the second stage condensation treatment is 100°C, the time of the second stage condensation treatment is 1h, the temperature of the third stage condensation treatment is 50°C, the time of the third stage condensation treatment is 1h, and vanadium trichloride is obtained.

[0042] Example 3

[0043] The difference from Example 1 is that the vanadium-containing stone coal with a vanadium content of 1% by mass is crushed to an average particle size of 0.1 mm, and then sent to a boiling furnace, into which 60 Nm 3 / h of oxygen-enriched air for decarbonization, the oxygen content in the oxygen-enriched air is 60%, and the ratio of the mass of stone coal to the volume of oxygen-enriched air is 150g:~60Nm 3 During the decarburization process, the temperature is first raised to 700°C and kept for 1 hour, then raised to 850°C and kept for 1 hour to obtain a decarburized intermediate. The heat generated in this stage is used to produce steam. The decarburized intermediate is discharged into a boiling furnace and 10Nm 3 / h chlorine and 50Nm 3 / h of air for chlorination vanadium extraction, the mass of decarburization intermediates, the volume of chlorine and the volume of air are 150g:4Nm 3 :50Nm 3 In the chlorination treatment, the temperature is first raised to 700℃ and kept for 2h, then raised to 950℃ and kept for 1h to obtain chlorinated gas. The chlorinated gas is heated at 100Nm 3 / h flow rate is passed into a three-stage condenser for graded condensation treatment, the temperature of the first stage condensation treatment is 200°C, the time of the first stage condensation treatment is 1h, the temperature of the second stage condensation treatment is 100°C, the time of the second stage condensation treatment is 1h, the temperature of the third stage condensation treatment is 50°C, the time of the third stage condensation treatment is 1h, and vanadium trichloride is obtained.

[0044] Example 4

[0045] The difference from Example 1 is that the ratio of the mass of the decarbonized intermediate, the volume of chlorine gas and the volume of air is 50 g:10 Nm 3 :80Nm 3 , and finally vanadium oxychloride was obtained.

[0046] Example 5

[0047] The difference from Example 1 is that the ratio of the mass of the decarbonized intermediate, the volume of chlorine gas and the volume of air is 200g:3Nm 3 :40Nm 3 , and finally vanadium oxychloride was obtained.

[0048] Example 6

[0049] The difference from Example 1 is that in the chlorination vanadium extraction treatment, the temperature is first raised to 900° C. and kept warm for 0.5 h, and then the temperature is raised to 1100° C. and kept warm for 0.5 h, and finally vanadium trichloride is obtained.

[0050] Example 7

[0051] The difference from Example 1 is that in the vanadium extraction by chlorination treatment, the temperature is first raised to 1000° C. and kept for 2.5 hours, and then the temperature is raised to 1200° C. and kept for 0.5 hours, to finally obtain vanadium oxychloride.

[0052] Example 8

[0053] The difference from Example 1 is that the temperature of the first stage condensation treatment is 300°C, the time of the first stage condensation treatment is 0.5h, the temperature of the second stage condensation treatment is 200°C, the time of the second stage condensation treatment is 0.5h, the temperature of the third stage condensation treatment is 100°C, the time of the third stage condensation treatment is 0.5h, and vanadium trichloride is finally obtained.

[0054] Example 9

[0055] The difference from Example 1 is that the temperature of the first stage condensation treatment is 150°C, the time of the first stage condensation treatment is 0.3h, the temperature of the second stage condensation treatment is 80°C, the time of the second stage condensation treatment is 0.3h, the temperature of the third stage condensation treatment is 40°C, the time of the third stage condensation treatment is 0.3h, and vanadium trichloride is finally obtained.

[0056] Example 10

[0057] The difference from Example 1 is that the ratio of the mass of vanadium-containing stone coal to the volume of oxygen-enriched air is 50 g:100 Nm 3 , and finally vanadium oxychloride was obtained.

[0058] Embodiment 11

[0059] The difference from Example 1 is that the ratio of the mass of vanadium-containing stone coal to the volume of oxygen-enriched air is 200 g:50 Nm 3 , and finally vanadium oxychloride was obtained.

[0060] Example 12

[0061] The difference from Example 1 is that during the decarburization treatment, the temperature is first raised to 800° C. and kept for 0.25 h, and then the temperature is raised to 1000° C. and kept for 0.25 h, to finally obtain vanadium oxychloride.

[0062] Example 13

[0063] The difference from Example 1 is that during the decarburization treatment, the temperature is first raised to 900° C. and kept for 0.25 h, and then the temperature is raised to 1100° C. and kept for 0.25 h, to finally obtain vanadium oxychloride.

[0064] Embodiment 14

[0065] The difference from Example 1 is that the oxygen content in the oxygen-enriched air is 80%, and vanadium oxychloride is finally obtained.

[0066] Embodiment 15

[0067] The difference from Example 1 is that the oxygen content in the oxygen-enriched air is 50%, and vanadium oxychloride is finally obtained.

[0068] Comparative Example 1

[0069] The difference from Example 1 is that the vanadium-containing stone coal is crushed to an average particle size of 0.5 mm and then sent to a fluidized bed furnace, into which 70 Nm 3 / h of oxygen-enriched air for decarbonization, the oxygen content in the oxygen-enriched air is 60%, and the ratio of the mass of stone coal to the volume of oxygen-enriched air is 150g:~60Nm 3 During the decarburization process, the temperature is first raised to 700°C and kept for 1 hour, then raised to 850°C and kept for 1 hour to obtain a decarburized intermediate. The heat generated in this stage is used to produce steam. The decarburized intermediate is discharged into a boiling furnace and 70Nm 3 / h of air for vanadium conversion treatment, the mass ratio of decarburization intermediates to the volume of air is 150g:50Nm 3 In the vanadium conversion treatment, the temperature is first raised to 700°C and kept for 2 hours, and then raised to 950°C and kept for 1 hour to obtain the conversion product. The conversion product is added to sulfuric acid with a mass concentration of 4% for acid leaching, and the leaching solid-liquid mass ratio is 1:2. After acid leaching at 75°C for 5 hours, solid-liquid separation is performed to obtain a vanadium aqueous solution. The vanadium aqueous solution is subjected to vanadium resin exchange adsorption-desorption and ammonium salt precipitation to obtain ammonium metavanadate precipitation, which is heated to decompose the precipitation to obtain vanadium pentoxide.

[0070] The vanadium compounds prepared in the examples and comparative examples were tested for vanadium recovery and purity. The test results are shown in Table 1.

[0071] Table 1

[0072]

[0073]

[0074] As can be seen from Table 1, the main difference between the embodiment and the comparative example is that chlorine is not used for chlorination vanadium extraction in the comparative example. Although the final vanadium pentoxide has a higher purity, the recovery rate of vanadium is much lower than that of the embodiment. It can be seen that the vanadium extraction process of the present application reduces the use of chemical reagents, especially avoids the consumption of a large amount of acid or alkali, thereby reducing potential pollution to the environment. Compared with the traditional vanadium extraction process, the vanadium extraction process of the present application is simpler and has a higher vanadium recovery rate.

[0075] From the above description, it can be seen that the above embodiments of the present invention achieve the following technical effects:

[0076] In step S1, vanadium-containing stone coal and oxygen-enriched air are decarbonized in a fluidized bed furnace. The oxygen-enriched air has a high oxygen content, which helps to fully remove the carbon in the vanadium-containing stone coal, thereby helping to reduce the content of impurities in vanadium oxychloride. In step S2, the decarbonized intermediate, chlorine and air are subjected to chlorination vanadium extraction in a fluidized bed furnace. The vanadium, chlorine and air in the decarbonized intermediate react to form chlorinated gas. In step S3, graded condensation treatment is performed according to the different condensation points of different substances in the chlorinated gas to obtain vanadium oxychloride with higher purity. The vanadium extraction process of the present application reduces the use of chemical reagents, especially avoids the consumption of a large amount of acid or alkali, thereby reducing potential pollution to the environment. Compared with the traditional vanadium extraction process, the vanadium extraction process of the present application is simpler and has a higher vanadium recovery rate.

[0077] The above are only embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A vanadium extraction process, characterized in that: The vanadium extraction process comprises the following steps: Step S1, decarburizing vanadium-containing stone coal and oxygen-enriched air in a fluidized bed furnace to obtain a decarburized intermediate; Step S2, subjecting the decarburization intermediate, chlorine and air to chlorination and vanadium extraction in a boiling furnace to obtain chlorinated gas; Step S3, subjecting the chlorinated gas to graded condensation treatment to obtain vanadium oxychloride.

2. The vanadium extraction process according to claim 1, characterized in that: In step S2, the ratio of the mass of the decarbonized intermediate, the volume of the chlorine gas and the volume of the air is (50-150 g): (4-10 Nm 3 ):(50~80Nm 3 ); Preferably, the mass content of vanadium in the vanadium-containing stone coal is 0.2% to 1%.

3. The vanadium extraction process according to claim 1 or 2, characterized in that: In step S2, the temperature of the chlorination vanadium extraction treatment is 700-1100° C.; and / or, the time of the chlorination vanadium extraction treatment is 1-3 hours; Preferably, the vanadium extraction by chlorination treatment comprises a first vanadium extraction by chlorination treatment and a second vanadium extraction by chlorination treatment performed sequentially; the temperature of the first vanadium extraction by chlorination treatment is 700-900°C; and / or, the time of the first vanadium extraction by chlorination treatment is 0.5-2h; and / or, the temperature of the second vanadium extraction by chlorination treatment is 950-1100°C; and / or, the time of the second vanadium extraction by chlorination treatment is 0.5-1h.

4. The vanadium extraction process according to any one of claims 1 to 3, characterized in that: In step S2, the flow rate of chlorine gas is 4-10 Nm 3 / h; and / or, the air flow rate is 50-80Nm 3 / h.

5. The vanadium extraction process according to any one of claims 1 to 4, characterized in that: In step S3, the graded condensation process includes sequentially performing a first stage condensation process, a second stage condensation process and a third stage condensation process; Preferably, the temperature of the first stage condensation treatment is 200-300° C.; and / or, the time of the first stage condensation treatment is 0.5 h-1 h; and / or, the temperature of the second stage condensation treatment is 100-200° C.; and / or, the time of the second stage condensation treatment is 0.5 h to 1 h; And / or, the temperature of the third stage condensation treatment is 50-100° C.; and / or, the time of the third stage condensation treatment is 0.5 h to 1 h.

6. The vanadium extraction process according to any one of claims 1 to 5, characterized in that: In step S3, the chlorinated gas is introduced into a fractional condenser for fractional condensation. Preferably, the flow rate of the chlorinated gas is 50-100 Nm 3 / h.

7. The vanadium extraction process according to any one of claims 1 to 6, characterized in that: In step S1, the ratio of the mass of the vanadium-containing stone coal to the volume of the oxygen-enriched air is (50-150 g): (60-100 Nm 3 ).

8. The vanadium extraction process according to any one of claims 1 to 7, characterized in that: In the step S1, the temperature of the decarburization treatment is 700-1000°C; and / or the time of the decarburization treatment is 0.5h-2h; Preferably, the decarburization treatment includes a first decarburization treatment and a second decarburization treatment performed sequentially; the temperature of the first decarburization treatment is 700-800°C; and / or the time of the first decarburization treatment is 0.25-1h; and / or the temperature of the second decarburization treatment is 850-1000°C; and / or the time of the second decarburization treatment is 0.25-1h.

9. The vanadium extraction process according to any one of claims 1 to 8, characterized in that: In step S1, the flow rate of the oxygen-enriched air is 60-100 Nm 3 / h; and / or, the oxygen content in the oxygen-enriched air is 60-80%.

10. The vanadium extraction process according to any one of claims 1 to 9, characterized in that: In the step S1, the average particle size of the vanadium-containing stone coal is 0.1-1 mm.

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