Converter indirect oxidation vanadium extraction process based on solid oxide

Abstract

The invention discloses a solid oxide-based converter indirect oxidation vanadium extraction process, which comprises the following steps of: crushing and screening at least one iron-containing mineral raw material such as hematite, sintered ore, iron oxide red and iron oxide scale, and preparing a solid oxidant through the procedures of proportioning, uniformly mixing and the like; the solid oxidizing agent is added into the vanadium-containing molten iron, and the vanadium element in the molten iron is oxidized through bottom blowing stirring. Based on the indirect oxidation reaction characteristic of the solid oxidant, the severe fluctuation of the temperature of the molten pool is avoided, and the dependence on a coolant is eliminated; meanwhile, by controlling the components and granularity of the solid oxide, the reaction kinetics conditions are remarkably improved, the high efficiency and stability of the vanadium extraction process are ensured, and a new technical route is provided for the molten iron vanadium extraction process. Compared with the prior art, the method has the advantages of simple process route, low production investment cost, simplicity and convenience in operation and control and the like, and has a good industrial application prospect.

Description

Technical Field

[0001] The present invention relates to the field of iron and steel metallurgy, and particularly to a converter indirect oxidation vanadium extraction process based on solid oxides. Background Art

[0002] Vanadium is an important rare metal, widely used in fields such as steel alloys, chemical catalysis, energy storage, and aerospace. China's vanadium resource reserves account for about 40% of the global total. Among them, vanadium-titanium magnetite, as the main source, has the largest reserves in the world. Therefore, the rational development and utilization of vanadium-titanium magnetite resources are of great significance to China's economic development and metallurgical industry. Currently, the mainstream process for vanadium extraction from hot metal in China is the "blast furnace-converter" process. Its core is to blow oxygen into the converter bath, and use the oxidation reaction to oxidize the vanadium in the hot metal and enrich it in the slag, thereby realizing vanadium extraction from hot metal. However, this process mainly relies on direct oxidation by oxygen. The reaction process releases heat violently, resulting in temperature fluctuations in the bath. In order to avoid the phenomenon of vanadium reversion caused by too high bath temperature, coolants need to be added to control the bath temperature. This regulation method makes it impossible to stably control the vanadium extraction efficiency and product quality.

[0003] To solve the problems faced by converter oxygen blowing for vanadium extraction, researchers have focused on exploring indirect oxidation technologies. Compared with direct oxidation, indirect oxidation can be carried out under milder reaction conditions, effectively reducing the problem of temperature runaway caused by over-oxidation, thereby better balancing the hot metal composition and bath temperature, and improving the vanadium extraction efficiency and product quality. Patent CN201510005928.3 proposes to spray iron oxide powder with nitrogen as the carrier, partially replacing oxygen spraying. Although this technology reduces the amount of coolant added while ensuring the vanadium oxidation rate, it still uses oxygen as the main oxygen source and fails to fundamentally solve the problem. In addition, patents CN201510006728.X and CN202210815516.6 respectively achieve indirect oxidation vanadium extraction through top feeding and CO2 carrier gas spraying methods, combined with mechanical stirring. Although direct oxygen spraying is avoided, long-term mechanical stirring is required to ensure the mass transfer efficiency between iron oxide and hot metal. The stirring time in the examples exceeds 15 minutes, greatly increasing the production cost and reducing the process efficiency.

[0004] It can be seen that although the existing indirect oxidation technologies have advantages in thermodynamics, problems such as low dissolution rate of iron oxides and insufficient oxygen transfer efficiency at the slag-metal interface have not been solved, resulting in low resource utilization rate of the process. Therefore, developing a new high-efficiency indirect oxidation vanadium extraction process compatible with the existing metallurgical process has become the key research direction to break through the industry's technical bottleneck. Summary of the Invention

[0005] To solve the above technical problems, the present invention provides a converter indirect oxidation vanadium extraction process based on solid oxides. This process makes full use of the characteristics of low heat release and strong process controllability of indirect oxidation reactions, effectively solves the problem of molten pool temperature fluctuations caused by intense oxidation reactions in traditional oxygen blowing processes, and at the same time avoids the adverse effects of coolant addition on the quality of vanadium slag. By controlling the composition and particle size of the solid oxidant, the reaction kinetic conditions are significantly improved, achieving a simultaneous increase in process efficiency and resource utilization rate.

[0006] To achieve the above technical objectives, the present invention adopts the following technical solutions:

[0007] The present invention first discloses a converter indirect oxidation vanadium extraction process based on solid oxides, including:

[0008] S1. At least one of hematite, sinter, iron oxide red, and mill scale is separately loaded into a pair of roll crushers for crushing;

[0009] S2. The products after crushing in S1 are screened through a vibrating screen, and the products on the screen are returned to S1 for secondary crushing;

[0010] S3. The products passing through the screen in S2 are proportioned and mixed to obtain the solid oxidant;

[0011] S4. The solid oxidant is fed into the raw material bin. After the hot metal is charged into the converter, the temperature of the hot metal is maintained at 1300 - 1400 °C, and the material is discharged from the raw material bin into the converter;

[0012] S5. An inert gas is blown in through bottom blowing;

[0013] S6. Timing starts after the addition of the solid oxidant is completed. After the reaction ends, the vanadium slag is poured out, and the hot metal is sent to converter steelmaking.

[0014] Further, the total iron content of the hematite in step S1 is 55 - 65 wt%, the FeO content is 0 - 1 wt%, the CaO content is 0 - 2 wt%, the SiO2 content is 5 - 10 wt%, the Al2O3 content is 0 - 2 wt%, and the balance is inevitable impurities;

[0015] The total iron content of the sinter is 55 - 60 wt%, the FeO content is 5 - 10 wt%, the CaO content is 8 - 15 wt%, the SiO2 content is 4 - 8 wt%, the Al2O3 content is 1 - 2 wt%, and the balance is inevitable impurities;

[0016] The total iron content of the iron oxide red is 65 - 70 wt%, the CaO content is 0 - 1 wt%, the SiO2 content is 0 - 5 wt%, the Al2O3 content is 0 - 1 wt%, and the balance is inevitable impurities;

[0017] The total iron content of the scale is 65-75wt%, the FeO content is 20-30wt%, the CaO content is 1-3wt%, the SiO2 content is 1-2wt%, the Al2O3 content is 1-2wt%, and the balance is inevitable impurities.

[0018] Further, the screen size of the screening in step S2 is 1 mm.

[0019] Further, the total iron content of the solid oxidant in step S3 is 60-75wt%, the FeO content is 5-30wt%, the CaO content is 0-15wt%, the SiO2 content is 1-10wt%, and the Al2O3 content is 1-2wt%.

[0020] Further, the discharging time in step S4 is 1-3 min, and the discharging addition amount is 30-60 kg / (tFe).

[0021] Further, the discharging time is 2 min, and the discharging addition amount is 45 kg / (tFe).

[0022] Further, the inert gas in step S5 is nitrogen or argon; the blowing intensity of the inert gas is 0.01-0.8 m 3 / (min·tFe).

[0023] Further, the inert gas is nitrogen; the blowing intensity is 0.7 m 3 / (min·tFe).

[0024] Further, after the reaction in step S6 reaches 6-10 min, the vanadium slag is poured out.

[0025] Further, the reaction time is 6 min.

[0026] Compared with the prior art, the advantages of the present invention are as follows:

[0027] (1) The solid oxidant raw material selected in the present invention is an iron-containing mineral, the raw material source is wide, it is easy to obtain, and at the same time, during the reaction process, the iron element in the solid oxidant can enter the molten iron, which can achieve the effect of reducing iron loss and improve the comprehensive utilization rate of resources;

[0028] (2) During the vanadium extraction process in the converter in the present invention, the characteristics of low heat release of the indirect oxidation reaction and the accompanying endothermic reaction are fully utilized. By adding the solid oxidant, the dual functions of oxidation and temperature control are achieved, which not only simplifies the process flow, but also greatly improves the resource utilization value of the iron-containing mineral;

[0029] (3) By controlling the composition and particle size of the iron-containing mineral raw materials, the present invention improves the reaction kinetic conditions. The optimized solid oxidant has higher oxidation ability and faster reaction rate, ensuring the high efficiency and stability of the vanadium extraction process. Meanwhile, it reduces energy consumption and production costs, providing reliable technical support for industrial application. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is the process flow chart of the embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0031] The technical solutions in the embodiments of the present invention and the comparative examples will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0032] In the present invention, "kg / (tFe)" represents the mass of a certain substance corresponding to each unit mass of total iron, and the unit is kilograms per (ton of total iron).

[0033] In the present invention: m 3 / (min·tFe)" is a composite unit, representing cubic meters per minute per (ton of total iron). In the context of the present invention, it means that for every 1 ton of total iron produced, 0.01 - 0.8 m 3 of inert gas participates in the reaction or is consumed, discharged, etc.

[0034] Example 1

[0035] A converter indirect oxidation vanadium extraction process based on solid oxides

[0036] S1. Load hematite and sinter into a pair-roll crusher respectively for crushing until the particle size is below 1 mm.

[0037] S2. Screen the products after crushing in S1 through a vibrating screen with a screen hole size of 1 mm. The products on the screen are returned to S1 for secondary crushing.

[0038] S3. Charge and mix the undersize hematite and sinter in S2 to obtain the solid oxidant, with the specific composition being: the total iron content is 60 wt%, the FeO content is 4 wt%, the CaO content is 6 wt%, the SiO2 content is 5 wt%, the Al2O3 content is 3 wt%, and the balance is inevitable impurities.

[0039] S4. Feed the solid oxidant described in S3 into the raw material bin. After the hot metal is charged into a 120t converter, the temperature of the hot metal is measured to be 1310°C. Feed the material from the raw material bin into the converter. The feeding time is 3 min, and the total addition amount is 60 kg / (tFe).

[0040] S5. Inject nitrogen through bottom blowing, and the blowing intensity is 0.6 m 3 / (min·tFe);

[0041] S6. Start timing after the addition of the solid oxidant is completed. After the reaction reaches 9 min, pour out the vanadium slag and send the hot metal to the converter for steelmaking.

[0042] After detection, the hot metal contains [C] 4.30%, [V] 0.33%. The semi-steel obtained from vanadium extraction contains [C] 3.80%, [V] 0.020%. The total iron content of the vanadium slag is 42 wt%, the metallic iron content is 18 wt%, the V2O5 content is 13 wt%, the SiO2 content is 7 wt%, the Al2O3 content is 5 wt%, the MnO content is 6 wt%, the Cr2O3 content is 3 wt%, the CaO content is 8 wt%, the P content is 0.6 wt%, and the balance is inevitable impurities.

[0043] Example 2

[0044] A converter indirect oxidation vanadium extraction process based on solid oxides

[0045] S1. Load the sinter and mill scale into a pair-roll crusher respectively for crushing until the particle size is below 1 mm.

[0046] S2. Screen the products after crushing in S1 through a vibrating screen. The screen hole size is 1 mm. The products on the screen are returned to S1 for secondary crushing.

[0047] S3. Charge and mix the undersize sinter and mill scale in S2 to obtain the solid oxidant. The specific composition is: the total iron content is 70 wt%, the FeO content is 24 wt%, the CaO content is 1.5 wt%, the SiO2 content is 1 wt%, the Al2O3 content is 0.5 wt%, and the balance is inevitable impurities.

[0048] S4. Feed the solid oxidant described in S3 into the raw material bin. After the hot metal is charged into a 160t converter, the temperature of the hot metal is measured to be 1370°C. Feed the material from the raw material bin into the converter. The feeding time is 3 min, and the total addition amount is 55 kg / (tFe).

[0049] S5. Inject nitrogen through bottom blowing, and the blowing intensity is 0.35 m 3 / (min·tFe);

[0050] S6. After adding the solid oxidant, start timing. After the reaction reaches 8 minutes, pour out the vanadium slag and send the hot metal to the converter for steelmaking.

[0051] After detection, the hot metal contains [C] 4.35%, [V] 0.30%. The semi-steel obtained from vanadium extraction contains [C] 3.75%, [V] 0.010%. The total iron content of the vanadium slag is 50 wt%, the metallic iron content is 22 wt%, the V2O5 content is 15 wt%, the SiO2 content is 4 wt%, the Al2O3 content is 2 wt%, the MnO content is 10 wt%, the Cr2O3 content is 3 wt%, the CaO content is 3 wt%, the P content is 0.7 wt%, and the balance is inevitable impurities.

[0052] Example 3

[0053] A converter indirect oxidation vanadium extraction process based on solid oxides

[0054] S1. Load hematite, sinter, and mill scale into a pair-roll crusher respectively for crushing until it is less than 1 mm.

[0055] S2. Screen the products after crushing in S1 through a vibrating screen with a screen hole size of 1 mm. The products on the screen are returned to S1 for secondary crushing.

[0056] S3. Charge and mix the undersize hematite, sinter, and mill scale in S2 to obtain the solid oxidant. The specific composition is: total iron content is 65 wt%, FeO content is 15 wt%, CaO content is 4 wt%, SiO2 content is 3 wt%, Al2O3 content is 2 wt%, and the balance is inevitable impurities.

[0057] S4. Send the solid oxidant described in S3 into the raw material bin. After the hot metal is poured into a 90 t converter, the temperature of the hot metal is measured to be 1340 °C. Feed the material from the raw material bin into the converter. The feeding time is 3 minutes, and the total addition amount is 60 kg / (tFe).

[0058] S5. Inject nitrogen through bottom blowing with a blowing intensity of 0.45 m 3 / (min·tFe);

[0059] S6. After adding the solid oxidant, start timing. After the reaction reaches 8 minutes, pour out the vanadium slag and send the hot metal to the converter for steelmaking.

[0060] After detection, the hot metal contains [C] 4.36%, [V] 0.32%. The semi-steel obtained from vanadium extraction contains [C] 3.80%, [V] 0.016%. The total iron content of the vanadium slag is 44 wt%, the metallic iron content is 17 wt%, the V2O5 content is 12 wt%, the SiO2 content is 5 wt%, the Al2O3 content is 3 wt%, the MnO content is 5 wt%, the Cr2O3 content is 8 wt%, the CaO content is 6 wt%, the P content is 1 wt%, and the balance is inevitable impurities.

[0061] Example 4

[0062] A converter indirect oxidation vanadium extraction process based on solid oxide

[0063] S1. Load hematite into a pair-roll crusher and crush it to less than 1 mm.

[0064] S2. Screen the product crushed in S1 through a vibrating screen with a screen hole size of 1 mm. The product on the screen is returned to S1 for secondary crushing.

[0065] S3. Mix the undersize hematite in S2 with iron red to obtain a solid oxidant. The specific composition is: total iron content 65 wt%, FeO content 0.5 wt%, CaO content 1 wt%, SiO2 content 3 wt%, Al2O3 content 1 wt%, and the balance is inevitable impurities.

[0066] S4. Feed the solid oxidant described in S3 into the raw material bin. After the hot metal is charged into a 120 t converter, the temperature of the hot metal is measured to be 1380 °C. Feed the material from the raw material bin into the converter. The feeding time is 2 min, and the total addition amount is 45 kg / (tFe).

[0067] S5. Inject nitrogen through bottom blowing, and the blowing intensity is 0.70 m 3 / (min·tFe);

[0068] S6. Start timing after the addition of the solid oxidant is completed. After the reaction reaches 6 min, pour out the vanadium slag and send the hot metal to the converter for steelmaking.

[0069] After detection, the hot metal contains [C] 4.43%, [V] 0.32%. The semi-steel obtained from vanadium extraction contains [C] 3.81%, [V] 0.011%. The total iron content of the vanadium slag is 43 wt%, the metallic iron content is 10 wt%, the V2O5 content is 15 wt%, the SiO2 content is 6 wt%, the Al2O3 content is 3 wt%, the MnO content is 4 wt%, the Cr2O3 content is 6 wt%, the CaO content is 2 wt%, the P content is 0.05 wt%, and the balance is inevitable impurities.

[0070] Comparative Example 1

[0071] After the hot metal is charged into the 160t vanadium extraction converter, the temperature of the hot metal is measured to be 1380 °C. Top blowing oxygen is carried out using an oxygen lance. Within 1 minute of blowing, the position of the oxygen lance is 2m, and then it drops to 1.1m; the oxygen supply flow rate of the oxygen lance is 300m 3 / min; After blowing for 1 minute, 60 kg / (tFe) of coolant (scale) is added. The specific composition is: total iron content is 70wt%, FeO content is 47wt%, CaO content is 0.6wt%, SiO2 content is 3wt%, Al2O3 content is 1wt%, and the balance is inevitable impurities; After blowing for 8 minutes, semi-steel and vanadium slag are tapped.

[0072] After detection, the hot metal contains [C] 4.25% and [V] 0.465%. In the semi-steel obtained from vanadium extraction, [C] is 3.13% and [V] is 0.03%. The total iron content of the vanadium slag is 29wt%, the metallic iron content is 10wt%, the V2O5 content is 15wt%, the SiO2 content is 18wt%, the Al2O3 content is 4wt%, the MnO content is 14wt%, the Cr2O3 content is 3wt%, the CaO content is 1.3wt%, the P content is 0.04wt%, and the balance is inevitable impurities.

[0073] Comparative Example 2

[0074] After the hot metal is charged into the 20t vanadium extraction converter, the temperature of the hot metal is measured to be 1400 °C. Bottom blowing air is carried out using an oxygen lance; the oxygen supply flow rate of the oxygen lance is 50m 3 / min; Before charging the hot metal, 60 kg / (tFe) of coolant (sinter) is added to the converter. The specific composition is: total iron content is 61wt%, FeO content is 32wt%, CaO content is 1wt%, SiO2 content is 6wt%, Al2O3 content is 1.5wt%, and the balance is inevitable impurities; After blowing for 7 minutes, semi-steel and vanadium slag are tapped.

[0075] After detection, the hot metal contains [C] 4.5% and [V] 0.515%. In the semi-steel obtained from vanadium extraction, [C] is 3.6% and [V] is 0.01%. The total iron content of the vanadium slag is 34wt%, the metallic iron content is 26wt%, the V2O5 content is 16wt%, the SiO2 content is 19wt%, the Al2O3 content is 2wt%, the MnO content is 7wt%, the Cr2O3 content is 16wt%, the CaO content is 1.1wt%, the P content is 0.04wt%, and the balance is inevitable impurities.

[0076] Comparative Example 3

[0077] After the hot metal is charged into the 140t vanadium extraction converter, the temperature of the hot metal is measured to be 1370 °C. Top blowing oxygen is carried out using an oxygen lance; the oxygen supply flow rate of the oxygen lance is 400m 3 / min; At the same time, a spray gun is immersed in the hot metal to spray iron oxide. The spraying speed is 100 kg / min, and the spraying amount is 20 kg / (tFe). The specific composition is that the total iron content is 58 wt%, the CaO content is 1 wt%, the SiO2 content is 6 wt%, the Al2O3 content is 2.5 wt%, and the balance is inevitable impurities; the carrier gas is nitrogen, and the carrier gas pressure is 0.7 MPa; after the iron oxide spraying is completed, semi-steel and vanadium slag are discharged.

[0078] After detection, the hot metal contains [C] 4.30%, [V] 0.27%. In the semi-steel obtained by vanadium extraction, [C] is 3.46% and [V] is 0.032%. The total iron content of the vanadium slag is 36 wt%, the metallic iron content is 12 wt%, the V2O5 content is 20 wt%, the SiO2 content is 16 wt%, the Al2O3 content is 4 wt%, the MnO content is 4 wt%, the Cr2O3 content is 5 wt%, the CaO content is 3 wt%, the P content is 0.01 wt%, and the balance is inevitable impurities.

[0079] According to the results of the above examples and comparative examples, it can be seen that the vanadium content in the semi-steel in the examples is generally lower than that in the comparative examples, while the carbon content is significantly higher than that in the comparative examples. At the same time, the SiO2 content in the vanadium slag in the examples is lower, and the quality of the vanadium slag is higher. In addition, the examples do not rely on oxygen spraying, thus avoiding the need for additional coolant addition. Therefore, the present invention has the advantages of higher vanadium extraction efficiency, better quality of vanadium slag, low process heat load, and simple operation.

[0080] Finally, it should be noted that the above examples are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the purpose and scope of the technical solutions of the present invention, and they should all be covered within the scope of the claims of the present invention.

Claims

1. A converter indirect oxidation vanadium extraction process based on solid oxide, comprising: S1, respectively loading at least one of hematite, sintered ore, red iron ore and iron oxide scale into a double-roll crusher for crushing; S2, the crushed product in S1 is screened through a vibrating screen, and the screened product is returned to S1 for secondary crushing; S3, batching and mixing the undersize product in S2 to obtain a solid oxidant; S4, sending solid oxidant into the raw material bin, after the molten iron is added into the converter, the molten iron is maintained at 1300-1400°C, and the material is discharged from the raw material bin into the converter; S5, injecting inert gas by bottom blowing; S6. After the solid oxidant is added, the timing starts. After the reaction is completed, the vanadium slag is poured out and the molten iron is sent to the converter for steelmaking.

2. The converter indirect oxidation vanadium extraction process according to claim 1, wherein: The hematite in step S1 has a total iron content of 55-65wt%, a FeO content of 0-1wt%, a CaO content of 0-2wt%, a SiO2 content of 5-10wt%, an Al2O3 content of 0-2wt%, and the remainder being unavoidable impurities; The sintered ore has a total iron content of 55-60wt%, a FeO content of 5-10wt%, a CaO content of 8-15wt%, a SiO2 content of 4-8wt%, an Al2O3 content of 1-2wt%, and the remainder is unavoidable impurities; The iron red has a total iron content of 65-70wt%, a CaO content of 0-1wt%, a SiO2 content of 0-5wt%, an Al2O3 content of 0-1wt%, and the remainder is inevitable impurities. The iron oxide scale has a total iron content of 65-75wt%, a FeO content of 20-30wt%, a CaO content of 1-3wt%, a SiO2 content of 1-2wt%, an Al2O3 content of 1-2wt%, and the remainder is inevitable impurities.

3. The converter indirect oxidation vanadium extraction process according to claim 1, wherein: The screen size of the screening in step S2 is 1 mm.

4. The converter indirect oxidation vanadium extraction process according to claim 1, wherein: The solid oxidant in step S3 has a total iron content of 60-75wt%, a FeO content of 5-30wt%, a CaO content of 0-15wt%, a SiO2 content of 1-10wt%, and an Al2O3 content of 1-2wt%.

5. The converter indirect oxidation vanadium extraction process according to claim 1, wherein: The discharge time of step S4 is 1-3 min, and the discharge amount is 30-60 kg / (tFe).

6. The converter indirect oxidation vanadium extraction process according to claim 5, wherein: The discharge time is 2 minutes, and the discharge amount is 45 kg / (tFe).

7. The converter indirect oxidation vanadium extraction process according to claim 1, wherein: The inert gas in step S5 is: nitrogen or argon; The blowing intensity of the inert gas is 0.01-0.8m 3 / (min·tFe).

8. The converter indirect oxidation vanadium extraction process according to claim 7, wherein: The inert gas is nitrogen; The blowing intensity is 0.7m 3 / (min·tFe).

9. The converter indirect oxidation vanadium extraction process according to claim 1, wherein: After the reaction in step S6 reaches 6-10 minutes, the vanadium slag is poured out.

10. The converter indirect oxidation vanadium extraction process according to claim 9, wherein: After the reaction lasted for 6 minutes, the vanadium slag was poured out.

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