Method for extracting vanadium from low-silicon high-chromium molten iron

Abstract

The application discloses a vanadium element extraction method in low-silicon high-chromium molten iron, and relates to the field of blast furnace ironmaking.The method solves the problems of high cost and low extraction efficiency of the existing vanadium element extraction method in low-silicon high-chromium molten iron.The vanadium element extraction method comprises the following steps: S1, providing low-silicon high-chromium molten iron, a cooling agent and a slag adjusting agent;S2, adding the cooling agent and the low-silicon high-chromium molten iron into a converter respectively to perform first mixing, and obtaining a first mixture;S3, igniting the converter, adding the slag adjusting agent into the first mixture to perform second mixing, and then performing blowing and smelting to obtain a second mixture;S4, after the blowing and smelting are completed, tilting the converter to discharge semi-steel in the second mixture, pouring the semi-steel into a semi-steel ladle, and leaving vanadium slag remaining in the converter;S5, repeating steps S3 and S4 for a preset number of times, and then pouring all the vanadium slag remaining in the converter into a vanadium slag tank to obtain finished vanadium slag.The method has low cost and high extraction efficiency.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of blast furnace ironmaking, in particular to a method for extracting vanadium elements from low-silicon high-chromium molten iron. BACKGROUND

[0002] Vanadium-titanium magnetite can be used in blast furnace for ironmaking to obtain molten iron containing vanadium and titanium, and because vanadium-titanium magnetite contains vanadium and chromium, the molten iron also contains a certain amount of chromium. Vanadium slag is a product obtained by selective oxidation of vanadium-iron molten iron in a converter for extracting vanadium in steelmaking. In order to control the cost and improve the yield, the low [Si+Ti] smelting process is implemented in the blast furnace. In China, there are more lean ores and the distribution of iron ore resources is relatively scattered. Therefore, it is an inevitable trend to increase the proportion of vanadium-titanium ore in the blast furnace and comprehensively develop and utilize vanadium-titanium magnetite.

[0003] Under the background of increasing the proportion of vanadium-titanium ore in the blast furnace and strengthening the smelting of the low [Si+Ti] process, the composition of the molten iron has changed greatly. The silicon content of the molten iron is reduced from 0.28% to below 0.15%, and the chromium content of the molten iron is increased from 0.15% to about 0.30%, forming low-silicon high-chromium molten iron. In the vanadium extraction process in the subsequent steelmaking process, less SiO2 and more Cr2O3 are generated by oxidizing low-silicon high-chromium molten iron and enter the vanadium slag. SiO2 is a component of low-melting silicate phase in vanadium slag, and Cr2O3 is a component of high-melting spinel phase in vanadium slag. The decrease of low-melting phase and the increase of high-melting phase lead to the increase of the melting point of vanadium slag and the increase of the viscosity of vanadium slag. In the vanadium extraction blowing process, it is difficult for the iron beads in the vanadium slag with high viscosity to return to the semi-steel, and the difficulty in slag-iron separation leads to the high content of metallic iron (MFe) in the vanadium slag, which is about 40%, increases the iron loss in the vanadium extraction process, and increases the difficulty in deep processing of vanadium slag.

[0004] However, the existing method for extracting vanadium elements from low-silicon high-chromium molten iron has high cost and low extraction efficiency. SUMMARY

[0005] The present application aims to solve the problem of high cost and low extraction efficiency of the existing method for extracting vanadium elements from low-silicon high-chromium molten iron.

[0006] In order to achieve the above-mentioned purpose, the present application specifically adopts the following technical scheme:

[0007] A method for extracting vanadium elements from low-silicon high-chromium molten iron, comprising the following steps:

[0008] S1, providing low-silicon high-chromium molten iron, a cooling agent, and a slag adjusting agent;

[0009] S2, adding the cooling agent and the low-silicon high-chromium molten iron into a converter respectively to perform first mixing to obtain a first mixture;

[0010] S3, igniting the converter, adding the slag adjusting agent into the first mixture to perform second mixing, and then performing blowing to obtain a second mixture.

[0011] S4, after the blowing is finished, the semi-steel in the second mixture is discharged from the converter, and the semi-steel is poured into a semi-steel ladle, and the vanadium slag remaining in the converter is reserved;

[0012] S5, the steps S3 and S4 are repeated for a preset number of times, and then all the vanadium slag remaining in the converter is poured into a vanadium slag tank to obtain finished vanadium slag.

[0013] Optionally, the extraction method further comprises top blowing oxygen and bottom blowing nitrogen.

[0014] Optionally, in the top blowing oxygen, the oxygen supply time is 260-320 seconds per furnace; the oxygen supply pressure is 0.60-0.85 MPa; and the oxygen supply flow rate is 10000-12500 m 3 / h.

[0015] Optionally, in the bottom blowing nitrogen, the bottom blowing intensity is 0.03-0.05 Nm 3 / t·min; and the single-branch flow rate is 40 Nm 3 / h.

[0016] Optionally, in the S5, the preset number of times is 2-4 times.

[0017] Optionally, the cooling agent is pig iron.

[0018] Optionally, the slag adjusting agent is iron sand ball.

[0019] Optionally, in the low-silicon high-chromium molten iron, the content of Si element is less than 0.15%, the content of V element is 0.25%-0.35%, and the content of Cr element is 0.25%-0.35%.

[0020] Optionally, the adding amount of the slag adjusting agent and the cooling agent is specifically as follows: when the content of Si in the molten iron is 0.10%-0.15%, the adding amount of the pig iron is 1.0-1.2 t per furnace, and the adding amount of the slag adjusting agent is 1.5-2.0 tons per furnace; when the content of Si in the molten iron is less than 0.10%, no cooling agent is added, and the adding amount of the slag adjusting agent is 2.0-3.0 tons per furnace.

[0021] Optionally, the end point control of the blowing is as follows: the temperature of the semi-steel is 1360-1400 degrees Celsius; the content of C in the semi-steel is greater than or equal to 3.4%; and the content of residual V in the semi-steel is less than or equal to 0.045%.

[0022] Compared with the prior art, the application has the following advantages:

[0023] 1. The present application relates to a kind of low silicon high chromium molten iron vanadium element extraction method, by adding coolant, low silicon high chromium molten iron, slag conditioner to converter and adjusting suitable proportion to mix and blow, discharge semi-steel after blowing, realize the accumulation of vanadium slag, process is simple, only need to add suitable additive and adjust appropriate proportion to extract vanadium element in low silicon high chromium molten iron efficiently, solve the problem of high cost, low extraction efficiency of existing low silicon high chromium molten iron vanadium element extraction method.

[0024] At present, the commonly used for vanadium extraction slagging in domestic is silicon iron, potassium / sodium feldspar, quartz sand, etc., there are high cost, not convenient to enter the furnace, slow slagging effect and high residual vanadium and other shortcomings, and the iron sand ball added in the present application has the advantages of easy to press, easy to enter the furnace and fast slagging, and corresponding process measures are controlled during vanadium extraction, the vanadium slag grade and metal iron content are balanced by controlling the vanadium slag state, the vanadium extraction cost is low, the efficiency is high, and it has wide application prospect and great popularization value.

[0025] To make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be described clearly and completely below. Obviously, the described embodiments are part of the embodiments of the present application, not all.

[0026] Therefore, the following detailed description of the embodiments of the present application provided herein is not intended to limit the scope of the claimed application, but only represents selected embodiments of the application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application. DETAILED DESCRIPTION

[0027] A kind of low silicon high chromium molten iron vanadium element extraction method, comprising the following steps:

[0028] S1, provide low silicon high chromium molten iron, coolant, slag conditioner;

[0029] S2, first mixing is carried out by adding coolant and low silicon high chromium molten iron into converter respectively, to obtain first mixture;

[0030] S3, first mixture is added into converter after ignition, second mixing is carried out, then blowing is carried out, to obtain second mixture;

[0031] S4, after blowing is finished, semi-steel in second mixture is discharged by tilting converter, and semi-steel is poured into semi-steel ladle, and the remaining vanadium slag in converter is retained;

[0032] S5, repeat steps S3 and S4 for a predetermined number of times, then pour all the remaining vanadium slag in converter into vanadium slag tank, to obtain finished product vanadium slag.

[0033] It can be understood that the method for extracting vanadium element in low-silicon high-chromium molten iron relates to a method for extracting vanadium element in low-silicon high-chromium molten iron, which realizes accumulation of vanadium slag by adding a cooling agent, low-silicon high-chromium molten iron and a slag adjusting agent into a converter, mixing and blowing, discharging semi-steel after blowing, and has the advantages of simple process, efficient extraction of vanadium element in low-silicon high-chromium molten iron by adding appropriate additives and adjusting appropriate proportions, and solving the problems of high cost and low extraction efficiency of the existing method for extracting vanadium element in low-silicon high-chromium molten iron.

[0034] Further, at present, silicon iron, potassium / sodium feldspar and quartz sand are generally used for vanadium extraction and slag adjustment in China, and there are disadvantages of high cost, inconvenience of entering the furnace, slow slag forming effect and high residual vanadium, while the iron sand ball added in the present application has the advantages of easy pressing, easy entering the furnace and fast slag forming, and through control of corresponding process measures in the vanadium extraction process, the vanadium slag grade and metallic iron content are balanced through control of the vanadium slag state, the vanadium extraction cost is low, the efficiency is high, and the present application has wide application prospect and great popularization value.

[0035] In some embodiments of the present application, the extraction method further comprises top blowing oxygen supply and bottom blowing nitrogen supply.

[0036] In some embodiments of the present application, in the top blowing oxygen supply, the oxygen supply time is 260-320 seconds per furnace, the oxygen supply pressure is 0.60-0.85 MPa, and the oxygen supply flow rate is 10000-12500 m 3 / h.

[0037] In some embodiments of the present application, in the bottom blowing nitrogen supply, the bottom blowing intensity is 0.03-0.05 Nm 3 / t.min, and the single branch flow rate is 40 Nm 3 / h.

[0038] In some embodiments of the present application, the blowing time in S3 is 260-320 seconds.

[0039] In some embodiments of the present application, the preset number of times in S5 is 2-4 times.

[0040] In some embodiments of the present application, the cooling agent is pig iron.

[0041] In some embodiments of the present application, the slag adjusting agent is an iron sand ball.

[0042] In some embodiments of the present application, the Si element content in the low-silicon high-chromium molten iron is less than 0.15%, the V element content is 0.25%-0.35%, and the Cr element content is 0.25%-0.35%.

[0043] In some embodiments of the present application, the adding amount of the slag modifier and the cooling agent is specifically: when the Si content in the molten iron is 0.10%-0.15%, the pig iron is used in an amount of 1.0-1.2 t / furnace, and the adding amount of the slag modifier is 1.5-2.0 t / furnace; when the Si content in the molten iron is less than 0.10%, no cooling agent is added, and the adding amount of the slag modifier is 2.0-3.0 t / furnace.

[0044] In some embodiments of the present application, the end point control after blowing is as follows: the temperature of the semi-steel is 1360-1400 degrees Celsius; the C content in the semi-steel is greater than or equal to 3.4%; and the residual V content in the semi-steel is less than or equal to 0.045%.

[0045] Embodiment 1

[0046] In the present embodiment, a method 1 for extracting vanadium element in low-silicon high-chromium molten iron is provided, comprising the following steps:

[0047] S1, providing low-silicon high-chromium molten iron, a cooling agent, and a slag modifier;

[0048] S2, adding the cooling agent and the low-silicon high-chromium molten iron into a converter respectively to perform first mixing to obtain a first mixture;

[0049] S3, igniting the converter, adding the slag modifier into the first mixture to perform second mixing, and then performing blowing to obtain a second mixture;

[0050] S4, after the blowing is completed, tilting the converter to discharge semi-steel in the second mixture, pouring the semi-steel into a semi-steel ladle, and leaving the vanadium slag remaining in the converter;

[0051] S5, repeating steps S3 and S4 for a preset number of times, and then pouring all the vanadium slag remaining in the converter into a vanadium slag tank to obtain a finished vanadium slag.

[0052] The extraction method further comprises top blowing oxygen supply and bottom blowing nitrogen supply. In the top blowing oxygen supply, the oxygen supply time is 260-320 seconds / furnace; the oxygen supply pressure is 0.60-0.85 MPa; and the oxygen supply flow rate is 10000-12500 m 3 / h.

[0053] In the bottom blowing nitrogen supply, the bottom blowing intensity is 0.03-0.05 Nm 3 / t·min; and the flow rate of a single branch is 40 Nm 3 / h.

[0054] The preset number of times in S5 is 2. The cooling agent is pig iron. The slag modifier is iron sand ball.

[0055] The low-silicon high-chromium molten iron has a content of Si less than 0.15%, a content of V of 0.25%-0.35%, and a content of Cr of 0.25%-0.35%.

[0056] The adding amount of the slag modifier and the cooling agent is specifically: when the content of Si in the molten iron is 0.10%-0.15%, the amount of pig iron is 1.0-1.2 t / furnace, and the adding amount of the slag modifier is 1.5-2.0 t / furnace; when the content of Si in the molten iron is less than 0.10%, no cooling agent is added, and the adding amount of the slag modifier is 2.0-3.0 t / furnace.

[0057] The end point control of the blowing is that the temperature of the semi-steel is 1360-1400 degrees Celsius, the content of C in the semi-steel is greater than or equal to 3.4%, and the residual content of V in the semi-steel is less than or equal to 0.045%.

[0058] Embodiment 2

[0059] In the embodiment, a method 2 for extracting vanadium elements from low-silicon high-chromium molten iron is provided, comprising the following steps:

[0060] S1, providing low-silicon high-chromium molten iron, a cooling agent, and a slag modifier;

[0061] S2, adding the cooling agent and the low-silicon high-chromium molten iron into a converter respectively to perform first mixing, to obtain a first mixture;

[0062] S3, igniting the converter, adding the slag modifier into the first mixture to perform second mixing, and then performing blowing, to obtain a second mixture;

[0063] S4, after the blowing is completed, discharging semi-steel in the second mixture by tilting the converter, and pouring the semi-steel into a semi-steel ladle, and leaving vanadium slag remaining in the converter;

[0064] S5, repeating steps S3 and S4 for a preset number of times, and then pouring all the vanadium slag remaining in the converter into a vanadium slag tank, to obtain finished vanadium slag.

[0065] The method further comprises top blowing oxygen supply and bottom blowing nitrogen supply. In the top blowing oxygen supply, the oxygen supply time is 260-320 seconds / furnace, the oxygen supply pressure is 0.60-0.85 MPa, and the oxygen supply flow rate is 10000-12500 m 3 / h.

[0066] In the bottom blowing nitrogen supply, the bottom blowing intensity is 0.03-0.05 Nm 3 / t·min, and the flow rate of a single branch is 40 Nm 3 / h.

[0067] The preset number of times in S5 is 3. The cooling agent is pig iron. The slag modifier is iron sand ball.

[0068] The Si content in the low-silicon high-chromium molten iron is less than 0.15%, the V content is 0.25%-0.35%, and the Cr content is 0.25%-0.35%.

[0069] The adding amount of the slag adjusting agent and the cooling agent is specifically as follows: when the Si content in the molten iron is 0.10%-0.15%, the pig iron is used in an amount of 1.0-1.2 t / furnace, and the adding amount of the slag adjusting agent is 1.5-2.0 t / furnace; when the Si content in the molten iron is less than 0.10%, no cooling agent is added, and the adding amount of the slag adjusting agent is 2.0-3.0 t / furnace.

[0070] The end point control after blowing is as follows: the temperature of the semi-steel is 1360-1400 degrees Celsius; the C content in the semi-steel is greater than or equal to 3.4%; and the residual V content in the semi-steel is less than or equal to 0.045%.

[0071] Example 3

[0072] The low-silicon high-chromium molten iron in the example mainly contains C, Si, Mn, P, S, V, Cr and Fe, wherein the Si content is less than 0.15%, the V content is 0.25%-0.35%, and the Cr content is 0.25%-0.35%, compared with ordinary molten iron.

[0073] The cooling agent pig iron in the example is blast furnace molten iron cast pig iron, and the present vanadium extraction cold charge includes pig iron, cold solid pellets, waste vanadium slag and iron ore, and the cooling effect ratio of each is pig iron:waste vanadium slag: cold solid pellets: iron ore = 1:1.5:3.5:5.6. The cooling agent in the application selects the pig iron with the smallest cooling capacity as the cooling agent.

[0074] The slag adjusting agent iron sand ball in the example is made of iron oxide scale and river sand through a ball pressing process, and mainly contains FeO and SiO2. The composition and weight content of the slag adjusting agent iron sand ball are as follows: the Al2O3 content is 4-6%, the SiO2 content is 15-20%, and the rest is mainly iron oxide.

[0075] The low-silicon high-chromium molten iron loading amount in the vanadium extraction converter in the example is controlled to be 80±1 t / furnace; the low-silicon high-chromium molten iron needs to be added with the slag adjusting agent to improve the vanadium slag state, the W(SiO2) and W(V2O5+Cr2O3) ratio in the vanadium slag is adjusted, the silicate phase and spinel phase ratio is controlled, and "dry slag" with iron is avoided.

[0076] The adding amount of the slag adjusting agent iron sand ball in the example is controlled as follows:

[0077] 1) When the Si content in the molten iron is 0.10%-0.15%, the pig iron is used in an amount of 1.0-1.2 t / furnace, and the adding amount of the slag adjusting agent iron sand ball is controlled to be 1.5-2.0 t / furnace;

[0078] 2) when the Si content in molten iron is below 0.10%, no pig iron is added, and the amount of iron sand ball added as a fluxing agent is controlled according to 2.0-3.0 tons / furnace;

[0079] The process parameter control requirements in the vanadium extraction process in the embodiment are as follows:

[0080] 1) in the top blowing oxygen supply, the oxygen supply time is 260-320 seconds / furnace; the oxygen supply pressure is 0.60-0.85 MPa; and the oxygen supply flow rate is 10000-12500 m 3 / h.

[0081] 2) bottom blowing nitrogen: bottom blowing intensity: 0.03-0.05 Nm 3 / t·min; single branch flow rate: 40 Nm 3 / h; the slag retaining operation is adopted, and the vanadium slag is discharged every 3 furnaces, and the half steel operation is adopted by using the slag blocking ball to block the slag for the relatively dilute furnace.

[0082] In the blowing end point control in the embodiment, the half steel temperature is controlled according to 1360-1400 degrees Celsius; the half steel C content is greater than or equal to 3.4%; and the half steel residual V is less than or equal to 0.045%.

[0083] In a certain production, the vanadium element extraction method of one kind of low-silicon high-chromium molten iron in embodiments 1-3 is adopted, and the existing extraction method is adopted in the control group, the vanadium slag indicators of the prepared finished product vanadium slag are detected, and the specific finished product vanadium slag indicators are shown in the following table.

[0084] Cr203 SiO2% [V2O5%] Mild iron (MFe) Example 1 7.91 19.23 18.73 16.35 Example 2 8.90 20.80 18.76 16.98 Example 3 8.56 19.43 17.61 16.31 Control group 8.90 19.88 16.20 18.38

[0085] It can be seen that in the vanadium element extraction method of one kind of low-silicon high-chromium molten iron in embodiments 1-3, the vanadium element in the final finished product vanadium slag is effectively extracted, the content of V2O5 is all above 17.61%, and the content of wustite (MFe) is below 16.98%. In the control group, the vanadium element in the vanadium slag is relatively low, which is 16.20%, and the content of wustite (MFe) is relatively high, which is 18.38%. It can be seen that the extraction method involved in the present application can efficiently extract the vanadium element in low-silicon high-chromium molten iron, and has superiority compared with the existing extraction method.

[0086] The above embodiments are only one kind of implementation of the present application, the description is more specific and detailed, but it cannot be understood as a limitation on the patent scope of the present application. It should be noted that for ordinary skilled persons in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which all belong to the protection scope of the present application. Therefore, the protection scope of the present application patent should be subject to the appended claims.

Claims

1. A method for extracting vanadium from low-silicon high-chromium molten iron, characterized by, The method comprises the following steps: S1, providing low-silicon high-chromium molten iron, a cooling agent, and a slag conditioner; S2, adding the cooling agent and the low-silicon high-chromium molten iron into a converter respectively to perform first mixing to obtain a first mixture; S3, igniting the converter, adding the slag conditioner into the first mixture to perform second mixing, and then performing blowing to obtain a second mixture; S4, after the blowing is completed, tilting the converter to discharge semi-steel in the second mixture, pouring the semi-steel into a semi-steel ladle, and leaving vanadium slag remaining in the converter; S5, repeating steps S3 and S4 for a preset number of times, and then pouring all the vanadium slag left in the converter into a vanadium slag tank to obtain finished vanadium slag; the slag adjusting agent is iron sand ball; the Si element content in the low-silicon high-chromium molten iron is less than 0.15%, the V element content is 0.25%-0.35%, and the Cr element content is 0.25%-0.35%; the adding amount of the slag adjusting agent and the cooling agent is specifically: when the Si content in the molten iron is 0.10%-0.15%, the pig iron dosage is 1.0-1.2 t / furnace, and the adding amount of the slag adjusting agent is 1.5-2.0 tons / furnace; when the Si content in the molten iron is less than 0.10%, no cooling agent is added, and the adding amount of the slag adjusting agent is 2.0-3.0 tons / furnace; the end point control after blowing is completed is: the temperature of the semi-steel is 1360-1400 degrees Celsius; the C content in the semi-steel is greater than or equal to 3.4%; the residual V content in the semi-steel is less than or equal to 0.045%; the extraction method further comprises top blowing oxygen supply and bottom blowing nitrogen supply, in the top blowing oxygen supply, the oxygen supply time is 260-320 seconds / furnace; the oxygen supply pressure is 0.60-0.85 MPa; the oxygen supply flow rate is 10000-12500 m³ / h; in the bottom blowing nitrogen supply, the bottom blowing intensity is 0.03-0.05 Nm 3 / t.min; the single branch flow rate is 40 Nm 3 / h; the cooling agent is pig iron; the preset number of times in S5 is 2-4 times.