Gas mixed blowing gas supply method for converter vanadium extraction smelting

Abstract

The invention provides a gas mixed blowing gas supply method for vanadium extraction smelting of a converter, which comprises the following steps: (1) after iron is added into the vanadium extraction converter, sampling molten iron to obtain the temperature and chemical components of the molten iron; (2) when the temperature of the molten iron is greater than or equal to 1420 DEG C, carrying out first mixed blowing on the molten iron; and when the content of Si in the molten iron is larger than or equal to 0.3 wt% and the content of C is smaller than or equal to 3.8 wt%, second mixed blowing is conducted on the molten iron. Different gas mixed blowing modes are adopted for molten iron under different conditions, the temperature of the molten pool and the stirring effect can be accurately controlled, the oxidation rate and the recovery rate of vanadium can be remarkably increased, and the content of residual vanadium is reduced; meanwhile, the method provided by the invention can also reduce the loss of carbon element and ensure the requirements of subsequent steelmaking operation.

Description

Technical Field

[0001] The invention belongs to the technical field of steel production, and relates to a gas mixed blowing and supplying method for converter vanadium extraction and smelting. Background Art

[0002] China is a major producer of vanadium-titanium magnetite. Vanadium-containing molten iron is mainly obtained by smelting vanadium-titanium magnetite in blast furnaces. The main methods for extracting vanadium from vanadium-containing molten iron at home and abroad include the atomization vanadium extraction adopted by China's Panzhihua Iron and Steel Group in the early days, the air bottom blowing converter vanadium extraction method of Russia's Chusov Metallurgical Plant, the top and bottom combined blowing converter vanadium extraction method, the shaking ladle vanadium extraction method adopted by South Africa's High Wilder Steel and Vanadium Company, and the iron ladle oxygen blowing vanadium extraction method adopted by New Zealand Steel. Among them, the top and bottom combined blowing converter vanadium extraction method is the most commonly used.

[0003] The process of vanadium extraction from a converter is to add vanadium-containing molten iron into a vanadium-extracting converter. An oxygen lance that can move up and down to supply oxygen to the converter is installed above the converter. There are air-permeable bricks at the bottom of the converter, which can supply inert gases such as nitrogen and argon from the bottom. When the furnace is opened for blowing, the oxygen is turned on during the descent of the oxygen lance, and the oxygen contacts the high-temperature molten iron, which ignites. The oxygen lance is lowered to a position 1.3m to 2.2m from the molten iron surface, and oxygen is supplied to the molten pool. The carbon, silicon, manganese, chromium, vanadium, titanium and other elements in the molten iron contact with oxygen for oxidation to form oxides, which float up into the slag. Vanadium is oxidized to form high-valent oxides of vanadium, which enter the slag to form vanadium slag. The process of vanadium extraction from a converter is a selective oxidation process, and there is a carbon-vanadium conversion temperature, which is about 1360℃. When the molten pool temperature is lower than 1360℃, vanadium undergoes oxidation reaction before carbon, and the oxidation of vanadium is dominant, while the oxidation of carbon is slower. When the molten pool temperature is higher than 1360℃, carbon undergoes oxidation before vanadium, and the oxidation rate of carbon is greater than the oxidation rate of vanadium. During the vanadium extraction process, coolant is added to the molten pool to slow down the temperature rise of the molten pool and fully oxidize the vanadium in the molten iron. During the converter vanadium extraction process, the carbon and silicon in the molten iron are oxidized at the same time as the vanadium is oxidized, resulting in low carbon and silicon in the semi-steel after vanadium extraction, and the chemical heat source of the semi-steel decreases, affecting the next converter steelmaking operation.

[0004] The heat source of molten iron mainly consists of chemical heat source and physical heat source. The temperature of molten iron is the physical heat source, and the carbon, silicon and other components of molten iron are the chemical heat source. In the process of vanadium extraction and gas supply in the converter, the carbon and silicon of molten iron are oxidized to generate heat. According to experience, every 0.01% oxidation of carbon mass fraction in molten iron can generate 1°C temperature, and every 0.01% oxidation of silicon mass fraction in molten iron can generate 4°C molten iron temperature.

[0005] CN 102127613A discloses a converter composite blowing vanadium extraction method, which uses a mixed gas of oxygen and nitrogen to replace pure oxygen for composite blowing on vanadium-containing molten iron, and simultaneously cooperates with converter bottom blowing of nitrogen or other inert gases to extract vanadium, and reduces the oxygen concentration in the gas medium provided to the molten pool, while ensuring the gas supply pressure required for molten pool stirring, so as to ensure that the molten pool temperature rises steadily during the blowing process, and at the same time meet the requirements of vanadium extraction dynamic conditions. The patented method can increase the cooling intensity of vanadium extraction, reduce the heating rate of vanadium extraction, and is conducive to the oxidation of vanadium in molten iron, but for molten iron with low carbon, low silicon and low temperature, there will be problems of low semi-steel carbon and poor semi-steel conditions. Summary of the invention

[0006] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a gas mixed blowing and supply method for converter vanadium smelting. The present invention adopts different gas mixed blowing methods for molten iron under different conditions, which can achieve precise control of the molten pool temperature and stirring effect, significantly improve the oxidation rate and recovery rate of vanadium, and reduce the residual vanadium content; at the same time, the method provided by the present invention can also reduce the loss of carbon elements and ensure the needs of subsequent steelmaking operations.

[0007] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0008] The present invention provides a gas mixed blowing gas supply method for converter vanadium extraction smelting, the gas supply method comprising the following steps:

[0009] (1) After the vanadium-extracting converter is fully charged with iron, the molten iron is sampled to obtain the temperature and chemical composition of the molten iron;

[0010] (2) When the temperature of the molten iron is ≥1420°C, the molten iron is subjected to the first mixed blowing;

[0011] When the Si content in the molten iron is ≥0.3wt% and the C content is ≤3.8wt%, the molten iron is subjected to a second mixed-blowing process.

[0012] It is worth noting that the average steel output of the converter equipment used in the converter vanadium extraction smelting of the present invention is 120 tons.

[0013] The present invention performs the first mixed blowing and refining on molten iron with high physical heat (molten iron temperature ≥ 1420°C); and performs the second mixed blowing and refining on molten iron with high chemical heat (Si content ≥ 0.3wt%, C content ≤ 3.8wt%). For molten iron under different conditions, the present invention adopts different blowing methods to achieve precise control of the molten pool temperature and stirring effect, which can significantly improve the oxidation rate and recovery rate of vanadium and reduce the residual vanadium content; at the same time, the method provided by the present invention can also reduce the loss of carbon elements and ensure the needs of subsequent steelmaking operations.

[0014] In addition, the method provided by the present invention can reduce the amount of cold material for vanadium extraction, which is 1.1t / furnace lower than that of pure oxygen blowing. According to the annual gas mixed blowing application ratio of 30%, the annual cost can be saved by 4.03 million yuan; and by increasing the recovery of vanadium, the annual benefit can be about 1.23 million yuan.

[0015] Exemplarily, the temperature of molten iron with higher physical heat is ≥1420°C, for example, it can be 1420°C, 1440°C, 1460°C, 1480°C or 1500°C, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0016] The Si content in the hot metal with higher chemical heat is ≥ 0.3wt%, for example, it can be 0.3wt%, 0.32wt%, 0.34wt%, 0.36wt%, 0.38wt% or 0.4wt%, but is not limited to the listed values, and other values ​​not listed in the numerical range are also applicable;

[0017] The C content is ≤3.8wt%, for example, it can be 3.8wt%, 3.7wt%, 3.6wt%, 3.5wt%, 3.4wt% or 3.3wt%, etc., but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0018] As a preferred technical solution of the present invention, the mixed gas used in the first mixed blowing and the second mixed blowing includes oxygen and inert gas.

[0019] Preferably, the inert gas comprises any one of nitrogen, argon or helium, preferably nitrogen.

[0020] Preferably, the purity of the oxygen is ≥99.3%, for example, it may be 99.3%, 99.4%, 99.5%, 99.6% or 99.7%, etc., but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0021] As a preferred technical solution of the present invention, step (2) the first mixed blowing comprises: first, using an inert gas to cool and blow the molten iron under stirring conditions, and then using oxygen to blow the molten iron with pure oxygen.

[0022] It is worth noting that, in the first mixed blowing and refining of the present invention, the inert gas is used first and then the oxygen is used, and the inert gas and oxygen will not exist at the same time.

[0023] Preferably, the stirring speed is 150-250 r / min, for example, it can be 150 r / min, 170 r / min, 190 r / min, 210 r / min or 250 r / min, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0024] Preferably, the cooling and blowing time is 50 to 90 s, for example, 50 s, 55 s, 60 s, 65 s, 70 s, 75 s, 80 s, 85 s or 90 s, etc., but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0025] Preferably, the flow rate of the inert gas during the cooling and blowing is 18000-20000m 3 / h, for example, it can be 18000m 3 / h、18500m 3 / h、19000m 3 / h、19500m 3 / h or 20000m 3 / h, etc., but are not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0026] Preferably, the working pressure of the inert gas in the cooling and blowing is 0.8-0.9 MPa, for example, it can be 0.8 MPa, 0.82 MPa, 0.84 MPa, 0.86 MPa, 0.88 MPa or 0.9 MPa, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0027] Preferably, the terminal temperature of the cooling and blowing is ≤1400°C, for example, it can be 1400°C, 1350°C, 1300°C, 1250°C or 1200°C, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0028] Preferably, the pure oxygen blowing time is 3.5 to 4.5 min, for example, 3.5 min, 3.7 min, 3.9 min, 4.1 min, 4.3 min or 4.5 min, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0029] Preferably, the flow rate of oxygen in the pure oxygen blowing is 18000-20000m 3 / h, for example, it can be 18000m 3 / h、18500m 3 / h、19000m 3 / h、19500m 3 / h or 20000m 3 / h, etc., but are not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0030] Preferably, the working pressure of oxygen in the pure oxygen blowing is 0.8-0.9 MPa, for example, it can be 0.8 MPa, 0.82 MPa, 0.84 MPa, 0.86 MPa, 0.88 MPa or 0.9 MPa, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0031] It is worth noting that the present invention realizes physical cooling of molten iron by cooling and blowing, and then realizes efficient oxidation of vanadium in molten iron by pure oxygen blowing;

[0032] Furthermore, a high flow rate of the inert gas or oxygen in the cooling blowing and pure oxygen blowing will lead to excessive stirring of the molten pool, which may cause splashing and other problems, thereby affecting the safety of operation and the quality of the molten steel; a low flow rate will lead to poor stirring effect, uneven element oxidation, and reduced vanadium oxidation rate and recovery rate;

[0033] In addition, the pure oxygen blowing time is 3.5 to 4.5 minutes. If the time is too long, it will lead to excessive oxidation of carbon elements, making the carbon content of steel too low during subsequent steelmaking, affecting the performance of the steel; if the time is too short, it will lead to insufficient oxidation of vanadium elements, reducing the recovery rate of vanadium.

[0034] As a preferred technical solution of the present invention, step (2) the second mixed blowing comprises the following steps:

[0035] (a) After lowering the oxygen lance to the first lance position, the inert gas regulating valve of the oxygen lance is opened to blow the molten iron once until the inert gas flow rate meets the standard; then, the oxygen lance is further lowered to the second lance position, the oxygen regulating valve of the oxygen lance is opened to blow the molten iron twice until the molten iron meets the standard;

[0036] (b) After lifting the oxygen gun, close the oxygen regulating valve first, and then close the inert gas regulating valve after the oxygen returns to zero.

[0037] In the present invention, for molten iron with high chemical heat, the gas mixed blowing and gas supply method provided by the present invention is: first use inert gas for blowing, and then turn on the oxygen (use inert gas and oxygen for blowing at the same time), and during the gas mixed blowing process, the oxygen concentration is reduced to ensure the gas supply pressure required for stirring the molten pool, and at the same time ensure that the molten pool temperature rises steadily during the blowing process, thereby improving the oxidation rate and recovery rate of vanadium.

[0038] Preferably, in the one blowing in step (a), the distance between the first gun position and the furnace bottom is 5.8 to 6.2 m, for example, 5.8 m, 5.9 m, 6.0 m, 6.1 m or 6.2 m, etc., but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0039] Preferably, in the secondary blowing of step (a), the distance between the second gun position and the furnace bottom is 4.5 to 5.5 m, for example, 4.5 m, 4.7 m, 4.9 m, 5.1 m, 5.3 m or 5.5 m, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0040] Preferably, in the first blowing of step (a), the inert gas flow rate reaches a standard of 4500-5500 m 3 / h, for example, 4500m 3 / h、4700m 3 / h、4900m 3 / h、5100m 3 / h、5300m 3 / h or 5500m 3 / h, etc., but are not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0041] Preferably, in the secondary blowing of step (a), the flow rate of oxygen is 14500-15500m 3 / h, for example, it can be 14500m 3 / h、14700m 3 / h、14900m 3 / h、15100m 3 / h、15300m 3 / h or 15500m 3 / h, etc., but are not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0042] In the present invention, accurate control of the molten pool temperature and stirring effect can be achieved by reasonably allocating the flow rates of oxygen and inert gas in the mixed gas, which can significantly improve the oxidation rate and recovery rate of vanadium and reduce the residual vanadium content. If the oxygen content in the second mixed blowing is too high, the molten pool temperature will rise too fast, the carbon element will be over-oxidized, and the carbon content requirement of subsequent steelmaking will be affected. At the same time, the vanadium oxidation may be terminated prematurely, reducing the vanadium recovery rate. On the contrary, if the oxygen content is too low, it will lead to insufficient vanadium oxidation, low vanadium extraction efficiency, extended blowing time, and increased costs.

[0043] Preferably, in the secondary blowing of step (a), the working pressure of oxygen is 0.8-1.2 MPa, for example, 0.8 MPa, 0.9 MPa, 0.95 MPa, 1.0 MPa, 1.05 MPa, 1.1 MPa, 1.15 MPa or 1.2 MPa, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0044] Preferably, in the secondary blowing of step (a), the working pressure of the inert gas is 0.7-0.8 MPa, for example, 0.7 MPa, 0.72 MPa, 0.74 MPa, 0.76 MPa, 0.78 MPa or 0.8 MPa, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0045] Preferably, the secondary blowing time in step (a) is 5.5 to 6.5 min, for example, 5.5 min, 5.7 min, 5.9 min, 6.1 min, 6.3 min or 6.5 min, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0046] Preferably, the standard for the molten iron to meet the standard in step (a) is: the terminal temperature of the molten iron is 1360-1400°C, for example, it can be 1360°C, 1370°C, 1380°C, 1390°C or 1400°C, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0047] In the present invention, when the molten iron in step (a) reaches 1360-1400°C, the flame will be slightly blue, gradually shrink and shorten, and the flame will gradually become softer, but still maintain a certain brightness and stability. This standard indicates that the oxidation reaction of the main elements in the molten iron has reached a relative equilibrium state, the oxidation of vanadium is relatively sufficient, and the temperature and composition of the molten pool are also stable.

[0048] The numerical range described in the present invention not only includes the point values ​​listed above, but also includes any point values ​​between the above numerical ranges that are not listed. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0049] Compared with the prior art, the present invention has the following beneficial effects:

[0050] (1) The present invention adopts different gas mixed blowing and gas supply methods to perform full coverage vanadium extraction according to different molten iron conditions, further improving the vanadium recovery of the system;

[0051] (2) The present invention adopts different gas mixing blowing modes, which can achieve precise control of the molten pool temperature and stirring effect, significantly improve the oxidation rate and recovery rate of vanadium, and reduce the residual vanadium content;

[0052] (3) The method provided by the present invention can reduce the loss of carbon element during the blowing process and ensure the requirements of subsequent steelmaking operations. DETAILED DESCRIPTION

[0053] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0054] In a specific embodiment, the present invention provides a gas mixed blowing gas supply method for converter vanadium smelting, the gas supply method comprising the following steps:

[0055] (1) After the vanadium-extracting converter is fully charged with iron, the molten iron is sampled to obtain the temperature and chemical composition of the molten iron;

[0056] (2) When the temperature of the molten iron is ≥1420°C, the molten iron is subjected to the first mixed blowing;

[0057] The first mixed blowing comprises: first, using an inert gas to cool down the molten iron for 50 to 90 seconds under stirring conditions of 150 to 250 r / min, and then using oxygen to blow the molten iron with pure oxygen for 3.5 to 4.5 minutes;

[0058] Wherein, the flow rate of the inert gas is 18000~20000m 3 / h, the working pressure is 0.8~0.9MPa; the flow rate of the oxygen is 18000~20000m 3 / h, working pressure is 0.8~0.9MPa;

[0059] When the Si content in the molten iron is ≥0.3wt% and the C content is ≤3.8wt%, the molten iron is subjected to a second mixed blowing process;

[0060] The second mixed-blow blowing comprises the following steps:

[0061] (a) After lowering the oxygen lance to the first lance position, open the inert gas regulating valve of the oxygen lance and perform a primary blowing on the molten iron until the inert gas flow rate reaches the standard; then continue to lower the oxygen lance to the second lance position and open the oxygen regulating valve of the oxygen lance to perform a secondary blowing on the molten iron for 5.5 to 6.5 minutes until the terminal temperature of the molten iron is 1360 to 1400°C;

[0062] In the first blowing, the distance between the first gun position and the furnace bottom is 5.8-6.2m; the inert gas flow rate reaches the standard of 4500-5500m 3 / h;

[0063] In the secondary blowing, the distance between the second gun position and the furnace bottom is 4.5-5.5m; the oxygen flow rate is 14500-15500m 3 / h, the working pressure of oxygen is 0.8~1.2MPa, and the working pressure of inert gas is 0.7~0.8MPa.

[0064] (b) After lifting the oxygen gun, close the oxygen regulating valve first, and then close the inert gas regulating valve after the oxygen returns to zero.

[0065] (I) For molten iron with high physical heat:

[0066] Example 1

[0067] This embodiment provides a gas mixed blowing gas supply method for converter vanadium extraction smelting, the gas supply method comprising the following steps:

[0068] (1) After the vanadium-extracting converter is charged with iron, the molten iron is sampled and the temperature of the molten iron is 1450°C;

[0069] (2) performing a first mixing and blowing process on the molten iron;

[0070] The first mixed blowing comprises: first, using an inert gas (nitrogen) to cool down the molten iron for 60 seconds under a stirring condition of 200 r / min, and then using oxygen to blow the molten iron with pure oxygen for 4 minutes;

[0071] The flow rate of the inert gas (nitrogen) is 19000m 3 / h, the working pressure is 0.85MPa; the flow rate of the oxygen is 20000m 3 / h, working pressure is 0.85MPa.

[0072] Example 2

[0073] This embodiment provides a gas mixed blowing gas supply method for converter vanadium extraction smelting, the gas supply method comprising the following steps:

[0074] (1) After the vanadium-extracting converter is charged with iron, the molten iron is sampled and the temperature of the molten iron is 1420°C;

[0075] (2) performing a first mixing and blowing process on the molten iron;

[0076] The first mixed blowing comprises: first, using an inert gas (helium) to cool down the molten iron for 50 seconds under a stirring condition of 200 r / min, and then using oxygen to blow the molten iron with pure oxygen for 3.5 minutes;

[0077] The flow rate of the inert gas (helium) is 18000m 3 / h, the working pressure is 0.85MPa; the flow rate of the oxygen is 19000m 3 / h, working pressure is 0.8MPa.

[0078] Example 3

[0079] This embodiment provides a gas mixed blowing gas supply method for converter vanadium extraction smelting, the gas supply method comprising the following steps:

[0080] (1) After the vanadium-extracting converter is charged with iron, the molten iron is sampled and the temperature of the molten iron is 1500°C;

[0081] (2) performing a first mixing and blowing process on the molten iron;

[0082] The first mixed blowing comprises: first, using an inert gas (argon) to cool down the molten iron for 90 seconds under a stirring condition of 200 r / min, and then using oxygen to blow the molten iron with pure oxygen for 4.5 minutes;

[0083] The flow rate of the inert gas (argon) is 20000m 3 / h, the working pressure is 0.85MPa; the flow rate of the oxygen is 18000m 3 / h, working pressure is 0.9MPa.

[0084] Example 4

[0085] This embodiment provides a gas mixed blowing gas supply method for converter vanadium smelting, and the gas supply method is different from that of embodiment 1 only in that:

[0086] In this embodiment, the cooling and blowing time is adjusted to 30 seconds.

[0087] Example 5

[0088] This embodiment provides a gas mixed blowing gas supply method for converter vanadium smelting, and the gas supply method is different from that of embodiment 1 only in that:

[0089] In this embodiment, the cooling and blowing time is adjusted to 120 seconds.

[0090] Example 6

[0091] This embodiment provides a gas mixed blowing gas supply method for converter vanadium smelting, and the gas supply method is different from that of embodiment 1 only in that:

[0092] In this embodiment, the pure oxygen blowing time is adjusted to 3 minutes.

[0093] Example 7

[0094] This embodiment provides a gas mixed blowing gas supply method for converter vanadium smelting, and the gas supply method is different from that of embodiment 1 only in that:

[0095] In this embodiment, the pure oxygen blowing time is adjusted to 5 minutes.

[0096] Example 8

[0097] This embodiment provides a gas mixed blowing gas supply method for converter vanadium smelting, and the gas supply method is different from that of embodiment 1 only in that:

[0098] In this embodiment, the stirring process during the cooling and blowing is omitted.

[0099] Comparative Example 1

[0100] This comparative example provides a gas mixed blowing gas supply method for converter vanadium smelting, and the difference between the gas supply method and Example 1 is only that:

[0101] The cooling and blowing process was omitted in this comparative example.

[0102] Comparative Example 2

[0103] This comparative example provides a gas mixed blowing gas supply method for converter vanadium smelting, and the difference between the gas supply method and Example 1 is only that:

[0104] In this comparative example, the composition of the molten iron in step (1) is adjusted to a Si content of 0.35wt% and a C content of 3.5wt%; that is, the first mixed blowing treatment is used to treat the molten iron with a relatively high chemical heat.

[0105] (II) For molten iron with high chemical heat:

[0106] Example 9

[0107] This embodiment provides a gas mixed blowing gas supply method for converter vanadium extraction smelting, the gas supply method comprising the following steps:

[0108] (1) After the vanadium-extracting converter is fully charged with iron, the molten iron is sampled and the Si content and C content in the molten iron are found to be 0.35 wt% and 3.5 wt% respectively;

[0109] (2) performing a second mixed blowing process on the molten iron;

[0110] The second mixed-blow blowing comprises the following steps:

[0111] (a) After lowering the oxygen lance to the first position, open the inert gas regulating valve of the oxygen lance and perform a first blowing on the molten iron until the inert gas (nitrogen) flow rate reaches the standard; then continue to lower the oxygen lance to the second position and open the oxygen regulating valve of the oxygen lance to perform a second blowing on the molten iron for 6 minutes until the terminal temperature of the molten iron reaches 1380°C;

[0112] In the first blowing, the distance between the first gun position and the furnace bottom is 5.96m; the inert gas flow rate reaches the standard of 5000m 3 / h;

[0113] In the secondary blowing, the distance between the second gun position and the furnace bottom is 5m; the oxygen flow rate is 15000m 3 / h, the working pressure of oxygen is 1.0MPa, and the working pressure of inert gas is 0.8MPa.

[0114] (b) After lifting the oxygen gun, close the oxygen regulating valve first, and then close the inert gas regulating valve after the oxygen returns to zero.

[0115] Example 10

[0116] This embodiment provides a gas mixed blowing gas supply method for converter vanadium extraction smelting, the gas supply method comprising the following steps:

[0117] (1) After the vanadium-extracting converter is charged with iron, the molten iron is sampled and processed, and the Si content and C content in the molten iron are found to be 0.3wt% and 3.8wt% respectively;

[0118] (2) performing a second mixed blowing process on the molten iron;

[0119] The second mixed-blow blowing comprises the following steps:

[0120] (a) After the oxygen lance is lowered to the first position, the inert gas (argon) regulating valve of the oxygen lance is opened to blow the molten iron once until the inert gas flow rate reaches the standard; then the oxygen lance is further lowered to the second position, the oxygen regulating valve of the oxygen lance is opened to blow the molten iron twice for 5.5 minutes until the terminal temperature of the molten iron reaches 1360°C;

[0121] In the first blowing, the distance between the first gun position and the furnace bottom is 5.8m; the inert gas flow rate reaches the standard of 5500m 3 / h;

[0122] In the secondary blowing, the distance between the second gun position and the furnace bottom is 4.5m; the oxygen flow rate is 15500m 3 / h, the working pressure of oxygen is 1.2MPa, and the working pressure of inert gas is 0.8MPa.

[0123] (b) After lifting the oxygen gun, close the oxygen regulating valve first, and then close the inert gas regulating valve after the oxygen returns to zero.

[0124] Embodiment 11

[0125] This embodiment provides a gas mixed blowing gas supply method for converter vanadium extraction smelting, the gas supply method comprising the following steps:

[0126] (1) After the vanadium-extracting converter was fully charged with iron, the molten iron was sampled and processed, and the Si content in the molten iron was found to be 0.37wt% and the C content was 3.1wt%;

[0127] (2) performing a second mixed blowing process on the molten iron;

[0128] The second mixed-blow blowing comprises the following steps:

[0129] (a) After lowering the oxygen lance to the first position, open the inert gas (helium) regulating valve of the oxygen lance to blow the molten iron once until the inert gas flow rate reaches the standard; then continue to lower the oxygen lance to the second position and open the oxygen regulating valve of the oxygen lance to blow the molten iron for 6.5 minutes twice until the terminal temperature of the molten iron reaches 1400°C;

[0130] In the first blowing, the distance between the first gun position and the furnace bottom is 6.2m; the inert gas flow rate reaches the standard of 4500m 3 / h;

[0131] In the secondary blowing, the distance between the second gun position and the furnace bottom is 4.5m; the oxygen flow rate is 14500m 3 / h, the working pressure of oxygen is 0.9MPa, and the working pressure of inert gas is 0.7MPa.

[0132] (b) After lifting the oxygen gun, close the oxygen regulating valve first, and then close the inert gas regulating valve after the oxygen returns to zero.

[0133] Example 12

[0134] This embodiment provides a gas mixed blowing gas supply method for converter vanadium smelting, and the gas supply method is different from that of embodiment 9 only in that:

[0135] In this embodiment, the distance between the first lance position and the furnace bottom in step (a) is adjusted to 5m, that is, the primary blowing and the secondary blowing are carried out at the same lance position.

[0136] Example 13

[0137] This embodiment provides a gas mixed blowing gas supply method for converter vanadium smelting, and the gas supply method is different from that of embodiment 9 only in that:

[0138] In this embodiment, the flow rate of the inert gas in step (a) is adjusted to 6000m 3 / h, and adjust the oxygen flow rate to 14000m 3 / h.

[0139] Embodiment 14

[0140] This embodiment provides a gas mixed blowing gas supply method for converter vanadium smelting, and the gas supply method is different from that of embodiment 9 only in that:

[0141] In this embodiment, the flow rate of the inert gas in step (a) is adjusted to 3000m 3 / h, and adjust the oxygen flow rate to 17000m 3 / h.

[0142] Embodiment 15

[0143] This embodiment provides a gas mixed blowing gas supply method for converter vanadium smelting, and the gas supply method is different from that of embodiment 9 only in that:

[0144] In this embodiment, in the secondary blowing of step (a), the working pressure of oxygen is adjusted to 0.6 MPa, and the working pressure of the inert gas is adjusted to 1.4 MPa.

[0145] Example 16

[0146] This embodiment provides a gas mixed blowing gas supply method for converter vanadium smelting, and the gas supply method is different from that of embodiment 9 only in that:

[0147] In this comparative example, in the secondary blowing of step (a), the working pressure of oxygen is adjusted to 1.5 MPa, and the working pressure of the inert gas is adjusted to 0.5 MPa.

[0148] Embodiment 17

[0149] This embodiment provides a gas mixed blowing gas supply method for converter vanadium smelting, and the gas supply method is different from that of embodiment 9 only in that:

[0150] In this embodiment, the secondary blowing time is adjusted to 5 minutes.

[0151] Embodiment 18

[0152] This embodiment provides a gas mixed blowing gas supply method for converter vanadium smelting, and the gas supply method is different from that of embodiment 9 only in that:

[0153] In this embodiment, step (a) is adjusted as follows: after lowering the oxygen lance to the first lance position, the oxygen regulating valve of the oxygen lance is opened to blow the molten iron once until the oxygen flow rate reaches 15000m 3 / h; then continue to lower the oxygen lance to the second gun position and open the inert gas regulating valve of the oxygen lance to carry out secondary blowing on the molten iron for 6 minutes until the molten iron meets the standard.

[0154] That is, in this embodiment, oxygen is blown first and then inert gas is blown in the second mixed blowing.

[0155] Comparative Example 3

[0156] This comparative example provides a gas mixed blowing gas supply method for converter vanadium smelting, and the difference between the gas supply method and Example 9 is that:

[0157] In this comparative example, the temperature of the molten iron in step (1) is adjusted to 1450°C, that is, the second mixed blowing treatment is used to treat the molten iron with higher physical heat.

[0158] The semi-steel obtained by the methods provided in the above embodiments and comparative examples was tested, and the results are shown in Table 1.

[0159] Table 1

[0160]

[0161]

[0162] According to Table 1, we can know the following points:

[0163] (1) Comprehensive analysis of Examples 1-3, 9-11 shows that the present invention can provide different gas supply methods for molten iron under different conditions, thereby increasing the oxidation rate and recovery rate of vanadium, reducing the residual vanadium content, and reducing the loss of carbon element;

[0164] (2) Comprehensive analysis of Example 1, Examples 4-5, 8 and Comparative Example 1 shows that the cooling blowing in the first mixed blowing will affect the cooling effect of the molten iron;

[0165] When the cooling and blowing time is too short, the stirring process is omitted, or the cooling and blowing is directly omitted, the temperature of the molten iron will be too high when the molten iron is blown with pure oxygen, thereby affecting the oxidation rate of vanadium (too high temperature will cause carbon to be oxidized before vanadium, resulting in a decrease in the oxidation rate of vanadium) and the loss of carbon element (high temperature accelerates carbon oxidation, and the loss of carbon content increases);

[0166] If the cooling and blowing time is too long, the molten iron temperature will be too low, the blowing time will be prolonged, the energy consumption will be increased, and the vanadium oxidation reaction may be insufficient, thereby reducing the vanadium oxidation rate.

[0167] (3) Comprehensive analysis of Example 1 and Examples 6-7 shows that a long time in the pure oxygen blowing process will lead to excessive oxidation of carbon elements, resulting in too low carbon content in the semi-steel, affecting the performance of subsequent steelmaking, while a short time will lead to insufficient oxidation of vanadium, reducing the oxidation rate of vanadium;

[0168] (4) Comprehensive analysis of Example 9 and Example 12 shows that in the second mixed blowing, if the first blowing and the second blowing are performed at the same gun position, the gas stirring effect will be poor, the reaction in the molten pool will be uneven, and the oxidation rate of vanadium will be reduced;

[0169] (5) Comprehensive analysis of Example 9 and Examples 13-16 shows that in the second mixed blowing, the mixing ratio of inert gas and oxygen and the working pressure will affect the temperature control, stirring effect and element oxidation process of the molten pool, thereby affecting the vanadium oxidation rate, semi-steel temperature and carbon content in the semi-steel;

[0170] (6) Comprehensive analysis of Example 9 and Example 17 shows that if the secondary blowing time is too short, the vanadium oxidation reaction will be incomplete, thereby reducing the vanadium oxidation rate;

[0171] (7) Comprehensive analysis of Example 9 and Example 18 shows that if oxygen is blown first and then inert gas is blown in the second mixed blowing, the oxygen concentration will be too high in the early stage, carbon will be over-oxidized, affecting the oxidation environment of vanadium and reducing the oxidation rate of vanadium;

[0172] (8) Comprehensive analysis of Examples 1, 9 and Comparative Examples 2-3 shows that if the first mixed blowing method is used to treat molten iron with high chemical heat, the molten pool temperature cannot be effectively controlled, carbon is over-oxidized, the vanadium oxidation rate is reduced, and the semi-steel quality is reduced;

[0173] If the second mixed blowing method is used to treat molten iron with high physical heat, it will lead to the inability to accurately match the molten iron state and poor cooling effect. It will also reduce the vanadium oxidation rate and increase the loss of carbon elements, affecting subsequent steelmaking.

[0174] In summary, the present invention adopts different gas mixing blowing methods for molten iron under different conditions, which can achieve precise control of the molten pool temperature and stirring effect, and can significantly improve the oxidation rate and recovery rate of vanadium and reduce the residual vanadium content; at the same time, the method provided by the present invention can also reduce the loss of carbon element and ensure the needs of subsequent steelmaking operations.

[0175] The applicant declares that the specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A gas mixed blowing and supply method for converter vanadium smelting, characterized in that: The gas supply method comprises the following steps: (1) After the vanadium-extracting converter is fully charged with iron, the molten iron is sampled to obtain the temperature and chemical composition of the molten iron; (2) When the temperature of the molten iron is ≥1420°C, the molten iron is subjected to the first mixed blowing; When the Si content in the molten iron is ≥0.3wt% and the C content is ≤3.8wt%, the molten iron is subjected to a second mixed-blowing process.

2. The gas supply method according to claim 1, characterized in that: The mixed gas used in the first mixed blowing and the second mixed blowing includes oxygen and inert gas; Preferably, the inert gas comprises any one of nitrogen, argon or helium or a combination of at least two thereof, preferably nitrogen; Preferably, the purity of the oxygen is ≥99.3%.

3. The gas supply method according to claim 1 or 2, characterized in that: Step (2) The first mixed blowing comprises: first, using an inert gas to cool down the molten iron under stirring conditions, and then using oxygen to blow the molten iron with pure oxygen.

4. The gas supply method according to claim 3, characterized in that: The stirring speed is 150-250 r / min; Preferably, the cooling and blowing time is 50 to 90 seconds; Preferably, the flow rate of the inert gas during the cooling and blowing is 18000-20000m 3 / h; Preferably, the working pressure of the inert gas during the cooling and blowing is 0.8-0.9 MPa; Preferably, the terminal temperature of the cooling and blowing is ≤1400°C; Preferably, the pure oxygen blowing time is 3.5 to 4.5 minutes; Preferably, the flow rate of oxygen in the pure oxygen blowing is 18000-20000m 3 / h; Preferably, the working pressure of oxygen in the pure oxygen blowing is 0.8-0.9 MPa.

5. The gas supply method according to claim 1 or 2, characterized in that: Step (2) The second mixing and blowing comprises the following steps: (a) After lowering the oxygen lance to the first lance position, the inert gas regulating valve of the oxygen lance is opened to blow the molten iron once until the inert gas flow rate meets the standard; then, the oxygen lance is further lowered to the second lance position, the oxygen regulating valve of the oxygen lance is opened to blow the molten iron twice until the molten iron meets the standard; (b) After lifting the oxygen gun, close the oxygen regulating valve first, and then close the inert gas regulating valve after the oxygen returns to zero.

6. The gas supply method according to claim 5, characterized in that: In the first blowing of step (a), the distance between the first gun position and the furnace bottom is 5.8 to 6.2 m; Preferably, in the secondary blowing of step (a), the distance between the second lance position and the furnace bottom is 4.5-5.5 m.

7. The gas supply method according to claim 5 or 6, characterized in that: In the first blowing of step (a), the inert gas flow rate reaches the standard of 4500-5500m 3 / h; Preferably, in the secondary blowing of step (a), the flow rate of oxygen is 14500-15500m 3 / h.

8. The gas supply method according to any one of claims 5 to 7, characterized in that: In the secondary blowing of step (a), the working pressure of oxygen is 0.8-1.2 MPa; Preferably, in the secondary blowing of step (a), the working pressure of the inert gas is 0.7-0.8 MPa.

9. The gas supply method according to any one of claims 5 to 8, characterized in that: The time of the secondary blowing in step (a) is 5.5 to 6.5 minutes.

10. The gas supply method according to any one of claims 5 to 9, characterized in that: The standard for the molten iron to meet the standards in step (a) is that the terminal temperature of the molten iron is 1360-1400°C.

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