Method for removing iron and extracting nickel by using nickel-containing pre-solution in converter

Abstract

The invention belongs to the technical field of iron-nickel alloy smelting, and relates to a method for removing iron and increasing nickel by using an iron-nickel alloy pre-solution in a converter. An electric furnace is adopted for melting an iron-nickel alloy raw material, the iron-nickel alloy raw material is added into a converter for oxygen blowing, C removal, Si removal, Fe removal and P removal are completed, pre-melting liquid is provided for an argon-oxygen refining furnace, and stainless steel refining is achieved through the argon-oxygen refining furnace; the nickel content in the iron-nickel alloy produced through the method is increased by 20%-40%, P is removed while Fe is removed, nickel-containing molten iron with the P content smaller than 20 ppm is produced, dependence on high-quality ferronickel resources and pure nickel resources in the stainless steel production process is reduced, full utilization of the iron-nickel alloy resources is achieved, and the production cost is reduced. The bottleneck problem that precious metal becomes the production cost restricting stainless steel production is solved.

Description

Technical Field

[0001] The invention relates to the technical field of nickel-containing pre-solution smelting, and in particular to a method for removing iron and extracting nickel from a converter using a nickel-containing pre-solution. Background Art

[0002] Nickel and nickel-iron alloys are the main raw materials for stainless steel production: At present, the market demand for nickel-based alloys, heat-resistant steels, and high-nickel steels is strong, raw material prices are rising, and nickel prices are at a high level. Therefore, affected by resource and market price fluctuations, profits per ton of steel are damaged, production costs increase, and precious metals have become an important factor restricting the production cost of stainless steel.

[0003] Therefore, in order to implement the concept of accounting management and reduce the cost per ton of steel, it is urgently necessary to develop a low-cost, high-efficiency, high-quality method for producing nickel-containing stainless steel, so as to solve the problem of high-priced raw materials while solving the problem of P content, and achieve a comprehensive improvement in the competitiveness of quality, profit and cost.

[0004] The purpose of the present invention is to provide a production method for removing iron and extracting nickel from an iron-nickel alloy pre-solution in a converter, so as to achieve full utilization of iron-nickel alloy resources and make the stainless steel production process no longer affected by the limitations of high-grade nickel-iron resources and pure nickel resources. The nickel content of the iron-nickel alloy pre-solution is increased by the converter iron removal and nickel extraction process, while the P content of the pre-solution is reduced, thereby solving the problem that precious metals become a bottleneck restricting the production cost of stainless steel. Summary of the invention

[0005] The purpose of the present invention is to solve the above problems and provide a method for removing iron and extracting nickel in a converter using a nickel-containing pre-solution.

[0006] The object of the present invention is achieved in this way: a method for removing iron and extracting nickel from a converter using a nickel-containing pre-solution, comprising the following steps: step one: a medium frequency furnace is charged with a high chromium alloy raw material for melting, the tapping temperature is 1580±20°C, and the medium frequency furnace consumes 500±20Kwh / t of electricity per ton of steel; step two: an electric furnace is charged with a nickel-iron alloy raw material for melting. During the whole process, the electric furnace consumes 220±20Kwh / t of electricity per ton of steel, consumes 40±10Kg / t of lime, consumes 8.5±1Kg / t of fluorite, and consumes 60±5Nm / t of oxygen per ton of steel. 3 / t, the tapping temperature of the electric furnace is 1600±20℃; Step 3: After the tapping of the electric furnace, the steel is added into the carbon steel converter for smelting, and the pre-solution, that is, the nickel-iron alloy solution melted in the electric furnace, is controlled at 160±5t, without adding scrap steel, the target tapping amount is 131±3t, and the bottom blowing gas flow rate of the carbon steel converter is adjusted to 18-22Nm 3 / min, converter oxygen lance flow rate is 550-600Nm 3 / min blowing, set oxygen consumption 5000-6300m 3At the end, the slag is removed by gun, and the sample is taken and analyzed. The target end temperature is 1550-1580℃; auxiliary materials are added during the blowing process: 21±3 tons of limestone, 4-5 tons of light burning; Step 4: After the carbon steel converter smelting is completed, the converter is blown again: oxygen flow rate 550-600Nm 3 / min, oxygen consumption set to 2000-2500m 3 , auxiliary materials for the supplementary blowing process: 3-4 tons of lime, 5-10 tons of limestone, 3-3.5 tons of light burning, after the supplementary blowing, the slag is removed by the gun, sampling and analysis are carried out, the target steel tapping temperature is 1600-1630℃, and the steel tapping operation is carried out, with a total oxygen consumption of 7000-7500m 3 , oxygen consumption per ton of steel 58±2m 3 / t; Step 5: The slag pot is padded with 300-500mm of carbon steel slag, and 3-4 slag pots are prepared; after the supplementary blowing operation is completed, the slag is poured out slowly along the edge of the slag pot, and the carbon steel ladle is used to tap the steel. The ladle is bottom blown and stirred during the tapping process; ferrosilicon is added for deoxidation at the beginning of tapping, and the amount of ferrosilicon added is 550-650kg. The molten steel level is calm during the tapping process, and the molten steel is first ensured to be fully tapped, and the slag thickness is controlled to be less than 100mm; if the liquid level is churning violently, lift the furnace, close the slide, and tap the steel again after the liquid level is calm; Step 6: After tapping from the converter, it is hoisted to the medium frequency furnace to receive 45±5 tons of high chromium pre-solution, and after adding it to the argon oxygen refining furnace, the slag is sampled and analyzed for the composition to meet the internal control requirements of the steel grade, and the tapping operation is carried out.

[0007] In step 1, the chemical composition and mass percentage of the high chromium alloy raw material are Cr: 55-68%, C: 6.0-9.0%, Si: 0.50-0.70%, and Fe, P, and S are other elements.

[0008] The chemical composition and mass percentage of the nickel-iron alloy raw material in step 2 are Ni: 8-10%, Cr: 1.5-3%, C: 2.0-3.0%, and Fe, P, and S are other elements.

[0009] The beneficial effects of the present invention are as follows: the present invention adopts a process combining "intermediate frequency furnace + electric furnace + converter + AOD", the electric furnace melts the iron-nickel alloy to form a pre-solution, oxygen blowing and slag making operations are performed in the converter to provide a high-nickel pre-solution for AOD. During the oxygen blowing process, the converter completes C removal, Si removal, partial Fe removal, and P removal, increasing the nickel content in the iron-nickel alloy by 20% to 40%, and P removal is performed while Fe removal, realizing the production of nickel-containing molten iron with a P content of less than 10ppm. DETAILED DESCRIPTION

[0010] The present invention utilizes a converter to achieve iron removal and nickel addition, thereby providing a high-nickel pre-solution resource for AOD; and utilizes a converter to remove iron and increase nickel while simultaneously performing dephosphorization, thereby providing a pre-solution with P≤0.002% for AOD.

[0011] 1. Process route: EAF batching → EAF smelting → EAF tapping and slag removal → adding to converter to remove iron and increase nickel → medium frequency furnace to melt high chromium → tapping and then receiving converter deironization melt → adding to AOD to smelt stainless steel. 2. The medium frequency furnace is loaded with high chromium alloy raw materials (Cr: 55-68%, C: 6.0-9.0%, Si: 0.50-0.70%, Fe, P, S and other elements) for melting. The tapping temperature is 1580±20℃, and the power consumption of the medium frequency furnace is 500±20Kwh / t per ton of steel. 3. The electric furnace is loaded with nickel-iron alloy raw materials (Ni: 8-10%, Cr: 1.5-3%, C: 2.0-3.0%, Fe, P, S and other elements) for melting. The power consumption of the electric furnace per ton of steel is 220±20Kwh / t, the lime consumption is 40±10Kg / t, the fluorite consumption is 8.5±1Kg / t, and the oxygen consumption per ton of steel is 60±5Nm 3 / t, the tapping temperature of the electric furnace is 1600±20℃; 4. After the tapping of the electric furnace, the steel is added to the carbon steel converter for smelting, and the pre-solution (nickel-iron alloy solution melted in the electric furnace) is controlled at 160±5t, without adding scrap steel, and the target tapping amount is 131±3t. The bottom blowing gas flow rate of the carbon steel converter is adjusted to 18Nm 3 / min, converter oxygen lance flow rate is 550-600Nm 3 / min blowing, set oxygen consumption 5000m 3 , lift the gun to dump the slag at the end, take samples, and perform other analyses. The target end temperature is 1550-1580℃; process auxiliary materials: limestone 21±3 tons, light burning 4-5 tons. 5. Re-blowing of the converter: oxygen flow rate 550-600Nm 3 / min, oxygen consumption set to 2000-2500m 3 , auxiliary materials for the re-blowing process: 3 tons of lime, 5-10 tons of limestone, 3 tons of light burning, after the re-blowing, the gun is lifted to pour the slag, sampling, etc. are analyzed, and the target steel tapping temperature is 1600-1630℃. Steel tapping operation is carried out. Total oxygen consumption is 7000-7500m 3 , oxygen consumption per ton of steel 58±2m 3 / t or so. 6. The slag pot must be padded with slag, and 3-4 slag pots must be prepared; during the slag pouring operation, the slag must be poured slowly along the edge of the slag pot. Use a carbon steel ladle to tap steel, and the ladle should be bottom blown and stirred during the tapping process; add ferrosilicon for deoxidation at the beginning of tapping, and the amount of ferrosilicon added refers to the fixed oxygen amount: 550-650kg ferrosilicon. During the tapping process, the molten steel level is calm, and priority is given to ensuring that all the molten steel is tapped, and the slag thickness is controlled to be less than 100mm; if the liquid level is churning violently, lift the furnace, close the slide, and tap steel again after the liquid level is calm. 7. After tapping from the converter, lift it to the medium frequency furnace to receive high chromium pre-solution (Cr: 55-68%, C: 6.0-9.0%, Si: 0.50-0.70%, Fe, P, S and other elements), add it to the argon oxygen refining furnace slag, take samples for component analysis, and tap steel.

[0012] Process flow: Electric furnace batching → Electric furnace smelting → Electric furnace tapping and slag removal → Add to converter to remove iron and increase nickel → Medium frequency furnace to melt high chromium → After tapping, connect to converter deironization molten liquid → Add to AOD to smelt stainless steel.

[0013] In order to make the purpose, technical scheme and advantages of the present invention clearer, the technical scheme of the present invention will be clearly and completely described in combination with the specific implementation methods of the present invention and the corresponding process flow. Obviously, the described implementation methods are only part of the implementation methods of the present invention, not all of the implementation methods. The technical scheme provided by the implementation methods of the present invention is described in detail in combination with the process flow. The medium frequency furnace is loaded with high chromium alloy raw materials for melting, the steel tapping temperature is 1580±20℃, and the power consumption of the medium frequency furnace is 500±20Kwh / t per ton of steel; the electric furnace is loaded with iron-nickel alloy raw materials with a mass percentage of Ni of 10-15%. The power consumption of the electric furnace per ton of steel in the whole process is 220±20Kwh / t, the lime consumption is 40±10Kg / t, the fluorite consumption is 8.5±1Kg / t, and the oxygen consumption per ton of steel is 60±5Nm 3 / t, the tapping temperature of the electric furnace is 1600±20℃; after the tapping of the electric furnace, the steel is added to the carbon steel converter for smelting, and the pre-solution is charged at 160±5t, without adding scrap steel, and the target tapping amount is 131±3t. The bottom blowing gas flow rate of the carbon steel converter is adjusted to 18Nm 3 / min, the converter oxygen lance flow rate is 550-600Nm3 / min, and the oxygen consumption is set at 5000m 3 At the end, the slag is removed by gun, and samples are taken for analysis. The target end temperature is 1550-1580℃; process auxiliary materials: limestone 21±3 tons, light burning 4-5 tons. The converter is blown again: oxygen flow rate 550-600Nm 3 / min, oxygen consumption set to 2000-2500m 3 , auxiliary materials for the re-blowing process: 3 tons of lime, 5-10 tons of limestone, 3 tons of light burning, after the re-blowing, the gun is lifted to pour the slag, sampling, etc. are analyzed, and the target steel tapping temperature is 1600-1630℃. Steel tapping operation is carried out. Total oxygen consumption is 7000-7500m 3 , oxygen consumption per ton of steel 58±2m 3 / t. Carbon steel ladle is used for steel tapping, and the ladle is stirred at the bottom during tapping. Ferrosilicon is added for deoxidation at the beginning of tapping. The amount of ferrosilicon added refers to the fixed oxygen amount: 550-650kg ferrosilicon. After tapping from the converter, it is hoisted to the medium frequency furnace to receive the high chromium pre-solution, added to the argon oxygen refining furnace, and then sampled for composition analysis and tapping. Embodiment 1

[0014] The following was implemented on a 160t electric furnace, a 180t converter, a 50t medium frequency furnace, and a 180t AOD: 49.6 tons of high chromium alloy raw materials were loaded into the medium frequency furnace for melting, the tapping temperature was 1598°C, and the power consumption of the medium frequency furnace was 24521 Kwh; the electric furnace was loaded with an iron-nickel alloy raw material with a nickel mass percentage of 10.2%. During the whole process, the electric furnace consumed 34936 Kwh of power, 6121 kg of lime, 1185 kg of fluorite, and 8692 m3 of oxygen. 3 The tapping temperature is 1611℃; the steel is added to the carbon steel converter after slag removal, and the pre-solution is charged at 158.8t, without adding scrap steel, and the tapping volume is 129.1t. The bottom blowing gas flow rate of the carbon steel converter is adjusted to 18Nm 3 / min, converter oxygen lance flow rate is 558Nm 3 / min blowing, oxygen consumption 4953m 3 At the end, the slag is removed by gun, and samples are taken for analysis. The end temperature is 1568℃; process auxiliary materials: 19.3 tons of limestone, 4.2 tons of light burning. The converter is blown again: the oxygen flow rate is 552Nm 3 / min, oxygen consumption 2321m 3 , auxiliary materials for the supplementary blowing process: 3.5 tons of lime, 7.1 tons of limestone, 2.8 tons of light burning, after the supplementary blowing, the slag is removed by the gun, and the sampling and other analyses are performed. The steel tapping temperature is 1621℃, and the steel tapping operation is carried out; the total oxygen consumption is 7274m 3 , oxygen consumption per ton of steel is 56.3m 3 / t. Carbon steel ladle is used for steel tapping, and the ladle is stirred at the bottom during the tapping process; ferrosilicon is added for deoxidation at the beginning of tapping, and the amount of ferrosilicon added is 600kg. After tapping from the converter, it is hoisted to the medium frequency furnace to receive 48.5t of high chromium pre-solution, added to the argon oxygen refining furnace, and then sampled for composition analysis and tapping.

[0015] Embodiment 2

[0016] The following was implemented on a 160t electric furnace, a 180t converter, a 50t medium frequency furnace, and a 180t AOD: 47.3t of high carbon ferrochrome raw material was loaded into the medium frequency furnace for melting, the tapping temperature was 1611°C, and the medium frequency furnace consumed 23228Kwh of electricity. 173.2t of iron-nickel alloy raw material with a nickel mass percentage of 10.8% was loaded into the electric furnace. The electric furnace consumed 34818Kwh of electricity during the whole process, consumed 6326Kg of lime, 1035Kg of fluorite, and consumed 8531m3 of total oxygen. 3 The tapping temperature is 1617℃. After the steel is tapped from the electric furnace, it is added to the carbon steel converter for smelting. The pre-solution is charged at 161.2t, without adding scrap steel, and the tapping volume is 130.5t; the bottom blowing gas flow rate of the carbon steel converter is adjusted to 21Nm 3 / min, the converter oxygen lance flow rate is 551Nm3 / min, and the oxygen consumption is 5058m 3At the end, the slag is removed by gun, and samples are taken for analysis. The end temperature is 1561℃; auxiliary materials for blowing process: 21.2 tons of limestone, 3.9 tons of light burning. The converter is blown again: oxygen flow rate is 550Nm 3 / min, oxygen consumption 2291m 3 , auxiliary materials for the supplementary blowing process: 3.7 tons of lime, 7.9 tons of limestone, 2.3 tons of light burning, after the supplementary blowing, the slag is removed by the gun, and the samples are taken for analysis. The steel tapping temperature is 1629℃, and the steel tapping operation is carried out; the total oxygen consumption is 7349m 3 , oxygen consumption per ton of steel is 56.3m 3 / t. Carbon steel ladle is used for steel tapping, and the ladle is stirred at the bottom during the tapping process; ferrosilicon is added for deoxidation at the beginning of tapping, and the amount of ferrosilicon added is 600kg. After tapping from the converter, the steel is hoisted to the medium frequency furnace to receive 46.6t of high chromium pre-solution, added to the argon oxygen refining furnace, and then sampled for composition analysis and tapping.

[0017]

[0018] The above description is only a specific embodiment of the present invention, but the structural features of the protection scope of the present invention are not limited thereto. Any changes or modifications made by any technician in the field of the present invention are all covered by the patent scope of the present invention.

Claims

1. A method for removing iron and extracting nickel from a converter using a nickel-containing pre-solution, characterized in that: The following steps are involved: Step 1: The medium frequency furnace is loaded with high chromium alloy raw materials for melting, the tapping temperature is 1580±20℃, and the power consumption of the medium frequency furnace is 500±20Kwh / t per ton of steel; Step 2: Load nickel-iron alloy raw materials into the electric furnace for melting. The power consumption of the electric furnace per ton of steel is 220±20Kwh / t, the lime consumption is 40±10Kg / t, the fluorite consumption is 8.5±1Kg / t, and the oxygen consumption per ton of steel is 60±5Nm 3 / t, electric furnace tapping temperature 1600±20℃; Step 3: After the steel is tapped from the electric furnace, it is added to the carbon steel converter for smelting. The pre-solution, i.e. the nickel-iron alloy solution melted in the electric furnace, is loaded and controlled at 160±5t. No scrap steel is added. The target steel output is 131±3t. The bottom blowing gas flow rate of the carbon steel converter is adjusted to 18-22Nm 3 / min, converter oxygen lance flow rate is 550-600Nm 3 / min blowing, set oxygen consumption 5000-6300m 3 At the end, the slag is discharged by gun, and samples are taken and analyzed. The target end temperature is 1550-1580℃. Auxiliary materials are added during the blowing process: 21±3 tons of limestone and 4-5 tons of light burning; Step 4: After adding carbon steel into the converter, the converter is blown again: oxygen flow rate 550-600Nm 3 / min, oxygen consumption set to 2000-2500m 3 , auxiliary materials for the supplementary blowing process: 3-4 tons of lime, 5-10 tons of limestone, 3-3.5 tons of light burning, after the supplementary blowing, the slag is removed by the gun, sampling and analysis are carried out, the target steel tapping temperature is 1600-1630℃, and the steel tapping operation is carried out, with a total oxygen consumption of 7000-7500m 3 , oxygen consumption per ton of steel 58±2m 3 / t; Step 5: The slag pot is padded with 300-500mm of carbon steel slag, and 3-4 slag pots are prepared; after the supplementary blowing operation is completed, the slag is poured slowly along the edge of the slag pot, and the carbon steel ladle is used to tap the steel. The ladle is stirred by bottom blowing during the tapping process; ferrosilicon is added for deoxidation at the beginning of tapping, and the amount of ferrosilicon added is 550-650kg. The molten steel level is calm during the tapping process, and the molten steel is firstly ensured to be tapped out, and the slag thickness is controlled to be less than 100mm; if the liquid level is violently churning, lift the furnace, close the slide plate, and tap the steel again after the liquid level is calm; Step 6: After the steel is tapped from the converter, it is hoisted to the medium frequency furnace to receive 45±5 tons of high chromium pre-solution. After adding it into the argon oxygen refining furnace slag discharge, samples are taken for analysis of the composition to ensure that it meets the internal control requirements for the steel grade, and then the steel tapping operation is carried out.

2. The method for removing iron and extracting nickel from a converter using a nickel-containing pre-solution according to claim 1, characterized in that: In step 1, the chemical composition and mass percentage of the high chromium alloy raw material are Cr: 55-68%, C: 6.0-9.0%, Si: 0.50-0.70%, and Fe, P, and S are other elements.

3. The method for removing iron and extracting nickel from a converter using a nickel-containing pre-solution according to claim 1, characterized in that: The chemical composition and mass percentage of the nickel-iron alloy raw material in step 2 are Ni: 8-10%, Cr: 1.5-3%, C: 2.0-3.0%, and Fe, P, and S are other elements.

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