Low-cost blast furnace molten iron silicon increasing method
By adding thin and thin scrap silicon steel sheets to the red hot air molten iron bag and mixing them with molten iron, the problems of insufficient heat and difficulty in adding materials in converter steelmaking are solved, and the effect of efficiently improving the scrap steel ratio and the yield rate of thin and thin scrap silicon steel sheets is achieved.
Patent Information
- Application Number
- CN202510364138.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-26
- Publication Date
- 2025-06-20
AI Technical Summary
In the prior art, the chemical and physical heat of the furnace raw materials entering the furnace during the converter steelmaking process limits the increase in the proportion of scrap steel, and there are problems such as low yield and difficulty in addition during use.
By adding thin and thin scrap silicon steel sheets to the red hot air molten iron bag and mixing them with molten iron in the blast furnace, the silicon increase of molten iron is achieved, the chemical heat of molten iron is increased, and the yield of thin and thin scrap silicon steel sheets is improved through preheating and sufficient stirring.
This method effectively improves the yield rate of light and thin scrap silicon steel sheets, reduces raw material costs, and increases the scrap steel ratio, solving the problem of hard heat replenishment and material addition.
Smart Images
Figure CN120174169A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of metallurgy, and in particular to a method for increasing silicon content in blast furnace hot metal with low cost. Background Art
[0002] In order to reduce carbon emissions in the steelmaking process and meet the requirements for exporting steel products, the converter workshop adopts the method of increasing the scrap ratio in converter steelmaking, such as the following forms:
[0003] I. Adding scrap to the ladle: During the steelmaking process, the scrap is usually preheated by a baking furnace, and the preheated scrap is added to the ladle and mixed with the hot metal, and then the subsequent steelmaking process is carried out;
[0004] II. Adding scrap to the converter: During the converter steelmaking process, by adding scrap, the excessive dependence on iron ore resources can be effectively reduced, and at the same time, carbon emissions during the steelmaking process can be reduced;
[0005] III. Adding scrap during tapping from the ladle: Adding scrap during tapping from the ladle can effectively reduce the raw material expenditure, and the utilization of scrap also helps to reduce resource waste and environmental pollution.
[0006] However, the scrap ratios of the above several forms are close to 30% or even 40%, resulting in insufficient chemical heat and physical heat of the raw materials charged into the furnace, which restricts the increase of the converter scrap ratio. Therefore, it is necessary to increase the heat-generating elements in the scrap to enhance the chemical heat of the raw materials charged into the furnace. At present, the silicon content in silicon steel sheets in the scrap raw materials is relatively high and can be used as a heat-generating element. However, due to many limiting reasons for silicon steel sheets, such as being thin and light, difficult to add, large blowing loss, low recovery rate, etc., their large-scale use is restricted. Summary of the Invention
[0007] The technical problem to be solved by the present invention is: In order to overcome the deficiencies existing in the prior art, a method for increasing silicon content in blast furnace hot metal with low cost is provided, which can effectively improve the recovery rate of thin and light scrap silicon steel sheets, reduce the raw material cost, and further increase the scrap ratio.
[0008] The technical solution adopted by the present invention is: A method for increasing silicon content in blast furnace hot metal with low cost, comprising the following steps:
[0009] Step 1: After the hot metal in the hot metal ladle is poured into the converter, the red-hot empty hot metal ladle after pouring the hot metal is returned to the hot metal car;
[0010] Step 2: Add thin and light scrap silicon steel sheets to the red-hot empty hot metal ladle after pouring the hot metal;
[0011] Step 3: The thin and light scrap silicon steel sheets are preheated by the red-hot empty hot metal ladle during the process of the red-hot empty hot metal ladle returning to the blast furnace;
[0012] Step 4: During the process of tapping the hot metal from the blast furnace into the ladle, the hot metal in the ladle is mixed with thin and light waste silicon steel sheets to increase the silicon content of the hot metal.
[0013] Step 5: Use the hot metal car to transport the ladle to the converter shop, and use the overhead crane in the converter shop to lift the ladle in front of the converter.
[0014] Step 6: Scrap steel is added to the converter, and the hot metal in the ladle is poured into the converter and then blown.
[0015] More specifically, in the above technical solution, in the second, third, and fourth steps, the thin and light waste silicon steel sheets are in the form of broken thin flakes.
[0016] More specifically, in the above technical solution, the thickness dimension of the thin and light waste silicon steel sheets is less than or equal to 0.65 mm.
[0017] More specifically, in the above technical solution, the length and width dimensions of the thin and light waste silicon steel sheets are less than or equal to 200 mm.
[0018] More specifically, in the above technical solution, in the sixth step, the scrap steel is ordinary social scrap steel and internal returned scrap steel.
[0019] More specifically, in the above technical solution, the silicon content (mass percentage) in the thin and light waste silicon steel sheets is 1.0% - 4.5%.
[0020] More specifically, in the above technical solution, in the seventh step, the temperature control range of the hot metal from the blast furnace without mixing thin and light waste silicon steel sheets is 1450 - 1550 °C; in the seventh step, the temperature control range of the hot metal from the blast furnace with mixed thin and light waste silicon steel sheets is 1300 - 1450 °C.
[0021] More specifically, in the above technical solution, in the seventh step, the silicon content (mass percentage) of the hot metal from the blast furnace without mixing thin and light waste silicon steel sheets is normally controlled at 0.2 - 0.4%; in the seventh step, the silicon content (mass percentage) of the hot metal from the blast furnace with mixed thin and light waste silicon steel sheets can reach 0.4 - 0.6% according to the addition amount.
[0022] More specifically, in the above technical solution, in the seventh step, the hot metal from the blast furnace and the thin and light waste silicon steel sheets are fully stirred evenly by a stirring device.
[0023] The beneficial effects of the present invention are as follows: This method can ensure the chemical heat of hot metal under the premise of reducing costs in low-silicon smelting in blast furnaces, digest thin and light waste silicon steel sheets. The hot metal ladle filled with thin and light waste silicon steel sheets can fully preheat the thin and light waste silicon steel sheets, reduce heat loss, effectively improve the yield rate of thin and light waste silicon steel sheets, reduce raw material costs, and further increase the scrap ratio. It effectively solves the problems of hot metal heat supplement under the conditions of low iron consumption and high scrap ratio, and the problem that the addition of thin and light materials is difficult and affects the production rhythm. Description of the Drawings
[0024] Figure 1 is the flow chart of the present invention.
[0025] Figure 2 is a schematic diagram of a red-hot empty hot metal ladle and thin and light waste silicon steel sheets.
[0026] The reference numerals in the figure are: 1, red-hot empty hot metal ladle; 2, thin and light waste silicon steel sheets. Detailed Embodiments
[0027] The embodiments of the present invention will be described in detail below. The embodiments are implemented on the premise of the technical solution of the present invention, and detailed implementation manners and specific operation processes are given. However, the protection scope of the present invention is not limited to the following embodiments.
[0028] Embodiment 1
[0029] See Figure 1 and Figure 2 , a method for increasing the silicon content of hot metal in a blast furnace with low cost, belonging to the field of green steelmaking with low iron consumption and high scrap ratio. Calculated based on adding 105 tons of hot metal to a converter, 10 tons of thin and light waste silicon steel sheets 2 are added. The feeding amount can be specifically controlled by a weighing device, which can further increase the scrap ratio, reduce carbon emissions, and achieve green steelmaking. The specific steps are as follows:
[0030] Step 1: After the hot metal in the hot metal ladle is poured into the converter, the red-hot empty hot metal ladle 1 after pouring the hot metal is returned to the hot metal car.
[0031] Step 2: Add 10 tons of thin and light waste silicon steel sheets 2 to the red-hot empty hot metal ladle 1 after pouring the hot metal; among them, the thin and light waste silicon steel sheets 2 belong to thin and light scrap steel materials, are in the form of broken thin sheets, have a light bulk density, and the purchase price is lower than that of heavy scrap and other scrap steels. The silicon content (mass percentage) in the thin and light waste silicon steel sheets 2 is 2.1%. Adding the thin and light waste silicon steel sheets 2 can increase the chemical heat of hot metal. Because the thin and light waste silicon steel sheets 2 have a light specific gravity, the empty hot metal ladle can be filled, and the empty hot metal ladle can be fully utilized to preheat the thin and light waste silicon steel sheets 2. It should be added that the thin and light waste silicon steel sheets 2 are important raw materials for manufacturing the cores of motors, generators, and transformers, and the purchase requirement is that the silicon content > 1.0%. The silicon content in the thin and light waste silicon steel sheets 2 needs to be moderate. If it is too small, the chemical heat is low.
[0032] If the thin and light waste silicon steel sheets 2 are added to the converter using a conventional scrap bucket, it will take a long time and affect the production rhythm. If the thin and light waste silicon steel sheets 2 are added to the converter using a conventional scrap bucket, the iron loss during converter blowing will be large, its recovery rate will be low, less than 85%, and the production cost will be high.
[0033] Step 3: Cover the full molten iron ladle with the thin and light waste silicon steel sheets 2 added and return it to the blast furnace to wait for tapping. During the process of the red-hot empty molten iron ladle 1 returning to the blast furnace, the thin and light waste silicon steel sheets 2 are preheated by the red-hot empty molten iron ladle 1;
[0034] Step 4: During the process of the blast furnace molten iron tapping into the molten iron ladle, the blast furnace molten iron in the molten iron ladle is mixed and flushed with the thin and light waste silicon steel sheets 2 to achieve silicon enrichment of the molten iron; among them, the blast furnace molten iron and the thin and light waste silicon steel sheets 2 are fully stirred evenly by a stirring device. The silicon content of the tapped molten iron is 0.25%, that is, the silicon content (mass percentage) of the blast furnace molten iron when the thin and light waste silicon steel sheets 2 are not mixed in is relatively low, specifically 0.25%; the silicon content (mass percentage) of the blast furnace molten iron when the thin and light waste silicon steel sheets 2 are already mixed in is 0.41%; the temperature of the tapped molten iron is 1500°C, that is, the temperature of the blast furnace molten iron when the thin and light waste silicon steel sheets 2 are not mixed in is 1500°C; the temperature of the blast furnace molten iron when the thin and light waste silicon steel sheets 2 are already mixed in is 1400°C (it should be noted that on-site temperature measurement shows that normally 1 ton of thin and light waste silicon steel sheets 2 causes a 10°C drop in the molten iron temperature). The thin and light waste silicon steel sheets 2 are extremely easy to be melted by the mixing and flushing of the molten iron, and the recovery rate of the thin and light waste silicon steel sheets 2 dissolved in the molten iron can be close to 100%, without affecting the converter blowing. At this time, the molten iron ladle weighs 115 tons after weighing, and the full ladle of molten iron enters the converter workshop for temperature measurement at 1320°C, and the sampled silicon content is 0.41%.
[0035] Step 5: Use the molten iron car to transport the molten iron ladle to the converter workshop, and use the overhead crane in the converter workshop to lift the molten iron ladle in front of the converter;
[0036] Step 6: Add 35 tons of scrap steel to the converter through the hopper, and the feeding takes 2 minutes. After the molten iron in the molten iron ladle is poured into the converter, blowing is carried out, and the scrap ratio reaches 30%, and the oxygen blowing is 6400m 3 , the end point carbon is 0.06%, the end point temperature is 1600°C, and the weight of the molten steel tapped is 138 tons. Among them, the scrap steel is ordinary social scrap steel and internal returned scrap steel. There are many types of scrap steel. Normal procurement is based on heavy scrap (divided into grades 1, 2, and 3, and internal returned scrap is basically heavy scrap with a high recovery rate), light scrap 1, light scrap 2, sheared scrap 1, sheared scrap 2, shavings, crushed materials, etc., with different recovery rates and different prices. It should be noted that ordinary social scrap steel refers to the scrap iron and steel materials generated in social life. Internal returned scrap steel refers to the scrap steel generated during the production process of the steel plant.
[0037] Example 2
[0038] See Figure 1 and Figure 2, A low-cost method for increasing the silicon content of blast furnace hot metal in the present invention belongs to the field of green steelmaking with low iron consumption and high scrap ratio. Calculated based on the stable addition of 106 tons of hot metal to the converter, 9 tons of light and thin waste silicon steel sheets 2 are added. Specifically, the feeding amount is controlled by a weighing device, which can further increase the scrap ratio, reduce carbon emissions, and achieve green steelmaking. The specific steps are as follows:
[0039] Step 1: After the hot metal in the hot metal ladle is poured into the converter, the red-hot empty hot metal ladle 1 after pouring the hot metal is returned to the hot metal car.
[0040] Step 2: Add 9 tons of light and thin waste silicon steel sheets 2 to the red-hot empty hot metal ladle 1 after pouring the hot metal. Among them, the light and thin waste silicon steel sheets 2 belong to light and thin scrap materials, are in the form of broken thin flakes, have a low bulk density, and the purchase price is lower than that of heavy scrap and other scrap. The silicon content (mass percentage) in the light and thin waste silicon steel sheets 2 is 2.3%. Adding the light and thin waste silicon steel sheets 2 can increase the chemical heat of the hot metal. Because the light and thin waste silicon steel sheets 2 have a low density, the empty hot metal ladle can be filled, and the empty hot metal ladle can be fully utilized to preheat the light and thin waste silicon steel sheets 2.
[0041] If the light and thin waste silicon steel sheets 2 are added to the converter using a conventional scrap bucket, it will take a long time and affect the production rhythm. If the light and thin waste silicon steel sheets 2 are added to the converter using a conventional scrap bucket, the iron loss during converter blowing is large, its recovery rate is low, less than 85%, and the production cost is high.
[0042] Step 3: Cover the full hot metal ladle with the light and thin waste silicon steel sheets 2 added and return it to the blast furnace to wait for tapping. During the process of the red-hot empty hot metal ladle 1 returning to the blast furnace, the light and thin waste silicon steel sheets 2 are preheated by the red-hot empty hot metal ladle 1.
[0043] Step 4: During the process of the blast furnace hot metal tapping into the hot metal ladle, the blast furnace hot metal in the hot metal ladle is mixed and flushed with the light and thin waste silicon steel sheets 2 to achieve silicon increase in the hot metal. Among them, the blast furnace hot metal and the light and thin waste silicon steel sheets 2 are fully stirred evenly by a stirring device. The silicon content of the tapped hot metal is 0.21%, that is, the silicon content (mass percentage) of the blast furnace hot metal without mixing the light and thin waste silicon steel sheets 2 is relatively low, specifically 0.21%; the silicon content (mass percentage) of the blast furnace hot metal after mixing the light and thin waste silicon steel sheets 2 is 0.37%; the tapped hot metal temperature is 1510 °C, that is, the temperature of the blast furnace hot metal without mixing the light and thin waste silicon steel sheets 2 is 1510 °C; the temperature of the blast furnace hot metal after mixing the light and thin waste silicon steel sheets 2 is 1420 °C. The light and thin waste silicon steel sheets 2 are extremely easy to be melted by the mixing and flushing of the hot metal, and the recovery rate of the light and thin waste silicon steel sheets 2 dissolved in the hot metal can be close to 100%, without affecting the converter blowing. At this time, the hot metal ladle weighs 115 tons after weighing, and the full ladle of hot metal enters the converter workshop for temperature measurement at 1340 °C, and the sampled silicon content is 0.37%.
[0044] Step 5: Use the hot metal car to transport the hot metal ladle to the converter workshop, and use the overhead crane in the converter workshop to lift the hot metal ladle in front of the converter.
[0045] Step 6: Add 37 tons of scrap steel into the converter through a hopper. The feeding takes 2 minutes. After the hot metal in the hot metal ladle is poured into the converter, blowing is carried out. The scrap ratio reaches 30%, and the oxygen blowing is 6300 m 3 , the final carbon content is 0.07%, the final temperature is 1620 °C, and the weight of the molten steel tapped is 139.8 tons. Among them, the scrap steel is ordinary social scrap steel and internally recycled scrap steel. There are many types of scrap steel. Normal procurement is based on heavy scrap (divided into grades 1, 2, and 3. Internally recycled scrap is basically heavy scrap with a high recovery rate), light scrap 1, light scrap 2, sheared scrap 1, sheared scrap 2, wood shavings, shredded materials, etc. The recovery rates and prices are different. It should be noted that ordinary social scrap steel refers to scrap iron and steel materials generated in social life. Internally recycled scrap steel refers to scrap steel generated during the production process of steel mills.
[0046] Example 3
[0047] See Figure 1 and Figure 2 , a method for increasing silicon in blast furnace hot metal with low cost of the present invention belongs to the field of green steelmaking with low iron consumption and high scrap ratio. Calculated based on the stable addition of 107 tons of hot metal to the converter, 8 tons of thin and light waste silicon steel sheets 2 are added. Specifically, the feeding amount is controlled by a weighing device, which can further increase the scrap ratio, reduce carbon emissions, and achieve green steelmaking. The specific steps are as follows:
[0048] Step 1: After the hot metal in the hot metal ladle is poured into the converter, return the empty hot metal ladle 1 after pouring the hot metal to the hot metal car;
[0049] Step 2: Add 8 tons of thin and light waste silicon steel sheets 2 to the empty hot metal ladle 1 after pouring the hot metal; among them, the thin and light waste silicon steel sheets 2 belong to thin and light scrap steel materials, in the form of broken thin flakes, with a low bulk density, and the purchase price is lower than that of heavy scrap and other scrap steels. The silicon content (mass percentage) in the thin and light waste silicon steel sheets 2 is 1.1%. Adding the thin and light waste silicon steel sheets 2 can increase the chemical heat of the hot metal. Because the thin and light waste silicon steel sheets 2 have a low density, the empty hot metal ladle can be filled, and the empty hot metal ladle can be fully utilized to preheat the thin and light waste silicon steel sheets 2.
[0050] If the thin and light waste silicon steel sheets 2 are added to the converter using a conventional scrap steel hopper, it will take a long time and affect the production rhythm. If the thin and light waste silicon steel sheets 2 are added to the converter using a conventional scrap steel hopper, the iron loss during the blowing and smelting in the converter is large, and its recovery rate is low, less than 85%, and the production cost is high.
[0051] Step 3: Cover the full hot metal ladle after adding the thin and light waste silicon steel sheets 2 and return it to the blast furnace to wait for tapping. During the process of the empty hot metal ladle 1 returning to the blast furnace after adding the thin and light waste silicon steel sheets 2, the thin and light waste silicon steel sheets 2 are preheated by the empty hot metal ladle 1;
[0052] Step 4: During the process of tapping the blast furnace molten iron into the ladle, the blast furnace molten iron in the ladle is mixed with the thin and light waste silicon steel sheets 2 to increase the silicon content of the molten iron. Among them, the blast furnace molten iron and the thin and light waste silicon steel sheets 2 are fully stirred evenly by a stirring device. The silicon content of the tapped molten iron is 0.35%, that is, the silicon content (mass percentage) of the blast furnace molten iron without mixing the thin and light waste silicon steel sheets 2 is relatively low, specifically 0.35%; the silicon content (mass percentage) of the blast furnace molten iron after mixing the thin and light waste silicon steel sheets 2 is 0.40%; the temperature of the tapped molten iron is 1518 °C, that is, the temperature of the blast furnace molten iron without mixing the thin and light waste silicon steel sheets 2 is 1518 °C; the temperature of the blast furnace molten iron after mixing the thin and light waste silicon steel sheets 2 is 1435 °C. The thin and light waste silicon steel sheets 2 are extremely easy to be melted by mixing with the molten iron, and the recovery rate of the thin and light waste silicon steel sheets 2 dissolved in the molten iron can be close to 100%, which does not affect the converter blowing. At this time, the ladle weighs 115 tons after weighing, and the molten iron in the full ladle enters the converter workshop for temperature measurement at 1355 °C, and the sampled silicon content is 0.40%.
[0053] Step 5: Use the molten iron car to transport the ladle to the converter workshop, and use the overhead crane in the converter workshop to lift the ladle in front of the converter;
[0054] Step 6: Add 35 tons of scrap steel to the converter through the hopper. The feeding time is 2 minutes. After the molten iron in the ladle is poured into the converter, blowing is carried out. The scrap steel ratio reaches 29%, and the oxygen blowing is 6220m 3 , the end point carbon is 0.08%, the end point temperature is 1610 °C, and the weight of the molten steel tapped is 138 tons. Among them, the scrap steel is ordinary social scrap steel and internal returned scrap steel. There are many types of scrap steel. Normal procurement is based on heavy scrap (divided into grades 1, 2, and 3, and internal returned scrap is basically heavy scrap with a high recovery rate), light scrap 1, light scrap 2, sheared scrap 1, sheared scrap 2, wood shavings, shredded materials, etc. The recovery rates are different and the prices are different. It should be noted that ordinary social scrap steel refers to the scrap iron and steel materials generated in social life. Internal returned scrap steel refers to the scrap steel generated during the production process of the steel plant.
[0055] Example 4
[0056] See Figure 1 and Figure 2 , a low-cost method for increasing the silicon content of blast furnace molten iron according to the present invention belongs to the field of green steelmaking with low iron consumption and high scrap steel ratio. Calculated based on the stable addition of 105 tons of molten iron to the converter, 10 tons of thin and light waste silicon steel sheets 2 are added. Specifically, the feeding amount is controlled by a weighing device, which can further increase the scrap steel ratio, reduce carbon emissions, and achieve green steelmaking. The specific steps are as follows:
[0057] Step 1: After the molten iron in the ladle is poured into the converter, the red-hot empty ladle 1 after pouring the molten iron is returned to the molten iron car;
[0058] Step 2: Add 10 tons of light and thin waste silicon steel sheets 2 to the red-hot empty molten iron ladle 1 filled with molten iron. Among them, the light and thin waste silicon steel sheets 2 belong to light and thin scrap steel materials, are in the form of broken thin flakes, have a low bulk specific gravity, and the purchase price is lower than that of heavy scrap and other scrap steels. The silicon content (mass percentage) in the light and thin waste silicon steel sheets 2 is 3.7%. Adding the light and thin waste silicon steel sheets 2 can increase the chemical heat of the molten iron. Because the light and thin waste silicon steel sheets 2 have a low specific gravity, the empty molten iron ladle can be filled up, and the empty molten iron ladle can be fully utilized to preheat the light and thin waste silicon steel sheets 2.
[0059] If the light and thin waste silicon steel sheets 2 are added to the converter using a conventional scrap steel bucket, it will take a long time and affect the production rhythm. If the light and thin waste silicon steel sheets 2 are added to the converter using a conventional scrap steel bucket, the iron loss during the converter blowing is large, its yield is low, less than 85%, and the production cost is high.
[0060] Step 3: Cover the full molten iron ladle with the light and thin waste silicon steel sheets 2 added and return it to the blast furnace to wait for tapping. During the process of the red-hot empty molten iron ladle 1 returning to the blast furnace with the light and thin waste silicon steel sheets 2, the light and thin waste silicon steel sheets 2 are preheated by the red-hot empty molten iron ladle 1.
[0061] Step 4: During the process of the blast furnace molten iron tapping into the molten iron ladle, the blast furnace molten iron in the molten iron ladle is mixed and flushed with the light and thin waste silicon steel sheets 2 to achieve silicon enrichment of the molten iron. Among them, the blast furnace molten iron and the light and thin waste silicon steel sheets 2 are fully stirred evenly by a stirring device. The silicon content of the tapped molten iron is 0.20%, that is, the silicon content (mass percentage) of the blast furnace molten iron without mixing in the light and thin waste silicon steel sheets 2 is relatively low, specifically 0.20%; the silicon content (mass percentage) of the blast furnace molten iron after mixing in the light and thin waste silicon steel sheets 2 is 0.50%; the temperature of the tapped molten iron is 1525°C, that is, the temperature of the blast furnace molten iron without mixing in the light and thin waste silicon steel sheets 2 is 1525°C; the temperature of the blast furnace molten iron after mixing in the light and thin waste silicon steel sheets 2 is 1420°C. The light and thin waste silicon steel sheets 2 are extremely easy to be melted by the mixing and flushing of the molten iron, and the yield of the light and thin waste silicon steel sheets 2 dissolved in the molten iron can be close to 100%, without affecting the converter blowing. At this time, the molten iron ladle weighs 115 tons after weighing, and the full ladle of molten iron enters the converter workshop for temperature measurement at 1345°C, and the sampled silicon content is 0.50%.
[0062] Step 5: Use the molten iron car to transport the molten iron ladle to the converter workshop, and use the overhead crane in the converter workshop to lift the molten iron ladle in front of the converter.
[0063] Step 6: Add 37 tons of scrap steel to the converter through a hopper. The feeding time is 2 minutes. After the molten iron in the molten iron ladle is poured into the converter, blowing is carried out, and the scrap steel ratio reaches 31%. The oxygen blowing is 6450m 3, the final carbon content is 0.09%, the final temperature is 1623 °C, and the weight of the molten steel tapped is 139.8 tons. Among them, the scrap steel includes ordinary social scrap steel and internally returned scrap steel. There are many types of scrap steel. For normal procurement, there are heavy scrap (classified into grades 1, 2, and 3, and the internally returned scrap is basically heavy scrap with a high recovery rate), light scrap 1, light scrap 2, sheared scrap 1, sheared scrap 2, shavings, shredded materials, etc. The recovery rates and prices vary. It should be noted that ordinary social scrap steel refers to the scrap steel materials generated in social life. Internally returned scrap steel refers to the scrap steel generated during the production process of the steel plant.
[0064] Comparative Example 1
[0065] (1) Return the empty hot metal ladle after charging iron to the hot metal car.
[0066] (2) Add 10 tons of ordinary scrap steel to the red-hot empty hot metal ladle after charging iron (it should be noted that the ordinary scrap steel here is similar in specification to the scrap steel in step 6 of Example 1, and this ordinary scrap steel is ordinary social scrap steel and / or internally returned scrap steel).
[0067] (3) Cover the hot metal ladle after adding ordinary scrap steel and return it to the blast furnace to wait for tapping.
[0068] (4) The temperature of the tapped hot metal is 1510 °C, the silicon content of the hot metal is 0.26%, and the tapped hot metal is mixed and thoroughly stirred with the ordinary scrap steel in the hot metal ladle. The temperature of the hot metal at the end of tapping is 1410 °C.
[0069] (5) The mass of the tapped hot metal weighed under the furnace is 105 tons, the hot metal ladle weighs 115 tons after weighing, and the full ladle of hot metal enters the converter shop for temperature measurement at 1320 °C, and the sampled silicon content is 0.25%.
[0070] (6) The converter adds 35 tons of scrap steel through the hopper (it should be noted that the scrap steel here is similar in specification to the scrap steel in step 6 of Example 1, and this scrap steel is ordinary social scrap steel and / or internally returned scrap steel), the feeding takes 2 minutes, the hot metal is charged and blown, the scrap ratio reaches 30%, and the oxygen blowing is 6320 m 3 , the sampled carbon content at the end point is 0.05%, due to the low silicon content of the heating element, the tapping temperature is 1570 °C. Because the tapping temperature is too low to meet the process requirements, the converter is re-blown to raise the temperature. The tapping temperature of the molten steel at the end point is 1600 °C, the iron loss of the over-oxidized molten steel is large, and the weight of the molten steel tapped is 137 tons.
[0071] Comparative Example 2
[0072] (1) Return the empty hot metal ladle after charging iron to the hot metal car.
[0073] (2) Cover the red-hot empty hot metal ladle after charging iron.
[0074] (3) The covered empty hot metal ladle is returned to the blast furnace to wait for tapping.
[0075] (4) The ladle is opened to discharge molten iron, with the temperature of the molten iron being 1500 °C and the silicon content in the molten iron being 0.25%.
[0076] (5) The molten iron ladle weighs 105 tons. The temperature of the molten iron entering the converter workshop is measured to be 1400 °C, and the sampled silicon content is 0.25%.
[0077] (6) 35 tons of scrap steel are added to the converter through a hopper (it should be noted that the scrap steel here is similar in specification to the scrap steel in step 6 of Example 1, and this scrap steel is ordinary social scrap steel and / or internally returned scrap steel), and 10 tons of secondary scrap silicon steel sheets (it should be noted that the secondary scrap silicon steel sheets added here are similar in specification to the thin and light scrap silicon steel sheets 2 in Example 1 and are also in sheet form) are added. The feeding is difficult, and the total feeding time is 6 minutes. The molten iron is charged for blowing, and the scrap ratio reaches 30%. The oxygen blowing is 6400 m 3 , the final carbon content is 0.05%, and the final temperature is 1608 °C. Since the thin sheet-like scrap silicon steel sheets belong to light scrap, they are prone to floating above the liquid metal after being added to the converter and undergo an oxidation reaction during the oxygen blowing in the converter, resulting in a low yield of about 85% or so, a small amount of molten steel during tapping, and the weighed amount being only 136 tons.
[0078] Therefore, according to the above embodiments and comparative examples, it can be seen that when producing low iron consumption and high scrap ratio by this method, by adding thin and light scrap silicon steel sheets 2 to the red-hot empty molten iron ladle 1, the chemical heat of the molten iron can be increased, the problem of the thin and light material added to the scrap steel hopper affecting the production rhythm can be avoided, the yield of the thin and light scrap steel increases, and the economic benefits are remarkable.
[0079] The above is only the preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, makes equivalent substitutions or changes, and all should be covered by the protection scope of the present invention.
Claims
1. A low-cost method for increasing silicon in molten iron in a blast furnace, characterized in that: The following steps are involved: Step 1: After the molten iron in the ladle is added into the converter, the red-hot empty ladle with the molten iron added is returned to the molten iron car; Step 2: Add thin scrap silicon steel sheets into the red-hot empty ladle filled with molten iron; Step 3: The thin scrap silicon steel sheets are preheated by the red-hot empty iron ladle when the red-hot empty iron ladle is returned to the blast furnace; Step 4: During the process of blast furnace molten iron being tapped into the ladle, the blast furnace molten iron in the ladle is mixed with light and thin waste silicon steel sheets to achieve silicon enrichment of the molten iron; Step 5: Use a molten iron car to transport the molten iron ladle to the converter workshop, and use a crane in the converter workshop to lift the molten iron ladle to the front of the converter; Step 6: Add scrap steel into the converter, and add the molten iron in the ladle into the converter for blowing.
2. The low-cost method for increasing silicon in molten iron of a blast furnace according to claim 1, characterized in that: In the second step, the third step and the fourth step, the thin scrap silicon steel sheets are in the form of broken thin sheets.
3. The low-cost method for increasing silicon in molten iron of blast furnace according to claim 2, characterized in that: The thickness of the thin scrap silicon steel sheet is less than or equal to 0.65 mm.
4. The low-cost method for increasing silicon in molten iron of a blast furnace according to claim 2, characterized in that: The length and width of the thin waste silicon steel sheet are less than or equal to 200 mm.
5. The low-cost method for increasing silicon in molten iron of blast furnace according to claim 1, characterized in that: In the sixth step, the scrap steel is common social scrap steel and / or internally returned scrap steel.
6. The low-cost method for increasing silicon in molten iron of a blast furnace according to claim 1, characterized in that: The silicon content (mass percentage) in the light and thin waste silicon steel sheet is 1.0% to 4.5%.
7. The low-cost method for increasing silicon in molten iron of a blast furnace according to claim 1, characterized in that: In the seventh step, the temperature of the blast furnace molten iron without light and thin scrap silicon steel sheets is controlled in the range of 1450-1550° C.; In the seventh step, the temperature of the blast furnace molten iron after the thin scrap silicon steel sheets are mixed is controlled in the range of 1300-1450°C.
8. The low-cost method for increasing silicon in molten iron of a blast furnace according to claim 1, characterized in that: In the seventh step, the silicon content (mass percentage) of the blast furnace molten iron when the thin and light silicon steel scrap sheets are not mixed is normally controlled to be 0.2-0.4%; In the seventh step, the silicon content (mass percentage) of the blast furnace molten iron after the thin and light waste silicon steel sheets have been mixed can reach 0.4-0.6% depending on the added amount.
9. The low-cost method for increasing silicon in molten iron of a blast furnace according to claim 1, characterized in that: In the seventh step, the blast furnace molten iron and the thin scrap silicon steel sheets are fully and evenly stirred by a stirring device.