Ultrahigh scrap ratio smelting method for converter

Abstract

The invention provides an ultrahigh scrap ratio smelting method for a converter. The method comprises the following steps: adding scrap steel into an iron ladle, baking the iron ladle, tapping without desulfurization, adding scrap steel and a cosolvent into the converter for smelting, adding iron, lowering a gun into the converter for blowing, and tapping and alloying the converter. On the basis that existing tool conditions are not changed, the loading system can be flexibly adjusted according to the market scrap steel price, the scrap steel ratio can reach 50% or above, the production process is stable, solid waste is greatly reduced, and the novel converter smelting method with the ultrahigh scrap steel ratio is environmentally friendly and verified.

Description

Technical Field

[0001] The invention relates to the technical field of converter smelting, and in particular to a converter ultra-high scrap steel ratio smelting method. Background Art

[0002] Converter blowing is the core link of the current long-process steelmaking, and it is also the key link that distinguishes it from the short-process electric furnace steelmaking. At present, converter blowing usually adopts the system of loading molten iron + scrap steel to organize production. Scrap steel loading is not only a key adjustment indicator for various steel companies to carry out cost reduction and efficiency improvement work, but also a core element of stable production of the team and reflects the level of operating skills; different steel companies adopt slightly different scrap steel ratios according to their actual conditions, but they are all within 0-30%.

[0004] Converter steelmaking can further increase the amount of scrap steel charged on the basis of the current scrap steel ratio to achieve the purpose of reducing carbon and solids, but the production difficulty and feasibility of operation have discouraged many steel companies. Through repeated demonstration and practice, the present invention proposes a smelting process with ultra-high scrap steel ratio in converters, with the highest scrap steel ratio reaching 50.95% and the average 50.08%. The present invention not only increases the amount of scrap steel used under the existing converter tooling conditions and achieves the effect of green environmental protection, but also lays a solid foundation for participating in the formulation of national standards for ultra-high scrap steel ratios. Summary of the invention

[0005] The present invention provides a converter ultra-high scrap steel ratio smelting method, aiming to solve the problems of low scrap steel ratio in the existing converter smelting process and high electric furnace smelting cost.

[0006] In order to achieve the above-mentioned purpose, the present invention adopts the following technical scheme: a method for smelting a converter with ultra-high scrap steel ratio, the method comprising: adding scrap steel to an iron ladle → baking the iron ladle → tapping iron from a blast furnace without desulfurization → adding scrap steel and solvent to a converter for smelting → adding iron → blowing from a converter → alloying of steel tapped from a converter.

[0007] Preferably, in the process of adding scrap steel to the iron ladle, the amount of scrap steel added is 10%-14% of the total amount.

[0008] Preferably, in the iron ladle baking process, the baking time is 3-3.5 hours, the baking temperature is 780° C.-820° C., and the baking is completed until the scrap steel turns red.

[0009] Preferably, in the converter smelting process, slag steel, granular steel and granular iron are added to the high-level silo of the blowing converter in advance and used as coolants during the blowing process. The amount of slag steel, granular steel and granular iron added is 5-6t / furnace.

[0010] Preferably, in the converter smelting process, the method of adding scrap steel is as follows: the scrap steel is added in two buckets, and the amount added in each bucket is 39-41% of the total scrap steel. Each bucket of scrap steel must contain general scrap steel, heavy scrap steel, and counterweight scrap steel, among which the proportion of general scrap steel is 28%, the proportion of heavy scrap steel is 36%, and the proportion of counterweight scrap steel is 36%. General scrap steel refers to scrap steel with a weight of 10kg-100kg per piece; heavy scrap steel refers to self-produced scrap steel with a weight of 200kg-500kg per piece; counterweight scrap steel refers to purchased scrap steel with a weight of 200kg-500kg per piece.

[0011] Preferably, in the blast furnace iron-tapping process, the molten iron is required to meet the following conditions: temperature ≥1400°C, molten iron Si content ≥0.80%, molten iron Mn content ≥0.60%, molten iron P content ≤0.125%, and molten iron S content ≤0.030%.

[0012] Preferably, in the converter smelting process, the blowing process is controlled as follows: the ignition gun position is set to 1.5m when the blowing starts, and the gun position is 1.4-1.6m after the ignition is normal; the ignition flow rate is 15000m 3 / h, working oxygen flow rate 23000m 3 / h; for smelting high carbon steel, before starting the lance at the end of the converter, blow at alternating lance positions, the deep blowing time is greater than 30s, the deep blowing lance position shall not be lower than 1.1m, and the molten steel composition and temperature shall be uniform; bottom blowing mode: argon blowing throughout the process.

[0013] Preferably, the solvent is added to the converter along with the first bucket of scrap steel in an amount of 3.5 t / furnace, and the solvent is coke powder, and the coke foam carbon content is ≥85%.

[0014] Preferably, the first batch of lime can be added after the ignition gun ignites normally, and the added amount is 1 / 3-1 / 2 of the total amount. If the flame is abnormal, stop adding in time and add in time after the flame is normal; Process control: according to the slagging situation and flame temperature, sintered ore and fluorite can be added in appropriate amounts to ensure good fluidity of the slag. The amount of each batch of slag added is 200-300Kg.

[0015] Preferably, the particle size of the slag steel, granular steel and granular iron is 10-50 mm.

[0016] Compared with the prior art, the advantages and positive effects of the present invention are:

[0017] Without changing the existing tooling conditions, the loading system can be flexibly adjusted according to the market scrap steel price. The scrap steel ratio can reach more than 50%, the production process is stable, and solid waste is greatly reduced. It is a green, environmentally friendly and proven new method for converter ultra-high scrap steel ratio smelting. DETAILED DESCRIPTION

[0018] In order to more clearly understand the above-mentioned purpose, features and advantages of the present invention, the present invention is further described below by way of embodiments. It should be noted that the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

[0019] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways than those described herein. Therefore, the present invention is not limited to the specific embodiments of the following disclosure.

[0020] The method of the present invention is described in detail below by taking the smelting of tire bead SWRH72A steel grade as an example. The chemical composition of the steel grade is as follows:

[0021]

[0022] Example 1: This example provides a converter ultra-high scrap steel ratio smelting method, the method comprising:

[0023] 5.9t of ordinary scrap steel was added to the bottom of S1 and No. 14 iron ladle.

[0024] S2. The iron ladle is baked before being tapped. The baking time is 3 hours and the baking temperature is 820℃. The baking is completed until the scrap steel turns red.

[0025] S3, 61.5t molten iron enters the blast furnace, the temperature is 1404℃, the output is 61.5t, the output is not desulfurized, and the output molten iron is required to meet the following conditions: temperature ≥1400℃, molten iron Si content ≥0.80%, molten iron Mn content

[0026] ≥0.60%, molten iron P content ≤0.125%, molten iron S content ≤0.030%.

[0027] S4, adding scrap steel and flux to the converter for smelting. Specifically, 5t of slag steel, granular steel and granular iron are added to the high-level silo of the blowing converter in advance, and used as coolants during the blowing process. The slag steel, granular steel and granular iron added in this embodiment have a particle size of 10-40mm. After the slag splashing of the converter is completed, all the slag is poured out, and 25t of the first bucket of scrap steel + 3.5t of flux are first added to the converter, and then 25t of the second bucket of scrap steel is added. The added scrap steel must include general scrap, heavy scrap and counterweight scrap steel, of which general scrap is 7t, heavy scrap is 9t, and counterweight scrap is also 9t. After adding scrap steel, shake the furnace backward to 35° to prepare for adding molten iron. The total amount of scrap steel is 60.9t, the total load is 122.4t, and the scrap steel ratio is 49.75%. The solvent used in this embodiment is coke powder, and the carbon content of coke powder is ≥85%. The amount of coke powder used is calculated based on the heat balance of the chemical elements of the current molten iron. Specifically, the amount of coke powder added is calculated according to the following formula: According to the heat balance calculation, the total amount of solvent used = physical heat supplement amount + chemical heat supplement amount; physical heat supplement amount = total loading amount * temperature increase amount * molten iron specific heat capacity / calorific value of coke powder / 1000; the chemical heat supplement amount is calculated to be 2.2 tons based on the normal use of the heat balance of the chemical elements of the molten iron.

[0028] S5. Pour 61.5t of molten iron from the blast furnace in step 3 into the converter using an overhead crane to complete the iron addition.

[0029] S6, converter lower gun blowing, specifically, the ignition gun position is set to 1.5m, and the gun position is 1.4-1.6m after normal ignition; ignition flow rate is 15000m 3 / h, working oxygen flow rate 23000m 3 / h; for smelting high carbon steel, before starting the lance at the end of the converter, blow at alternating lance positions, the deep blowing time is greater than 30s, the deep blowing lance position shall not be lower than 1.1m, and the molten steel composition and temperature shall be uniform; bottom blowing mode: argon blowing throughout the process.

[0030] Adding materials during blowing: The first batch of lime can be added after ignition is normal. The amount added is 1 / 3-1 / 2 of the total amount. The total amount added in this embodiment is 4350kg. Process control: Add sintered ore and fluorite in appropriate amounts according to the slagging situation and flame temperature to ensure good fluidity of the slag. The amount of each batch of slag added is 200-300Kg.

[0031] S7, converter steel alloying. In this embodiment, the converter end point C: 0.064%, Mn: 0.031%, P: 0.0098%, S: 0.0285%, temperature 1601°C, average steel output 108.6t.

[0032] Example 2: This example provides a converter ultra-high scrap steel ratio smelting method, the method comprising:

[0033] 6.5t of ordinary scrap steel was added to the bottom of S1 and No. 23 iron ladle.

[0034] S2. The iron ladle is baked before being tapped. The baking time is 3.2 hours and the baking temperature is 780°C. The baking is completed until the scrap steel turns red.

[0035] S3, 61.5t molten iron enters the blast furnace, the temperature is 1371℃, the output is 61.5t, the output is not desulfurized, and the output molten iron is required to meet the following conditions: temperature ≥1400℃, molten iron Si content ≥0.80%, molten iron Mn content

[0036] ≥0.60%, molten iron P content ≤0.125%, molten iron S content ≤0.030%.

[0037] S4, adding scrap steel and flux to the converter for smelting. Specifically, 5t of slag steel, granular steel and granular iron are added to the high-level silo of the blowing converter in advance, and used as coolants during the blowing process. The slag steel, granular steel and granular iron added in this embodiment have a particle size of 20-50mm. After the slag splashing of the converter is completed, all the slag is poured out, and 25t of the first bucket of scrap steel + 3.5t of flux are first added to the converter, and then 25t of the second bucket of scrap steel is added. The added scrap steel must include general scrap, heavy scrap and counterweight scrap steel, of which 7t of general scrap, 9t of heavy scrap and 9t of counterweight scrap steel. After adding scrap steel, the furnace is shaken backward to 35° to prepare for the addition of molten iron. The total amount of scrap steel is 61.5t, the total assembly is 123t, and the scrap steel ratio is 50%. The solvent used in this embodiment is coke powder, and the carbon content of coke powder is ≥85%. The amount of coke powder used is calculated based on the heat balance of the chemical elements of the current molten iron. Specifically, the amount of coke powder added is calculated according to the following formula: According to the heat balance calculation, the total amount of solvent used = physical heat supplement amount + chemical heat supplement amount; physical heat supplement amount = total loading amount * temperature increase amount * molten iron specific heat capacity / calorific value of coke powder / 1000; the chemical heat supplement amount is calculated to be 2.2 tons based on the normal use of the heat balance of the chemical elements of the molten iron.

[0038] S5. Pour 61.5t of molten iron from the blast furnace in step 3 into the converter using an overhead crane to complete the iron addition.

[0039] S6, converter lower gun blowing, specifically, the ignition gun position is set to 1.5m, and after normal ignition, the gun position is 1.4-1.6m; ignition flow rate is 15000m 3 / h, working oxygen flow rate 23000m 3 / h; for smelting high carbon steel, before starting the lance at the end of the converter, blow at alternating lance positions, the deep blowing time is greater than 30s, the deep blowing lance position shall not be lower than 1.1m, and the molten steel composition and temperature shall be uniform; bottom blowing mode: argon blowing throughout the process.

[0040] Adding materials during blowing: The first batch of lime can be added after ignition is normal. The amount added is 1 / 3-1 / 2 of the total amount. The total amount added in this embodiment is 4340 kg. Process control: Add sintered ore and fluorite in appropriate amounts according to the slagging situation and flame temperature to ensure good fluidity of the slag. The amount of each batch of slag added is 200-300 kg.

[0041] S7, converter steel alloying. In this embodiment, the converter end point C: 0.051%, Mn: 0.017%, P: 0.0136%, S: 0.0303%, temperature 1631°C, average steel output 102.7t.

[0042] Embodiment 3, this embodiment provides a converter ultra-high scrap steel ratio smelting method, the method is:

[0043] 6.3t of ordinary scrap steel was added to the bottom of S1 and No. 38 iron ladle.

[0044] S2. The iron ladle is baked before being tapped. The baking time is 3.3 hours and the baking temperature is 805°C. The baking is completed until the scrap steel turns red.

[0045] S3, 61.5t molten iron enters the blast furnace, the temperature is 1369℃, the output is 61.5t, the output is not desulfurized, and the output molten iron is required to meet the following conditions: temperature ≥1400℃, molten iron Si content ≥0.80%, molten iron Mn content

[0046] ≥0.60%, molten iron P content ≤0.125%, molten iron S content ≤0.030%.

[0047] S4, adding scrap steel and flux to the converter for smelting. Specifically, 5t of slag steel, granular steel and granular iron are added to the high-level silo of the blowing converter in advance, and used as coolants during the blowing process. The slag steel, granular steel and granular iron added in this embodiment have a particle size of 20-30mm. After the slag splashing of the converter is completed, all the slag is poured out, and 25t of the first bucket of scrap steel + 3.5t of flux are first added to the converter, and then 25t of the second bucket of scrap steel is added. The added scrap steel must include general scrap, heavy scrap and counterweight scrap steel, of which 7t of general scrap, 9t of heavy scrap and 9t of counterweight scrap steel are also added. After adding the scrap steel, the furnace is shaken backward to 35° to prepare for the addition of molten iron. The total amount of scrap steel is 61.3t, the total load is 122.8t, and the scrap steel ratio is 49.92%. The solvent used in this embodiment is coke powder, and the carbon content of coke powder is ≥85%. The amount of coke powder used is calculated based on the heat balance of the chemical elements of the current molten iron. Specifically, the amount of coke powder added is calculated according to the following formula: According to the heat balance calculation, the total amount of solvent used = physical heat supplement amount + chemical heat supplement amount; physical heat supplement amount = total loading amount * temperature increase amount * molten iron specific heat capacity / calorific value of coke powder / 1000; the chemical heat supplement amount is calculated to be 2.2 tons based on the normal use of the heat balance of the chemical elements of the molten iron.

[0048] S5. Pour 61.5t of molten iron from the blast furnace in step 3 into the converter using an overhead crane to complete the iron addition.

[0049] S6, converter lower gun blowing, specifically, the ignition gun position is set to 1.5m, and the gun position is 1.4-1.6m after normal ignition; ignition flow rate is 15000m3 / h, working oxygen flow rate 23000m 3 / h; for smelting high carbon steel, before starting the lance at the end of the converter, blow at alternating lance positions, the deep blowing time is greater than 30s, the deep blowing lance position shall not be lower than 1.1m, and the molten steel composition and temperature shall be uniform; bottom blowing mode: argon blowing throughout the process.

[0050] Adding materials during blowing: The first batch of lime can be added after ignition is normal. The amount added is 1 / 3-1 / 2 of the total amount. The total amount added in this embodiment is 4355 kg. Process control: Add appropriate amounts of sintered ore and fluorite according to the slagging situation and flame temperature to ensure good fluidity of the slag. The amount of each batch of slag added is 200-300 kg.

[0051] S7, converter steel alloying. In this embodiment, the converter end point C: 0.061%, Mn: 0.057%, P: 0.0162%, S: 0.0424%, temperature 1625°C, average steel output 102.3t.

[0052] Example 4: This example provides a converter ultra-high scrap steel ratio smelting method, the method comprising:

[0053] 5.9t of ordinary scrap steel was added to the bottom of S1 and No. 20 iron ladle.

[0054] S2. The iron ladle is baked before being tapped. The baking time is 3.5 hours and the baking temperature is 810°C. The baking is completed until the scrap steel turns red.

[0055] S3, 61.5t molten iron enters the blast furnace, the temperature is 1369℃, the output is 61.5t, the output is not desulfurized, and the output molten iron is required to meet the following conditions: temperature ≥1400℃, molten iron Si content ≥0.80%, molten iron Mn content

[0056] ≥0.60%, molten iron P content ≤0.125%, molten iron S content ≤0.030%.

[0057] S4, adding scrap steel and flux to the converter for smelting. Specifically, 5t of slag steel, granular steel and granular iron are added to the high-level material bin of the blowing converter in advance, and used as coolants during the blowing process. The slag steel, granular steel and granular iron added in this embodiment have a particle size of 30-40mm. After the slag splashing of the converter is completed, all the slag is poured out, and 25t of the first bucket of scrap steel + 3.5t of flux are first added to the converter, and then 25t of the second bucket of scrap steel is added. The added scrap steel must include general scrap, heavy scrap and counterweight scrap steel, of which 7t of general scrap, 9t of heavy scrap and 9t of counterweight scrap steel. After adding scrap steel, the furnace is shaken backward to 35° to prepare for the addition of molten iron. The total amount of scrap steel is 60.9t, the total load is 122.4t, and the scrap steel ratio is 49.75%. The solvent used in this embodiment is coke powder, and the carbon content of coke powder is ≥85%. The amount of coke powder used is calculated based on the heat balance of the chemical elements of the current molten iron. Specifically, the amount of coke powder added is calculated according to the following formula: According to the heat balance calculation, the total amount of solvent used = physical heat supplement amount + chemical heat supplement amount; physical heat supplement amount = total loading amount * temperature increase amount * molten iron specific heat capacity / calorific value of coke powder / 1000; the chemical heat supplement amount is calculated to be 2.2 tons based on the normal use of the heat balance of the chemical elements of the molten iron.

[0058] S5. Pour 61.5t of molten iron from the blast furnace in step 3 into the converter using an overhead crane to complete the iron addition.

[0059] S6, converter lower gun blowing, specifically, the ignition gun position is set to 1.5m, and after normal ignition, the gun position is 1.4-1.6m; ignition flow rate is 15000m 3 / h, working oxygen flow rate 23000m 3 / h; for smelting high carbon steel, before starting the lance at the end of the converter, blow at alternating lance positions, the deep blowing time is greater than 30s, the deep blowing lance position shall not be lower than 1.1m, and the molten steel composition and temperature shall be uniform; bottom blowing mode: argon blowing throughout the process.

[0060] Adding materials during blowing: The first batch of lime can be added after ignition is normal. The amount added is 1 / 3-1 / 2 of the total amount. The total amount added in this embodiment is 4355 kg. Process control: Add appropriate amounts of sintered ore and fluorite according to the slagging situation and flame temperature to ensure good fluidity of the slag. The amount of each batch of slag added is 200-300 kg.

[0061] S7, converter steel alloying. In this embodiment, the converter end point C: 0.070%, Mn: 0.025%, P: 0.0182%, S: 0.0362%, temperature 1619°C, average steel output 106.1t.

[0062] Example 5: This example provides a converter ultra-high scrap steel ratio smelting method, the method comprising:

[0063] 8.9t of ordinary scrap steel was added to the bottom of S1 and No. 29 iron ladle.

[0064] S2. The iron ladle is baked before being tapped. The baking time is 3 hours and the baking temperature is 805°C. The baking is completed until the scrap steel turns red.

[0065] S3, 61.5t molten iron enters the blast furnace, the temperature is 1356℃, the output is 61.5t, the output is not desulfurized, and the output molten iron is required to meet the following conditions: temperature ≥1400℃, molten iron Si content ≥0.80%, molten iron Mn content

[0066] ≥0.60%, molten iron P content ≤0.125%, molten iron S content ≤0.030%.

[0067] S4, adding scrap steel and flux to the converter for smelting. Specifically, 5t of slag steel, granular steel and granular iron are added to the high-level silo of the blowing converter in advance, and used as coolants during the blowing process. The slag steel, granular steel and granular iron added in this embodiment have a particle size of 30-40mm. After the slag splashing of the converter is completed, all the slag is poured out, and 25t of the first bucket of scrap steel + 3.5t of flux are first added to the converter, and then 25t of the second bucket of scrap steel is added. The added scrap steel must include general scrap, heavy scrap and counterweight scrap steel, of which 7t of general scrap, 9t of heavy scrap and 9t of counterweight scrap steel are also added. After adding the scrap steel, the furnace is shaken backward to 35° to prepare for the addition of molten iron. The total amount of scrap steel is 63.9t, the total load is 125.4t, and the scrap steel ratio is 50.95%. The solvent used in this embodiment is coke powder, and the carbon content of coke powder is ≥85%. The amount of coke powder used is calculated based on the heat balance of the chemical elements of the current molten iron. Specifically, the amount of coke powder added is calculated according to the following formula: According to the heat balance calculation, the total amount of solvent used = physical heat supplement amount + chemical heat supplement amount; physical heat supplement amount = total loading amount * temperature increase amount * molten iron specific heat capacity / calorific value of coke powder / 1000; the chemical heat supplement amount is calculated to be 2.2 tons based on the normal use of the heat balance of the chemical elements of the molten iron.

[0068] S5. Pour 61.5t of molten iron from the blast furnace in step 3 into the converter using an overhead crane to complete the iron addition.

[0069] S6, converter lower gun blowing, specifically, the ignition gun position is set to 1.5m, and the gun position is 1.4-1.6m after normal ignition; ignition flow rate is 15000m 3 / h, working oxygen flow rate 23000m 3 / h; for smelting high carbon steel, before starting the lance at the end of the converter, blow at alternating lance positions, the deep blowing time is greater than 30s, the deep blowing lance position shall not be lower than 1.1m, and the molten steel composition and temperature shall be uniform; bottom blowing mode: argon blowing throughout the process.

[0070] Adding materials during blowing: The first batch of lime can be added after ignition is normal. The amount added is 1 / 3-1 / 2 of the total amount. The total amount added in this embodiment is 4355 kg. Process control: Add appropriate amounts of sintered ore and fluorite according to the slagging situation and flame temperature to ensure good fluidity of the slag. The amount of each batch of slag added is 200-300 kg.

[0071] S7, converter steel alloying. In this embodiment, the converter end point C: 0.070%, Mn: 0.052%, P: 0.0159%, S: 0.0478%, temperature 1626°C, average steel output 113t.

[0072] It can be seen from Examples 1-5 that the scrap steel ratio of the method of the present invention is as high as 50.95% at the highest, and the average scrap steel ratio is 50.08%.

[0073] The above description is only a preferred embodiment of the present invention and does not limit the present invention in other forms. Any technician familiar with the profession may use the technical content disclosed above to change or modify it into an equivalent embodiment with equivalent changes and apply it to other fields. However, any simple modification, equivalent change and modification made to the above embodiment based on the technical essence of the present invention without departing from the content of the technical solution of the present invention still falls within the protection scope of the technical solution of the present invention.

Claims

1. A converter ultra-high scrap ratio smelting method, characterized in that: The method is as follows: adding scrap steel to an iron ladle → baking the iron ladle → tapping iron without desulfurization → adding scrap steel and solvent to a converter for smelting → adding iron → blowing with a gun in the converter → alloying steel tapped from the converter.

2. The converter ultra-high scrap ratio smelting method according to claim 1, characterized in that: In the process of adding scrap steel to the iron ladle, the amount of scrap steel added is 10%-14% of the total amount.

3. The converter ultra-high scrap ratio smelting method according to claim 1, characterized in that: In the ladle baking process, the baking time is 3-3.5 hours, the baking temperature is 780° C.-820° C., and the baking is completed until the scrap steel turns red.

4. The converter ultra-high scrap ratio smelting method according to claim 1, characterized in that: In the converter smelting process, slag steel, granular steel and granular iron are added to the high-level silo of the blowing converter in advance and used as coolants during the blowing process. The amount of slag steel, granular steel and granular iron added is 5-6t / furnace.

5. The converter ultra-high scrap steel ratio smelting method according to claim 1, characterized in that: In the converter smelting process, the method of adding scrap steel is: the scrap steel is added in two buckets, and the amount added in each bucket is 39-41% of the total scrap steel. Each bucket of scrap steel must contain three types of scrap steel: general scrap, heavy scrap, and counterweight scrap steel, among which the proportion of general scrap is 28%, the proportion of heavy scrap is 36%, and the proportion of counterweight scrap is 36%.

6. The converter ultra-high scrap ratio smelting method according to claim 1, characterized in that: In the blast furnace iron-tapping process, the molten iron is required to meet the following conditions: temperature ≥1400°C, molten iron Si content ≥0.80%, molten iron Mn content ≥0.60%, molten iron P content ≤0.125%, and molten iron S content ≤0.030%.

7. The converter ultra-high scrap steel ratio smelting method according to claim 1, characterized in that: In the converter smelting process, the blowing process is controlled as follows: the ignition gun position is set to 1.5m when the blowing starts, and the gun position is 1.4-1.6m after the ignition is normal; the ignition flow rate is 15000m 3 / h, working oxygen flow rate 23000m 3 / h; for smelting high carbon steel, before starting the lance at the end of the converter, blow at alternating lance positions, the deep blowing time is greater than 30s, the deep blowing lance position shall not be lower than 1.1m, and the molten steel composition and temperature shall be uniform; bottom blowing mode: argon blowing throughout the process.

8. The converter ultra-high scrap ratio smelting method according to claim 5, characterized in that: The flux is added into the converter along with the first bucket of scrap steel at an amount of 3.5-3.7t / furnace. The flux is coke powder, and the coke foam carbon content is ≥85%.

9. The converter ultra-high scrap steel ratio smelting method according to claim 7, characterized in that: The first batch of lime can be added after the ignition gun ignites normally, and the added amount is 1 / 3-1 / 2 of the total amount. If the flame is abnormal, stop adding in time and add in time after the flame is normal; Process control: according to the slag formation situation and flame temperature, sintered ore and fluorite can be added in appropriate amounts to ensure good fluidity of the slag. The amount of each batch of slag added is 200-300Kg.

10. The converter ultra-high scrap steel ratio smelting method according to claim 4, characterized in that: The particle size of the slag steel, granular steel and granular iron is 10-50 mm.

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