A cold-pressed converter temperature-raising agent, its preparation method, converter smelting method and converter smelting system

Abstract

The present application provides a cold-pressed converter heating agent, a preparation method thereof, a converter smelting method and a converter smelting system, relating to the metallurgy field. The cold-pressed converter heating agent, calculated based on the total mass of its raw materials being 100%, comprises: 1% - 89% of iron-containing materials, 1% - 95% of biomass carbon powder and 4% - 10% of binder; the iron-containing materials include one or more of mill scale, slag iron, sinter and iron ore. The preparation method of the cold-pressed converter heating agent comprises: mixing the iron-containing materials, the biomass carbon powder and the binder, and then pressing them into the cold-pressed converter heating agent. The converter smelting method comprises: adding the above-mentioned cold-pressed converter heating agent during the process of converter smelting. The converter smelting system comprises: a mixing machine, a briquetting device, a storage bin and a converter. The cold-pressed converter heating agent provided by the present application improves the utilization efficiency of the biomass carbon in the heating agent by the converter, which is beneficial to reducing the smelting cost of the converter and reducing carbon emissions.

Description

Technical Field

[0001] The present application relates to the field of metallurgy, and particularly to a converter heating agent in the form of cold-pressed briquettes, a preparation method thereof, a converter smelting method, and a converter smelting system. Background Art

[0002] Converter smelting with a high scrap ratio is an important method to reduce carbon emissions in the iron and steel industry. However, when the scrap ratio is high, it is easy to have insufficient heat in converter smelting, resulting in the formation of nodules in the molten steel during the smelting process, a large deviation of the end-point molten steel from the target composition, and a significant increase in the proportion of returned steel. Therefore, to ensure the smooth operation of the converter during high-scrap-ratio smelting, carbonaceous heating agents such as coke and anthracite are usually added to supplement heat. However, these heating agents float on the surface of the molten steel, and the chemical heat they provide is difficult to be absorbed by the molten steel, with too low utilization rate, resulting in an increase in oxygen consumption and carbon emissions.

[0003] Therefore, it is necessary to develop a new type of converter heating agent to solve the above problems. Summary of the Invention

[0004] The purpose of the present application is to provide a converter heating agent in the form of cold-pressed briquettes, a preparation method thereof, a converter smelting method, and a converter smelting system to solve the above problems.

[0005] To achieve the above purpose, the present application adopts the following technical solutions:

[0006] A converter heating agent in the form of cold-pressed briquettes, calculated based on the total mass of its raw materials being 100%, includes:

[0007] Iron-containing materials 1% - 89%, biomass carbon powder 1% - 95%, and binder 4% - 10%;

[0008] The iron-containing materials include one or more of scale, slag iron, sinter, and iron ore.

[0009] Preferably, the converter heating agent in the form of cold-pressed briquettes includes one or more of high-carbon-ratio cold-pressed briquettes, medium-carbon-ratio cold-pressed briquettes, and low-carbon-ratio cold-pressed briquettes;

[0010] The high-carbon-ratio cold-pressed briquettes, calculated based on the total mass of itself being 100%, include: the iron-containing materials 1% - 15%, the biomass carbon powder 79% - 95%, and the binder 4% - 6%;

[0011] The medium-carbon-ratio cold-pressed briquettes, calculated based on the total mass of itself being 100%, include: the iron-containing materials 15% - 50%, the biomass carbon powder 42% - 79%, and the binder 6% - 8%;

[0012] The low-carbon-ratio cold-pressed briquettes, calculated based on the total mass of itself being 100%, include: the iron-containing materials 50% - 89%, the biomass carbon powder 1% - 42%, and the binder 8% - 10%.

[0013] Preferably, the compressive strength of the high-carbon ratio cold-compressed briquette, the medium-carbon ratio cold-compressed briquette, and the low-carbon ratio cold-compressed briquette is not less than 1500 N.

[0014] Preferably, the cold-compressed briquette converter temperature raising agent satisfies one or more of the following conditions:

[0015] A. The binder includes sodium silicate and / or steelmaking sludge;

[0016] B. The total iron content of the iron-containing material is 40%-60%;

[0017] C. The biomass carbon powder is biomass carbon powder pyrolyzed from one or more of corn straw, wheat straw, and wood chips as raw materials.

[0018] The present application also provides a preparation method of the cold-compressed briquette converter temperature raising agent, including:

[0019] Mix the iron-containing material, the biomass carbon powder, and the binder, and then press them into the cold-compressed briquette converter temperature raising agent.

[0020] Preferably, the iron-containing material is pre-crushed into a powdery iron-containing material with a fineness of 100-200 meshes before use;

[0021] And / or,

[0022] The linear pressure of the pressing is 40-150 kN / cm.

[0023] The present application also provides a converter smelting method, including: adding the cold-compressed briquette converter temperature raising agent during the converter smelting process.

[0024] Preferably, the cold-compressed briquette converter temperature raising agent includes a high-carbon ratio cold-compressed briquette, a medium-carbon ratio cold-compressed briquette, and a low-carbon ratio cold-compressed briquette;

[0025] The addition satisfies one or more of the following conditions:

[0026] (1) Add the high-carbon ratio cold-compressed briquette in the early stage of converter smelting, and the addition amount is 60-90 wt% of the total addition amount;

[0027] (2) When there is sufficient heat during the converter smelting process, that is, the temperature measured by the TSC sublance is greater than 1580 °C, but there is a dry return situation in the middle stage, add the low-carbon ratio cold-compressed briquette; when there is insufficient heat during the converter smelting process, that is, the temperature measured by the TSC sublance is less than 1580 °C, but there is a dry return situation in the middle stage, add the medium-carbon ratio cold-compressed briquette;

[0028] (3) When the tapping carbon temperature at the end of the converter is too high, that is, the temperature measured by the TSO sublance is greater than 1650 °C, add the low-carbon ratio cold-compressed briquette;

[0029] (4) The relationship between the mass content of biomass carbon powder in the high-carbon ratio cold briquette and the scrap ratio in converter steelmaking is as follows:

[0030] When the scrap ratio is 20 - 30%, the mass content of biomass carbon powder in the high-carbon ratio cold briquette is 79 - 85%; when the scrap ratio is 30 - 35%, the mass content of biomass carbon powder in the high-carbon ratio cold briquette is 85 - 90%; when the scrap ratio is 35 - 40%, the mass content of biomass carbon powder in the high-carbon ratio cold briquette is 85 - 95%; when the scrap ratio is 40 - 45%, the mass content of biomass carbon powder in the high-carbon ratio cold briquette is 90 - 95%;

[0031] (5) During the process of converter steelmaking, the top-blowing O2 intensity is 3.10 - 3.80 Nm 3 / (min·t), the bottom-blowing intensity is 0.02 - 0.08 Nm 3 / (min·t), and the bottom-blowing gas is one of Ar, N2 or CO2.

[0032] This application also provides a converter steelmaking system, including: a mixer, a briquetting device, a silo and a converter;

[0033] The mixer is used to mix the raw materials of the cold briquette converter temperature-raising agent, the briquetting device is used to press the raw materials into the cold briquette converter temperature-raising agent, the silo is used to store the cold briquette converter temperature-raising agent from the briquetting device and add the cold briquette converter temperature-raising agent to the converter, and the converter is used for steelmaking.

[0034] Preferably, the silo includes a high-carbon ratio cold briquette silo, a medium-carbon ratio cold briquette silo and a low-carbon ratio cold briquette silo;

[0035] and / or

[0036] The converter steelmaking system further includes a crusher for crushing iron-containing materials.

[0037] Compared with the prior art, the beneficial effects of this application include:

[0038] The cold briquette converter temperature-raising agent provided by this application uses biomass carbon and iron-containing materials to be briquetted under the action of a binder, as a converter temperature-raising agent, which improves the utilization efficiency of biomass carbon in converter steelmaking, is beneficial to reducing the cost of converter steelmaking and reducing carbon emissions.

[0039] The preparation method of the cold briquette converter temperature-raising agent provided by this application is simple in operation.

[0040] The converter smelting method and system provided by this application utilize the above-mentioned cold-pressed converter heating agent, which is beneficial to making the converter smelting process more stable and reducing the number of abnormal converter smelting batches. At the same time, the scrap ratio of the converter can be increased to 45%, the consumption of carbonaceous heating agent per ton of steel can be reduced by 54 - 136 kg, and the CO2 emissions per ton of steel can be reduced by 200 - 500 kg. Description of the Drawings

[0041] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings required for the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as limiting the scope of this application.

[0042] Figure 1 It is a schematic diagram of the converter smelting system provided for the embodiment.

[0043] Reference Signs:

[0044] 1 - Crushing machine, 2 - Mixing machine, 3 - Briquetting device, 4 - High-level bin for cold-pressed briquettes, 4-1 - High-carbon-ratio cold-pressed briquette high-level bin, 4-2 - Medium-carbon-ratio cold-pressed briquette high-level bin, 4-3 - Low-carbon-ratio cold-pressed briquette high-level bin, 5 - Converter. Detailed Embodiments

[0045] To better explain the technical solutions provided by this application, before the embodiments, a general statement of the technical solutions is made as follows:

[0046] A cold-pressed converter heating agent, calculated based on the total mass of its raw materials being 100%, includes:

[0047] 1% - 89% of iron-containing materials, 1% - 95% of biomass carbon powder, and 4% - 10% of binder;

[0048] The iron-containing materials include one or more of scale, slag iron, sinter, and iron ore.

[0049] Optionally, for the cold-pressed converter heating agent, calculated based on the total mass of its raw materials being 100%, the dosage of iron-containing materials can be 1%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 89% or any value between 1% - 89%, the dosage of biomass carbon powder can be 1%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95% or any value between 1% - 95%, and the dosage of binder can be 4%, 5%, 6%, 7%, 8%, 9%, 10% or any value between 4% - 10%.

[0050] The cold-pressed briquette is generally made by adding an adhesive to iron-containing materials. It can be used as a coolant and a flux in converter steelmaking because it can control the mixing ratio of slag iron, sinter ore, iron ore, and steelmaking sludge, so that the total iron content in the cold-pressed briquette can be effectively controlled within a certain range.

[0051] As a carbon-neutral energy fuel, according to the life cycle theory, the net amount of carbon dioxide released during the combustion of biochar is considered to be 0. And compared with coke and anthracite, biochar contains a lower sulfur and hydrogen content and has better combustion reactivity, causing less pollution to the molten steel.

[0052] Using the briquette of biochar and iron-containing materials as a converter heating agent can, on the one hand, solve the problem that it is difficult for the heating agent to enter the surface of the molten steel to participate in the heating reaction, improve the utilization rate of the heating agent, and provide room for further increasing the scrap ratio in the converter. In addition, it can also play the role of slag melting and fluxing of iron oxides, which is beneficial to enhancing the dephosphorization smelting effect in the early stage of the converter. Finally, using the briquette of carbon-neutral biochar and iron-containing materials can further reduce the carbon emissions during converter smelting, which is a measure for the green and low-carbon production of the converter.

[0053] In an optional embodiment, the cold-pressed briquette converter heating agent includes one or more of high-carbon ratio cold-pressed briquettes, medium-carbon ratio cold-pressed briquettes, and low-carbon ratio cold-pressed briquettes;

[0054] Taking its own total mass as 100%, the high-carbon ratio cold-pressed briquette includes: 1%-15% of the iron-containing material, 79%-95% of the biochar powder, and 4%-6% of the adhesive;

[0055] The high-carbon ratio cold-pressed briquette is the main heating agent under the condition of high scrap ratio smelting in the converter.

[0056] Taking its own total mass as 100%, the medium-carbon ratio cold-pressed briquette includes: 15%-50% of the iron-containing material, 42%-79% of the biochar powder, and 6%-8% of the adhesive;

[0057] Taking its own total mass as 100%, the low-carbon ratio cold-pressed briquette includes: 50%-89% of the iron-containing material, 1%-42% of the biochar powder, and 8%-10% of the adhesive.

[0058] In an optional embodiment, the compressive strength of the high-carbon ratio cold-pressed briquette, the medium-carbon ratio cold-pressed briquette, and the low-carbon ratio cold-pressed briquette is not less than 1500 N.

[0059] Ensuring that the compressive strength of the cold-pressed briquette is above 1500 N, thereby ensuring that the biochar-iron-containing material briquette can enter the molten steel to participate in the reaction.

[0060] In an optional embodiment, the cold-pressed converter temperature-raising agent satisfies one or more of the following conditions:

[0061] A. The binder includes sodium silicate and / or steelmaking sludge;

[0062] Sodium silicate is conducive to the rapid curing of cold-pressed pellets and obtains strong compressive strength. Its dosage can be greatly reduced compared with the use of inferior binders such as water glass, cement, and asphalt, and the silica impurities brought in are reduced, which is beneficial to the smooth operation of converter smelting with a high scrap ratio.

[0063] A large amount of sodium silicate is contained in steelmaking sludge, which can be used instead of pure sodium silicate.

[0064] B. The total iron content of the iron-containing material is 40%-60%;

[0065] The abbreviation of total iron is TFe, and the mass fraction of various iron-containing materials is expressed as. The calculation formula for total iron in the iron-containing material is:

[0066] TFe (含铁物料) =Wt (渣铁) ·TFe (渣铁) +Wt (氧化铁皮) ·TFe (氧化铁皮) +Wt (烧结矿) ·TFe (烧结矿) +...

[0067] Optionally, the total iron content of the iron-containing material can be 40%, 45%, 50%, 55%, 60% or any value between 40%-60%;

[0068] C. The biomass carbon powder is biomass carbon powder obtained by pyrolysis of one or more of corn straw, wheat straw, and wood chips as raw materials.

[0069] The present application also provides a preparation method of the cold-pressed converter temperature-raising agent, including:

[0070] Mix the iron-containing material, the biomass carbon powder, and the binder, and then press them into the cold-pressed converter temperature-raising agent.

[0071] In an optional embodiment, the iron-containing material is pre-crushed into a powdery iron-containing material with a fineness of 100-200 mesh before use;

[0072] And / or,

[0073] The linear pressure of the pressing is 40-150 kN / cm.

[0074] Optionally, the pressing linear pressure may be 40 kN / cm, 50 kN / cm, 60 kN / cm, 70 kN / cm, 80 kN / cm, 90 kN / cm, 100 kN / cm, 110 kN / cm, 120 kN / cm, 130 kN / cm, 140 kN / cm, 150 kN / cm or any value between 40 - 150 kN / cm.

[0075] The present application also provides a converter smelting method, including: adding the above-mentioned cold-pressed converter temperature-raising agent during the converter smelting process.

[0076] In an optional embodiment, the cold-pressed converter temperature-raising agent includes high-carbon-ratio cold-pressed blocks, medium-carbon-ratio cold-pressed blocks and low-carbon-ratio cold-pressed blocks;

[0077] The addition satisfies one or more of the following conditions:

[0078] (1) Add the high-carbon-ratio cold-pressed blocks in the early stage of converter smelting, and the addition amount is 60 - 90 wt% of the total addition amount;

[0079] Optionally, add the high-carbon-ratio cold-pressed blocks in the early stage of converter smelting, and the addition amount may be 60 wt%, 65 wt%, 70 wt%, 75 wt%, 80 wt%, 85 wt%, 90 wt% or any value between 60 - 90 wt% of the total addition amount;

[0080] (2) When there is sufficient heat during the converter smelting process, that is, the temperature measured by the TSC sublance is greater than 1580 °C, but there is a dry return situation in the middle stage, add the low-carbon-ratio cold-pressed blocks; when there is insufficient heat during the converter smelting process, that is, the temperature measured by the TSC sublance is less than 1580 °C, but there is a dry return situation in the middle stage, add the medium-carbon-ratio cold-pressed blocks;

[0081] (3) When the tapping carbon temperature at the end of the converter is too high, that is, the temperature measured by the TSO sublance is greater than 1650 °C, add the low-carbon-ratio cold-pressed blocks;

[0082] The cold-pressed blocks are mainly added to the converter in 2 - 3 times, namely in the early stage and the middle stage of converter smelting. When there is overblowing at the end point, the cold-pressed blocks can be added one more time.

[0083] (4) The relationship between the mass content of the biomass carbon powder in the high-carbon-ratio cold-pressed blocks and the scrap ratio of the converter smelting is:

[0084] When the scrap ratio is 20 - 30%, the mass content of biomass carbon powder in the high-carbon ratio cold-pressed briquette is 79 - 85%; when the scrap ratio is 30 - 35%, the mass content of biomass carbon powder in the high-carbon ratio cold-pressed briquette is 85 - 90%; when the scrap ratio is 35 - 40%, the mass content of biomass carbon powder in the high-carbon ratio cold-pressed briquette is 85 - 95%; when the scrap ratio is 40 - 45%, the mass content of biomass carbon powder in the high-carbon ratio cold-pressed briquette is 90 - 95%.

[0085] Table 1 Relationship between biomass carbon content and scrap ratio in high-carbon ratio cold-pressed briquettes

[0086]

[0087] The mass content of biomass carbon powder in the high-carbon ratio cold-pressed briquette increases with the increase of the scrap ratio. Basically, when the scrap ratio increases by 5%, the mass content of biomass carbon powder in the briquette increases by 5%. At the same time, appropriate adjustments can also be made according to the actual situation.

[0088] (5) During the process of converter smelting, the top-blowing O2 intensity is 3.10 - 3.80 Nm 3 / (min·t), the bottom-blowing intensity is 0.02 - 0.08 Nm 3 / (min·t), and the bottom-blowing gas is one of Ar, N2 or CO2.

[0089] Optionally, the top-blowing O2 intensity can be 3.10 Nm 3 / (min·t), 3.20 Nm 3 / (min·t), 3.30 Nm 3 / (min·t), 3.40 Nm 3 / (min·t), 3.50 Nm 3 / (min·t), 3.60 Nm 3 / (min·t), 3.70 Nm 3 / (min·t), 3.80 Nm 3 / (min·t) or any value between 3.10 - 3.80 Nm 3 / (min·t), and the bottom-blowing intensity can be 0.02 Nm 3 / (min·t), 0.03 Nm 3 / (min·t), 0.04 Nm 3 / (min·t), 0.05 Nm 3 / (min·t), 0.06 Nm 3 / (min·t), 0.07 Nm 3 / (min·t), 0.08 Nm 3 / (min·t) or 0.02 - 0.08 Nm 3 Any value between / (min·t).

[0090] This application also provides a converter smelting system, including: a mixing machine, a briquetting device, a silo, and a converter;

[0091] The mixing machine is used to mix the raw materials of the cold briquette converter temperature raising agent, the briquetting device is used to press the raw materials into the cold briquette converter temperature raising agent, the silo is used to store the cold briquette converter temperature raising agent from the briquetting device and add the cold briquette converter temperature raising agent to the converter, and the converter is used for smelting.

[0092] In an optional embodiment, the silo includes a high-carbon ratio cold briquette silo, a medium-carbon ratio cold briquette silo, and a low-carbon ratio cold briquette silo;

[0093] To ensure the smooth operation of the furnace condition during smelting, the three cold briquette silos are respectively used to store high-carbon ratio cold briquettes, medium-carbon ratio cold briquettes, and low-carbon ratio cold briquettes.

[0094] And / or,

[0095] The converter smelting system further includes a crusher for crushing iron-containing materials.

[0096] The following will describe the implementation scheme of this application in detail with specific embodiments. However, those skilled in the art will understand that the following embodiments are only used to illustrate this application and should not be regarded as limiting the scope of this application. For those without specific conditions indicated in the embodiments, they are carried out according to conventional conditions or the conditions recommended by the manufacturer. For reagents or instruments without the manufacturer indicated, they are all conventional products that can be obtained through commercial purchase.

[0097] Example 1

[0098] As Figure 1 shown, this embodiment provides a converter smelting system, specifically including: a crushing machine 1, a mixing machine 2, a briquetting device 3, a cold briquette high-level silo 4 (high-carbon ratio cold briquette high-level silo 4-1, medium-carbon ratio cold briquette high-level silo 4-2, low-carbon ratio cold briquette high-level silo 4-3), and a converter 5.

[0099] For the converter smelting production of a 150t converter in a certain factory, with a scrap ratio of 38%, a biomass carbon and iron-containing material briquette is used as the converter temperature raising agent. The preparation method and smelting method are as follows:

[0100] S1. The types of iron-containing materials in this factory are slag iron and iron ore, and their total iron contents are respectively: Wt (渣铁) = 16% - 19%, Wt (铁矿石)= 50% - 58%. The total iron content of the iron-containing material is taken as 48%. According to the formula calculation, the addition ratio of slag and iron is 0 - 24%, and the addition ratio of iron ore is 74% - 94%.

[0101] The iron-containing material is crushed in the crushing machine 1 to form a powdery iron-containing material with a fineness of 100 - 200 mesh.

[0102] S2. Add the powdery iron-containing material, biomass powder and binder into the mixer 2 and stir for 2 - 3 min to fully mix.

[0103] According to the different types of cold-pressed blocks produced, it is specifically divided into three types of cold-pressed blocks, namely: high-carbon ratio cold-pressed blocks, medium-carbon ratio cold-pressed blocks and low-carbon ratio cold-pressed blocks.

[0104] Because the scrap ratio in converter steelmaking is 38%, it can be found from Table 1 that the mass ratio of biomass charcoal in high-carbon ratio cold-pressed blocks is 85% - 95%. According to the actual production of this factory, the material ratios of the three types of cold-pressed blocks are shown in Table 2:

[0105] Table 2 Proportion of main materials of cold-pressed blocks for 150t converter high-scrap ratio smelting

[0106] Cold-pressed briquette with high carbon ratio Cold-pressed briquette with medium carbon ratio Cold-pressed briquette with low carbon ratio Iron-containing material 1％～10％ 15～50％ 50～82％ Biochar 85％～95％ 42％～79％ 1％～42％ Binder 4％～5％ 6％～8％ 8％～10％

[0107] About 87wt% of sodium silicate in the steelmaking sludge of the binder raw material.

[0108] S3. The mixed briquette raw materials are loaded into the briquetting device 3 to be pressed into cold-pressed blocks. The linear pressure of the briquetting machine is 85 kN / cm, and the compressive strength of the cold-pressed blocks is guaranteed to be above 1800 N.

[0109] S4. The pressed cold-pressed blocks are respectively loaded into the high-position bins 4 for high-carbon ratio, medium-carbon ratio and low-carbon ratio cold-pressed blocks according to the different ratios of iron-containing materials and biomass charcoal for standby.

[0110] S5. The scrap ratio of the converter is 38%. In the early stage of smelting, high-carbon ratio cold-pressed blocks are added through the high-position bin 4-1 for high-carbon ratio cold-pressed blocks to provide heat for the converter 5. The addition amount of cold-pressed blocks in the early stage is about 80% - 88% of the total addition amount, and the addition quality is between 1.7 t and 1.9 t.

[0111] During the converter smelting process, there is sufficient heat, and there is a situation of dry return in the middle stage of the furnace. Low-carbon ratio cold-pressed blocks are added through the high-position bin 4-3 for low-carbon ratio cold-pressed blocks to melt the slag and ensure the removal of impurity elements. The addition amount of low-carbon ratio cold-pressed blocks is about 12% - 20% of the total addition amount, and the addition quality is between 200 kg and 475 kg.

[0112] After normal blowing, the converter smelting is completed. During the process, the top-blowing O2 intensity of the converter is controlled at 3.30 Nm 3 / (min·t), and the bottom-blowing intensity is 0.04 Nm3 / (min·t), where the bottom-blowing gas is CO2.

[0113] The smelting results show that after adopting the method of pressing the temperature-raising agent in this embodiment, the converter smelting process is stable, the number of abnormal end-point furnace charges is reduced, and the utilization rate of the temperature-raising agent is significantly increased. Among them: the scrap ratio of the converter is 38%, and the CO2 emissions per ton of steel are reduced by 360 kg. Compared with using coke as the temperature-raising agent, the coke consumption per ton of steel can be reduced by 98 kg.

[0114] Example 2

[0115] For the converter smelting production of a 200t converter in a certain factory, with a scrap ratio of 32%, a method of using a briquette of biomass carbon and iron-containing materials as the converter temperature-raising agent is as follows:

[0116] S1. The types of iron-containing materials in this factory are iron ore, sinter, and steelmaking sludge, and their total iron contents are: Wt (铁矿石) = 48% - 55%, Wt (烧结矿) = 60% - 64%, Wt (炼钢污泥) = 22% - 28%. The total iron content of the iron-containing materials is taken as 55%, the addition ratio of iron ore is 0 - 90%, the addition ratio of sinter is 0 - 78%, and the addition ratio of steelmaking sludge is 0 - 14%.

[0117] The iron-containing materials are crushed in the crushing machine 1 to form a powdered iron-containing material with a fineness of 100 - 200 mesh.

[0118] S2. Add the powdered iron-containing material, biomass powder, and binder into the mixer 2 and stir for 2 - 3 min to fully mix.

[0119] According to the different types of cold briquettes produced, it is specifically divided into three types of cold briquettes, namely: high-carbon ratio cold briquettes, medium-carbon ratio cold briquettes, and low-carbon ratio cold briquettes.

[0120] Because the scrap ratio of the converter smelting is 32%, it can be found from Table 1 that the mass ratio of biomass carbon in the high-carbon ratio cold briquettes is 85% - 90%. According to the actual production of this factory, the material ratios of the three types of cold briquettes are shown in Table 3:

[0121] Table 3 Main material proportions of cold briquettes for 200t converter smelting with high scrap ratio

[0122] Cold-pressed briquette with high carbon ratio Cold-pressed briquette with medium carbon ratio Cold-pressed briquette with low carbon ratio Iron-containing material 6％～10％ 15～50％ 50～82％ Biochar 85％～90％ 42％～79％ 1％～42％ Binder 4％～5％ 6％～8％ 8％～10％

[0123] About 85wt% of sodium silicate in the steelmaking sludge, which is the binder raw material.

[0124] S3. The mixed briquette raw materials are put into the briquetting device 3 to be pressed into cold briquettes. The linear pressure of the briquetting machine is 90 kN / cm, and the compressive strength of the cold briquettes is guaranteed to be above 1900 N.

[0125] S4. Load the pressed cold compacts into the high-position bins 4 of cold compacts with high carbon ratio, medium carbon ratio and low carbon ratio respectively according to different ratios of iron-containing materials and biomass charcoal for standby.

[0126] S5. The scrap ratio of the converter is 32%. In the early stage of smelting, cold compacts with high carbon ratio are added through the high-position bin 4-1 of cold compacts with high carbon ratio to provide heat for the converter 5. The addition amount of cold compacts in the early stage is about 80% - 85% of the total addition amount, and the addition quality is between 1.8t and 2.2t.

[0127] During the converter smelting process, there is insufficient heat, and there is a situation of dry return in the middle stage of the furnace. Cold compacts with low carbon ratio are added through the high-position bin 4-2 of cold compacts with medium carbon ratio to slag, ensuring the removal of impurity elements. The addition amount of cold compacts with medium carbon ratio is about 15% - 20% of the total addition amount, and the addition quality is between 270kg and 440kg.

[0128] After the normal blowing is completed for converter smelting, the top blowing O2 intensity of the converter is controlled at 3.50 Nm 3 / (min·t), and the bottom blowing intensity is 0.05 Nm 3 / (min·t), where the bottom blowing gas is CO2.

[0129] The smelting results show that: after adopting the method of pressing the temperature-raising agent in this embodiment, the converter smelting process is stable, the number of abnormal end-point furnace charges is reduced, and the utilization rate of the temperature-raising agent is significantly increased. Among them: the scrap ratio of the converter is 32%, and the CO2 emission per ton of steel is reduced by 283kg. Compared with using coke as the temperature-raising agent, the coke consumption per ton of steel can be reduced by 77kg.

[0130] Example 3

[0131] For the converter smelting production of a 300t converter in a certain factory with a scrap ratio of 42%, a method of using biomass charcoal and iron-containing materials pressed into blocks as the converter temperature-raising agent is as follows:

[0132] S1. The types of iron-containing materials in this factory are iron ore and sinter, and their total iron contents are respectively: Wt (铁矿石) = 45% - 52%, Wt (烧结矿) = 62% - 66%. The total iron content of the iron-containing materials is taken as 60%. According to the formula calculation, the addition ratio of iron ore is between 11% and 42%, and the addition ratio of sinter is 58% - 99%.

[0133] The iron-containing materials are crushed in the crushing machine 1 to form powdered iron-containing materials with a fineness of 100 - 200 mesh.

[0134] S2. Add the powdered iron-containing materials, biomass powder and binder into the mixer 2 and stir for 2 - 3 minutes to fully mix.

[0135] According to the different types of cold briquettes produced, they are specifically divided into three types of cold briquettes, namely: high-carbon ratio cold briquettes, medium-carbon ratio cold briquettes, and low-carbon ratio cold briquettes.

[0136] Since the scrap ratio in converter steelmaking is 42%, it can be found from Table 1 that the mass ratio of biomass carbon in high-carbon ratio cold briquettes is 90% - 95%. According to the actual production of this factory, the material ratios of the three types of cold briquettes are shown in Table 4:

[0137] Table 4 Main material ratios of cold briquettes for 300t converter steelmaking with high scrap ratio

[0138] Cold-pressed briquette with high carbon ratio Cold-pressed briquette with medium carbon ratio Cold-pressed briquette with low carbon ratio Iron-containing material 1％～5％ 15～50％ 50～82％ Biochar 90％～95％ 42％～79％ 1％～42％ Binder 4％～5％ 6％～8％ 8％～10％

[0139] About 82wt% of sodium silicate in the steelmaking sludge, which is the binder raw material.

[0140] S3. The mixed briquette raw materials are put into the briquetting device 3 to be pressed into cold briquettes. The linear pressure of the briquetting machine is 95 kN / cm, and the compressive strength of the cold briquettes is guaranteed to be above 1900 N.

[0141] S4. The pressed cold briquettes are respectively put into the high-level bins 4 of high-carbon ratio, medium-carbon ratio, and low-carbon ratio cold briquettes according to the different ratios of iron-containing materials and biomass carbon for standby.

[0142] The scrap ratio of the converter is 42%. In the early stage of smelting, high-carbon ratio cold briquettes are added through the high-level bin 4-1 of high-carbon ratio cold briquettes to provide heat for the converter 5. The addition amount of cold briquettes in the early stage is about 86% - 91% of the total addition amount, and the added mass is between 3.5 t and 4.3 t.

[0143] During the converter smelting process, there is insufficient heat, and there is a situation of dry return in the middle stage of the furnace. Low-carbon ratio cold briquettes are added through the high-level bin 4-2 of medium-carbon ratio cold briquettes to melt the slag and ensure the removal of impurity elements. The addition amount of medium-carbon ratio cold briquettes is about 9% - 14% of the total addition amount, and the added mass is between 315 kg and 600 kg.

[0144] During the smelting process, the end-point temperature of the converter in individual furnace heats is slightly high. About 300 kg of low-carbon ratio cold briquettes are added through the high-level bin 4-3 of low-carbon ratio cold briquettes to balance the remaining heat at the end of the converter.

[0145] Normal blowing completes the converter smelting. During the process, the top-blowing O2 intensity of the converter is controlled at 3.70 Nm 3 / (min·t), and the bottom-blowing intensity is 0.06 Nm 3 / (min·t), where the bottom-blowing gas is Ar.

[0146] The smelting results show that after adopting the method of pressing the heating agent into blocks in this embodiment, the converter smelting process is stable, the number of abnormal end-point furnaces is reduced, and the utilization rate of the heating agent is significantly increased. Among them: the scrap ratio of the converter is 42%, and the CO2 emissions per ton of steel are reduced by 452 kg. Compared with using coke as the heating agent, the coke consumption per ton of steel can be reduced by 222 kg.

[0147] Comparative Example 1

[0148] For the converter smelting production of a 210t converter in a certain factory, with a scrap ratio of 30%, the traditional converter smelting process is adopted, and only coke is added at the furnace mouth as a heating agent to supplement heat for converter smelting:

[0149] The density of the coke blocks is small, and basically all the added heating agent is suspended on the surface of the molten steel. The statistical coke utilization rate is only about 20%.

[0150] When the scrap ratio is 30%, the coke addition per ton of steel is 18 kg, and a total of 3.0 - 3.8 t of coke is added. The coke loss caused by the insufficient absorption of coke heat by the molten steel is too large.

[0151] During the smelting process using coke as the converter heating agent, the oxygen consumption per ton of steel is 76.10 Nm 3 , and the oxygen consumption per ton of steel increases by about 20 Nm 3 .

[0152] After the normal blowing is completed for converter smelting, the top-blowing O2 intensity of the converter is controlled at 3.50 Nm 3 / (min·t), and the bottom-blowing intensity is 0.05 Nm 3 / (min·t), where the bottom-blowing gas is N2.

[0153] The smelting results show that when using coke as the heating agent, the utilization rate of the heating agent decreases with the increase of the scrap ratio, and the dosage of the heating agent increases significantly. When the scrap ratio is 30%, the coke dosage is about 4 times higher than that of the biomass carbon-iron-containing material cold-pressed block, the CO2 emissions per ton of steel increase by 51 kg, and the oxygen consumption per ton of steel increases by 20 Nm 3 , and the smelting time per furnace increases by about 5.7 min, seriously slowing down the smelting rhythm.

[0154] Comparative Example 2

[0155] For the converter smelting production of a 150t converter in a certain factory, with a scrap ratio of 28%, a method of using a pressed block of a biomass carbon and an iron-containing material as a converter heating agent is as follows. Only 260 kg of high-carbon ratio cold-pressed blocks are added as a heating agent at the early stage of smelting to supplement heat for converter smelting.

[0156] During the converter smelting process, there is insufficient heat. The temperature measured by the TSC sublance is 1542°C. There is a situation of dry return in the middle stage of the furnace. Only by increasing the oxygen flow rate to promote the carbon-oxygen reaction to increase heat, the splashing during the smelting process is severe.

[0157] When the converter smelting reaches the end high, the temperature measured by the TSO sublance is 1598°C, which is 22°C lower than the set target minimum temperature. On-site, heat is increased by means of spot blowing and burning iron.

[0158] For the smelting process, the top-blowing O2 intensity is increased to 4.20 Nm 3 / (min·t) during the process, and spot blowing operation is added in the later stage, making the smelting process not smooth and increasing the blowing duration.

[0159] The smelting results show that when only using high-carbon ratio cold briquettes as the heating agent in the early stage and not adding other cold briquettes according to the smelting process to adjust the heat of converter smelting, it will cause the blowing duration of the converter to increase by 3.2 min and the oxygen consumption per ton of steel to increase by 8.5 Nm 3 , because the iron loss in the slag increases by 3.5 kg per ton of steel due to splashing and spot blowing operations.

[0160] According to the above method, when using low-carbon ratio cold briquettes or medium-carbon ratio cold briquettes alone, similar phenomena will also occur.

[0161] Comparative Example 3

[0162] For the converter smelting production of a 120t converter in a certain factory, with a scrap ratio of 25%, a method of using a biomass carbon and iron-containing material briquette as the converter heating agent is as follows. In the early stage of converter smelting, no high-carbon ratio cold briquette is added as the heating agent to supplement heat for converter smelting. Only the scrap is preheated by rocking the furnace after adding the scrap.

[0163] During the early blowing process, the start time of the carbon-oxygen reaction in the molten bath is delayed, the intensity of the carbon-oxygen reaction is weakened, and the oxygen utilization rate during the smelting process is reduced.

[0164] During the converter smelting process, there is a serious shortage of heat. The temperature measured by the TSC sublance is 1520°C. There is a situation of dry return in the middle stage of the furnace. At this time, 250 kg of high-carbon ratio cold briquettes are added as the heating agent to supplement heat for converter smelting. Then, by increasing the oxygen flow rate to promote the carbon-oxygen reaction to increase heat, due to the too low molten bath temperature, the dissolution rate of the high-carbon ratio cold briquettes is slow, and the converter heating rate slows down.

[0165] When the converter smelting reaches the end high, the temperature measured by the TSO sublance is 1580°C, which is 40°C lower than the set target minimum temperature. On-site, heat is increased by means of long-term spot blowing and burning iron.

[0166] For the smelting process, the top-blowing O2 intensity is increased to 4.15 Nm3 / (min·t). In the later stage, spot blowing operations were added, which made the smelting process unstable and increased the blowing duration.

[0167] The smelting results show that when high-carbon ratio cold-compressed briquettes are added in the middle and later stages of smelting, it will cause uneven melting of scrap steel in the early stage, delay the start of the carbon-oxygen reaction and reduce the reaction intensity. The blowing duration of the converter increases by 5.4 min, and the oxygen consumption per ton of steel increases by 10.3 Nm 3 , because the spot blowing operation causes an increase in iron loss in the slag of 2.5 kg per ton of steel, and because a small amount of scrap steel does not melt and the residual scrap steel adheres to the furnace bottom, the furnace bottom rises, reducing the hearth ratio of the converter.

[0168] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, and are not intended to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A converter smelting method, characterized in that, Including: Adding a converter temperature increasing agent in the form of cold-pressed briquettes during the converter smelting process; The converter temperature increasing agent in the form of cold-pressed briquettes includes high-carbon ratio cold-pressed briquettes, medium-carbon ratio cold-pressed briquettes, and low-carbon ratio cold-pressed briquettes; Based on the total mass of the high-carbon ratio cold-pressed briquettes being 100%, it includes: 1%-15% of iron-containing materials, 79%-95% of biomass carbon powder, and 4%-6% of binder; Based on the total mass of the medium-carbon ratio cold-pressed briquettes being 100%, it includes: 15%-50% of iron-containing materials, 42%-79% of biomass carbon powder, and 6%-8% of binder; Based on the total mass of the low-carbon ratio cold-pressed briquettes being 100%, it includes: 50%-89% of iron-containing materials, 1%-42% of biomass carbon powder, and 8%-10% of binder; The iron-containing materials include one or more of scale, slag iron, sinter, and iron ore; the binder includes sodium silicate and / or steelmaking sludge; the total iron content of the iron-containing materials is 40%-60%; the biomass carbon powder is biomass carbon powder obtained by pyrolyzing one or more of corn straw, wheat straw, and wood chips as raw materials; The addition satisfies the following conditions: (1) Adding the high-carbon ratio cold-pressed briquettes in the early stage of converter smelting, and the addition amount is 60-90wt% of the total addition amount; (2) When there is sufficient heat during the converter smelting process, that is, the temperature measured by the TSC sublance is greater than 1580°C, but there is a dry return situation in the middle stage, adding the low-carbon ratio cold-pressed briquettes; when there is insufficient heat during the converter smelting process, that is, the temperature measured by the TSC sublance is less than 1580°C, but there is a dry return situation in the middle stage, adding the medium-carbon ratio cold-pressed briquettes; (3) When the tapping carbon temperature at the end of the converter is too high, that is, the temperature measured by the TSO sublance is greater than 1650°C, adding the low-carbon ratio cold-pressed briquettes; (4) The relationship between the mass content of the biomass carbon powder in the high-carbon ratio cold-pressed briquettes and the scrap ratio of the converter smelting is: When the scrap ratio is 20-30%, the mass content of the biomass carbon powder in the high-carbon ratio cold-pressed briquettes is 79-85%; when the scrap ratio is 30-35%, the mass content of the biomass carbon powder in the high-carbon ratio cold-pressed briquettes is 85-90%; when the scrap ratio is 35-40%, the mass content of the biomass carbon powder in the high-carbon ratio cold-pressed briquettes is 85-95%; when the scrap ratio is 40-45%, the mass content of the biomass carbon powder in the high-carbon ratio cold-pressed briquettes is 90-95%; During the process of converter smelting, the top blowing O2 intensity is 3.10 - 3.80 Nm 3 / (min•t), the bottom blowing intensity is 0.02 - 0.08 Nm 3 / (min•t), and the bottom blowing gas is one of Ar, N2 or CO2.

2. The converter smelting method according to claim 1, characterized in that, The compressive strength of the high-carbon ratio cold-pressed briquettes, the medium-carbon ratio cold-pressed briquettes, and the low-carbon ratio cold-pressed briquettes is not less than 1500N.

3. The converter smelting method according to claim 1, characterized in that, The preparation method of the converter temperature increasing agent in the form of cold-pressed briquettes includes: Mixing the iron-containing materials, the biomass carbon powder, and the binder, and then pressing them into the converter temperature increasing agent in the form of cold-pressed briquettes.

4. The converter smelting method according to claim 3, characterized in that, The iron-containing materials are pre-crushed into powdery iron-containing materials with a fineness of 100-200 meshes before use; And / or, The linear pressure of the pressing is 40-150kN / cm.

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