WO2020228240A1 - Method for smelting high-quality steel using zinc-containing scrap steel - Google Patents

Abstract

A method for smelting high-quality steel using zinc-containing scrap steel, the method comprising the following steps: melting a furnace charge containing zinc-containing scrap material, and adjusting the carbon content in the molten steel to be greater than the carbon content of a target steel type; in the process of pouring the molten steel into a ladle, blowing argon to the bottom of the ladle throughout the process, and adding lime with the steel flow to form alkaline slag; and creating an oxidisation environment, such that the carbon in the molten steel undergoes an oxidisation reaction to generate gas and escape. In the reaction process, increasing the carbon content in the molten steel makes same react with the oxygen in the molten steel in the subsequent reaction process to generate CO gas, and the process of releasing the CO gas drives the evaporation and oxidation of volatile substances such as volatile zinc and lead, which together enter a dust removal system so that the harmful components such as zinc and lead in the steel are removed, and a high quality steel is obtained.

Description

Method for smelting high-quality steel by using zinc-containing scrap steel

Cross references to related applications

This disclosure claims the priority of a Chinese patent application filed with the Chinese Patent Office on May 15, 2019, with application number 201910400409.5 and titled "A method for smelting high-quality steel using zinc-containing scrap steel".

Technical field

The present disclosure relates to the technical field of iron and steel smelting, and in particular to a method for smelting high-quality steel by using zinc-containing scrap steel.

Background technique

Scrap steel is an important raw material for the iron and steel industry. Compared with iron ore, its steelmaking process is shorter and production efficiency is higher.

Scrap steel is often configured as an addition to converter steelmaking and can be used as raw material for electric arc furnaces or intermediate frequency furnaces. The scrap added in the converter requires relatively clean scrap; the electric arc furnace can use relatively miscellaneous scrap, because the electric arc furnace has metallurgical refining functions, but the electric arc furnace equipment investment is relatively large, the operation is relatively complicated, and the cost is relatively high; intermediate frequency furnace The structure is simple, the investment is small, and the cost is low. However, the intermediate frequency furnace only has the melting function and does not have the metallurgical refining function. The large amount of low melting point substances such as zinc or lead can easily cause frequent shell cracks and breakouts in the continuous casting billet. The strength and toughness are greatly reduced, and the quality is not guaranteed. Usually, the so-called ground steel is the steel produced by some small steel mills using ordinary scrap steel to directly melt and cast in the intermediate frequency furnace. This is why the country wants to ban intermediate frequency furnace production. The main reason for bar steel, intermediate frequency furnace has also become synonymous with hitting ground bar steel.

However, the intermediate frequency furnace has the characteristics of simple equipment and low cost. How to use intermediate frequency furnace to produce high-quality and cheap steel is a road that needs to be actively explored in the steelmaking industry.

Summary of the invention

The purpose of the present disclosure includes, for example, to provide a method for smelting high-quality steel using zinc-containing scrap, to improve the problem that the intermediate frequency furnace is not suitable for smelting or the quality of the steel obtained from the smelting is low, so that the original intermediate frequency furnace equipment that does not have metallurgical functions, Through the oxidation reaction of the carbon in the molten steel to produce carbon monoxide gas, the combination of the process of bringing out the low boiling point substances such as zinc and lead out of the molten steel realizes the metallurgical function, removes the low melting point and other harmful substances, and produces high-quality steel.

The embodiments of the present disclosure are implemented as follows:

The present disclosure provides a method for smelting high-quality steel by using zinc-containing scrap steel, which includes the following steps:

Melt the charge including zinc-containing waste, and adjust the carbon content of the molten steel to be greater than the carbon content of the target steel;

When the molten steel is poured into the ladle, argon is blown to the bottom of the ladle all the way, and lime is added with the steel flow to form alkaline slag;

Create an oxidizing environment, so that the carbon in the molten steel is oxidized to generate gas to escape.

The beneficial effects of the embodiments of the present disclosure include, for example:

The present disclosure provides a method for smelting high-quality steel using zinc-containing scrap steel. By pre-adjusting the carbon content of molten steel in an intermediate frequency furnace, the carbon content of the molten steel is greater than that of the target steel grade, and the molten steel can be In an oxidizing environment, carbon reacts with iron oxide or O ₂ to generate a large amount of CO gas. In the process of escaping, CO gas combines with gaseous zinc and lead in molten steel, volatilizes into the atmosphere and is captured by the dust removal system. As a result, the low melting point substances in the molten steel are reduced, the molten steel is purified, and the carbon content is also controlled. The N, H, and B content in the molten steel is also reduced, which not only increases the strength of the steel, but also improves the continuous casting Pourability, at the same time, increases the strength of the slab shell and greatly reduces the frequency of continuous casting breakout; after CO, zinc and lead come out of the molten steel into the space, they are oxidized into CO ₂ , ZnO and PbO, reducing the emission of harmful substances .

In order to make the objectives, technical solutions, and advantages of the embodiments of the present disclosure clearer, the technical solutions in the embodiments of the present disclosure will be described clearly and completely below. If specific conditions are not indicated in the examples, it shall be carried out in accordance with the conventional conditions or the conditions recommended by the manufacturer. The reagents or instruments used without the manufacturer's indication are all conventional products that can be purchased commercially.

A method for smelting high-quality steel using zinc-containing scrap provided by the present disclosure will be specifically described below.

The present disclosure provides a method for smelting high-quality steel by using zinc-containing scrap steel, which includes the following steps:

Melt the charge including zinc-containing waste to form molten steel, and adjust the carbon content of molten steel to be greater than the carbon content of the target steel grade;

When the molten steel is poured into the ladle, argon is blown to the bottom of the ladle all the way, and lime is added with the steel flow to form alkaline slag;

An oxidizing environment is created to oxidize the carbon in the molten steel to generate gas to escape. In other words, in an oxidizing environment, the carbon in the molten steel is oxidized to generate gas and then escape.

In the method for smelting high-quality steel using zinc-containing waste steel provided by the present disclosure, the charge including zinc-containing waste is melted to obtain molten steel, and the carbon content in the molten steel is adjusted so that the carbon content in the molten steel is greater than that of the target steel grade. the amount. In this step, by adjusting the carbon content in the molten steel, the carbon content has a higher value. During oxidative decarburization, sufficient carbon concentration gradient and reaction power are provided; at the same time, the higher carbon content is also The conditions required for subsequent dezincification, as the carbon content increases, the ability of molten steel to generate CO gas increases, so that low-boiling substances such as zinc are removed with the escape of CO gas. At the same time, the N, H or The B content has also been reduced.

During the process of pouring molten steel into the ladle, argon is blown to the bottom of the ladle, and lime is added with the steel flow to form alkaline slag. In other words, argon is blown to the bottom of the ladle during the entire process of pouring the molten steel into the ladle, and follow The steel stream is added with lime to form alkaline slag. In this step, during the process of pouring molten steel into the ladle, lime is added along with the steel stream to obtain alkaline slag. The purpose of obtaining alkaline slag includes, for example, one is to remove phosphorus in the molten steel; the other is to reduce the ladle. Corrosion, because the refractory material of the ladle is mainly magnesia, which is also alkaline; third, it is beneficial to absorb acid inclusions in molten steel. Argon blowing at the bottom of the ladle is mainly used for stirring to promote the balance of the reaction and the uniformity of the composition.

In an oxidizing environment, the carbon in the molten steel is oxidized to generate gas and escape. This step is to increase the oxygen content in the molten steel or steel slag to facilitate the reaction of carbon and oxygen in the molten steel to generate CO gas. In the process of CO gas floating, the volatile zinc and lead vapors are carried out of the molten steel to reduce the amount of The content of low melting point metals and the content of N, H and B in molten steel are also reduced, eliminating the influence of low melting point substances on the surface quality and internal strength of the steel. At the same time, it can reduce the risk of continuous casting breakout in the continuous casting process. And to reduce the risk of cracks on the surface of the continuous casting slab that will continue to the surface defects of the steel.

In the present disclosure, during the melting of the charge, the carbon content in the molten steel is greater than the carbon content of the target steel type by adjusting the structure of the scrap steel or adding a recarburizer.

Optionally, the carbon content in the molten steel is adjusted to be greater than 0.12%, preferably greater than 0.15%, and more preferably, the carbon content in the molten steel is adjusted to 0.18%-0.28%.

The present disclosure provides a method for smelting high-quality steel by using zinc-containing scrap steel, wherein when batching in an intermediate frequency furnace, it is ensured that the C content of the batch is greater than 0.12%, optionally, the C content of the batch is greater than 0.15%; optionally, The C content of the ingredients is between 0.18% and 0.28%, which improves the ability of the molten steel to generate CO gas.

Optionally, the method for smelting high-quality steel provided in the present disclosure further includes: adding fluorite balls to the molten steel for slagging after the charge is melted and before tapping. Preferably, the amount of fluorite balls added is (0.6-1.0) Kg/ton steel, the thickness of the retained slag layer is not more than 10mm.

Optionally, the oxidizing environment is provided by the following steps: adding iron oxide powder along with the charge, and/or adding iron oxide powder along with the steel stream during the process of pouring molten steel into the ladle.

Preferably, during the production of an oxidizing environment, the step of adding iron oxide powder with the charge includes adding the charge while adding iron oxide powder when the charge is half melted; preferably, the iron oxide powder is added in batches, and the total added amount is ( 2-10) Kg/ton steel; more preferably, the total amount of iron oxide powder added is (7-10) Kg/ton steel,

Preferably, in the process of pouring molten steel into the ladle, the step of adding iron oxide powder along with the steel flow includes that the iron oxide powder added to the ladle along the steel flow is (2-12) Kg/ton steel, more preferably, iron oxide The total amount of powder added is (7-10) Kg/ton steel.

Optionally, the steps of blowing argon to the bottom of the ladle and adding lime along with the steel flow to form alkaline slag include: during the process of pouring molten steel into the ladle, blowing argon to the bottom of the ladle throughout the process, and the pressure of argon blowing is (0.3- 0.8) MPa, optional, the pressure is (0.4-0.6) MPa.

Optionally, the amount of lime added is (6-15) Kg/ton of steel, preferably, the amount of lime added is (8-12) Kg/ton of steel; optionally, it is added with the steel flow (2-4 ) Kg/ton steel light burnt dolomite.

The present disclosure provides a method for smelting high-quality steel by using zinc-containing scrap steel. The charge is melted, and after sampling and analysis, before tapping, fluorite balls are added to the furnace to make the slag thinner, and the slagging operation is performed. The slag process can be matched with slagging, and the thickness of the slag layer is controlled within 10mm. When discharging slag, the intermediate frequency furnace can be inclined at an angle to the nozzle, so that the liquid surface slag can be discharged in time, and the intermediate frequency furnace has metallurgical functions.

After the slag tapping is over, prepare for tapping. During the tapping process, argon is blown to the bottom of the ladle and argon is blown to the bottom of the ladle, which mainly plays a role of stirring molten steel, which can effectively increase the speed and uniformity of the metallurgical reaction.

In the process of pouring steel into the ladle, lime is added with the steel flow to make alkaline slag, which can absorb more acidic impurities; optionally, in the process of pouring steel into the ladle, adding light Burned dolomite, the main component of light burned dolomite is MgO, and the main component of the ladle material is also MgO. Adding light burned dolomite can reduce the degree of corrosion of the ladle. At the same time, adding light burned dolomite can adjust the viscosity of the slag.

Optionally, the oxidizing environment can be provided through the following steps:

After the molten steel is poured into the ladle, oxygen is blown to the top of the ladle, or oxygen is blown to the top of the ladle and iron oxide powder is added to the ladle.

Preferably, the oxygen supply intensity for blowing oxygen to the top of the ladle is (50-300) NL/(min·t), and the pressure is (0.5-2.0) MPa. Optionally, the oxygen supply intensity is (100-150)NL/(min·t), the pressure is (0.8-1.2)MPa, and the oxygen blowing time is 10-20 minutes. Optionally, (0.5～1.5) Kg/ton steel fluorite is added in the oxygen blowing process.

Preferably, iron oxide powder is added to the ladle. The iron oxide powder is added in one batch every 1-2 minutes. Optionally, 40Kg of iron oxide powder is added to each batch. A total of 4 batches of iron oxide powder are added. The amount is 160Kg.

Optionally, during the tapping process, keep argon blowing at the bottom of the ladle, and after tapping, the ladle is transferred to the oxygen blowing station. Fluorite can be added during the oxygen blowing process on the top of the ladle, and iron oxide powder can also be added during the oxygen blowing process; at the end of the oxygen blowing, the ladle is tilted, and the foam generator is added, and then the deoxidizer is added; after the argon blowing operation, the argon gas is turned off , And add carbonized rice husk covering agent to the molten steel, and lift the molten steel to the LF refining furnace for refining. , LF is the abbreviation of LADLE FURNACE, LF refining furnace is also called ladle refining furnace.

Optionally, tilt the ladle 10°-35° toward the ladle nozzle.

Optionally, after the deoxygenation is over, continue to blow argon (3-5) minutes, and then turn off the argon.

Optionally, the addition amount of the carbonized rice husk covering agent is (0.6-1.0) Kg/ton steel.

Preferably, the foam generating agent includes carbon powder and/or calcium carbide. Optionally, when the foam generating agent is selected from carbon powder, the addition amount of carbon powder is (0.3-0.5) Kg/ton steel; when the foam generating agent is selected from calcium carbide, the addition amount of calcium carbide is (0.4-0.6) Kg /Ton of steel; when the foam generator is selected from carbon powder and calcium carbide, the amount of carbon powder added is (0.2-0.4)Kg/ton steel, and the amount of calcium carbide added is (0.1-0.2)Kg/ton steel; what needs to be explained is , When the foam generator is selected from carbon powder and calcium carbide, add carbon powder first, and then add calcium carbide.

Optionally, the steps of blowing argon to the bottom of the ladle and adding lime along with the steel flow to form alkaline slag include: in the process of pouring steel into the ladle, the pressure of argon blowing is (0.3-0.8) MPa, optional, The pressure is (0.4-0.6) MPa.

The amount of lime added is (8-20) Kg/ton steel, optionally, the amount of lime added is (15-20) Kg/ton steel.

The present disclosure provides a method for producing low-phosphorus steel. After molten steel is poured into the ladle, fluorite can be added during the oxygen blowing process on the top of the ladle, and iron oxide powder can be added during the oxygen blowing process. Of course, fluorite may not be added. And no iron oxide powder is added. Appropriate addition of fluorite has the functions of melting slag, diluting slag and adjusting the viscosity of slag. Appropriate addition of iron oxide powder can increase the oxidability of the slag, which not only improves the ability to generate CO gas, but also enhances the decarburization function.

It should be noted that the amount of lime added is relatively higher in the case of oxygen blowing than in the case of adding iron oxide. The reason is that it can also dephosphorize in the case of oxygen blowing. Lime can easily absorb the phosphorus in the steel slag, especially in the case of oxygen blowing. Under circumstances, adding carbon powder or calcium carbide can instantly generate a large amount of CO gas, drive the foam slag, and discharge the ladle. The phosphorus content in the steel is reduced, and the steel slag is not easy to return to the phosphorus into the molten steel. Of course, in the case of oxygen blowing, low melting point substances Zinc and lead can also be discharged from molten steel, and the content of N, H, and B in molten steel is also effectively reduced.

Optionally, after tapping, continue to blow argon and add a deoxidizer to the ladle. The deoxidizer includes aluminum particles and/or silicon aluminum calcium.

Optionally, when the deoxidizer is aluminum particles, the added amount of aluminum particles is (1.5-3.0) Kg/ton steel.

Optionally, when the deoxidizer is calcium silicon aluminum oxide, the amount of calcium silicon aluminum oxide added is (3-6) Kg/ton steel.

Optionally, when the deoxidizer is aluminum particles and silicon-aluminum-calcium, the addition amount of aluminum particles is (1.3-2.0) Kg/ton steel, and the addition amount of silicon-aluminum calcium is (1.0-1.5) Kg/ton steel. Yes, the addition amount of aluminum particles is (1.5-1.7) Kg/ton steel, and the addition amount of silicon aluminum calcium is (1.1-1.3) Kg/ton steel.

Optionally, the melting of the charge is carried out in an intermediate frequency furnace. Optionally, the intermediate frequency furnace station and the ladle station share a dust removal system.

The features and performance of the present disclosure will be described in detail below.

Example 1: Add iron oxide powder in the furnace

Take the furnace number Z115012300340 as an example, the target steel grade Q345C is smelted, and the target steel grade weight is 50 tons. The smelting process is as follows:

1. In the intermediate frequency furnace, the type and ratio of scrap steel are:

Broken material: galvanized iron sheet briquetting: pig iron = 10:39:1;

2. Process sampling and feeding: Sampling when 25 tons of scrap steel is melted, calculated according to weight percentage, sampling composition includes: C: 0.18%, Si: 0.14%, Mn: 0.35%, P: 0.028%, S: 0.023%, Zn: 0.148%, Pb: 0.0012%; then add four batches of iron oxide powder at 50kg/batch between 25 tons and 40 tons, and then add 60kg iron oxide powder for the fifth time, adding iron oxide in total Powder 260Kg; throughout the adding process, the scrap type and ratio remain unchanged;

3. End-point sampling: After the furnace is charged, the temperature is increased to 1660°C and calculated according to weight percentage. The sampling components include: C: 0.11%, Si: 0.05%, Mn: 0.23%, P: 0.027%, S: 0.023%, Zn: 0.034%, Pb: 0.0003%;

4. Intermediate frequency furnace slagging: before tapping, add 40Kg of fluorite ball to the furnace to make the slag thinner, and then carry out slagging operation. The slagging process can use slagging, and the thickness of the slag layer is controlled within 10mm;

5. Steel tapping operation: During the tapping process, argon is blown to the bottom of the ladle, the pressure of argon is 0.6Mpa, and the flow rate is 3000L/min; in the process of pouring steel into the ladle, 500kg of lime is added to the ladle with the help of high temperature and stirring. Melt the slag; add 150Kg of light burned dolomite with molten steel. The main component of light burned dolomite is MgO, and the main component of ladle material is also MgO. Therefore, adding light burned dolomite can reduce the degree of corrosion of the ladle. At the same time, add light burned dolomite Stone has the function of adjusting the viscosity of the slag;

6. Deoxidation of steel and slag: after tapping, maintain the argon blowing state, add 80kg of aluminum particles and 60kg of silicon aluminum calcium into the ladle, and turn off the argon after blowing argon for 5 minutes;

7. Lift the molten steel to the LF refining furnace for normal refining operations. The purpose of LF furnace refining is to improve the effect of deoxidation, desulfurization, alloying, heating and removing inclusions.

Example 2: Add iron oxide powder to the ladle

Take the furnace number Z115012300341 as an example, the target steel grade Q345C is smelted, and the target steel grade weight is 50 tons. The smelting process is as follows:

1. The type and proportion of scrap steel added to the intermediate frequency furnace are: crushed material: galvanized iron sheet briquette: pig iron = 8:41:1;

2. Process sampling and feeding: Sampling when 25 tons of scrap steel is melted, calculated according to weight percentage, sampling composition includes: C: 0.16%, Si: 0.17%, Mn: 0.39%, P: 0.023%, S: 0.023%; Add 20Kg recarburizer for recarburization operation, continue to feed to the full furnace, the purpose of adding recarburizer is because the carbon content of molten steel is relatively low, appropriately increasing the recarburizer can increase the carbon content in molten steel, so that sufficient deoxidation is produced. The amount of carbon monoxide enhances the ability to remove zinc;

3. End-point sampling: After the furnace is charged, the temperature is raised to 1681℃, calculated according to weight percentage, the sampling components include: C: 0.20%, Si: 0.16%, Mn: 0.48%, P: 0.026%, S: 0.021%, Zn: 0.134%, Pb: 0.0009%; the temperature of molten steel is relatively high, which can ensure that when the lower ladle is deoxidized, the molten steel in the ladle can still have a higher temperature;

4. Intermediate frequency furnace slagging: before tapping, add 40Kg of fluorite ball to the furnace to make the slag thinner, and then carry out slagging operation. The slagging process can use slagging, and the thickness of the slag layer is controlled within 10mm;

5. Dezincification during tapping: During tapping, argon is blown to the bottom of the ladle, the pressure of argon is 0.8MPa, and the flow rate is 3500L/min; during the process of pouring steel into the ladle, lime is added to the ladle when the ladle sees red. 500kg, with the help of high temperature and stirring to melt the slag; in the process of adding lime, at the same time, 180Kg of light burned dolomite is added with molten steel. The main component of light burned dolomite is MgO, and the main component of ladle material is also MgO, so add light burned dolomite Stone can reduce the degree of corrosion of the ladle. At the same time, adding light-burned dolomite has the effect of adjusting the viscosity of the slag; adding 340kg of iron oxide powder evenly with the steel flow, it is obvious that a violent carbon-oxygen reaction and a large amount of white smoke are produced. Mainly zinc oxide.

6. Deoxidation of steel and slag: after tapping, ensure that the argon is blown, add 90kg of aluminum particles and 60kg of silicon-aluminum calcium to the ladle, and turn off the argon after blowing argon for 5 minutes; add 40Kg of carbonized rice husk covering agent to cover the molten steel evenly Surface, in order to play the role of heat preservation;

7. Ladle sampling: after dezincification, calculated by weight percentage, the components of the ladle sampling include: C: 0.12%, Si: 0.07%, Mn: 0.39%, P: 0.026%, S: 0.020%, Zn: 0.0315%, Pb : 0.0003%;

8. Lift the molten steel to the LF refining furnace for normal refining operations.

Example 3: Add iron oxide powder to the furnace and ladle separately

Taking the furnace number Z215012400352 as an example, the target steel grade Q345C is smelted, and the target steel grade weight is 50 tons. The smelting process is as follows:

1. The type and proportion of scrap steel added to the intermediate frequency furnace are: crushed material: galvanized iron sheet briquette: pig iron: other = 5:39:1:5;

2. Process sampling and feeding: take samples when the scrap is melted at about 25 tons, calculated according to weight percentage, the sampling components include: C: 0.26%, Si: 0.22%, Mn: 0.46%, P: 0.025%, S: 0.023%; Then, the iron oxide powder is evenly added in 50kg/batch between 25 tons and 40 tons. A total of 3 batches of 150Kg iron oxide powder are added. Throughout the joining process, the type and ratio of scrap steel remain unchanged;

3. Sampling at the end point: After the furnace is charged and heated to 1678°C, calculated by weight percentage, the sampling components include: C: 0.22%, Si: 0.14%, Mn: 0.43%, P: 0.025%, S: 0.024%, Zn: 0.120%, Pb: 0.0008%;

4. Intermediate frequency furnace slag discharge: 30Kg of fluorite balls are added to the intermediate frequency furnace before tapping to make the slag thinner, and then the slagging operation is performed. The slagging process can be coordinated with slagging, and the thickness of the slag layer is controlled within 10mm;

5. Dezincification during tapping: In the tapping process, argon is blown to the bottom of the ladle, the pressure of argon is 0.8MPa, and the flow rate is 3500L/min; during the process of pouring steel into the ladle, the ladle starts to add to the ladle with the flow of steel 500kg of lime, melt the slag with the help of high temperature and stirring; in the process of adding lime, 380kg of iron oxide powder is uniformly added with the steel flow at the same time. The amount of iron oxide powder added here is relatively large because the carbon content in the molten steel is too high. By adding more iron oxide powder, more carbon monoxide can be produced, and more zinc and lead in the molten steel can be removed; a violent carbon-oxygen reaction and a large amount of white smoke can be clearly observed;

6. Deoxidation of steel and slag: after tapping, ensure that the argon is blown, add 100kg of aluminum particles and 60kg of silicon-aluminum calcium into the ladle. After blowing argon for 5 minutes, turn off the argon; add 40Kg of carbonized rice husk covering agent to evenly cover the molten steel Surface, in order to play the role of heat preservation;

7. Ladle sampling: after dezincification, calculated by weight percentage, the components of the ladle sampling include: C: 0.11%, Si: 0.06%, Mn: 0.38%, P: 0.025%, S: 0.023%, Zn: 0.021%, Pb : 0.0004%;

8. Lift the molten steel to the LF refining furnace for normal refining operations.

Example 4: Ladle oxygen blowing

Taking the furnace number Z215012500365 as an example, the target steel grade Q345D is smelted, and the target steel grade weight is 50 tons. The smelting process is as follows:

1. Add scrap steel to the intermediate frequency furnace. The type and ratio of scrap steel are: crushed material: galvanized iron sheet briquetting: pig iron: other = 5: 39: 1.5: 4.5;

2. Process sampling and feeding: Sampling when the loading amount is 25 tons, calculated according to weight percentage, the sampling components include: C: 0.23%, Si: 0.12%, Mn: 0.46%, P: 0.024%, S: 0.027% . Keep the type and proportion of scrap steel unchanged, and add materials to the full furnace;

3. End-point sampling: After the furnace has been charged and heated to 1640°C, calculated in terms of weight percentage, the sampling components include: C: 0.25%, Si: 0.14%, Mn: 0.35%, P: 0.028%, S: 0.023%, Zn: 0.153%, Pb: 0.0010%;

4. Intermediate frequency furnace slagging: before tapping, add 40Kg of fluorite ball to the furnace to make the slag thinner, and then carry out slagging operation. The slagging process can use slagging, and the thickness of the slag layer is controlled within 10mm;

5. Steel tapping operation: During the tapping process, keep argon blowing at the bottom of the ladle. The argon pressure is 0.6Mpa and the flow rate is 3000L/min. During the process of pouring steel into the ladle, the ladle will see red and start adding 1000kg of lime to the ladle with the steel flow. The slag is melted with the help of high temperature and stirring, and a relatively large amount of lime is added here to obtain a relatively high slag basicity, thereby obtaining a better dephosphorization effect;

6. Lifting ladle: Lifting molten steel to the ladle oxygen blowing station, and measuring 1572℃ at the station;

7. Ladle oxygen blowing: argon is blown at the bottom of the ladle, the argon pressure is 0.6Mpa, and the flow is 3000L/min; the top of the ladle is blown with oxygen, the oxygen pressure is controlled at (0.8-1.5) MPa, and the oxygen flow: (500-600) m ³ /h, the gun position is at (-10-10) cm; 50Kg of fluorite ball is added to slag during oxygen blowing, and the total oxygen supply time is 17 minutes;

8. End-point slag discharge: At the end of the blowing, tilt the ladle about 30°, adjust the oxygen pressure to 1.3MPa, and add 25kg of special carbon powder. During this process, the steel slag foams rapidly, causing the slag to quickly overflow from the ladle mouth; The slag discharge rate is about 85%;

9. Deoxygenation of steel and slag: after oxygen blowing, ensure the argon blowing state, add 20kg of aluminum pellets into the ladle, after blowing argon for 5 minutes, turn off the argon; To heat preservation;

10. Sampling for end-point temperature measurement: the temperature is measured at 1578°C, calculated according to weight percentage, the sampling components include: C: 0.08%, Si: 0.01%, Mn: 0.24%, P: 0.007%, S: 0.023%, Zn: 0.017% , Pb: 0.0002%;

11. Lift the molten steel to the LF refining furnace for normal refining operations.

Example 5: Add iron oxide powder while blowing oxygen into the ladle

Take the furnace number Z115012500364 as an example, the target steel grade weight is 50 tons, and the target steel grade Q345E is smelted. The smelting process is as follows:

1. Add scrap steel to the intermediate frequency furnace. The type and proportion of scrap steel are: crushed material: galvanized iron sheet briquette: pig iron: other = 5:39:1:5;

2. Process sampling and feeding: Sampling when the loading amount is 25 tons, calculated according to weight percentage, the sampling components include: C: 0.22%, Si: 0.18%, Mn: 0.33%, P: 0.029%, S: 0.018% , Zn: 0.146%, Pb: 0.0008%. Keep the type and proportion of scrap steel unchanged, and add materials to the full furnace;

3. End-point sampling: After the furnace is charged, the temperature is increased to 1653°C and calculated according to weight percentage. The sampling components include: C: 0.24%, Si: 0.16%, Mn: 0.39%, P: 0.028%, S: 0.020%, Zn: 0.144%, Pb: 0.0008%;

4. Intermediate frequency furnace slagging: before tapping, add 40Kg of fluorite ball to the furnace to make the slag thinner, and then carry out slagging operation. The slagging process can use slagging, and the thickness of the slag layer is controlled within 10mm;

5. Steel tapping operation: During the whole tapping process, argon is blown at the bottom of the ladle, the argon pressure is 0.6kpa, and the flow rate is 3000L/min; during the process of pouring steel into the ladle, when the ladle starts to see red, add lime 950kg into the ladle along with the steel flow , With the help of high temperature and stirring to melt the slag;

6. Lifting ladle: Lifting molten steel to the ladle oxygen blowing station, and measuring 1575℃ at the station;

7. Ladle oxygen blowing: argon is blown at the bottom of the ladle, the argon pressure is 0.6Mpa, and the flow is 2900L/min; the top of the ladle is blown with oxygen, the oxygen pressure is controlled at (0.8-1.5) MPa, and the oxygen flow: (500-600) m ³ /h, the gun position is at (-10-10)cm; during the oxygen blowing process, 60Kg of fluorite ball is added to slag, and an appropriate amount of iron oxide powder is added at the same time. The iron oxide powder is added in one batch every 1-2 minutes, and each batch is added Iron oxide powder 40Kg, add 4 batches of 160Kg; total oxygen supply time 14min;

8. End-point slag discharge: At the end of the blowing, tilt the ladle about 30°, adjust the oxygen pressure to 1.3 MPa, and add 25kg of calcium carbide at the same time. During this process, the steel slag foams rapidly and overflows from the mouth of the ladle. The slag discharge rate is about 90 %;

9. Deoxygenation of steel and slag: after oxygen blowing, ensure the argon blowing state, add 25kg aluminum pellets into the ladle, after blowing argon for 5 minutes, turn off the argon; evenly add carbonized rice husk covering agent 40Kg to evenly cover the surface of molten steel. To heat preservation;

10. End point temperature measurement sampling: temperature measurement 1570℃, calculated according to weight percentage, sampling components include: C: 0.06%, Si: 0.01%, Mn: 0.23%, P: 0.006%, S: 0.021%, Zn: 0.0097, Pb: 0.0002;

11. Lift the molten steel to the LF refining furnace for normal refining operations.

In summary, the present disclosure provides a method for smelting high-quality steel using zinc-containing waste steel. The method includes the following steps: melting furnace charge including zinc-containing waste material to obtain molten steel, and adjusting the carbon content of the molten steel to be greater than the target steel type When the molten steel is poured into the ladle, argon is blown to the bottom of the ladle, and lime is added with the steel flow to form an alkaline slag; in an oxidizing environment, the carbon in the molten steel is oxidized to generate gas to escape . In the above reaction process, the iron oxide powder or oxygen in the oxidizing environment reacts with the carbon in the molten steel to release a large amount of carbon monoxide gas. During the release process, the carbon monoxide gas drives the volatile substances such as zinc and lead to evaporate. Into the dust removal system, the harmful components such as zinc and lead in the steel are removed, thereby obtaining a high-quality steel.

The embodiments described above are part of the embodiments of the present disclosure, but not all of the embodiments. The detailed description of the embodiments of the present disclosure is not intended to limit the scope of the claimed present disclosure, but merely represents selected embodiments of the present disclosure. Based on the embodiments in the present disclosure, all other embodiments obtained by those of ordinary skill in the art without creative work shall fall within the protection scope of the present disclosure.

Industrial applicability:

In summary, the present disclosure provides a method for smelting high-quality steel using zinc-containing scrap steel, and the steel obtained by smelting is of high quality.

Claims (16)

A method for smelting high-quality steel using zinc-containing scrap steel, which is characterized in that it comprises the following steps: Melt the charge including zinc-containing waste, and adjust the carbon content of molten steel to be greater than the carbon content of the target steel; During the process of pouring molten steel into the ladle, blow argon to the bottom of the ladle all the way, and add lime along with the steel flow to form alkaline slag; An oxidizing environment is created, so that the carbon in the molten steel undergoes oxidation reaction to generate gas to escape. The method for smelting high-quality steel using zinc-containing scrap steel according to claim 1, characterized in that, during the melting process of the charge: by adjusting the structure of the scrap steel or adding a recarburizer, the carbon content in the molten steel is greater than the target The carbon content of steel; Preferably, the carbon content in the molten steel is adjusted to be greater than 0.12%, preferably greater than 0.15%, and more preferably (0.18-0.28)%. The method for smelting high-quality steel using zinc-containing scrap steel according to claim 1 or 2, further comprising: adding fluorite balls to the molten steel for slagging after the charge is melted and before tapping. Yes, the added amount of the fluorite ball is (0.6-1.0) Kg/ton steel, and the thickness of the retained slag layer is not more than 10mm. The method for smelting high-quality steel using zinc-containing scrap steel according to any one of claims 1-3, wherein the oxidation environment is provided by the following steps: adding iron oxide powder with the charge, and/or In the process of pouring molten steel into the ladle, add iron oxide powder along with the steel flow; Preferably, the step of adding iron oxide powder along with the charge includes adding the charge while adding iron oxide powder when the charge is half melted. Preferably, the iron oxide powder is added in batches, and the total added amount is (2-10) Kg/ton steel, more preferably, the total added amount of iron oxide powder is (7-10) Kg/ton steel; Preferably, during the process of pouring the molten steel into the ladle, iron oxide powder is added with the steel flow. Preferably, the iron oxide powder added to the ladle with the steel flow is (2-12) Kg/ton steel, more preferably, The amount of iron oxide powder added is (7-10) Kg/ton steel. The method for smelting high-quality steel using zinc-containing scrap steel according to claim 4, wherein the step of adding iron oxide powder with the charge includes adding the iron oxide powder every (1-2) minutes One batch, the first four batches each add 40Kg iron oxide powder, and the fifth batch add 60kg iron oxide powder. The method for smelting high-quality steel by using zinc-containing scrap steel according to claim 4 or 5, wherein the step of blowing argon to the bottom of the ladle and adding lime along with the steel flow to form alkaline slag includes: During the process of pouring molten steel into the ladle, argon is blown to the bottom of the ladle all the way, the pressure of the argon blowing is (0.3-0.8) MPa, more preferably, the pressure is (0.4-0.6) MPa; The amount of lime added is (6-15) Kg/ton steel, preferably, the amount of lime added is (8-12K) g/ton steel; more preferably, it is added with the steel flow (2-4 ) Kg/ton steel light burnt dolomite. The method for smelting high-quality steel using zinc-containing scrap steel according to any one of claims 1 to 3, wherein the oxidizing environment is provided by the following steps: After pouring the molten steel into the ladle, blowing oxygen on the top of the ladle, or blowing oxygen on the top of the ladle, and adding iron oxide powder to the ladle; Preferably, the oxygen supply intensity for blowing oxygen to the top of the ladle is (50-300)NL/(min·t), the pressure is (0.5-2.0) MPa, and preferably, the oxygen supply intensity is (100-150) )NL/(min·t), the pressure is (0.8-1.2) MPa, the oxygen blowing time is (10-20) minutes, more preferably, (0.5-1.5) Kg/ton steel fluorite is added during the oxygen blowing process ； Preferably, iron oxide powder is added to the ladle, and the iron oxide powder is added in one batch every (1-2) minutes, 40Kg iron oxide powder is added in each batch, and 4 batches of iron oxide with a total weight of 160Kg are added. powder. The method for smelting high-quality steel by using zinc-containing scrap steel according to claim 7, wherein the step of blowing oxygen on the top of the ladle comprises: during the tapping process, keeping the bottom of the ladle blowing argon, and after the tapping, the ladle is transferred Enter the oxygen blowing station; during the top oxygen blowing of the ladle, fluorite can be added, and iron oxide powder can also be added during the oxygen blowing process; at the end of the oxygen blowing, the ladle is tilted, and foam generators are added, and then deoxidizers are added; After the argon blowing is finished, turn off the argon gas, add the carbonized rice husk covering agent, and lift the molten steel to the LF refining furnace for normal refining operations; Preferably, the ladle is inclined 10°-35° to the direction of the ladle mouth; Preferably, after the deoxygenation, continue to blow argon for (3-5) minutes and turn off the argon; Preferably, the added amount of the carbonized rice husk covering agent is (0.6-1.0) Kg/ton steel; Preferably, the foam generating agent includes carbon powder and/or calcium carbide. More preferably, when the foam generating agent is selected from carbon powder, the addition amount of the carbon powder is (0.3-0.5) Kg/ton steel, so When the foam generating agent is selected from calcium carbide, the addition amount of the calcium carbide is (0.4-0.6) Kg/ton steel; the foam generating agent is selected from carbon powder and calcium carbide, and the addition amount of the carbon powder is (0.2-0.4) ) Kg/ton of steel, the added amount of calcium carbide is (0.1-0.2) Kg/ton of steel, optionally, when the foam generating agent is selected from carbon powder and calcium carbide, the carbon powder is added first, and then the Calcium carbide. The method for smelting high-quality steel using zinc-containing scrap steel according to claim 7 or 8, wherein the step of blowing argon to the bottom of the ladle and adding lime along with the steel flow to form alkaline slag includes: During the ladle pouring process, the pressure of the argon blowing is (0.3-0.8) MPa, more preferably, the pressure is (0.4-0.6) MPa; The added amount of lime is (8-20) Kg/ton steel, preferably, the added amount of lime is (15-20) Kg/ton steel. The method for smelting high-quality steel using zinc-containing scrap steel according to any one of claims 1-9, further comprising: after tapping is completed, argon blowing is continued, and a deoxidizer is added to the ladle. The agent includes aluminum particles and/or silicon aluminum calcium; Preferably, when the deoxidizer is aluminum particles, the added amount of the aluminum particles is (1.5-3.0) Kg/ton steel; Preferably, when the deoxidizer is calcium silicon aluminum oxide, the amount of calcium silicon aluminum oxide added is (3-6) Kg/ton steel; Preferably, when the deoxidizer is aluminum particles and silicon aluminum calcium, the addition amount of the aluminum particles is (1.3-2.0) Kg/ton steel, and the addition amount of the silicon aluminum calcium is (1.0-1.5) Kg Per ton of steel, more preferably, the addition amount of the aluminum particles is (1.5-1.7) Kg/ton steel, and the addition amount of the silicon aluminum calcium is (1.1-1.3) Kg/ton steel. The method for smelting high-quality steel using zinc-containing scrap steel according to any one of claims 1-10, wherein the melting of the charge is carried out in an intermediate frequency furnace, and the intermediate frequency furnace station and the ladle worker Bits share a dust removal system. The method for smelting high-quality steel using zinc-containing scrap steel according to claim 1, characterized in that it comprises: In the intermediate frequency furnace, add the ratio of crushed material: galvanized iron sheet briquetting: pig iron = 10:39:1 scrap; After the scrap is melted to the set weight, take samples. Calculated by weight percentage, the sampled components include: C: 0.18%, Si: 0.14%, Mn: 0.35%, P: 0.028%, S: 0.023%, Zn: 0.148%, Pb ：0.0012%; then add four batches of iron oxide powder evenly at 50kg/batch between 25 tons and 40 tons; After the furnace is charged, the end point sampling is performed when the temperature is raised to the set temperature. The sampling composition includes: C: 0.11%, Si: 0.05%, Mn: 0.23%, P: 0.027%, S: 0.023 %, Zn: 0.034%, Pb: 0.0003%; Add fluorite balls to the furnace before tapping to make the slag thinner, and then carry out the slag discharge operation, the thickness of the slag layer is controlled within 10mm; During the tapping process, argon is blown to the bottom of the ladle during the whole process; After tapping is finished, maintain the argon blowing state, add aluminum particles and silicon aluminum calcium to the ladle, and turn off the argon after maintaining the argon blowing for a set time; Lift the molten steel to the LF refining furnace for normal refining operations. The method for smelting high-quality steel using zinc-containing scrap steel according to claim 1, characterized in that it comprises: In the intermediate frequency furnace, add the ratio of crushed material: galvanized iron sheet briquetting: pig iron = 8:41:1 scrap; Sampling after melting and setting the weight of scrap steel, calculated by weight percentage, the sampling components include: C: 0.16%, Si: 0.17%, Mn: 0.39%, P: 0.023%, S: 0.023%; adding recarburizer for recarburization Operation, continue to feed until the furnace is full; After the furnace is charged, the end point sampling is performed when the temperature is raised to the set temperature. Calculated by weight percentage, the sampling components include: C: 0.20%, Si: 0.16%, Mn: 0.48%, P: 0.026%, S: 0.021%, Zn: 0.134%, Pb: 0.0009%; Add fluorite balls to the furnace before tapping to make the slag thinner, and then carry out the slag discharge operation, the thickness of the slag layer is controlled within 10mm; During the tapping process, argon is blown to the bottom of the ladle during the whole process; After tapping is finished, maintain the argon blowing state, add aluminum particles and silicon aluminum calcium to the ladle, and turn off the argon after maintaining the argon blowing for a set time; After the dezincification is completed, the ladle sampling is carried out. Calculated by weight percentage, the components of the ladle sampling include: C: 0.12%, Si: 0.07%, Mn: 0.39%, P: 0.026%, S: 0.020%, Zn: 0.0315%, Pb : 0.0003%; Lift the molten steel to the LF refining furnace for normal refining operations. The method for smelting high-quality steel using zinc-containing scrap steel according to claim 1, characterized in that it comprises: In the intermediate frequency furnace, add the proportion of crushed material: galvanized iron sheet briquetting: pig iron: other = 5:39:1:5 scrap; After the scrap is melted and the weight is set, the sampling is calculated according to the weight percentage. The sampling components include: C: 0.26%, Si: 0.22%, Mn: 0.46%, P: 0.025%, S: 0.023%; then the loading amount is 25 Between ton and 40 tons, add iron oxide powder evenly according to 50kg/batch; After the furnace is charged, the end point sampling is performed when the temperature is raised to the set temperature. The sampling composition includes: C: 0.22%, Si: 0.14%, Mn: 0.43%, P: 0.025%, S: 0.024 %, Zn: 0.120%, Pb: 0.0008%; Add fluorite balls to the intermediate frequency furnace before tapping to make the slag thinner, and then carry out the slag discharge operation, and the thickness of the slag layer is controlled within 10mm; During the tapping process, argon is blown to the bottom of the ladle during the whole process; After tapping, keep the argon blowing state, add aluminum particles and silicon aluminum calcium into the ladle, keep the argon blowing for a set time, then turn off the argon; then, add the carbonized rice husk covering agent to evenly cover the surface of the molten steel; After the dezincification is completed, the ladle sampling is performed. Calculated by weight percentage, the components of the ladle sampling include: C: 0.11%, Si: 0.06%, Mn: 0.38%, P: 0.025%, S: 0.023%, Zn: 0.021%, Pb : 0.0004%; Lift the molten steel to the LF refining furnace for normal refining operations. The method for smelting high-quality steel using zinc-containing scrap steel according to claim 1, characterized in that it comprises: In the intermediate frequency furnace, add scrap steel with the ratio of crushed material: galvanized iron sheet briquetting: pig iron: other=5:39:1.5:4.5; Sampling after melting and setting the weight of scrap steel, calculated according to weight percentage, sampled components include: C: 0.23%, Si: 0.12%, Mn: 0.46%, P: 0.024%, S: 0.027%; After the furnace is charged, the end point sampling is performed when the temperature is raised to the set temperature. The sampling composition includes: C: 0.25%, Si: 0.14%, Mn: 0.35%, P: 0.028%, S: 0.023 %, Zn: 0.153%, Pb: 0.0010%; Add fluorite balls to the intermediate frequency furnace before tapping to make the slag thinner, and then carry out the slag discharge operation, and the thickness of the slag layer is controlled within 10mm; During the tapping process, argon is blown to the bottom of the ladle during the whole process; Lift the molten steel to the ladle oxygen blowing station for oxygen blowing on the top of the ladle; At the end of blowing, tilt the ladle, adjust the oxygen pressure, and add carbon powder at the same time; After oxygen blowing, keep the argon blowing state, add aluminum pellets into the ladle, keep the argon blowing for a set time, then turn off the argon; then, add the carbonized rice husk covering agent to evenly cover the molten steel surface; End-point temperature measurement sampling; calculated by weight percentage, sampling components include: C: 0.08%, Si: 0.01%, Mn: 0.24%, P: 0.007%, S: 0.023%, Zn: 0.017%, Pb: 0.0002%; Lift the molten steel to the LF refining furnace for normal refining operations. The method for smelting high-quality steel using zinc-containing scrap steel according to claim 1, characterized in that it comprises: In the intermediate frequency furnace, add the ratio of crushed material: galvanized iron sheet briquetting: pig iron: other = 5:39:1:5 scrap; Sampling after melting and setting the weight of scrap steel, calculated by weight percentage, the sampled components include: C: 0.22%, Si: 0.18%, Mn: 0.33%, P: 0.029%, S: 0.018%, Zn: 0.146%, Pb: 0.0008%; After the furnace is charged, the end point sampling is performed when the temperature is raised to the set temperature. Calculated by weight percentage, the sampling components include: C: 0.24%, Si: 0.16%, Mn: 0.39%, P: 0.028%, S: 0.020 %, Zn: 0.144%, Pb: 0.0008%; Add fluorite balls to the intermediate frequency furnace before tapping to make the slag thinner, and then carry out the slag discharge operation, and the thickness of the slag layer is controlled within 10mm; During the whole tapping process, argon is blown at the bottom of the ladle, and then the molten steel is lifted to the ladle oxygen blowing station for oxygen blowing at the top; At the end of blowing, tilt the ladle, adjust the oxygen pressure, and add carbon powder at the same time; After oxygen blowing, keep the argon blowing state, add aluminum pellets into the ladle, keep the argon blowing for a set time, then turn off the argon; then, add the carbonized rice husk covering agent to evenly cover the molten steel surface; End point temperature measurement sampling; calculated by weight percentage, the sampling components include: C: 0.06%, Si: 0.01%, Mn: 0.23%, P: 0.006%, S: 0.021%, Zn: 0.0097, Pb: 0.0002; Lift the molten steel to the LF refining furnace for normal refining operations.