CN114438284A - Electric furnace smelting method for hot charging direct reduced iron - Google Patents
Electric furnace smelting method for hot charging direct reduced iron Download PDFInfo
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- CN114438284A CN114438284A CN202210014466.1A CN202210014466A CN114438284A CN 114438284 A CN114438284 A CN 114438284A CN 202210014466 A CN202210014466 A CN 202210014466A CN 114438284 A CN114438284 A CN 114438284A
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- Prior art keywords
- furnace
- reduced iron
- electric
- direct reduced
- carbon
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Classifications
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C5/00—Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
- C21C5/52—Manufacture of steel in electric furnaces
- C21C5/5211—Manufacture of steel in electric furnaces in an alternating current [AC] electric arc furnace
- C21C5/5217—Manufacture of steel in electric furnaces in an alternating current [AC] electric arc furnace equipped with burners or devices for injecting gas, i.e. oxygen, or pulverulent materials into the furnace
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C5/00—Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
- C21C5/52—Manufacture of steel in electric furnaces
- C21C5/54—Processes yielding slags of special composition
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
- C21C7/0025—Adding carbon material
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
- C21C7/0037—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00 by injecting powdered material
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C2300/00—Process aspects
- C21C2300/02—Foam creation
Abstract
The invention discloses an electric furnace smelting method of hot charging direct reduced iron, which comprises the following steps: adding a metal mixture of scrap steel and direct reduced iron into an electric furnace, smelting the metal material by adopting an electric arc furnace, and sequentially adding a slagging flux in the smelting process; the metal mixture comprises scrap steel and direct reduced iron, wherein the direct reduced iron is hot-charged; the specific process of smelting the metal material by adopting the electric arc furnace comprises the following steps: the arc striking period supplies power to the electric arc furnace; after the arc striking period is finished, supplying power to the scrap steel, and preheating the scrap steel by using a furnace wall burner; stopping the furnace wall burner after 75-85% of the metal mixture supplied to the electric arc furnace is melted, and spraying carbon by using a carbon-oxygen gun to make foamed slag until the melting period is finished; after the melting period is finished, continuing to supply power to the electric arc furnace for heating, and adopting a carbon-oxygen gun to supply oxygen and spray carbon to make foam slag; and finishing smelting until the power consumption meets the requirement, and executing tapping operation. The energy efficiency is improved, the electric energy and the electrode consumption of electric furnace smelting can be reduced, and the smelting cost is reduced.
Description
Technical Field
The invention relates to the technical field of metallurgy, in particular to an electric furnace smelting method for hot charging direct reduced iron.
Background
The key industry field pollution and carbon reduction actions are implemented, and the promotion of green manufacturing in the industry field is the core of the current work. The carbon emission of the steel industry accounts for about 15% of the total carbon emission of China, the carbon emission of the steel industry mainly comes from the processes of sintering, blast furnace iron making and the like, and the high carbon emission process is effectively avoided by the electric furnace short-flow steel making process, so that the development of the short-flow electric furnace process has important significance for the green development of the future steel process. However, the supply of the steel scraps is insufficient and the price is too high at present, so that the short-flow raw material supply cannot be effectively supported. Therefore, the process for producing the crude steel by the direct reduced iron and electric furnace through the gas-based reduction (including hydrometallurgy) shaft furnace is an important way for solving the problems of insufficient waste steel raw materials and emission of ton steel carbon, and the development of the steelmaking process flow is guided in the future.
At present, most domestic steel enterprises still have few electric furnace smelting processes taking direct reduced iron as a raw material, so the electric furnace smelting method taking the direct reduced iron as the raw material is provided, and the electric furnace smelting method has important significance for adapting to the influence of the change of metal raw materials on the electric furnace smelting process. The patent CN 10775460A discloses an electric furnace steelmaking method using 100% low-quality tunnel kiln direct reduced iron as a raw material, the invention takes the melting rate of the direct reduced iron of 85% -95% as a node, and reasonably adds main and auxiliary materials such as furnace burden, flux and the like, although the invention can guide the electric furnace production to a certain extent, the specific procedures of power supply, carbon supply, oxygen supply and the like are not described in detail. Patent CN 209338592U discloses a short-flow steelmaking production system of electric furnace, which adopts a steelmaking system of shaft furnace and electric furnace, and can directly send the hot direct reduced iron generated by the shaft furnace to the electric furnace for steelmaking operation, however, no patent and paper provide relevant operation processes at present, the invention mainly provides an electric furnace smelting method using the hot direct reduced iron as raw material.
Disclosure of Invention
The invention aims to solve the technical problem of providing an electric furnace smelting method for hot charging direct reduced iron, aiming at the defects in the prior art, improving the energy efficiency, reducing the electric energy and electrode consumption of electric furnace smelting and reducing the smelting cost.
The technical scheme adopted by the invention for solving the technical problems is as follows:
an electric furnace smelting method of hot charging direct reduced iron comprises the following steps: adding a metal mixture of scrap steel and direct reduced iron into an electric furnace, smelting the metal mixture by adopting an electric arc furnace, and sequentially adding a slagging flux in the smelting process; the metal mixture comprises scrap steel and direct reduced iron, wherein the direct reduced iron is hot-charged; the smelting process of the metal mixture by the electric arc furnace is sequentially divided into three stages, namely an arc striking stage, a melting stage and an oxidation heating stage;
the specific process of smelting the metal mixture by adopting the electric arc furnace comprises the following steps:
step 1, supplying power to an electric arc furnace in an arc starting period;
step 2, after the arc striking period is finished, continuing to supply power to the electric arc furnace, and preheating the scrap steel by using a furnace wall burner;
step 3, stopping the work of the furnace wall burner after 75-85% of the metal mixture supplied to the electric arc furnace is melted, and spraying carbon by using a carbon-oxygen gun to produce foam slag until the melting period is finished;
step 4, after the melting period is finished, continuing to supply power to the electric arc furnace for heating, and adopting a carbon-oxygen gun to supply oxygen to spray carbon to make foamed slag;
and 5, finishing smelting until the power consumption of the electric arc furnace meets the requirement, and executing tapping operation.
According to the technical scheme, the proportion of the scrap steel in the added metal mixture is 40-60%, the proportion of the direct reduced iron is 40-60%, and the direct reduced iron is hot-charged.
According to the technical scheme, the temperature of the hot-charged direct reduced iron is 500-700 ℃.
According to the technical scheme, in the step 3, after the ton steel electric energy of the electric arc furnace is consumed at 220-260 kWh/t, the furnace wall burner operation is stopped, the electric arc furnace enters the final stage of melting, and the carbon oxygen lance is started to supply oxygen to spray carbon for foaming slag.
According to the technical scheme, in the step 3, the carbon spraying and slagging time is controlled to be 4-6 min at the final stage of melting, and the spraying flow rate of the sprayed powder is 30-50 kg/min.
According to the technical scheme, in the step 3, after the power consumption per ton of steel reaches 290-330 kWh/t, the first package of mixed metal furnace burden is melted, and the second package of mixed metal furnace burden is added;
and (3) repeating the steps 1-3 in the melting process of the second-package mixed metal material until the power consumption per ton of steel reaches 290-330 kWh/t, and ending the melting period.
According to the technical scheme, in the step 4, after the melting period is finished, a carbon oxygen lance is used for supplying oxygen to spray carbon to produce foam slag, the spraying flow rate of the sprayed powder is 40-60 kg/min, the carbon powder spraying time is 8-10 min, and after the power consumption per ton of steel reaches 380-420 kWh/t, the tapping operation is carried out.
According to the technical scheme, the amount of the blown carbon powder is 6-8 kg/t molten steel.
According to the technical scheme, lime and dolomite are added in batches in the whole smelting process, the addition amount of the lime is 40-50 kg/t molten steel, and the addition amount of the dolomite is 25-35 kg/t molten steel.
According to the technical scheme, in the step 1, the arc furnace is powered by low-grade power in an arc starting period, wherein the low-grade power is 35% -45% of rated power of a transformer for powering the arc furnace;
in the steps 2 and 4, the electric arc furnace is powered by high-grade power, and the high-grade power is 60% -70% of rated power of a transformer for powering the electric arc furnace.
The invention has the following beneficial effects:
the invention is beneficial to improving the energy efficiency by controlling a reasonable carbon supply system and a reasonable power supply system, can reduce the electric energy and the electrode consumption of electric furnace smelting, and reduces the smelting cost.
Detailed Description
The present invention will be described in detail with reference to examples.
The electric furnace smelting method for the hot charging direct reduced iron in one embodiment provided by the invention comprises the following steps: before power supply, adding a metal mixture of scrap steel and direct reduced iron into an electric furnace, smelting the metal material by adopting an ultrahigh-power electric arc furnace, and sequentially adding a slagging flux in the smelting process; the metal mixture comprises scrap steel and direct reduced iron, wherein the direct reduced iron is hot-charged; the smelting process of the metal mixture by the electric arc furnace is sequentially divided into three stages, namely an arc striking stage, a melting stage and an oxidation heating stage;
the specific process of smelting the metal mixture by adopting the electric arc furnace comprises the following steps:
step 1, adopting lower power to supply power to an electric arc furnace in an arc starting period;
step 2, after the arc striking period is finished, supplying power to the electric arc furnace by adopting higher power, and preheating scrap steel by adopting a furnace wall burner;
step 3, stopping the furnace wall burner after 75-85% of the metal mixture is melted (the best choice in the specific embodiment is 80% of the metal mixture is melted) by supplying power to the electric arc furnace, and spraying carbon by using a carbon-oxygen gun to make foam slag until the melting period is finished;
step 4, after the melting period is finished, continuously adopting higher power to supply power to the electric arc furnace for heating, adopting a carbon-oxygen gun to supply oxygen to spray carbon for foaming slag, and entering an oxidation heating period;
and 5, finishing smelting until the power consumption of the electric arc furnace meets the requirement, and executing tapping operation.
Furthermore, the proportion of the scrap steel in the added metal mixture is 40-60%, the proportion of the direct reduced iron is 40-60%, and the direct reduced iron is hot charging.
Further, the temperature of the hot-charged direct reduced iron is 500-700 ℃.
Further, in the step 3, when the ton steel electric energy consumption of the electric arc furnace (ton steel electric energy consumption means the ratio of the electric energy consumption reached by the power supply of the electric arc furnace divided by the actual steel tapping amount of the electric arc furnace and the total adding amount of the waste steel at the moment) is 220-260 kWh/t, the furnace wall burner operation is stopped, the electric arc furnace enters the final stage of melting, and the carbon oxygen lance is started to supply oxygen to spray carbon for foam slag production.
Further, in the step 3, the carbon spraying and slagging time in the final stage of melting is controlled to be 4-6 min, and the spraying flow rate of the sprayed powder is 30-50 kg/min.
Further, in the step 3, after the ton steel power consumption reaches 290-330 kWh/t, the first package of mixed metal furnace burden is melted, and a second package of mixed metal furnace burden is added;
and (4) repeating the steps 1-3 in the melting process of the second package mixed metal material until the power consumption per ton steel reaches 290-330 kWh/t, and ending the melting period.
Further, in the step 4, after the melting period is finished, a carbon oxygen lance is used for supplying oxygen and spraying carbon to produce foam slag, the flow rate of spraying powder and spraying carbon powder is 40-60 kg/min, the time of spraying carbon powder is 8-10 min, and when the power consumption per ton of steel reaches 380-420 kWh/t, the tapping operation is executed.
Further, the amount of the blown carbon powder is 6-8 kg/t molten steel.
Furthermore, in the whole smelting process, lime and dolomite are added in batches, the addition amount of the lime is 40-50 kg/t molten steel (namely, 40-50 kg of lime is consumed by each ton of molten steel), and the addition amount of the dolomite is 25-35 kg/t molten steel (namely, 25-35 kg of dolomite is consumed by each ton of molten steel).
In the step 1, the arc furnace is powered by low-grade power in an arc starting period, wherein the low-grade power is 35% -45% of rated power of a transformer for powering the arc furnace;
in the steps 2 and 4, the electric arc furnace is powered by high-grade power, and the high-grade power is 60% -70% of rated power of a transformer for powering the electric arc furnace.
In one embodiment of the invention, the electric furnace comprises the following ingredients: the smelting steel is taken as common carbon structural steel, and particularly, the invention provides a smelting method of a hot charging direct reduction iron electric arc furnace, which comprises the following steps;
1. charging scrap steel and direct reduced iron into an electric arc furnace, and then supplying power to the electric arc furnace;
the method comprises the following steps of charging 50% of scrap steel and 50% of direct reduced iron before power supply, wherein the charging temperature of the direct reduced iron is 600 ℃, adding a first coating flux after power supply and arcing, wherein the total amount of lime and dolomite is 500-1000 kg per minute, and preheating and cutting the scrap steel by using a furnace wall burner;
2. and when the power consumption of the ton steel reaches 310kWh/t, ending the carbon injection, starting adding the second furnace burden, wherein the melting process of the second furnace burden is the same as that of the first furnace.
3. When the electric power is supplied to the ton steel with the power consumption of 310kWh/t, the melting period is ended, carbon powder is sprayed to the electric furnace at the flow rate of 52kg/min for 9min, and when the ton steel with the power consumption of 395kWh/t, the carbon spraying is ended, and the steel tapping operation is executed.
TABLE 1 electric furnace smelting parameters
The above is only a preferred embodiment of the present invention, and certainly, the scope of the present invention should not be limited thereby, and therefore, the present invention is not limited by the scope of the claims.
Claims (9)
1. An electric furnace smelting method of hot charging direct reduced iron is characterized by comprising the following steps: adding a metal mixture of scrap steel and direct reduced iron into an electric furnace, smelting the metal mixture by adopting an electric arc furnace, and sequentially adding a slagging flux in the smelting process;
the metal mixture comprises scrap steel and direct reduced iron, wherein the direct reduced iron is hot-charged; the smelting process of the metal mixture by the electric arc furnace is sequentially divided into three stages, namely an arc striking stage, a melting stage and an oxidation heating stage;
the specific process of smelting the metal mixture by adopting the electric arc furnace comprises the following steps:
step 1, supplying power to an electric arc furnace in an arc starting period;
step 2, after the arc striking period is finished, continuing to supply power to the electric arc furnace, and preheating the scrap steel by using a furnace wall burner;
step 3, stopping the work of a furnace wall burner after 75-85% of the metal mixture is melted after the electric arc furnace is powered, and spraying carbon by using a carbon-oxygen gun to make foam slag until the melting period is finished;
step 4, after the melting period is finished, continuing to supply power to the electric arc furnace for heating, and adopting a carbon-oxygen gun to supply oxygen to spray carbon to make foamed slag;
and 5, finishing smelting until the power consumption of the electric arc furnace meets the requirement, and executing tapping operation.
2. The electric furnace smelting method for hot charging direct reduced iron according to claim 1, wherein the proportion of scrap steel in the metal mixture is 40% to 60%, and the proportion of direct reduced iron is 40% to 60%.
3. The electric furnace smelting method for hot-charged direct reduced iron according to claim 2, wherein the temperature of the hot-charged direct reduced iron is 500 to 700 ℃.
4. The electric furnace smelting method for hot charging direct reduced iron according to claim 1, wherein in the step 3, after the ton steel electric energy consumption of the electric arc furnace is 220-260 kWh/t, the furnace wall burner operation is stopped, the electric arc furnace enters the melting end stage, and carbon oxygen lance oxygen supply and carbon spraying are started to produce the foamed slag.
5. The electric furnace smelting method for hot-charged direct reduced iron according to claim 4, wherein in the step 3, the time for carbon injection and slag formation at the final stage of melting is controlled to be 4 to 6min, and the injection flow rate of the injection powder is 30 to 50 kg/min.
6. The electric furnace smelting method for hot-charged direct reduced iron according to claim 4, wherein in the step 3, after the ton steel power consumption reaches 290-330 kWh/t, the first package of mixed metal charge is melted, and the second package of mixed metal charge is added;
and (3) repeating the steps 1-3 in the melting process of the second-package mixed metal material until the power consumption per ton of steel reaches 290-330 kWh/t, and ending the melting period.
7. The electric furnace smelting method for hot charging direct reduced iron according to claim 1, wherein in the step 4, after the melting period is over, a carbon oxygen lance is used for supplying oxygen to spray carbon to produce foamed slag, the spraying flow rate of the sprayed powder is 40-60 kg/min, the carbon powder spraying time is 8-10 min, and after the power consumption per ton of steel reaches 380-420 kWh/t, tapping operation is performed.
8. The electric furnace smelting method for hot charging direct reduced iron according to claim 1, wherein the amount of the blowing carbon powder is 6 to 8kg/t molten steel.
9. The electric furnace smelting method for hot-charged direct reduced iron according to claim 1, wherein lime and dolomite are added in batches in the whole smelting process, the addition amount of the lime is 40-50 kg/t molten steel, and the addition amount of the dolomite is 25-35 kg/t molten steel.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210014466.1A CN114438284A (en) | 2022-01-05 | 2022-01-05 | Electric furnace smelting method for hot charging direct reduced iron |
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| CN202210014466.1A CN114438284A (en) | 2022-01-05 | 2022-01-05 | Electric furnace smelting method for hot charging direct reduced iron |
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| CN202210014466.1A Pending CN114438284A (en) | 2022-01-05 | 2022-01-05 | Electric furnace smelting method for hot charging direct reduced iron |
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5946339A (en) * | 1997-07-22 | 1999-08-31 | Itz A Gaz, Inc. | Steelmaking process using direct reduction iron |
| WO2010106466A1 (en) * | 2009-03-18 | 2010-09-23 | Rafic Boulos Daou | Steel production facility |
| CN112430705A (en) * | 2020-11-24 | 2021-03-02 | 中冶南方工程技术有限公司 | Full scrap steel smelting method and equipment based on electric arc furnace |
-
2022
- 2022-01-05 CN CN202210014466.1A patent/CN114438284A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5946339A (en) * | 1997-07-22 | 1999-08-31 | Itz A Gaz, Inc. | Steelmaking process using direct reduction iron |
| WO2010106466A1 (en) * | 2009-03-18 | 2010-09-23 | Rafic Boulos Daou | Steel production facility |
| CN112430705A (en) * | 2020-11-24 | 2021-03-02 | 中冶南方工程技术有限公司 | Full scrap steel smelting method and equipment based on electric arc furnace |
Non-Patent Citations (2)
| Title |
|---|
| 姜钧普: "《钢铁生产短流程新技术——沙钢的实践》", 30 September 2000, 冶金工业出版社 * |
| 杨若仪 等: "《冶金燃气与钢铁新流程》", 30 June 2013, 上海科学技术文献出版社 * |
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