阅读说明：本技术 一种电弧炉冶炼钢配料工艺 (Electric arc furnace steelmaking batching process ) 是由 薛正国 高英丽 王怡群 宗健 雷冲 王学玺 祁跃峰 于 2020-07-29 设计创作，主要内容包括：本发明涉及一种电弧炉冶炼钢配料工艺,取消使用生铁,配料时在料的下层配入焦炭,上部配入废钢,或分层配入焦炭和废钢,在送电开始熔化时向配置焦炭的位置吹入氧气,在氧气供应充分的条件下焦炭可剧烈燃烧,提供大量的热能熔化大部分废钢,此时停电,仅靠供氧进行熔化操作,在废钢熔化的同时,当上部熔化的钢液向熔池聚集时会经过焦炭层,焦炭中的一部分碳渗入钢液,为钢液提供足够的炭含量,当废钢全部熔化后再对钢液进行氧化冶炼,完成去气、去夹杂的冶金任务,这种工艺在实际生产中,可以有效降低材料成本,同时还能节约大量的电能,保证冶炼过程去气、去夹杂和脱磷效果的。(The invention relates to a smelting and steelmaking batching process of an electric arc furnace, which cancels the use of pig iron, coke is added at the lower layer of the material during batching, scrap steel is added at the upper part of the material, or coke and scrap steel are added in layers, oxygen is blown into the position where the coke is arranged when power is supplied for melting, the coke can be violently combusted under the condition of sufficient oxygen supply, a large amount of heat energy is provided for melting most of the scrap steel, at the moment, power is cut off, melting operation is carried out only by supplying oxygen, the molten steel melted at the time of melting the scrap steel passes through a coke layer when the molten steel melted at the upper part is gathered to a molten pool, part of carbon in the coke permeates into the molten steel to provide enough carbon content for the molten steel, and oxidation smelting is carried out on the molten steel after the molten steel is completely melted, thereby completing the metallurgical tasks of degassing and degassing, and simultaneously saving a large amount of electric energy, ensuring degassing, Removing impurities and dephosphorizing effect.)

1. The utility model provides an electric-arc furnace smelts steel batching technology, and is different by various scrap steel and pig iron constitution with conventional electric-arc furnace smelting furnace charge, when batching according to batching proportion and the required carbon content of steel grade oxidation smelting calculation join in metallurgical coke, its characterized in that: the specific control parameters and modes are as follows:

1) when the materials are mixed in the electric arc furnace for steelmaking, the mixing amount of the coke is controlled within the range of 2-7% of the total steel materials according to different carbon contents of steel types;

2) and controlling the specific blending proportion: the method is characterized in that the coke addition amount is 2-3% of the total steel for steel grades with the upper limit of carbon content lower than 0.25%; for steel grades with the upper limit of carbon content of 0.26-0.60%, the addition amount of coke is 3-5% of the total steel materials; the addition of the rest steel is 5 to 7 percent of the total steel;

3) controlling the injection mode: the first mode is as follows: firstly, 10-20% of all steel materials are added to the lowest part of a material bag or a material basket according to the weight percentage, then all coke is added and is arranged at the central position of the material bag or the material basket, and finally, all the remaining steel materials are added to the upper part of the coke; the second mode is that coke and steel materials are added in layers from the lower part, no more than 3 layers are needed, and the uppermost layer is waste steel;

4) coke requirements: the first-grade metallurgical coke in GB/T1996 standard is selected, the granularity is 40-100mm, and the percentages are weight percentages.

2. The electric arc furnace steelmaking batching process as claimed in claim 1, wherein: the specific operation steps of smelting steel ingredients in the electric arc furnace are as follows:

step 1), closing a furnace cover after charging is finished, starting power supply, directly starting an oxygen lance on the furnace wall to blow oxygen if reserved molten steel exists in the furnace, igniting a self-consuming oxygen lance in advance and then blowing coke if the oxygen lance on the furnace door is adopted, supplying oxygen to a coke batching area in an ignition mode, and gradually increasing the oxygen supply amount, or starting oxygen supply when an electrode penetrates a well and approaches the coke after power supply is carried out for 15-30 minutes;

step 2), under the combustion supporting effect of oxygen, coke can rapidly and violently burn with the increase of oxygen supply, and a large amount of heat energy is generated; at the moment, the power is cut off and the electrode is lifted, the steel material is melted only by oxygen supply and the combustion reaction of coke, when the steel material on the upper part or around the coke is melted and gathered to a molten pool, carbon in the coke can permeate into the molten steel, when the molten steel is completely melted, the carbon content in the steel reaches 0.6-1.2 percent, the process requirement that the decarburization amount is more than or equal to 0.4 percent for oxidation smelting is completely met, enough gas is generated during the oxidation smelting to fully stir the molten steel, the upward floating and the removal of the gas and impurities are promoted, the thorough dephosphorization reaction is ensured, and the molten steel has better purity;

step 3), after the coke combustion is basically finished, the power transmission operation is resumed, and all the steel materials in the low-temperature area are blown and melted by oxygen;

and 4) observing the conditions in the furnace, and for a small amount of coke which is not completely combusted and floats on the slag surface, performing formal oxidation pretreatment in an oxygen blowing, slag discharging and removing mode to be clean, sampling and measuring the temperature after the operation is finished, formally entering an oxidation smelting operation stage after the conditions are met, wherein the subsequent operation process is the same as the normal production process.

Technical Field

The invention belongs to the technical field of electric arc furnace steelmaking batching processes in steel smelting, and particularly relates to an electric arc furnace steelmaking batching process which can meet the requirement of molten steel carbon batching, reduce the cost of raw materials and the consumption of electric energy, and ensure the degassing, inclusion removal and dephosphorization effects in a smelting process.

Background

At present, more than 30 percent of steel products are produced by smelting in an electric arc furnace, for steel-making enterprises with blast furnaces, if the electric arc furnace is adopted for smelting, part of molten iron can be hot-charged during charging, the carbon distribution requirement of the molten steel is met, but most of the steel-making enterprises with the electric arc furnace do not supply the molten iron to the blast furnace, in order to ensure the carbon distribution requirement of the molten steel, the most conventional method is to add 10-30 percent of pig iron during material mixing, the pig iron is obtained after the blast furnace is discharged and injected into a special die for cooling, the heat is completely lost, the pig iron is already cold material during material mixing in the electric arc furnace, the pig iron needs to be heated and melted again after being charged, and the price of the pig iron is higher, so. Some steel plants can add powdery or blocky carburant during burdening in order to save pig iron, but the mode has poor effect, large material consumption and low recovery rate, generates a large amount of dust, pollutes the environment, brings great pressure to subsequent dust removal, and increases the environmental protection cost.

In the conventional smelting production of an electric arc furnace, most of ingredients comprise various waste steel and pig iron, and the pig iron is added for providing necessary carbon for oxidation smelting after the waste steel is melted so as to generate carbon-oxygen reaction after the oxidation smelting is started, generate gas to promote the boiling of molten steel and remove gas and impurities in steel; on the other hand, the cost of the pig iron is higher, compared with the cost of the scrap steel which is 2000 yuan per ton, the production cost is increased, therefore, a new furnace distribution mode is needed to replace the conventional process, and under the condition, in order to reduce the production cost, improve the carbon distribution mode, improve the effects of degassing, impurity removing and dephosphorization after carbon distribution, various material distribution process tests need to be researched and developed, and the scrap steel and coke are used as the optimized material distribution process to comprehensively replace the material distribution mode of the scrap steel and the pig iron or the scrap steel and the carbon increasing agent.

Disclosure of Invention

The invention aims to overcome the defects in the prior art and provide a batching process for smelting steel by an electric arc furnace, which can effectively reduce the material cost and save a large amount of electric energy.

The purpose of the invention is realized as follows:

the utility model provides an electric arc furnace smelts steel and smelts batching technology, and is different from conventional electric arc furnace smelting furnace charge by various scrap steel and pig iron composition, during batching according to batching proportion and the required carbon content of steel grade oxidation smelting calculation join in metallurgical coke, and specific control parameter and mode are as follows:

1) when the materials are mixed in the electric arc furnace for steelmaking, the mixing amount of the coke is controlled within the range of 2-7% of the total steel materials according to different carbon contents of steel types;

2) and controlling the specific blending proportion: the method is characterized in that the coke addition amount is 2-3% of the total steel for steel grades with the upper limit of carbon content lower than 0.25%; for steel grades with the upper limit of carbon content of 0.26-0.60%, the addition amount of coke is 3-5% of the total steel materials; the addition of the rest steel is 5 to 7 percent of the total steel;

3) controlling the injection mode: the first mode is as follows: firstly, 10-20% of all steel materials are added to the lowest part of a material bag or a material basket according to the weight percentage, then all coke is added and is arranged at the central position of the material bag or the material basket, and finally, all the remaining steel materials are added to the upper part of the coke; the second mode is that coke and steel materials are added in layers from the lower part, no more than 3 layers are needed, and the uppermost layer is waste steel;

4) coke requirements: the first-grade metallurgical coke in GB/T1996 standard is selected, the granularity is 40-100mm, and the percentages are weight percentages.

An electric arc furnace steelmaking batching process comprises the following specific operation steps:

step 1), closing a furnace cover after charging is finished, starting power supply, directly starting an oxygen lance on the furnace wall to blow oxygen if reserved molten steel exists in the furnace, igniting a self-consuming oxygen lance in advance and then blowing coke if the oxygen lance on the furnace door is adopted, supplying oxygen to a coke batching area in an ignition mode, and gradually increasing the oxygen supply amount, or starting oxygen supply when an electrode penetrates a well and approaches the coke after power supply is carried out for 15-30 minutes;

step 2), under the combustion supporting effect of oxygen, coke can rapidly and violently burn with the increase of oxygen supply, and a large amount of heat energy is generated; at the moment, the power is cut off and the electrode is lifted, the steel material is melted only by oxygen supply and the combustion reaction of coke, when the steel material on the upper part or around the coke is melted and gathered to a molten pool, carbon in the coke can permeate into the molten steel, when the molten steel is completely melted, the carbon content in the steel reaches 0.6-1.2 percent, the process requirement that the decarburization amount is more than or equal to 0.4 percent for oxidation smelting is completely met, enough gas is generated during the oxidation smelting to fully stir the molten steel, the upward floating and the removal of the gas and impurities are promoted, the thorough dephosphorization reaction is ensured, and the molten steel has better purity;

step 3), after the coke combustion is basically finished, the power transmission operation is resumed, and all the steel materials in the low-temperature area are blown and melted by oxygen;

and 4) observing the conditions in the furnace, and for a small amount of coke which is not completely combusted and floats on the slag surface, performing formal oxidation pretreatment in an oxygen blowing, slag discharging and removing mode to be clean, sampling and measuring the temperature after the operation is finished, formally entering an oxidation smelting operation stage after the conditions are met, wherein the subsequent operation process is the same as the normal production process.

The invention has the following positive effects:

after the batching process is adopted, the production cost can be greatly reduced, the smelting time is shortened, the production efficiency is improved, and the energy waste caused by remelting and smelting in production is avoided.

The implementation effect is compared as follows:

1. according to the process, the carbon content of the 42CrMo steel after melting down is generally between 0.65 and 0.77 percent, the carbon content is controlled between 0.25 and 0.35 percent after oxidation, the carbon content in the range can just meet the following normal smelting requirement, in addition, in the reduction process after tapping, the carbon deoxidizer is carburized, and carbon brought in the alloy is added, additional carburization is not needed in the smelting process, and a certain carbon content also ensures that the oxygen content in the initial molten steel of the electric furnace is in a lower level, the addition of a reducing agent is reduced, the reduction time is shortened, and the production efficiency is improved.

2. After the pig iron is removed, the price of pig iron per ton in different periods is higher than 500-2000 yuan of scrap steel according to the material price accounting, the loading amount of steel per ton is 250Kg according to the average 1000 yuan per ton, and the value is 250 yuan. After the coke is used, the average loading amount of steel per ton is 50Kg, the price of primary coke is about 1900 Yuan/ton, the cost of steel per ton is 95 Yuan, compared with pig iron, the cost of steel per ton can be saved by 155 Yuan, and the annual production cost is about 1500 Yuan by accounting for a special steel enterprise producing 10 million tons per year.

3. After the coke is used for replacing pig iron, unlike the situation that the pig iron is completely melted by heat absorption, the oxidation of the coke can generate a large amount of heat energy, the power consumption per ton of steel can be reduced by 100-150 ℃, the electricity consumption per ton of steel can be reduced by 50 yuan according to the calculation of saving 100 ℃ and 0.5 yuan per degree, and the electricity consumption per ton of steel can still be calculated by a special steel enterprise producing 10 ten thousand tons every year, so that the annual production cost is about 500 yuan.

During smelting, oxygen is blown into the coke-allocated position at the beginning of power supply melting, the coke can be vigorously combusted under the condition of sufficient oxygen supply, a large amount of heat energy is provided for melting most of the waste steel, power can be cut off at the moment, melting operation is carried out only by oxygen supply, when the waste steel is melted, the molten steel melted at the upper part passes through a coke layer when being gathered to a molten pool, part of carbon in the coke permeates into the molten steel, sufficient carbon content is provided for the molten steel, and after the waste steel is completely melted, the molten steel is subjected to oxidation smelting, so that the metallurgical tasks of degassing and removing impurities are completed.

Unlike the common electric arc furnace smelting, which uses scrap steel and pig iron as main steel materials, the process can completely abandon the pig iron, only uses scrap steel and coke as main ingredients, and the specific coke adding amount and adding mode can be determined according to the steel type, and the main process operation principle is as follows:

1. for steel grades smelted in an electric arc furnace, the coke loading is in the range of 2% to 7%.

2. Controlling the specific mixing proportion: the upper limit of the carbon content of the steel grade is lower than 0.25 percent, and the addition amount is 2 to 3 percent; the addition amount of steel grades with the upper limit of carbon content of 0.26-0.60 percent is 3-5 percent; the addition amount of the other steel grades is 5 to 7 percent.

3. The preparation method comprises the following steps: the middle-lower part of the material bag (or material basket) is added at one time, the lowest part is added with 10 percent to 20 percent of the total amount of the steel material, then all coke is added, the coke is arranged at the central position of the material bag (or material basket), and then all the steel material (namely scrap steel) is added; the other way is to mix the steel and the iron materials layer by layer from the middle lower part, no more than 3 layers are needed, and the uppermost layer must be scrap steel. Coke requirements: the first-grade metallurgical coke in GB/T1996 standard is selected, and the granularity is 40-100 mm.

Detailed Description