阅读说明：本技术 顶吹炉的开炉方法 (Blow-in method of top-blown furnace ) 是由 程利振 王勇 程宾 赵斌 李春玉 陆逊 王乾 于 2020-05-22 设计创作，主要内容包括：本发明属于金属冶炼领域,具体涉及一种顶吹炉的开炉方法,包括如下步骤：(1)阶梯式升温；(2)造熔池；(3)投料开炉；(4)开炉结束。采用上述方案,炉砖升温期间制定了科学的升温曲线,且采用天然气燃料和黑砂,燃烧产物干净清洁,且能完全燃烧,不存在环境污染,所造渣层厚度1000mm左右,喷枪不容易烧损,炉砖挂渣良好,能大大延长炉衬寿命,降低企业生产成本。(The invention belongs to the field of metal smelting, and particularly relates to a blow-in method of a top-blown furnace, which comprises the following steps: (1) heating in a stepped manner; (2) manufacturing a molten pool; (3) feeding and opening the furnace; (4) and (5) finishing opening the furnace. By adopting the scheme, a scientific temperature rise curve is formulated during the temperature rise of the furnace bricks, natural gas fuel and black sand are adopted, combustion products are clean and clean, the combustion products can be completely combusted, no environmental pollution exists, the thickness of the formed slag layer is about 1000mm, the spray gun is not easy to burn, the slag is well adhered to the furnace bricks, the service life of the furnace lining can be greatly prolonged, and the production cost of enterprises is reduced.)

1. A blow-in method of a top-blown converter comprises the following steps:

(1) step-type temperature rising: injecting natural gas and oxygen into the furnace by using a spray gun for combustion, heating the furnace bricks, and alternately heating for at least four times and keeping constant temperature for three times until the thermocouple temperature of the furnace bricks exceeds 1200 ℃;

(2) making a molten pool: adding black sand into the furnace, and stopping adding the black sand when the smelting height of a molten pool reaches 1000-1200 mm;

(3) feeding and opening the furnace: adding high-iron high-sulfur copper concentrate into the furnace for smelting, and controlling the grade of matte to be 54-57%, the ratio of iron to silicon dioxide to be 1.15-1.3 and the smelting temperature to be 1180-1250 ℃;

(4) and (5) finishing opening the furnace: when the liquid level of the melt in the furnace reaches 1500-1700 mm, discharging the melt in the furnace to a siphon weir and entering a chute, sampling and testing the melt in the chute, testing qualified, and opening the furnace.

2. The blow-in method of the top-blown converter according to claim 1, wherein: in the step (1), if the furnace brick is used for the first time after the new building is finished, dry firewood with the thickness of 500-800 mm is paved at the bottom of the furnace before the temperature is raised, and the firewood is ignited when the temperature of the furnace brick is raised for the first time.

3. The blow-in method of the top-blown converter according to claim 1, wherein: in the step (1), natural gas and oxygen are injected into the furnace by using a spray gun for combustion, wherein the consumption of the natural gas of the spray gun is 150-1500 Nm³The combustion ratio is 11:1, and the temperature is raised in a stepped mode by taking the temperature of a furnace brick thermocouple as a reference: heating to 150 ℃, keeping the temperature for 60-65 h, heating to 450 ℃, keeping the temperature for 35-40 h, heating to 850 ℃, keeping the temperature for 18-22 h, and finally heating to a furnace brick temperature of over 1200 ℃.

4. The blow-in method of the top-blown converter according to claim 1, wherein: in the step (2), the black sand mainly comprises the following components: 0.5 to 1% of Cu, 0.5 to 1% of S, 32 to 37% of Fe, and SiO₂28～32％、CaO 6～8％、MgO 2～3％、Al₂O₃6～7％、H₂O<20％。

5. The blow-in method of the top-blown converter according to claim 1, wherein: in the step (2), the black sand feeding speed is 5-10 t/h, and the natural gas consumption is 1350-1500 Nm³Perh, combustion ratio of 9:1, primary air pressure of 130KPa and secondary air volume of 3000Nm³And h, the distance from the head of the spray gun to the furnace bottom is 1600-1900 mm.

6. The blow-in method of the top-blown converter according to claim 1, wherein: in the step (3), the speed of the concentrate entering the furnace is 70-90 t/h, and the concentrate is added into the copper concentrate of the high-iron high-sulfur ore: the Cu content is 22-24%, the Fe content is 27-29%, the S/Cu ratio is 1.15-1.3, and the oxygen concentration of a spray gun is 55-60% in the smelting process.

7. The blow-in method of the top-blown converter according to claim 1, wherein: in the step (3), the natural gas amount of the spray gun is 200-500 Nm³The primary air quantity of the spray gun is 18000-22000 Nm³The oxygen content of the spray gun is 9000-12000 Nm³The primary air pressure of the spray gun is 140-160 KPa, and the secondary air quantity of the spray gun is 2000-3000 Nm³And h, controlling the air back pressure of the spray gun to be 39-44 KPa.

8. The blow-in method of the top-blown converter according to claim 1, wherein: in the step (4), the Fe/SiO of the melt is obtained during sampling and testing from the chute₂The ratio is 1.15-1.3, the temperature is 1180-1250 ℃, and the blow-in is finished.

Technical Field

The invention belongs to the field of metal smelting, and particularly relates to a blow-in method of a top-blown converter.

Background

In the metallurgical industry, after the submerged arc furnace is stopped for a long time or furnace bricks are replaced, the submerged arc furnace needs to be opened again when in use, a large amount of electric energy and fuel are consumed in the opening process, the opening process also needs to be long time, the opening process is closely related to the service life of the furnace bricks, an improper opening method is adopted, the furnace bricks are seriously peeled off in the production process, the furnace bricks need to be frequently replaced, the normal smelting operation is influenced, and the cost input is greatly increased.

Both the Osmant furnace and the Isa furnace belong to top-blown furnaces, and the research on the temperature rise blow-in technology of the two metallurgical furnaces is few at present. The related Osmant furnace and the Isa furnace are heated and opened by using a spare burner and a spray gun, the fuel for heating is pulverized coal, heavy oil and diesel oil, a copper concentrate is generally added into a melting pool for quickly making the melting pool, the environmental pollution is serious, and the service life of a furnace lining and the service life of the spray gun are not favorable.

Regarding how to clean and efficiently carry out temperature rise and blow-in of furnace bricks of a top-blown furnace, the Chinese patent 'a method for quickly manufacturing a molten pool by molten pool smelting' (invention publication number 104357650A) discloses a scheme that black sand is paved at the bottom of the furnace firstly, then furnace baking is started, direct feeding smelting is finished after the furnace baking, the time is fast, and the efficiency is high. However, the method belongs to the field of rapid molten pool manufacturing, does not conform to the temperature rise curve of furnace bricks, greatly damages the service life of a furnace lining, and directly throws copper concentrate in the molten pool manufacturing stage, thereby causing serious environmental pollution. In the scheme disclosed by the Chinese patent ' a rapid blow-in method of a copper bottom blowing smelting furnace ' (invention publication number 107460340A '), specific heating and molten pool making processes are not determined, and an oxygen lance needs to be installed and adjusted again in the blow-in process, so that the operation is complicated, and certain potential safety hazards exist.

The two methods only introduce a molten pool making process and a furnace opening process, both belong to a rapid temperature raising process, furnace bricks are easy to generate thermal shock in the process, the furnace bricks are easy to strip, the service life of a furnace lining is reduced, and fuel and raw materials in the process have high sulfur content, are not beneficial to flue gas treatment, and do not accord with the environmental protection strategy of the metallurgical industry in China.

The method has practical operation verification that the inventor adopts the method to blow in the Osmant furnace of the company (Jinguan copper division of the bronze Ling nonferrous metals group, controlled and stocked Limited company), the cost of the furnace brick is about 1300 ten thousand yuan of RMB, the furnace brick peeling phenomenon happens after the furnace is blown in and put into normal use, the number of the furnace bricks is reduced from more than six hundred to more than two hundred after one year, the use of the Osmant furnace is seriously influenced, and the furnace brick has to be replaced again. That is to say, the furnace bricks are opened by adopting the prior art, the service life of the furnace bricks is only about one year, and a large amount of cost is required to be invested in the process of replacing the furnace bricks every year so as to maintain normal operation. Therefore, an effective blow-in method is needed to prolong the service life of the furnace bricks and reduce the production cost.

Disclosure of Invention

The invention aims to provide a blow-in method of a top-blown converter, which can greatly prolong the service life of furnace bricks and is environment-friendly.

In order to achieve the purpose, the invention adopts the technical scheme that: a blow-in method of a top-blown converter comprises the following steps:

(1) step-type temperature rising: injecting natural gas and oxygen into the furnace by using a spray gun for combustion, heating the furnace bricks, and alternately heating for at least four times and keeping constant temperature for three times until the thermocouple temperature of the furnace bricks exceeds 1200 ℃;

(2) making a molten pool: adding black sand into the furnace, and stopping adding the black sand when the smelting height of a molten pool reaches 1000-1200 mm;

(3) feeding and opening the furnace: adding high-iron high-sulfur copper concentrate into the furnace for smelting, and controlling the grade of matte to be 54-57%, the ratio of iron to silicon dioxide to be 1.15-1.3 and the smelting temperature to be 1180-1250 ℃;

(4) and (5) finishing opening the furnace: when the liquid level of the melt in the furnace reaches 1500-1700 mm, discharging the melt in the furnace to a siphon weir and entering a chute, sampling and testing the melt in the chute, testing qualified, and opening the furnace.

By adopting the scheme, a scientific temperature rise curve is formulated during the temperature rise of the furnace bricks, natural gas fuel and black sand are adopted, combustion products are clean and clean, the combustion products can be completely combusted, no environmental pollution exists, the thickness of the formed slag layer is about 1000mm, the spray gun is not easy to burn, the slag is well adhered to the furnace bricks, the service life of the furnace lining can be greatly prolonged, and the production cost of enterprises is reduced.

Preferably, in the step (1), if the furnace brick is used for the first time after the new masonry is completed, dry firewood with the thickness of 500-800 mm is paved at the bottom of the furnace before the temperature is raised, and the firewood is ignited when the temperature of the furnace brick is raised for the first time.

Preferably, in the step (1), natural gas and oxygen are injected into the furnace by using a spray gun for combustion, and the consumption of the natural gas of the spray gun is 150-1500 Nm³The combustion ratio is 11:1, the primary air pressure is 50-70 KPa, and the temperature is raised in a stepped manner by taking the temperature of a furnace brick thermocouple as a reference: heating to 150 ℃, keeping the temperature for 60-65 h, heating to 450 ℃, keeping the temperature for 35-40 h, heating to 850 ℃, keeping the temperature for 18-22 h, and finally heating to a furnace brick temperature of over 1200 ℃.

Specifically, after the new building in the first furnace period is completed, dry firewood is paved at the bottom of the furnace, then the spray gun is ignited by using the handheld automatic igniter, the spray gun is descended to be 800mm away from the bottom of the furnace, the firewood is ignited, the road temperature is slowly increased, and the firewood can be burned. And when the temperature of the furnace brick thermocouple reaches 150 ℃, the first-stage constant-temperature operation is carried out, the natural gas quantity, the combustion ratio and the wind pressure of the spray gun are unchanged, the distance from the spray gun head to the furnace bottom is 800-850 mm, and the firewood combustion is basically finished. After the first-stage constant temperature is finished, the amount of the natural gas is increased by 250-500 Nm³The combustion ratio and the primary air pressure are unchanged, the temperature of the spray gun from the head to the bottom of the furnace is 850mm, the road rotation temperature continues to rise, the second stage of constant temperature operation is carried out after the temperature reaches 450 ℃, and the natural gas quantity of the spray gun is 400-500 Nm at the moment³The combustion ratio is 11:1, the primary air pressure is 70-90 KPa, the distance from the head of the spray gun to the bottom of the furnace is 950mm, the temperature of furnace bricks is continuously increased to 850 ℃, the furnace bricks enter a third stage for constant temperature operation, and the natural gas amount of the spray gun is 800-1200 Nm³The combustion ratio is 11:1, the primary air pressure is 90-120 KPa, the distance from the head of the spray gun to the bottom of the furnace is 950-1300 mm, and the using amount of natural gas is increased by 1200-1500 Nm after the constant temperature stage is finished³And h, the combustion ratio is 11:1, the primary air pressure is 120-130 KPa, the distance from the head of the spray gun to the bottom of the furnace is 1300-1600 mm, the temperature of the furnace brick is continuously increased until the temperature of the furnace brick exceeds 1200 ℃, and the furnace brick enters a molten pool making stage.

Preferably, in the step (2), the black sand mainly comprises the following components: 0.5 to 1% of Cu, 0.5 to 1% of S, 32 to 37% of Fe, and SiO₂28～32％、CaO 6～8％、MgO 2～3％、Al₂O₃6～7％、H₂O<20％。

In the step (2), the furnace charging speed of the black sand5 to 10t/h, and 1350 to 1500Nm of natural gas³Perh, combustion ratio of 9:1, primary air pressure of 130KPa and secondary air volume of 3000Nm³And h, the distance from the head of the spray gun to the furnace bottom is 1600-1900 mm.

Specifically, after entering a molten pool making stage, a furnace top feeding belt is started, the speed of black sand entering the furnace is set, when the smelting height of the molten pool reaches 1000-12000 mm and the turnover of melt in the furnace can be obviously observed from a furnace opening, the black sand feeding is stopped, and a top-blown furnace feeding and blowing stage is entered.

Preferably, in the step (3), the speed of the concentrate entering the furnace is 70-90 t/h, and in the high-iron high-sulfur ore copper concentrate: the Cu content is 22-24%, the Fe content is 27-29%, the S/Cu ratio is 1.15-1.3, and the oxygen concentration of a spray gun is 55-60% in the smelting process.

In the step (3), the natural gas amount of the spray gun is 200-500 Nm³The primary air quantity of the spray gun is 18000-22000 Nm³The oxygen content of the spray gun is 9000-12000 Nm³The primary air pressure of the spray gun is 140-160 KPa, and the secondary air quantity of the spray gun is 2000-3000 Nm³And h, controlling the air back pressure of the spray gun to be 39-44 KPa.

Specifically, when the liquid level in the furnace reaches 1500-1700 mm, the inner opening of a siphon weir of the top-blown furnace is opened from the outer side of the furnace body, the melt enters the siphon weir through a discharge channel, and when the melt height in the weir exceeds 1600mm, the melt enters a chute and is sampled to test Fe/SiO₂Temperature, and comparing with the set value, Fe/SiO₂The ratio is 1.15-1.3, the temperature is 1180-1250 ℃, and the blow-in is finished and the normal production stage is started.

The invention has the beneficial effects that: a scientific temperature rise curve is formulated during the temperature rise of the furnace bricks, so that the service life of the furnace bricks can be prolonged to the maximum extent; the natural gas fuel and the black sand are adopted in the temperature rising stage and the molten pool making stage, the combustion products are clean and clean, and can be completely combusted, so that the environmental pollution is avoided; the thickness of the slagging layer is about 1000mm, the spray gun is not easy to burn, the slag is well adhered to the furnace brick, and the service life of the furnace lining is further prolonged. The blow-in method is suitable for most top-blown furnaces to heat and blow in, and reduces the production cost of enterprises.

Drawings

FIG. 1 is a graph of the temperature rise of the furnace bricks in the example of the invention.

Detailed Description

The technical solution of the present invention is further described below with reference to the accompanying drawings and examples.