Ring-blowing carbon gun and carbon spraying method

Abstract

The present invention discloses a ring-blowing carbon gun and a carbon spraying method. The ring-blowing carbon gun comprises a gun core, the front end of the gun core is connected to a nozzle, the rear end of the gun core is connected to a blowing aid, the blowing aid comprises a main pipe and a carbon blowing pipe that are interconnected, the rear end of the main pipe is connected to an outer thread of the blowing aid; a protective air pipe and an outer wall pipe are sequentially sleeved on the outside of the gun core, the front ends of the protective air pipe and the outer wall pipe are connected to a copper head, and the rear end of the protective air pipe is connected to a protective gas inlet pipe. The present invention uses carbon dioxide gas as a protective gas and a protective powder, and uses the low temperature generated by the reaction of carbon dioxide and carbon to form a slag barrel at the front of the spray gun, and uses the slag barrel to protect the powder from entering the molten steel smoothly. At the same time, the powder increases its speed with the help of gas protection, thereby increasing the utilization rate of the powder.

Description

Technical Field

[0001] The invention relates to the field of carbon guns for steelmaking, in particular to a ring-blowing carbon gun and a carbon spraying method. Background Art

[0002] Carbon powder plays an important role in electric furnace smelting. It can reduce metal burning, promote slag reaction, promote dephosphorization, promote foam slag travel, and remove gas and inclusions. The traditional method of spraying powder into an electric arc furnace is to use a spray gun. The existing carbon gun is made of water cooling and is set at a place where the furnace wall is more than 300mm away from the molten pool. The spraying distance is far, and the powder is easily affected by the slag during the spraying process and cannot enter the molten pool, thus failing to achieve the expected effect. Summary of the invention

[0003] In order to solve the above technical problems, the present invention provides a ring-blowing carbon gun and a carbon spraying method. The present invention uses carbon dioxide gas as a protective gas to protect the powder, and uses the low temperature generated by the reaction of carbon dioxide and carbon to form a slag barrel at the front of the spray gun, and uses the slag barrel to protect the powder from entering the molten steel smoothly. At the same time, the powder increases its speed with the help of gas protection, thereby improving the utilization rate of the powder.

[0004] In a first aspect, the present invention provides a ring-blowing carbon gun, which is realized by the following technical solution.

[0005] A ring-blowing carbon gun comprises a gun core, the front end of which is connected to a nozzle, the rear end of which is connected to a blowing aid, the blowing aid comprising a main pipe and a carbon blowing pipe which are interconnected, the rear end of which is connected to an outer blowing air thread; a protective air pipe and an outer wall pipe are sequentially sleeved on the outside of the gun core, the front ends of which are connected to a copper head, and the rear end of which is connected to a protective air inlet pipe.

[0006] Furthermore, the gun core comprises a core body, and an inner wall tube is arranged outside the core body.

[0007] Furthermore, the core is formed by splicing together multiple sections of ceramic tubes.

[0008] Furthermore, a water-blocking pipe is provided between the protective air pipe and the outer wall pipe.

[0009] Furthermore, the rear end of the outer wall tube is connected to a water inlet pipe and a water outlet pipe.

[0010] Furthermore, a wind head is provided at the front end of the outer blowing air thread.

[0011] In a second aspect, the present invention provides a carbon injection method, which is achieved through the following technical solution.

[0012] A carbon spraying method using the above-mentioned ring-blowing carbon gun comprises the following steps:

[0013] a. Toner filling: put the toner into the toner can;

[0014] b. Adjust the toner tank pressure

[0015] Close the exhaust of the carbon powder tank, and the pressure in the carbon powder tank is increased to 0.25Mpa-0.5Mpa. At this time, only the protective gas is turned on in the carbon gun, and the other gases are turned off;

[0016] At the beginning of blowing, the auxiliary blowing gas at the tail of the carbon gun is pressurized, and the auxiliary blowing gas is oxygen. The protective gas ring blowing is started synchronously, and the protective gas is carbon dioxide; the oxygen flow rate is 150Nm 3 / h, pressure is 0.4Mpa-0.8Mpa, carbon dioxide ring blowing flow rate is 800-1200Nm 3 / h, pressure is 0.8Mpa-1.2Mpa;

[0017] c. Electric arc furnace smelting

[0018] ⅰ. During normal smelting, after the last batch of steel is tapped, the electric furnace returns to normal. When power is supplied to start smelting, the auxiliary air is turned on to spray carbon powder and carbon dioxide ring blowing at the same time. The carbon powder injection flow rate is 20-60Kg / min, and horizontal feeding is started at the same time;

[0019] ⅱ. During the whole smelting process, the level of foam slag is maintained by continuously spraying carbon powder and providing reaction materials for carbon-oxygen reaction to ensure sufficient heat source in the furnace;

[0020] ⅲ. When blowing is near the end point, take temperature measurements and samples. If the temperature is lower than the tapping process requirements, continue to blow oxygen and spray an appropriate amount of carbon powder to supplement heat to increase the end point temperature. At the same time, perform slag removal to reduce the amount of slag left in the electric furnace.

[0021] ⅳ. During the overall smelting process, the amount of carbon powder is controlled between 18Kg / t-25Kg / t. If the proportion of high-carbon scrap steel entering the furnace is too high, the amount of carbon powder injection will tend to the lower limit. If the proportion of high-carbon scrap steel entering the furnace is too low, the amount of carbon powder injection will tend to the upper limit.

[0022] Furthermore, the particle size of the carbon powder is 0.2mm≤φ≤5mm, of which 3mm accounts for 70% or more; the water content of the carbon powder is ≤0.5%, and the sulfur content is ≤2.5%.

[0023] This application has the following beneficial effects.

[0024] 1. The present invention further improves the speed and impact force of the powder jet by adding carbon dioxide gas as the carbon powder protective gas, ensures that the carbon powder can smoothly enter the molten steel, improves the utilization rate of the powder, and provides sufficient and stable conditions for the reaction in the furnace;

[0025] 2. The carbon dioxide gas added in the present invention can react with carbon powder at high temperature and absorb heat, which can play a role in cooling the equipment, and also reduce the heat loss taken away by the circulating cooling water, thereby improving the thermal efficiency;

[0026] 3. The present invention improves the utilization rate of carbon powder, thereby reducing the amount of carbon powder used in the smelting process, which can be reduced by an average of 2-4 kg / t. For a steel plant with an annual output of 1 million tons, it is estimated that the annual cost savings will be 3.6 million to 7.2 million yuan. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of the structure of the present invention;

[0028] Figure 2 It is a cross-sectional view of the present invention.

[0029] Among them, 1. core body; 2. inner wall tube; 3. protective air pipe; 4. water-proof pipe; 5. outer wall tube; 6. nozzle; 7. copper head; 8. blowing aid; 81. main pipe; 82. carbon blowing tube; 9. blowing air outer wire; 10. protective air inlet pipe; 11. water inlet pipe; 12. water outlet pipe; 13. wind head. DETAILED DESCRIPTION

[0030] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0031] like Figure 1-2 As shown, a ring-blowing carbon gun mainly includes a gun core, a protective air pipe 3, an outer wall tube 5, a nozzle 6, a copper head 7, and a blowing aid 8.

[0032] The gun core includes a core body 1 and an inner wall tube 2. Specifically, the core body 1 is formed by splicing multiple sections of ceramic tubes, the inner wall of which is smooth and wear-resistant, and is convenient for spraying carbon powder; the inner wall tube 2 is arranged outside the multiple sections of ceramic tubes, and the inner wall tube 2 plays a role in fixing the ceramic tube. A flange is provided at the rear of the gun core of the present application, and the flange matches the flange at the rear end of the protective air pipe 3 and the outer wall tube 5. The flange connection facilitates the replacement of the gun core and reduces the difficulty of repairing the carbon gun.

[0033] The front end of the gun core of the present application is connected to the nozzle 6, and the rear end of the gun core is connected to the blowing aid 8. Specifically, the rear end of the gun core is connected to the blowing aid 8 through a quick-connect male and female head, which is convenient for the installation and removal of the blowing aid 8. The blowing aid 8 forms a main pipe 81 and a carbon blowing pipe 82 that are interconnected and arranged at a certain angle. The rear end of the main pipe 81 is connected to the outer wire 9 of the blowing gas, and the front end of the outer wire 9 of the blowing gas is connected to a wind head 13. The wind head 13 can make the blowing gas form a vortex to make the injection of carbon powder more uniform; oxygen is selected as the blowing gas in the present application.

[0034] The gun core outer shell is provided with a protective air pipe 3, and a protective air cavity is formed between the inner wall tube 2 and the protective air pipe 3. The rear end of the protective air pipe 3 is connected to the protective air inlet pipe 10 through a connecting joint, and the protective air inlet pipe 10 is used to introduce carbon dioxide protective gas.

[0035] The outer wall tube 5 is arranged outside the protective air pipe 3, and a cooling cavity is formed between the protective air pipe 3 and the outer wall tube 5. The front ends of the protective air pipe 3 and the outer wall tube 5 are connected to the copper head 7, and the rear end of the outer wall tube 5 is connected to the water inlet pipe 11 and the water outlet pipe 12. In order to increase the water cooling effect, a water riser 4 is arranged between the protective air pipe 3 and the outer wall tube 5. The cooling water enters the cooling cavity from the water inlet pipe 11, flows to the gun head, and then deflects, and finally is discharged from the water outlet pipe 12. This process allows the cooling water to fully exchange heat in the carbon gun, thereby achieving a cooling effect on the gun core.

[0036] When the carbon gun of the present invention is working, carbon powder enters the blowing aid 8 from the carbon blowing pipe 82, oxygen enters the blowing aid 8 from the blowing gas outer wire 9, the carbon powder and oxygen merge in the main pipe 81 and then enter the gun core, and at the same time, carbon dioxide enters the protective gas cavity between the inner wall tube 2 and the protective gas pipe 3 from the protective gas inlet pipe 10, and finally the carbon powder and oxygen are sprayed out from the nozzle 6, and carbon dioxide is sprayed out from between the nozzle 6 and the copper head 7. The sprayed carbon dioxide gas can be used as a protective gas for the carbon powder, and a slag barrel is formed at the front part of the spray gun by utilizing the low temperature generated by the reaction of carbon dioxide and carbon. The carbon powder can be smoothly protected by the slag barrel and enter the molten steel. At the same time, the carbon powder increases its speed with the help of gas protection, thereby improving the utilization rate of the powder.

[0037] The present invention also provides a carbon spraying method using the above carbon gun, comprising:

[0038] a.Toner filling

[0039] Put the purchased carbon powder into the carbon powder tank, with the following requirements: particle size 0.2mm≤φ≤5mm, of which 3mm accounts for 70% and above, water content ≤0.5%, sulfur content ≤2.5%;

[0040] b. Adjust the toner tank pressure

[0041] Close the exhaust of the carbon powder tank, and the pressure in the carbon powder tank will automatically increase to 0.25Mpa-0.5Mpa. At this time, only the remaining protective gas of the carbon gun is open to prevent blockage, and the other gases are closed; when the blowing starts, the carbon gun tail pressure boosting and carbon dioxide ring blowing are started simultaneously, and the flow rate of the tail pressure boosting device is 150Nm 3 / h, pressure is 0.4Mpa-0.8Mpa, carbon dioxide ring blowing flow rate is 800-1200Nm 3 / h, pressure 0.8Mpa-1.2Mpa;

[0042] c. Electric arc furnace smelting:

[0043] (1) During normal smelting, after the last batch of steel is tapped, the electric furnace returns to normal. When power is supplied to start smelting, the carbon gun is turned on to spray carbon powder (including CO2 ring blowing). The carbon powder injection flow rate is 20-60 kg / min to ensure the speed and impact performance of the carbon powder jet and to ensure that the foam slag is quickly made. At the same time, the feeding trolley is in place to start horizontal feeding;

[0044] (2) During the entire smelting process, carbon powder is continuously sprayed to maintain the foam slag level and provide reactive materials for carbon-oxygen reaction, ensuring sufficient heat source in the furnace;

[0045] (3) When the blowing reaches the end point, temperature measurement and sampling are carried out. If the temperature is lower than the steel-making process requirements, continue to blow oxygen and spray an appropriate amount of carbon powder to supplement heat to increase the end point temperature. At the same time, slag removal is carried out to reduce the amount of slag left in the electric furnace.

[0046] (4) During the overall smelting process, the amount of carbon powder is controlled between 18 kg / t and 25 kg / t. If the proportion of high-carbon scrap steel entering the furnace is too high, the amount of carbon powder sprayed will tend to the lower limit. If the proportion of high-carbon scrap steel entering the furnace is too low, the amount of carbon powder sprayed will tend to the upper limit.

[0047] The embodiments of this specific implementation method are all preferred embodiments of the present invention, and are not intended to limit the protection scope of the present invention. Therefore, any equivalent changes made based on the structure, shape, and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A ring-blowing carbon gun, comprising a gun core, characterized in that: The front end of the gun core is connected to the nozzle (6), and the rear end of the gun core is connected to the blowing aid (8), the blowing aid (8) comprises a main pipe (81) and a carbon blowing pipe (82) which are interconnected, and the rear end of the main pipe (81) is connected to an outer blowing gas thread (9); a protective gas pipe (3) and an outer wall pipe (5) are sequentially sleeved on the outside of the gun core, the front ends of the protective gas pipe (3) and the outer wall pipe (5) are connected to the copper head (7), and the rear end of the protective gas pipe (3) is connected to a protective gas inlet pipe (10).

2. The ring-blowing carbon gun according to claim 1, characterized in that: The gun core comprises a core body (1), and an inner wall tube (2) is arranged outside the core body (1).

3. The ring-blowing carbon gun according to claim 2, characterized in that: The core (1) is formed by splicing together a plurality of sections of ceramic tubes.

4. The ring-blowing carbon gun according to claim 1, characterized in that: A water-blocking pipe (4) is provided between the protective air pipe (3) and the outer wall pipe (5).

5. The ring-blowing carbon gun according to claim 1, characterized in that: The rear end of the outer wall tube (5) is connected to a water inlet pipe (11) and a water outlet pipe (12).

6. The ring-blowing carbon gun according to claim 1, characterized in that: The front end of the auxiliary air outer thread (9) is provided with a wind head (13).

7. A carbon spraying method using the ring-blowing carbon gun according to any one of claims 1 to 6, characterized in that: The following steps are involved: a. Toner filling: put the toner into the toner can; b. Adjust the toner tank pressure Close the exhaust of the carbon powder tank, and the pressure in the carbon powder tank is increased to 0.25Mpa-0.5Mpa. At this time, only the protective gas is turned on in the carbon gun, and the other gases are turned off; At the beginning of blowing, the auxiliary blowing gas at the tail of the carbon gun is pressurized, and the auxiliary blowing gas is oxygen. The protective gas ring blowing is started synchronously, and the protective gas is carbon dioxide; the oxygen flow rate is 150Nm 3 / h, pressure is 0.4Mpa-0.8Mpa, carbon dioxide ring blowing flow rate is 800-1200Nm 3 / h, pressure is 0.8Mpa-1.2Mpa; c. Electric arc furnace smelting ⅰ. During normal smelting, after the last batch of steel is tapped, the electric furnace returns to normal. When power is supplied to start smelting, the auxiliary air is turned on to spray carbon powder and carbon dioxide ring blowing at the same time. The carbon powder injection flow rate is 20-60Kg / min, and horizontal feeding is started at the same time; ⅱ. During the whole smelting process, the level of foam slag is maintained by continuously spraying carbon powder and providing reaction materials for carbon-oxygen reaction to ensure sufficient heat source in the furnace; ⅲ. When blowing is near the end point, take temperature measurements and samples. If the temperature is lower than the tapping process requirements, continue to blow oxygen and spray an appropriate amount of carbon powder to supplement heat to increase the end point temperature. At the same time, perform slag removal to reduce the amount of slag left in the electric furnace. ⅳ. During the overall smelting process, the amount of carbon powder is controlled between 18Kg / t-25Kg / t. If the proportion of high-carbon scrap steel entering the furnace is too high, the amount of carbon powder injection will tend to the lower limit. If the proportion of high-carbon scrap steel entering the furnace is too low, the amount of carbon powder injection will tend to the upper limit.

8. The carbon injection method according to claim 7, characterized in that: The particle size of the carbon powder is 0.2mm≤φ≤5mm, of which 3mm accounts for 70% and above; the water content of the carbon powder is ≤0.5%, and the sulfur content is ≤2.5%.

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