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CN-121975987-A - Treatment method for tapping and deslagging of converter

CN121975987ACN 121975987 ACN121975987 ACN 121975987ACN-121975987-A

Abstract

The invention discloses a converter tapping slag discharging treatment method, which specifically comprises the following steps of adding 40% -60% of deoxidized alloy or no deoxidized alloy according to the control requirements of the phosphorus content and the carbon content of steel types in the converter tapping process or in the tapping finishing furnace lifting stage, adding activated lime into a ladle after slag discharging, starting bottom argon blowing, adopting a ladle car to carry out low-gear front-rear running, starting bottom argon blowing again after tapping, adopting a speed gear in the ladle car to carry out front-rear running, starting the ladle car in the opposite direction to carry out front-rear running by adopting a high-speed gear after argon blowing and running are finished, repeating steel slag pretreatment and secondary treatment if steel slag still exists over 2/3 of the surface area of the ladle, adding activated lime into the ladle after the front-rear reciprocating movement of the ladle is finished, and then adding deoxidized alloy to carry out alloying treatment.

Inventors

  • LI CHAO
  • JI BOWEN
  • ZHAO ZIXIN
  • LI CHAO
  • YI XIAOMING
  • CAI QINGXIU
  • SHEN GUANGHUI
  • SU XIAOLI
  • LONG SHAN
  • ZHANG AIJUN

Assignees

  • 鞍钢股份有限公司

Dates

Publication Date
20260505
Application Date
20260209

Claims (7)

  1. 1. The method for treating the tapping and slag discharging of the converter is characterized by comprising the following steps of: Step 1, deoxidizing and alloying treatment, namely adding 40-60% of deoxidizing alloy or not adding deoxidizing alloy in the converter deoxidizing and alloying process according to the phosphorus content and the carbon content in a steel finished product in the converter tapping process or in the tapping finishing furnace lifting stage; Step 2, steel slag pretreatment, namely adding active lime into a steel ladle after deslagging, starting bottom blowing argon, and adopting a ladle car to perform low gear forward and backward running; Step 3, secondary treatment of steel slag, namely, after tapping, starting bottom argon blowing again, and adopting a speed gear in the ladle to walk forwards and backwards, after argon blowing and walking are finished, starting the ladle in the opposite direction, and adopting a high speed gear to walk forwards and backwards, and if steel slag still exists in more than 2/3 of the surface area of the ladle, repeating the pretreatment and secondary treatment of the steel slag; And 4, secondary deoxidization alloying treatment, namely adding active lime into the molten steel tank according to the phosphorus content and the carbon content in the steel finished product after the front and back reciprocating movement of the molten steel tank is finished, and then adding deoxidization alloy for deoxidization alloying treatment.
  2. 2. The method according to claim 1, wherein the deoxidizing alloying treatment in step 1 is specifically performed by adding 40-60% deoxidizing alloy to prevent the phosphorus and carbon contents from exceeding the standard after deoxidizing and tranquilizing when the phosphorus content in the steel product is less than or equal to 0.020% and the carbon content is less than or equal to 0.06%.
  3. 3. The method according to claim 1, wherein the deoxidizing alloying treatment in step 1 is specifically that no deoxidizing alloy is added to the steel product when the content of phosphorus element in the steel product is less than or equal to 0.015 percent.
  4. 4. The treatment method according to claim 1, wherein the steel slag pretreatment in the step 2 is characterized in that after slag tapping, active lime with the weight of 0.5-4.0 kg/ton molten steel is added into a steel ladle, meanwhile, bottom blowing argon is started, the flow rate of argon in the bottom blowing argon is 50-60L/min, the bottom blowing time is 3-8 s, after bottom blowing is finished, the active lime and the steel slag are subjected to preliminary reaction by adopting a low-speed gear to travel for 5-15 s before and after 5-10 m/min, wherein the calcium oxide content in the active lime is >90%, and the activity degree is >300ml.
  5. 5. The treatment method according to claim 1, wherein the secondary treatment of the steel slag in the step 3 comprises three steps, namely, after tapping, starting bottom blowing argon to blow for 5-15 s at a flow rate of 50-60L/min, and adopting a speed gear of a ladle car to run for 3-8 s before and after 10-20 m/min; The second stage, after argon blowing and running are finished, the running ladle car adopts a high-speed gear to run for 2-4 s at 20-30 m/min along the direction opposite to the first stage; And the third stage, the ladle car carries out back and forth movement along the travelling direction of the ladle car, the duration time of the travelling direction of each back and forth movement is 1-3 s, the total time of the back and forth movement is 30-60 s, when the back and forth movement is 15-25 s, the flow rate of bottom blowing argon is 10-30L/min, the time is 25-35 s, reactants of steel slag and active lime fly out of the ladle along the edge of the ladle in the process, and if molten steel flies out, the flow rate of argon blowing is adjusted to be 5-15L/min or argon is closed.
  6. 6. The method according to claim 1, wherein the secondary deoxidization alloying treatment in the step 4 is specifically performed by adding 0.5-4.0 kg/ton of activated lime into the molten steel tank after the front and back round-trip movement of the molten steel tank is completed, diluting a small amount of residual steel slag by reaction, and then adding deoxidization alloy at the temperature of the molten steel of not less than 1600 ℃ for deoxidization alloying treatment.
  7. 7. The method according to claim 1, wherein the deoxidizing alloy in step 2 and step 4 is at least one selected from the group consisting of aluminum-based alloys, silicon-based alloys, and manganese-based alloys.

Description

Treatment method for tapping and deslagging of converter Technical Field The invention belongs to the technical field of ferrous metallurgy, and particularly relates to a method for treating tapping and slag discharging of a converter. Background In the converter steelmaking process, converter slag is a main byproduct and consists of metal oxide, silicate and the like, and can be divided into early-stage slag, medium-stage slag and final slag according to functions, wherein the final slag has high alkalinity and strong oxidizing property, and has obvious influence on molten steel quality. When tapping and deslagging are performed by a converter, the phenomenon that final slag enters a steel ladle along with molten steel is performed, and the deslagging amount is usually 1% -5% of the total amount of the molten steel. Iron oxide, manganese oxide and the like in the slag can cause molten steel to back phosphorus and increase oxygen, reduce alloy yield, increase steel lining erosion and increase subsequent refining difficulty, and are one of key problems affecting steel quality. The existing treatment technology is mainly divided into two types, namely a slag blocking steel tapping technology, such as a slag blocking cap, a slag blocking ball, pneumatic slag blocking and the like, slag discharging quantity is reduced through physical blocking, slag blocking efficiency can be controlled to be 70% -85%, part of residues still enter a ladle, and a slag discharging post-treatment technology comprises ladle top argon blowing stirring slag removal, slag steel separating agent addition and the like, wherein the slag discharging post-treatment technology is easy to improve the ladle, and a large amount of additives are consumed, so that production cost is increased, and slag removal effect is unstable. In addition, part of the processes adopt a slag removing machine to remove scum manually, so that operation links are required to be increased, the labor intensity is increased, and the risk of secondary pollution of molten steel is also caused. The slag discharge and blocking technology has limitations in practical application, steel slag cannot be completely prevented from entering a steel ladle, and the slag discharge post-treatment technology tends to increase production cost or labor intensity, so that the slag discharge treatment with high efficiency and low cost is difficult to realize. Therefore, the converter tapping and deslagging treatment method capable of simply and efficiently separating residual slag in the steel ladle, reducing fluctuation of molten steel components and reducing deoxidization cost is provided, and has important significance in improving steelmaking efficiency and steel quality. CN210596144U discloses a slag trap slag removing device of a converter, comprising a compressed air collecting pipe, wherein between the converter and a buggy ladle, a compressed air collecting pipe with the diameter of 50mm and the length of the slag trap is arranged in parallel with the length direction of the slag trap at the top end of the slag trap, holes with the diameter of 5mm are drilled at intervals of 10cm in the compressed air collecting pipe, the angle is consistent with the inclination angle of the slag trap, and the pressure of the compressed air is set to be 0, 60 and 8Mpa. The utility model has the characteristics of improving efficiency, reducing accidents, eliminating potential safety hazards and the like. The patent belongs to a traditional slag blocking mode, and does not mention how to solve the problem of slag blocking equipment failure after slag discharging. CN108265149A discloses a method for controlling tapping and deslagging of a converter by blowing gas through a ring-shaped converter tapping hole, which comprises the steps of 1) arranging ring-shaped air bricks around the converter tapping hole, connecting a blowing device at the bottom of the ring-shaped air bricks, wherein gas blown by the blowing device is inert gas, 2) introducing gas into the converter through the ring-shaped air bricks at the final stage of tapping of the converter when the tilting angle of the converter is 85-90 degrees, forming a circular convex area with exposed molten steel and no slag layer at the steel slag interface above the converter tapping hole, inhibiting tapping and deslagging of the converter, and 3) stopping introducing gas after tapping of the converter is stopped. However, the mode of arranging the annular bricks at the steel tapping hole has safety risk, and the special annular brick form can influence the slag blowing effect once being stuck by the steel slag. CN101818228B discloses a control system and a control method for tapping and discharging slag of a converter, the control system comprises a converter, a ladle and an operating platform, a slag discharging detection system and an automatic furnace lifting control system are arranged in the control system, and the slag discharging detecti