CN107012283B - Converter slag retention method - Google Patents

Abstract

The invention provides a method for leaving slag in a converter. The slag pouring angle is controlled according to the end temperature of the upper furnace smelting and the oxygen value. After the slag pouring is completed, the converter is shaken to zero position, nitrogen gas is used to splash the slag, and a slag splashing agent is added during the slag splashing; the slag splashing is finished Add activated lime and light-burned dolomite before the thick slag; after the slag splashing, the converter is shaken to 90°~98°, and the slag condition is confirmed. ～26500Nm ³ /h, gun position 2100～2250mm. The present invention can avoid explosion phenomenon when mixing iron, eliminate potential safety hazards, avoid the problem of dry dust removal and explosion relief caused by failure of ignition in the early stage of blowing, stabilize production rhythm, and ensure equipment safety; at the same time, it can greatly reduce flux consumption, The amount of active lime and light-burned dolomite per furnace is reduced by 11.1kg/t steel and 8kg/t steel respectively, thereby effectively reducing smelting costs.

Description

A method for leaving slag in a converter

technical field

The invention belongs to the technical field of steelmaking technology, and in particular relates to a converter slag retention method for preventing dry explosion venting and reducing the unit consumption of flux under the condition of dry dust removal.

Background technique

Reducing the cost of converter smelting has always been an important control indicator for steelmaking plants, in which flux components account for a large share of steelmaking costs, so it is imperative to reduce the cost of steelmaking fluxes. Usually, the slag is poured out after splashing slag in converter steelmaking equipped with dry dust removal, because the unsuitable amount of slag left will cause poor ignition during blowing, which will cause dry dust removal and explosion relief, and in severe cases Will damage the dry dust removal equipment.

Contents of the invention

The present invention aims to provide a method for leaving slag in a converter that can prevent poor ignition during blowing, avoid blasting during iron mixing, reduce flux consumption, and reduce smelting costs.

For reaching this purpose, the present invention has taken following technical solution:

A method for leaving slag in a converter, its specific method and steps are:

(1) Carry out slagging angle control according to the end point temperature and oxygen value of upper furnace smelting, the corresponding slagging angle of tapping temperature T at the end point of upper furnace smelting and tapping oxygen value [O] is:

(2) After the slag pouring is finished, shake the converter to zero position, use nitrogen gas for slag splashing, the flow rate of nitrogen gas is 38000-42000Nm ³ /h, the position of the slag splashing gun is gradually reduced from 2000mm to 500mm, and the amount of slag splashing agent added during slag splashing is as follows ( As shown in 1), the slag splashing time is controlled within 2 to 4 minutes;

(3) 18-22 seconds before the end of slag splashing, add 980-1050 kg of active lime and lightly burned dolomite to make thick slag;

(4) After the slag splashing is over, the converter is shaken to 90°~98°, and the slag condition is confirmed to ensure that the slag is splashed dry;

(5) After the slag is confirmed, add scrap steel to molten iron, and the iron mixing time is controlled at 4 to 6 minutes;

(6) The oxygen flow rate is 25000-26500Nm ³ /h at the end of blowing after mixing iron, and the gun position is 2100-2250mm. If the ignition is not smooth after starting blowing for 30 seconds, immediately raise the gun and shake the furnace, and shake the furnace backward to - 40°, shake forward to 60°, then shake the converter to zero position to continue blowing.

The slag splashing agent mainly contains C and MgO, wherein C: 9-11wt%, MgO: 55-60wt%. The beneficial effects of the present invention are:

The method of pouring slag first, then splashing slag and thick slag in the present invention can avoid the phenomenon of blasting when mixing iron, and eliminate potential safety hazards; by reasonably controlling the amount of slag remaining, dryness caused by failure to ignite in the early stage of blowing can be avoided. The problem of dedusting and explosion relief by means of method stabilizes the production rhythm and ensures the safety of equipment; at the same time, the invention can greatly reduce the consumption of flux, reducing the consumption of active lime and light-burned dolomite by 11.1kg/t steel and 8kg/t respectively per furnace. steel, thereby effectively reducing the cost of smelting.

Detailed ways

The slag splashing agent contains C: 9-11wt%, and MgO: 55-60wt%.

Example 1:

1. The tapping temperature at the end of the upper furnace smelting is T1710℃, the tapping oxygen value [O] is 840ppm, and the slag pouring angle is determined to be 116°.

2. After the slag pouring is finished, shake the converter to zero position, use nitrogen gas for slag splashing, the nitrogen flow rate is 39500Nm ³ /h, the position of the slag splashing gun is gradually reduced from high to low, from 2000mm to 500mm, and the amount of slag splashing agent added during slag splashing is 2.75kg/t steel, slag splashing time 4min.

3. Add 1000kg of activated lime and lightly burned dolomite 20s before the end of slag splashing to make thick slag.

4. After the slag splash is over, the converter is shaken to 95°, and the slag condition is confirmed to ensure that the slag is splashed dry.

5. After the slag is confirmed, add scrap steel to molten iron. When mixing iron, it is mixed slowly in a small flow, and the time is controlled within 5 minutes.

6. The oxygen flow rate is 26000Nm ³ /h and the gun position is 2200mm when the blowing is completed. If the ignition is not smooth after 30 seconds of blowing, immediately raise the gun and shake the furnace. When shaking the furnace, shake the furnace backward to -40° and forward to 60°, and then shake the converter to zero to continue blowing.

Example 2:

1. The tapping temperature at the end of upper furnace smelting is T1650℃, the tapping oxygen value [O] is 855ppm, and the slag pouring angle is determined to be 106°.

2. After the slag pouring is finished, shake the converter to zero position, use nitrogen gas for slag splashing, the nitrogen flow rate is 40000Nm ³ /h, the position of the slag splashing gun is gradually reduced from high to low, from 2000mm to 500mm, and the amount of slag splashing agent added during slag splashing is 1.65kg/t steel, slag splashing time 2.5min.

3. Add 990kg of activated lime and 1020kg of lightly burned dolomite 19s before the end of slag splashing to make thick slag.

4. After the slag splash is over, the converter is shaken to 95°, and the slag condition is confirmed to ensure that the slag is splashed dry.

5. After the slag is confirmed, add scrap steel to molten iron. When mixing iron, add it in a small flow and slowly, and the time is controlled at 5.5 minutes.

6. The oxygen flow rate is 25500Nm ³ /h and the gun position is 2150mm when the blowing is completed.

Example 3:

1. The tapping temperature at the end of the upper furnace smelting is T1690℃, the tapping oxygen value [O] is 840ppm, and the slag pouring angle is determined to be 109°.

2. After the slag pouring is completed, the converter is shaken to zero position, nitrogen slag splashing is used, the nitrogen flow rate is 41000Nm ³ /h, the slag splashing gun position is gradually reduced from high to low, from 2000mm to 500mm, and the amount of slag splashing agent added during slag splashing is 2.2kg/t steel, slag splashing time 3min.

3. Add 1010kg of activated lime and 990kg of lightly burned dolomite 21s before the end of slag splashing to make thick slag.

4. After the slag splash is over, the converter is shaken to 95°, and the slag condition is confirmed to ensure that the slag is splashed dry.

5. After the slag is confirmed, add scrap steel to molten iron. When mixing iron, it will be mixed in a small flow and slowly, and the time will be controlled within 4.5 minutes.

6. The oxygen flow rate is 26200Nm ³ /h and the gun position is 2210mm when the blowing is completed.

Claims (1)

1. A method for leaving slag in a converter, characterized in that, the specific methods and steps are: (1) Carry out slagging angle control according to the end point temperature and oxygen value of upper furnace smelting, the corresponding slagging angle of tapping temperature T at the end point of upper furnace smelting and tapping oxygen value [O] is: The slag splashing agent mainly contains C and MgO, wherein C: 9-11wt%, MgO: 55-60wt%; (2) After the slag pouring is finished, shake the converter to zero position, use nitrogen gas for slag splashing, the flow rate of nitrogen gas is ^{38000-42000Nm3} /h, the position of the slag splashing gun is gradually reduced from 2000mm to 500mm, and the amount of slag splashing agent added during slag splashing is as follows: As shown in 1), the slag splashing time is controlled within 2 to 4 minutes; (3) 18-22 seconds before the end of slag splashing, add 980-1050 kg of active lime and lightly burned dolomite to make thick slag; (4) After the slag splashing is over, the converter is shaken to 90°~98°, and the slag condition is confirmed to ensure that the slag is splashed dry; (5) After the slag is confirmed, add scrap steel to molten iron, and the iron mixing time is controlled at 4 to 6 minutes; (6) The oxygen flow rate is 25000-26500Nm ³ /h at the end of blowing after iron mixing, and the gun position is 2100-2250mm. If the ignition is not smooth after starting blowing for 30 seconds, immediately raise the gun and shake the furnace, and shake the furnace backward to - 40°, shake forward to 60°, then shake the converter to zero position to continue blowing.