Who knows the detailed process flow and operation points of converter gasification cooling

Converter Steelmaking Process

The oxidizing agent used in this method of steelmaking is oxygen. Air is blown into the molten pig iron to oxidize impurities such as silicon and manganese. In the process of oxidation, a large amount of heat is released (1% of silicon can raise the temperature of pig iron by 200 degrees Celsius), which allows the furnace to reach a high enough temperature. Therefore, converter steelmaking does not need to use additional fuel.

Converter steelmaking is carried out in a converter. The shape of the converter is like a pear, the inner wall has refractory bricks, there are many small holes on the side of the furnace (air), compressed air from these small holes to blow the furnace, also known as the side-blowing converter. At the beginning, the converter is in the horizontal, into the liquid pig iron at 1300 degrees Celsius, and add a certain amount of quicklime, and then drum into the air and rotate the converter to make it upright. At this time the liquid pig iron surface violent reaction, so that the iron, silicon, manganese oxidation (FeO,SiO2 , MnO,) slag generation, the use of molten steel and slag convection effect, so that the reaction throughout the furnace. After a few minutes, when only a small amount of silicon and manganese remains in the liquid steel, carbon begins to oxidize, producing carbon monoxide (exothermic) and causing the liquid steel to boil violently. A huge flame appears at the furnace mouth due to the combustion of the overflowing carbon monoxide. Finally, phosphorus also oxidizes and further produces ferrous phosphate. Ferrous phosphate then reacts with quicklime to form stable calcium phosphate and calcium sulfide, which together become slag.

When the phosphorus and sulfur gradually reduced, the flame recedes, the mouth of the furnace appeared brown steam of iron tetraoxide, indicating that the steel has been refined. At this point should immediately stop the blast, and the converter to the horizontal position, the steel pouring to the ladle, and then add the deoxidizer deoxygenation. The whole process takes only about 15 minutes. If the air is blown in from the furnace low, it is a low blow converter.

With the development of oxygen technology, it is now common to use oxygen top-blowing converter (also side-blowing converter). This kind of converter blowing such as high pressure industrial pure oxygen, the reaction is more violent, can further improve the production efficiency and steel quality.

The basic smelting process of a furnace of steel in a converter. Top-blowing converter smelting a furnace steel operation process mainly consists of the following six steps:

(1) on the furnace out of steel, pour slag, check the furnace lining and tilting equipment and make the necessary repairs and repairs;

(2) tilting the furnace, add scrap, to iron, shaking the body of the furnace (to the vertical position);

(3) lowering the gun to open the blowing, and at the same time to add the first batch of slag material (the furnace at first the larger noise)

(3) lower the gun to blow, while adding the first batch of slag (at first the noise in the furnace is big, from the mouth of the furnace out of the reddish smoke, followed by spraying dark red flames; 3 ~ 5min after the silicon-manganese oxygen is close to the end of the carbon-oxygen reaction is gradually intense, the mouth of the furnace flames become larger, the brightness increases; at the same time the slag melting, the noise weakened);

(4) 3 ~ 5min to add the second batch of slag continue to blowing (with the blowing of the carbon in the steel is gradually reduced, about 12min after the flames are weak, stop blowing)

(5) pouring furnace, temperature measurement, sampling, and to determine the time to make up the blowing or out of the steel;

(6) out of the steel, at the same time (will be calculated to add alloy to the ladle) for deoxidation alloying.

After the steel is discharged from the upper furnace, the slag is poured, the steel outlet is blocked, the iron is blended and scrap is added, the oxygen is supplied by the lowering gun, and the blowing is started. At the same time in the oxygen supply open blowing, add the first batch of slag, add the amount equivalent to two-thirds of the total amount of slag furnace, open blowing 3-5 minutes after the first batch of slag material, and then add the second batch of slag material. If the furnace slag is not good, then Xu added the third batch of fluorite slag.

Oxygen supply intensity during blowing:

2.5-4.5m3/(t-min) for small converter; 2.8-3.6m3/(t-min) for converter above 120t.

◆Oxygen gun position adopts high gun position when blowing, which is for early slag, more phosphorus removal and furnace lining protection;

◆Decrease the gun position appropriately in the process of blowing to ensure that the slag does not "return to dryness", does not spatter, rapid decarburization and desulfurization, and the melting pool is uniformly warming as a principle;

◆Lower the gun in the end of blowing, mainly for the purpose of the molten pool. The main purpose is to lower the gun, the main purpose is the molten pool steel composition and temperature uniformity, strengthen the molten pool stirring, stabilize the flame, easy to judge the end point, and at the same time reduce the Fe content in the slag, reduce the iron loss, and meet the requirements of the sputtering slag.

◆When blowing to the end of the carbon range of the requirements of the steel, that is to stop blowing, pouring furnace sampling, determination of the temperature of molten steel, take samples to quickly analyze the content of [C], [S], [P], when the temperature and composition meets the requirements, then out of the steel.

◆When the steel flow out of the total amount of one quarter, to the ladle in the deoxidation alloying agent, deoxidation, alloying, and thus a furnace steel smelting is completed.