The blast furnace is the most common steel-making equipment. In simple terms, iron ore, coke, etc. are fed proportionally from the top of the furnace to the lower tuyere, and then enter the high-temperature blast of 1,000 to 1,200 degrees Celsius, and are oxidized in the blast furnace. The reduction reaction generates iron slag. The slag iron flows out from the lower iron hole of the blast furnace, and separates the iron slag, slag tools, slag trench, flushing slag or enters the dry slag pit. sent to the cast iron machine. Finally, the blast furnace gas is discharged through the dust removal equipment, and the whole smelting process is probably like this.
With the development and progress of the iron and steel industry in various countries, blast furnaces are gradually developing towards large-scale, high-efficiency and longevity. The blast furnace lining refractories have c
orrespondingly higher requirements. Such as good refractoriness, high temperature stability, density, thermal conductivity, wear resistance, erosion resistance and compression resistance.
At present, there are many types of refractory materials for blast furnaces, and different parts should choose appropriate refractory materials according to different requirements.
Furnace throat
Here, the refractory gas is used as a protective lining for reasonable cloth. The temperature is between 400 and 500 degrees Celsius. It is affected by the direct impact and friction of the charge, and the air scouring effect is slightly lighter. Excellent clay bricks and high alumina bricks can be used here. , clay pouring material, spray paint, etc. for masonry.
Furnace body parts
The furnace body is an important part of the blast furnace, which is used for charging, reduction and slag troughing. Here, the scouring of the material and the high-temperature airflow is more serious. The temperature in the middle of the furnace body is between 400 and 800 degrees Celsius, and there is no impact of slag erosion. It is mainly affected by the erosion of rising dust gas, thermal shock alkalinity and damage caused by carbon deposition. Therefore, dense clay bricks, high-alumina bricks, anti-stripping and wear-resistant phosphate clay bricks, high-alumina bricks, and sillimanite bricks are used for masonry in the upper part of this part. The lower part of the furnace body is built with dense wear-resistant clay bricks, high alumina bricks, corundum bricks and silicon carbide bricks.
Hearth position
The furnace body plays a buffering role for the updraft. Part of the charge is reduced here to form slag, and the furnace lining is seriously eroded by iron slag. At 1650 degrees Celsius, the combined effects of high temperature radiation, alkali erosion, hot dust-laden rising furnace gas, etc., caused serious damage to the refractory lining of the furnace. Therefore, refractory materials with strong slag erosion resistance and erosion resistance should be selected here. High-quality clay bricks with low porosity and high alumina bricks, graphite bricks, silicon carbide bricks, corundum bricks, etc.
Hearth parts
The hearth part is the bearing part of molten iron and molten slag. The maximum temperature in the sealing area is between 1,700 and 2,000 degrees Celsius, and the temperature at the bottom of the furnace is between 1,450 and 1,500 degrees Celsius. In addition to being affected by high temperature, the refractory lining of the hearth is also subjected to the physical pressure from the molten iron slag and the upper refractory material because it has been immersed in molten iron for a long time. The scouring and erosion of molten iron slag, as well as the effect of molten iron on the buoyancy of furnace steel refractories, the sealing part of furnace steel can be built with steel jade graphite bricks, brown steel jade bricks, and sillimanite bricks. The slag iron contacts the hot surface, using steel jade graphite to stone bricks, brown steel jade bricks, and dense carbon bricks, graphite semi-graphite carbon bricks, microporous carbon bricks, and milled carbon bricks for the cold surface.
Other parts
Clay bricks, silicon carbide bricks, graphite bricks, fused corundum castables, silicon carbide castables, and iron hook hot-spraying repair materials can be used in the tapping ditch of the blast furnace.
The hook cover uses low-cement high-aluminum castables.
A low cement corundum castable is used for the skimmer.
The refractory material of the swing nozzle is similar to the iron hook material.
Slag ditch can use slightly lower material.
