Steel Industry
70% of the downstream demand for refractory materials is the steel industry, which is used in blast furnaces, converters, electric furnaces, ladle furnaces, LF furnaces, RH furnaces and continuous casting systems.
Refractories for the steel industry
The iron and steel production process is to smelt iron ore into pig iron in a blast furnace, pour molten iron into a converter or an electric furnace to smelt steel, and then cast the molten steel into continuous casting slabs or steel ingots, and process them into steel products for various purposes by rolling and other plastic deformation methods. Due to the different working environments and usage requirements of various furnaces in steel production, there are also different requirements for refractory materials.
Refractories for blast furnaces
The main refractory materials used in blast furnace ironmaking are unshaped refractory materials, carbonaceous refractory materials, clay bricks, high alumina bricks, etc. Carbonaceous refractories include graphite, semi-graphite, carbon, and Si3N4 bonded SiC bricks.
Different parts of the blast furnace have different operating environments, and the requirements and choices for refractory materials differ.
Mainly use high-quality clay bricks and high-alumina bricks for masonry.
The middle and upper-temperature zones are 400°C~800°C. High-quality clay bricks or high-alumina bricks are used to build these parts.
The lower part of the blast furnace shaft: After many investigations and studies on blast furnaces, the results show that about 23% of the blast furnaces use SiC refractory materials. The Si3N4 combined with SiC brick developed in my country has significantly improved the anti-erosion performance. It has begun to be applied to the masonry of central blast furnace shafts in my country, which has significantly improved the service life of blast furnaces.
The temperature during regular operation is 1400 ° C ~ 1600 ° C. Given the erosion and severe erosion of the furnace waist, my country has developed Si3N4 combined with SiC bricks. The practice has proved that this brick is resistant to erosion and erosion.
The temperature of the lower charge is about 1600°C~1650°C, and a large amount of intermediate slag is formed and begins to drip. Silicon carbide bricks made of carbonaceous refractory materials in China are generally used. Many refractory materials are also used in this part of the country abroad. The 3662m3 blast furnace bosh of Holland Hogowen Iron and Steel Company is built with semi-graphite bricks, and the effect is better.
The temperature is generally between 1450°C and 1500°C. The temperature in the tuyere area can reach 1700°C~2000°C. It is mainly built with charcoal bricks. In recent years, many domestic blast furnace hearths have adopted the carbonaceous material-ceramic material composite structure of French SAVOIE company and Nippon Electrode Company.
The central device in the iron mouth is the iron mouth sleeve, which is made of cast steel and welded with the furnace shell. Carbon bricks with excellent performance are mainly used in this part.
Converter
A converter kiln is an industrial kiln used in the steelmaking industry to convert pig iron into steel. The process involves heating pig iron, a combination of iron and carbon, to high temperatures in a furnace or kiln while blowing oxygen through it. This results in removing impurities such as carbon, silicon, and manganese and adding specific alloys to produce steel with the desired properties.
Today, different types of converter kilns are used in the steelmaking industry, such as the basic oxygen furnace (BOF) and the electric arc furnace (EAF). The BOF converter uses pure oxygen blown into the furnace to remove impurities, while the EAF converter uses electric arcs to melt and refine the steel scrap.
Magnesia carbon bricks for converters.
Fused magnesia
Sintered magnesia + asphalt + binder
Magnesia + Slaked lime + Water.
High-pressure air gunning, one repair for several furnaces.
Magnesia + Resin.
Magnesia + Chrome green.
Electric furnace
An electric furnace is a heating system that generates heat by converting electrical energy into heat energy. It works by passing an electric current through heating elements, which then radiate heat to warm the surrounding air. Electric furnaces are commonly used in residential and commercial settings as a primary or supplementary heat source. They are typically more expensive to operate than other types of heating systems, but they offer several benefits, such as being easy to install, clean, and maintain. Additionally, they do not produce any harmful emissions, making them an eco-friendly option for heating.
High alumina、Mullite、Corundum、Chrome corundum castables.
Directly combined with magnesia-chrome bricks
Pre-reaction magnesia-chrome bricks
Magnesia bricks
Oil-impregnated magnesia bricks
Direct bonded magnesia-chrome bricks
Fused cast magnesia-chrome bricks
Magnesia-carbon bricks
A layer of asbestos board, covered with diatomaceous earth powder, and laid with heat insulation bricks on it.
Staggered joint masonry such as fired magnesia bricks, asphalt-bonded magnesia bricks, etc.
Knotted furnace bottom: magnesia + pitch, tar, magnesia calcium iron sand.
Masonry bottom: asphalt bonded magnesia bricks, brine bonded magnesia bricks.
High strength magnesia carbon brick
Al2O3-SiC-C brick
Ladle Furnace
A ladle furnace is a type of secondary metallurgical furnace used for refining steel before casting. It is typically a small, electric arc furnace that is used to heat the steel from the primary furnace and then refine it by adjusting the chemical composition and temperature. The ladle furnace is an important tool for improving the quality and consistency of steel, and it is commonly used in steel mills around the world.
Magnesia carbon brick、 aluminum magnesia carbon brick
Low-carbon magnesia-carbon brick, aluminum-magnesia-carbon brick, aluminum-magnesium unfired brick (carbon-free brick), aluminum-magnesium castable
Al-Mg-C brick、 Al-Mg castable、 Corundum spinel castable.
Al-Mg-C brick、 Al-Mg castable、 Corundum spinel castable.
LF furnace
Refractory materials for slag line, high-quality magnesia carbon bricks with corrosion resistance and thermal shock resistance, added with antioxidant ZrB2 (1.5%); high alumina bricks for steel water line;
High alumina bricks and high alumina castables are used for the bottom of the package.
Datong Company uses magnesia carbon bricks for the full lining.
ASEA-SKF Furnace
Slag line position: magnesia carbon brick, magnesia chrome brick, magnesia brick, magnesia dolomite brick, high alumina brick with Al2O3>85%;
75% Al2O3 high alumina bricks and castables for side walls and bottom cladding;
Aluminum carbon bricks are used for the lower part of the steel water line.
RH vacuum refining equipment
The main refractory materials of the main body: magnesia-chrome bricks, magnesia spinel bricks, corundum spinel castables, corundum spinel prefabricated materials, are developing towards chrome-free.
Continuous casting tundish: blast furnace brick, magnesia coating.
