Calcium and magnesium belong to alkaline earth metals in the periodic table. In the refractory industry, refractory bricks with calcium oxide and magnesium oxide as the main chemical components are usually called basic refractory bricks. Basic refractory bricks have good corrosion resistance to metallurgical slag, cement clinker, glass kiln ingredients, and ash. Different heat media have different effects on basic bricks. RS Cheap Fire Bricks Factory is a powerful manufacturer and seller of refractory bricks. What are the characteristics of RS factory’s magnesium bricks? Contact us for detailed information and quotes.
Kinds of Magnesium Bricks in Rongsheng Manufacturer
What are the Characteristics of Alkaline Refractory Bricks?
The load softening temperature, high temperature flexural strength, high temperature volume stability and high temperature compression creep properties of each alkaline refractory brick change with the increase of brick-making raw material density, the decrease of impurity content and the increase of firing temperature.
The load softening temperature of ordinary alkaline products is 1550-1600℃. Magnesium dolomite bricks, magnesium spinel bricks, high purity magnesium bricks, direct bonded magnesium chrome bricks, etc. are above 1700℃. Semi-rebonded and rebonded magnesium chrome bricks can reach 1750-1800℃.
The high temperature flexural strength of each alkaline refractory brick decreases with the increase of test temperature. The high temperature strength of rebonded magnesium chrome bricks with high Cr2O3 content is higher. Alkaline bricks with fused raw materials have higher high temperature strength.
The thermal expansion rate of basic refractory bricks is higher than that of other products. The thermal expansion rates of various basic refractory bricks with MgO as the main component are not much different. At 1600℃, the linear expansion rate of magnesia bricks is large, about 2.0%; the linear expansion rate of magnesia chrome bricks is small, about 1.6%; the thermal expansion rates of other basic refractory bricks are between the two.
The thermal conductivity of basic refractory bricks is higher than that of high alumina bricks, clay bricks, and silica bricks.
How is the Thermal Shock Resistance of Basic Refractory Bricks?
The thermal shock resistance of basic refractory bricks is not as good as that of clay bricks and high alumina bricks. The thermal shock resistance of various basic refractory bricks decreases in the following order: magnesia spinel (magnesia aluminum) bricks>magnesia chrome bricks>magnesia dolomite bricks>magnesia bricks.
RS Cheap Fire Bricks manufacturers can provide high-quality refractory brick products according to actual production needs. Various basic refractory bricks, magnesia refractory bricks, magnesia chrome bricks, magnesia aluminum bricks, magnesia spinel bricks, etc. Contact us to buy high-quality refractory bricks and get free samples and quotes. Next, here is an introduction to several commonly used basic refractory bricks.
Application Characteristics of Magnesia Refractory Bricks
In a strong alkaline environment, such as the cement kiln firing zone, the order of resistance to cement clinker corrosion is: magnesia dolomite brick > magnesia chrome brick > magnesia spinel brick. When the AOD furnace produces stainless steel, the slag basicity is less than 2.2, and the slag resistance of magnesia chrome brick is better than that of magnesia dolomite brick; when the slag basicity is greater than 2.2, the slag resistance of magnesia dolomite brick is better than that of magnesia chrome brick. In heavy nonferrous metallurgical furnaces, the ability to resist FeO-SiO2 slag: magnesia chrome brick > magnesia brick > magnesia spinel brick > magnesia dolomite brick.
The refractoriness of alkaline refractory bricks is above 2000℃, which is higher than other refractory bricks.
Differences in Application and Performance between Fired Magnesia Brick and Re-Fired Magnesia Brick
Magnesia brick is a kind of alkaline product with MgO content higher than 80%. According to different production processes, it can be divided into fired magnesia brick, unfired magnesia brick and re-bonded magnesia brick.
(A) Fired Magnesia Brick
Fired magnesia brick is a product made of fired magnesia sand as the main raw material, which is fired at a high temperature of about 1500℃ after being pressed by machine. Because the raw materials used are not of high grade, the firing temperature is low and the price is cheap. Moreover, it has good high temperature performance and strong resistance to metallurgical slag. It is widely used in steelmaking furnace linings, ferroalloy furnaces, mixed iron furnaces, converter linings, non-ferrous industrial furnaces for copper, lead, tin and other linings in the steel industry.
(B) Re-bonded Magnesia Brick
Re-bonded magnesia brick is a kind of product made of fused magnesia sand as the main raw material, which is fired at a high temperature of 1800℃ after high pressure molding. In order to improve the slag erosion resistance of this kind of product, the re-bonded magnesia brick can be vacuum asphalt impregnated after firing. Since this kind of product uses fused magnesia as the main raw material, the raw material has high purity and the degree of direct bonding of periclase and periclase in the product is high, this kind of product is often used in the steel-making furnace tapping port and the slag line of non-ferrous metallurgical slag where slag erosion and wear are serious.
Magnesia-chrome bricks are mainly used in metallurgical industry, such as building open-hearth furnace roof, electric furnace roof, external refining furnace and various non-ferrous metal smelting furnaces. The high-temperature parts of the electric furnace wall use fused-cast magnesia-chrome bricks, and the high-erosion area of the external refining furnace uses magnesia-chrome bricks made of synthetic materials. The high-erosion area of the non-ferrous metal flash smelting furnace uses fused-cast magnesia-chrome bricks and magnesia-chrome bricks made of synthetic materials. In addition, magnesia-chrome bricks are also used in the firing zone of cement rotary kilns and the regenerator of glass kilns.
The raw materials usually used to produce MgO-Cr2O3 products are mainly magnesia sand, chromium ore, synthetic magnesia-chrome sand, and sometimes a small amount of additives are added. Sintered floor sand and electric fused mirror sand with different MgO contents (generally greater than 89%) are matched with refractory grade chromium ore, chromium concentrate, sintered or electric fused synthetic magnesia-chrome sand with different Cr2O3 contents (sometimes a small amount of chrome green is added) to produce a variety of magnesia-chrome products. Ordinary magnesia-chrome bricks are generally made of sintered magnesia sand (MgO content between 89% and 92%) and refractory chrome bricks. Due to the large amount of impurities, the refractory grains are combined by silicates. The so-called magnesia-chrome refractory bricks generally refer to fired ordinary magnesia-chrome bricks.
RS Refractory Brick Manufacturer
If you have a project that requires the purchase of magnesia series refractory bricks, alkaline refractory bricks, and other basic refractory bricks and want to get more detailed information, please send us an email.
What should I do if the refractory material cracks, falls off, or is easy to wear? Rongsheng Refractory Brick Manufacturer specializes in the design, construction, and material supply of refractory linings for high-temperature industrial furnaces. It aims to provide high-quality and long-life refractory linings for high-temperature industrial furnaces. Our refractory products have been sold to more than 120 countries around the world, such as South Africa, Chile, Egypt, Colombia, Uzbekistan, Italy, Indonesia, Ukraine, Hungary, Spain, Kenya, Syria, Zambia, Oman, Venezuela, India, Peru, the United States, Ethiopia, etc. Dig out the root cause, analyze the real cause, and provide solutions for high-temperature industrial furnace linings. Contact us for free consultation and technical exchanges.
