Dolomite Bricks manufacturing process in the roof of the arc furnace consume energy, which have a long life. The production steps of bricks are the same and according to the market needs and orders received, other types can be produced by changing the percentage of raw materials. Dolomite is first used as an alkaline refractory layer in steel making equipment. But in the last century, it is used as a raw material for the hearth of Siemens-Martin furnaces, approximately 0.7 dolomite is used to prepare one ton of molten steel, and this amount is 12 to 48 kilos per ton of steel for lining. . Is . Dolomnia and Magnesia can be used in LD furnaces. But the exact choice is difficult, because on the one hand magnesia is more effective and on the other hand it is cheap and available. The use of these two materials depends on the place of use in the furnace and it can be said that dolomite and magnesium bricks can be used in different parts of a furnace. Dolomite and magnesite bricks are also used. Dolomite is not only used to produce refractory bricks, but also has important uses as a smelting aid. Calcined dolomite is used as a melting aid in blast furnaces. Dolomite refractories can withstand a temperature of 1700 C and high static pressure, but they have low resistance to thermal shocks, and the presence of Ca0 is another disadvantage, because it disintegrates when it absorbs water. To use dolomite in refractory industries, first heat it until CO is completely removed. 
There are two common methods for preparing refractory dolomite products: 1- Dolomite bricks with ceramic connection, which shape and heat dolomite after mixing with tar and bitumen. 2- Alkaline dolomite bricks with tar and furnace connection, which is thermally processed at the place of use. The chemical properties of bricks are very high. Refractory bricks are composed of different minerals that have different temperature tolerances, but in general, temperatures between 1300 and 1700 degrees Celsius can be tolerated. are like ceramic soil, firebricks are composed of minerals such as silica that can withstand temperatures of over 1300 degrees Celsius and this makes them strong compared to other bricks. In addition to industrial use, the use of refractory bricks is also popular in the construction of houses. Due to its high strength against shaving, scratching, light, dandruff and high strength, refractory bricks are widely used in the interior. It has home decor and adds a lot of beauty to the space. In addition to being strong, firebrick can be combined with other materials used in the building, such as ceramics, cabinets, cornices, etc., due to the wide variety of colors and designs. can be coordinated. Firebrick is used in all parts of the house such as kitchen, living room, reception, rooms. Refractory bricks are widely used in the steelmaking and glassmaking industries. Refractory bricks are used in glass furnaces due to their lack of heat transfer and high strength against heat. They are also used in the construction of fireplaces. 
dolomite bricks chemical composition
There are two types of dolomite bricks, one with dead dolomite and the other with fused dolomite, which are made with a smaller amount of oxides other than CaO and MgO. Nowadays, the refractories of chamotte tiles are of dolomite type. Sintered dolomite brick with bituminous connection is used in rotary kilns for baking cement. The refractory bricks of the lime kiln are made of dolomite. B- Chromite refractories Chromite can be used as a refractory if the sum of two oxides Al2O3 and MgO is more than 60% and also the grade of silica is less than 6%. Forsterite refractories Forsterite is a mineral of the olivine group with the chemical formula (Fe, Mg) 2 (SiO4), which can be used as a refractory with the right composition. If the molecular ratio of MgO to SiO2 is one to two in this mineral, it can be used as a refractory, but if there is Fe in the mineral, this ratio will be mixed and during roasting, forsterite combines with the oxygen of the furnace and the mineral is menite. creates The excess SiO2 from the forsterite composition makes pyroxene rich in SiO2, which has a low refractoriness degree, and its presence causes a decrease in the incombustibility of roasted forsterite. 
To prevent this, according to the chemical analysis of forsterite, MgO is added so much that the ratio of 1:2 is stable. Moreover, because the forsterite material and its briquettes are not moldable, it is mixed with a moldable material and molded. The abundance of forsterite minerals and its association with chromite masses on the one hand, the pressures of environmental regulations to clean the environment from mineral tailings on the other hand, and the slow melting of forsterite are an incentive to try to import the mining tailings and ore dressing of forsterite deposits into the slow melting industry. This material can be used as an alkaline brick for lime and cement kilns, or in kilns where temperatures above 1000 degrees Celsius are not required, or the contamination of the load with Mg or Fe present in forsterite is not a problem for it. Magnesite is another refractory mineral that has the mineralogical composition of MgCO3. Pure magnesium is rarely found in nature. Magnesia is used in the refractories industry to produce periclase. Periclase is a magnesium-containing refractory mineral, which mineralogically is a high-temperature form of MgO (magnesia). This mineral also exists in nature, but its quantity is very small, so it is prepared artificially for use in the refractories industry in two ways. 1- Calcination of natural magnesite: Calcination of magnesite at a temperature of 1450 to 1500 degrees Celsius leads to the formation of MgO. 2- Mg(OH)2 brucite mineral calcination, brucite is a natural source, but due to its rarity compared to magnesite, it cannot be counted as a reliable source. 
Since magnesia is needed for the preparation of periclase, and on the other hand, it may not be possible to access these resources, therefore, in advanced countries, the method of extracting magnesia from sea water has been established as a refractory production industry. In this method, by using dead lime, dead dolomite or caustic soda, magnesium ions dissolved in sea water are forced to settle in the form of hydroxide. After being separated from the solution, the obtained deposit is calcined in rotating shaft furnaces at a very high temperature. Calcined magnesia grains, whether natural or chemical, are ineffective against moisture or carbon dioxide in the air, so they can be considered dead. Magnesia obtained from sea water is a uniform product with a purity of 98% or higher.