One of the types of refractory bricks is magnesite brick. This type of brick has alkaline properties. Magnesite bricks are prepared and produced using magnesite and magnesium chloride. The chemical formula of magnesite is 3MgCO and the chemical formula of magnesium chloride is 2MgCI. Also, magnesium chloride comes from water, salt lakes and salt deposits. Besides, magnesium chloride can be collected from industrial centers. Magnesia brick production method Magnesite bricks are prepared and produced using 2 methods, decorative and melting. 1- Zinteri method: In this method, the raw materials must first be calcined, then exposed to a special baking curve for sintering. In this process, special materials such as zirconium oxide and cream oxide are used to aid in baking. The chemical formula of zirconium oxide is 2ZrO and the chemical formula of chromium oxide is 3O2Cr. Usually, in this method, baking is done in a tunnel oven at a temperature of 1500 to 1800 degrees Celsius, and glue is used to maintain the strength of the body. Hydraulic pressing is primarily a forming method. 
2- Melting method: Magnesite bricks are produced by melting at a temperature of more than 2800 degrees Celsius and in an electric arc furnace. In this method, the raw materials must first be melted and then cooled. Magnesite bricks produced by this method have the highest density and lowest porosity. Advantages and disadvantages of magnesium brick: Magnesite brick has very high strength and chemical resistance against alkaline substances. This type of brick has a high coefficient of thermal expansion, which causes its low shock resistance and thus limits its use. Also, magnesite brick is affected by air humidity at a temperature of 40 to 120 degrees Celsius, which causes hydration and, as a result, causes defects in it. At the same time, this issue makes it difficult to store, transport and install this type of brick. Application of magnesium brick: Magnesite bricks are used in industries such as iron and steel, as a protective lining in Siemens and electric arc furnaces. Magnesite bricks have high hot strength and very good chemical resistance against alkaline materials (including steel slag). But these bricks have a high coefficient of thermal expansion and thus low shock resistance, which has limited the use of these bricks. Also, these bricks undergo hydration at a temperature of 40 to 120 degrees Celsius under the influence of air humidity, which leads to defects in the bricks. This issue has made it difficult to store, transport and install these bricks. chrome Magnesite Bricks properties are used in iron and steel industries as a protective lining in Siemens-Martin furnaces and electric arc furnaces. These bricks are also used as lining of non-metallic industry furnaces such as tunnel, rotary and vertical furnaces. These bricks are also used in glass melting furnaces and non-ferrous metal industry furnaces (such as copper, lead, zinc, aluminum and nickel). The raw materials that are mainly used to produce alkaline bricks are magnesite and magnesium chloride. Magnesite is found in the form of crystals in nature. The chemical formula of magnesite is MgCO3. Magnesium chloride with the chemical formula MgCl2 is obtained from sea water, salt lakes and salt deposits. Magnesium chloride can also be extracted from industrial wastewater. In relation to the production of this product as stated To produce magnesite brick by sintering method, the raw materials must be calcined first and then sintered under a special baking curve. In this process, special materials such as zirconium oxide (ZrO2) and crum oxide (Cr2O3) are used as sintering aids. Baking is usually done in a tunnel oven at a temperature of 1500 to 1800 degrees Celsius. 
magnesia chrome refractory
It is mainly made of chromium and magnesium ores, contains a lot of magnesium oxide and impurities, and ignites at about 1550 degrees Celsius. Because the silicate melts between the crystal grains to form a low melt, the refractory's firing temperature is also low, resulting in anti-washability and poor thermal shock resistance. With the development of non-ferrous metal smelting technology and the increasing severity of the environment, such materials are no longer used. It is composed of high-purity magnesium and chromium ore with less impurities and is synthesized at a temperature of 1700 degrees Celsius or higher. The advantage is that the grain is in direct contact between the grains. When the temperature is high, the chromium concentrate grains combine with periclase to form a solid, and when zinc reaches its melting point, which is always unchanged, it changes state, resulting in corrosion resistance and stability. A hit is guaranteed. Improves heat, performance is superior to normal. Chromium magnesium bricks are still used in zinc evaporation furnaces in some factories today. The amount of silicate phase in the direct bonding magnesium chromium brick is low, the amount of secondary spinel is high, there is direct bonding between periclase and periclase and between periclase and chromite, so this product has high temperature resistance, corrosion resistance and shock resistance. 
thermal In the high temperature sintering process, chromium enters the magnesium matrix and forms periclase solid solution. When the temperature decreases, the secondary spinel MgO-R2O3 is formed and then forms a direct bond structure. Chrome magnesia brick with direct glue has the property of hanging the furnace skin, so it is suitable for arranging the baking area of all types of cement furnaces. According to a general survey, the most widely used refractories worldwide are fire clays (46%) and magnesium-based refractories (26%). Refractory clays are used in a wide range of applications and industries. While magnesium refractories are very important for the steel industry and it is used in making refractory bricks for steel furnaces. Although dolomite makes up a small percentage of bricks worldwide (3%), it is strongly associated with the stainless steel industry, where dolomite refractories largely replace magnesium-chromium bricks. Fire bricks in various sizes and shapes are now available for a variety of applications. Common refractories include refractories, alumina, silica bricks, magnesite refractories, chromite refractories, zirconia refractories, insulating materials and integrated refractories. Refractory bricks are composed of a chemical composition of 23% aluminum and 73% silica. Ferric oxide, titanium and other metal oxides make up the remaining ingredients of firebricks. But the main composition of ordinary bricks is silica, alumina, magnesia, lime, iron oxide and alkaline materials, and if any of these ingredients are combined more or less than the specified amount, serious problems will arise for the structure of the bricks. The importance of material composition in ordinary bricks is generally less than in refractory bricks. The main purpose of firebrick, which is used inside the furnaces of the steel and cement industry, is to minimize the heat from burning the fuel in the furnace and also to reduce the heat loss from the furnace. Therefore, it is important that these materials have insulating properties and can withstand high temperatures. Also, the firebricks used in the furnace should not contaminate the material it comes in contact with. Refractory materials should have sufficient mechanical resistance and be able to withstand different forces. Materials (pure compounds) used to make refractory bricks (such as MgO, SiC, Fireclay, etc.) have a high melting point in the range of 1800 to 2800 degrees Celsius.