Composition of Furnace Linings and Classification of Magnesia Bricks
Furnace linings are one of the most important components of the industrial furnaces. Since the furnaces have to withstand very high temperatures, it is essential that the linings are strong and durable. Proper selection of the material and proper construction of the linings is of utmost importance to maintaing good furnace performance. The main components of furnace linings are refractory bricks, insulation bricks and castable refractory. These materials are available in different grades and types to suit different application and temperature requirements.
Refractory bricks are the most commonly used material for the construction of furnace linings. Refractory bricks come in a variety of shapes and sizes to suit different applications and temperatures. Refractory blocks can be made from basic and acid refractories, magnesia, clay, alumina, alumina-silica mixtures and so on. While basic and acid refractories are suitable for non-oxidizing atmospheres, magnesia, clay and alumina bricks are suitable for oxidizing atmospheres. Depending on the type of brick, they can withstand temperatures ranging from 1400 to 1800°C.
Another type of brick used in furnace linings is the insulating brick. These are made of lightweight materials such as alumina, silica, and magnesia. The bricks are available in different shapes and sizes to suit various applications. They are used to reduce heat losses and to prevent heat transfer between sections of the furnace. Insulating bricks are able to withstand temperatures up to 1500°C.
The third type of material used for furnace linings is castable refractory. This is a cement based material that can be shaped and formed into the required shape for the lining. It is available in two different types: monolithic and plastic casting. Castable refractory is available in different grades to suit different temperatures and applications.
Magnesia bricks are a special type of brick that can withstand temperatures up to 1800°C. Magnesia bricks contain a high content of magnesium oxide (MgO) which gives the brick its thermal properties. Magnesia bricks can be divided into three different categories based on their type and use: Bauxite-magnesia, Calcined-magnesia and Dead-burned-magnesia.
Bauxite-magnesia bricks are made from natural bauxite ore that is high in magnesium oxide. These bricks are suitable for applications in non-oxidizing atmospheres and can withstand temperatures up to 1300°C.
Calcined-magnesia bricks are made from powdered magnesite which is heated to high temperatures to form the desired bricks. These bricks are suitable for use in non-oxidizing atmospheres and can withstand temperatures up to 1300°C.
Dead-burned-magnesia bricks are made from high purity magnesite which is heated to very high temperatures to form the bricks. These bricks are suitable for use in oxidizing atmospheres and can withstand temperatures up to 1800°C.
In conclusion, furnace linings are composed of different materials to suit various applications and temperatures. Refractory bricks, insulating bricks and castable refractory are some of the main components used for furnace linings. Magnesia bricks are a special type of brick that can withstand high temperatures up to 1800°C. Magnesia bricks are further subdivided into Bauxite-magnesia, Calcined-magnesia and Dead-burned-magnesia bricks depending on their type and use.
