Magnesium aluminum bricks use square magnesium as the main crystal phase, and the magnesium aluminum spinelite as the matrix. In order to improve the heat shocks of magnesium bricks, the alumina or aluminum aluminum clinker fine powder is introduced in the ingredients to form a magnesium and aluminum spinelite matrix, there by making Magnesia Spinel Bricks. The characteristic of magnesium aluminum bricks is that the heat shock resistance is good, the load softening temperature is high, the load softening temperature is above 1580 ° C, and the glass resistance is good. With the increase of AL and Oz content, the pores of bricks increase. However, when the Al2O3 content is less than 10%, the bricks are still dense, and the air perforated rate can reach 14%, generally 15%to 18%.
Magnesium and aluminum bricks have been plastic flowing from 1000 ° C. It was significantly significant at 1200C. The flow accelerated at 1300 ° C. These are similar to the magnesium chromium bricks and are different from magnesium bricks, and the rapid flow temperature of magnesium bricks is 100 ~ 100 ~ 200C. When the amount of alumina adds less than 15%, the effect of Magnesia Spinel Bricks and iron oxide does not cause expansion, and the amount of adding is slightly expanded when the addition of 15%; the expansion is severe at 20%; the expansion is severe at 28%.
Most of the magnesium bricks are used in the metallurgical industry. Due to good thermal stability and high temperature intensity of magnesium aluminum bricks, it is mainly used for important parts such as steel making flat furnaces. High -purity magnesium bricks are used in the easily eroded damage area of refining furnaces outside the furnace and outside the furnace. Magnesium carbon bricks are mainly used for important parts of converter, electric furnace and out -of -furnace refinement furnace. Magnesium silicon bricks or higher magnesium olive bricks containing SIO2 can be used for the heat storage room and cement rotary kiln of the flat furnace and glass melting kiln. The melting particles are combined with magnesium bricks, which are mostly used in the key parts of severe erosion in the electric furnace, out -of -furnace refining furnace and non -ferrous metal smelting furnace.
The thermal expansion and thermal stability of the magnesium aluminum brick. Because the line expansion coefficient of the magnesium and aluminum spinels is small, the line expansion coefficient of magnesium and aluminum bricks is very small. In the range of 20 ~ 1000C, the inflation coefficient of the magnesium aluminum brick is only 10.6 × 10-6 ° C. Because magnesium aluminum spinels play a role in enhancing heat shocks in the bricks, the heat shock resistance of Magnesia Spinel Bricks is better, and the number of water cooling is more than 20 times.
