Chrome corundum brick (chrome corundum brick) refers to corundum refractory products containing Cr2O3. At high temperatures, Cr2O3 and Al2O3 form a continuous solid solution, so the high-temperature performance of chromium corundum products is better than pure corundum products. Performance Advantages of Chrome Corundum Brick. The chromium corundum bricks used in the petrochemical industrial gasifier should be low silicon, low iron, low alkali, high purity, and have higher density and strength.
Mineral Composition of Chrome Corundum Brick
The main mineral composition is α-Al2O3-Cr2O3 solid solution. The secondary mineral composition is a small amount of composite spinel (or no composite spinel), refractory brick with chromium oxide content of 1% to 30%. There are two kinds of fused corundum brick and sintered chrome corundum brick. In general, chrome corundum brick refers to sintered chrome corundum brick.
Performance Advantages of Chrome Corundum Brick
Corundum bricks are refractory bricks with an alumina content greater than 90%. Corundum bricks are divided into sintered corundum bricks and fused corundum bricks. The chrome corundum brick is made of refractory brick with Cr2O3 added to the corundum. The chromium corundum brick is divided into two types: fused cast chrome corundum brick and sintered chrome corundum brick. Corundum bricks are used in industrial kilns under high temperature and high pressure. Performance Advantages of Chrome Corundum Brick. Compared with corundum bricks, chrome corundum bricks have the following advantages.
Adding Cr2O3 to corundum material not only does not reduce the fire resistance of the material department but also improves the fire resistance of the material. The refractory degree of chrome corundum brick is greater than 1790℃, and the load softening temperature is greater than 1700℃.
The room temperature compressive strength of corundum bricks is 70-100MPa, and the room temperature compressive strength of high-performance chrome corundum bricks is generally greater than 150MPa, which is significantly higher than corundum bricks. During the firing process of corundum bricks and chrome corundum bricks, Al2O3-Cr2O3 solid solution is formed between particles and particles, between particles and fine powder, and between fine powder and fine powder. The solid solution connects the particles and fine powder together like a bridge to greatly improve the strength of the material.
Thermal shock stability
Add Cr2O3 to corundum raw materials. When the Cr2O3 content is 10%-66%, the thermal shock stability of the material decreases with the increase of Cr2O3 content. That is, chromium corundum bricks with low Cr2O3 content have higher thermal shock stability than chromium corundum bricks with high Cr2O3 content. The Cr2O3 content of high-performance chrome corundum brick is between 12%-20%, and its thermal shock stability is improved compared with corundum brick. Especially the addition of a small number of additives that produce phase change, and the AKZ type chrome corundum brick produced has better thermal shock stability.
Slag erosion resistance
Corundum bricks are severely eroded by slag. The slag will all penetrate into the brick, and penetrate into the surface along the pores inside the brick, and the brick becomes brown. Chrome corundum bricks are hardly attacked by slag. There is no obvious chemical reaction between the slag and the brick surface, and the boundary between the inner hole edge and the slag is clear. There is very little penetration of slag into the brick, and only about 5-10mm thick metamorphic layer is formed around the brick hole, and a large amount of molten slag remains in the crucible hole. The chromium corundum bricks are better than corundum bricks in chemical corrosion resistance and permeability in gasification furnace slag, and the structural spalling resistance is also superior to corundum bricks.
Application of chrome corundum brick
Rongsheng refractory manufacturer, Chrome corundum brick has excellent thermal vibration stability and high temperature creep performance. Therefore, the application of chrome corundum brick has been more widely used. The chromium corundum brick made of metal chromium slag as the main raw material is widely used in zinc smelting electric furnaces and volatile kilns. Chrome corundum bricks are used as linings for glass kilns, brushed glass flow hole covers, slab bricks, and for hot metal pretreatment devices, garbage incinerators, gasifier backings, etc.