Preparation of Microporous Corundum Aggregates and their Applications in Lightweight Alumina-Magnesia Castables
- 1 Downloads
There are large numbers of pores in the microporous corundum aggregate, which are uniformly distributed on the inside, the internal corundum grains grow well and there are short columnar crystals
Compared to the ordinary tabular corundum aggregate, the closed porosity of the microporous corundum aggregate is higher, the apparent porosity and the bulk density are lower, moreover, the pores inside it are smaller
When the thermal conductivity of the aggregates is compared, that in the microporous corundum aggregate is significantly lower than that of ordinary tabular corundum (its bulk density is 3.63 g/cm−3, this is 42% less).
Compared with the ordinary alumina magnesia castable which is made of tabular alumina, the lightweight castable has a lower linear change rate, greater apparent porosity and smaller bulk density. Its strength after baking and medium temperature heat treatment can reach the requirements of industrial production; however, the its strength improves obviously after heat treatment at 1500°C
When the thermal conductivity of castables are compared, the thermal conductivity of two kinds of castables is basically the same at 350°C. When the test temperature rises to 600 and 800°C, the thermal conductivity of the lightweight castable made of the microporous corundum aggregate is significantly lower
When the resistance to slag is compared, the two kinds of castables have basically the same corrosion index; the penetration index of the lightweight alumina-magnesia castable is 14.3% larger.
Keywordsmicroporous corundum alumina-magnesia castable thermal conductivity
Unable to display preview. Download preview PDF.
- Peng, C.H., Li, N., Han, B.Q.: Influence of microporous magnesia-rich spinel aggregates on properties of low carbon MgO-C refractories [J]. Refractories 43 (2009)  335–338Google Scholar
- Hisashi, T., Tomoaki, T., Hidenori, T.: Low thermal conductivity Al2O3-MgO-C bricks for steel ladle [J]. Taikabutsu 62 (2010)  34–35Google Scholar