Saline-Alkaline Corrosion of High Alumina Bricks Produced by Incinerators

The choice of furnace lining materials, first of all, according to the temperature of the furnace, fused aluminum chrome sand manufacturers choose refractory materials and heat insulation materials that can withstand the incineration temperature; secondly, the corrosiveness of the combustion products to the furnace lining must be considered. For example, when the alkaline waste liquid is incinerated, when the temperature in the furnace is as high as 1000 °C, Na is combined with Na2O in the fused aluminum-chromium-zirconium refractory brick to form low-melting-point minerals.

 Fused aluminum-chromium-zirconium company (Na2O·AL2O3·2SiO2), condensed on the surface of refractory brick and eroded. For example, the refractory brick is a high-alumina brick, although the SiO2 composition is small, but due to the reaction of AL2O3 and Na2O to form the intermediate sodium aluminate (Na2O·AL2O3), under high temperature conditions, expansion cracks will occur, making the refractory brick structure brittle. Therefore, high-alumina refractory materials with higher alumina are selected, or magnesia-chromium, magnesia and aluminum-magnesium refractories with higher alkali corrosion resistance are selected. In order to resist the penetration and erosion of media such as saline and alkali, and to improve the slag resistance of the material, materials with smaller porosity are generally selected.

Fused aluminum chrome sand manufacturers

 When choosing the lining material of the incinerator, pay attention to the temperature and corrosion conditions of different parts in the furnace, and choose different grades of materials, as shown in Figure 1. In the picture, the high temperature of the combustion chamber (ie zone I) is 1400~1600℃, and corundum bricks containing AL2O3=90% can be selected: the working temperature of the upper part of the furnace (ie zone I) is 900~1000℃, and there is a waste liquid nozzle at the cone part , High alumina bricks containing AL2O3>75% can be selected. The working temperature in the middle of the furnace (ie zone III) is 900 °C. There is molten salt and alkali flowing down the furnace lining, and the corrosion is serious. First-class high alumina bricks (LZ-75) can be used. The working conditions of the lower part of the furnace (zone IV) are basically the same as those of the middle part of the furnace. When there is a large amount of molten salt and alkali in the combustion product, it is easy to accumulate on the slope, the residence time is long, and it is easy to penetrate into the refractory material. If there is Na2CO3, the corrosion is more serious , so it is worse than the middle of the furnace, and dense materials with lower porosity should be selected, such as fused refractory products.

 The above situation is only for the selection of general saline-alkali corrosion materials. For those with strong alkalinity, the alkaline refractory containing aluminum content or magnesium-chromium and other elements should be increased. Usually, when Na2SO4 and NaOH are corroded, better materials are used, and the lining life is only 2 to 3 years; for Na2CO3, which is more corrosive, the service life is only about 1 year.