Ceramics-Silikáty

Aluminosilicate refractories are not resistant to the alkaline corrosion that occurs during biofuel combustion. Therefore, the chemical corrosion of refractory materials significantly reduces the durability of the internal structures (lining), leading to unplanned shutdowns of biofuel production facilities and requiring additional repair costs. These risks increase even more when biofuel ash contains a higher amount of potassium and sodium, which can increase the impermissibly (more than 10 times) when preventive measures against biofuel freezing, such as alkaline salts, are used. This practically inevitably leads to the corrosion of aluminosilicate materials and the rapid disintegration of the lining made of such materials. A case of an accident in practice, due to the alkaline corrosion of the lining material, is presented in the work, along with laboratory tests to find out the cause. This article examines two different classes of refractory bricks and their resistance to alkaline corrosion. One is classified as a low Al₂O₃ refractory brick, the other as a premium high Al₂O₃ refractory brick. Two different reagents (potassium carbonate and sodium carbonate) and their mixture were used in the alkaline resistance tests performed by the crucible method. Furthermore, X-ray studies and thermodynamic calculations were performed using the FactSage program package.