Latest Developments in the Field of Refractories for Cement Kilns Using Low-cost Fuels

摘要

The increasing use of secondary fuels for the production of cement clinker does not only affect the cement properties, but also the production process crucially. Additionally, due to the process conditions, the use of secondary fuels and the resulting composition of the kiln gas atmosphere has effects on the refractory lining and its behaviour in the pre-heating system with calcinatory, in the rotary kiln, and in the cooler. Due to the interaction between the cement raw meal/cement clinker and the lining, the development of refractory materials is of decisive importance for the cement production, considering also the aspect of an increasing use of secondary fuels. This development refers to all basic and aluminous products necessary for the lining of a kiln system. New brick grades from the system Al_2O_3-SiO_2-SiC are resistant to chloridic, sulphatic and sulphidic infiltration, thanks to modern firing techniques and an improved refractory material development. The resistance to volatile components from the kiln atmosphere is significantly increased. Modern monolithic linings from the system CaO-Al_2O_3-SiO_2-SiC do not only show an excellent infiltration resistance, but also an extremely high abrasion resistance. By adjusting a special structure, even basic bricks possessing the necessary structural flexibility can be used in thermochemically loaded rotary kilns. These developments in the field of refractories make it possible for cement rotary kiln systems to maintain their productivity in spite of the use of secondary fuels.