What is the most widely used refractory in burning zone of cement rotary kiln?

　　The most widely used refractory material in the burning zone of a cement rotary kiln is magnesia-spinel refractory brick or magnesia-chrome refractory brick. These bricks are composed of magnesia and spinel (magnesium aluminate) or magnesia and chromium oxide, respectively.

　　The burning zone of a cement rotary kiln is the hottest region where raw materials are transformed into clinker through intense heat treatment. This area is exposed to high temperatures, chemical reactions, and abrasion from raw materials, clinker, and gases. Magnesia-spinel or magnesia-chrome refractory bricks offer excellent thermal shock resistance, high-temperature strength, and resistance to chemical attacks, making them well-suited for this demanding environment.

　　These refractory bricks have a dense structure, providing good insulation and minimizing heat loss from the kiln. They can withstand the corrosive effects of alkaline materials and sulfur compounds present in cement production. Additionally, they exhibit good resistance to coating formation and spalling, ensuring the longevity and efficiency of the kiln lining.

　　It's worth noting that there may be variations in refractory selection based on specific factors such as kiln design, operating conditions, and clinker composition. Different cement plants might use slightly different refractory materials based on their particular requirements.