AGC Ceramics succeeded in developing chrome-free ceramics for cement kilns. At present, most of the ceramics that the company uses for the higher-temperature parts of its kilns are chrome-free. Conventional ceramics contain chromic oxide, which, if combined with calcium (Ca) contained in limestone (CaCO3) at high temperatures of around 1,450°C, produces hexavalent chrome, which is believed to be carcinogenic. This means that if conventional bricks are used to build cement kilns, hexavalent chrome will be contained-albeit in minute quantities-in the manufactured cement. Chrome-free ceramics are also excellent in durability and help prolong the lives of kilns.

Structure of a cement rotary kiln

Chrome-free ceramics are used as lining material for the high-temperature parts.