| 摘要 |
PROBLEM TO BE SOLVED: To produce cement having only a small content of repelling components by effectively causing reduction volatilization and chlorination volatilization by a reductive substance and a chlorine source at the prescribed region in a cement kiln.SOLUTION: The surface of a reductive substance R of coke powder or the like is covered with a chlorine source X, the circumference thereof is covered with a covering material C such as heat resistant glass powder or the like whose melting point or a decomposition temperature is lower than about 1,450°C which is the burning point of a cement kiln 2 so as to make a covered reductive substance-chlorine source CXR. When the covered reductive substance-chlorine source CXR is fed into the cement kiln, reduction volatilization and chlorination volatilization can be effectively caused at the prescribed region in the kiln. By promoting the volatilization or insolubilization of repelling components and removing the repelling components from a cement production process, cement having only a small content of repelling components can be produced. The softening point, melting point or decomposition temperature of the covering material is controlled to ≥700°C, and one or two or more among lead, zinc or the like can be removed. |
