| 摘要 |
<p>[PROBLEMS] To remove lead from a dust in a gas extracted from a cement kiln combustion gas with good efficiency, while suppressing equipment cost and operation cost to a low level. [MEANS FOR SOLVING PROBLEMS] A treating system (1) which comprises a probe (3) for extracting a combustion gas, with cooling, from the flow path for an exhaust gas from the bottom of a cement kiln (2) to a cyclone provided at the lowest stage, a first classifier (5) for separating a coarse power of the dust in the extracted combustion gas, a dust collector (7) for collecting a dust from the extracted gas containing a fine powder discharged from the first classifier (5), and a second classifier (8) for separating the dust discharged from the dust collector (7) into a fine powder and a coarse powder; and the like. Since lead is unevenly present in the fine powder separated by the second classifier (8), lead can be removed with no use of a chemical or the like. The fine powder obtained by the classification with the classifier (8) may be washed with water, desalinated, and washed with water, and the resultant cake having a high lead content may be recycled and the resultant aqueous salt solution may be added to a cement mill. The above coarse powder can be added to a cement crushing step or be re-supplied to a cement raw material crushing step after washing with water and desalination.</p> |
