| 摘要 |
<P>PROBLEM TO BE SOLVED: To highly efficiently oxidize, in a treatment process of mercury-containing exhaust gas, mercury (mainly zero-value Hg) in the exhaust gas by blowing hydrogen chloride gas and further passing a highly reactive powdery catalyst through the exhaust gas and incorporate it into exhaust-gas dust, to separate and remove the dust using a dust collector provided in the latter stage, to recover practically the whole quantity of the mercury in a metal state from the resulting dust by heating and wet treatment and further to recycle the dust after the treatment into a cement material etc. <P>SOLUTION: This method for recovering mercury from mercury-containing exhaust gas consists of a process for treating mercury-containing exhaust gas and a process for treating mercury-containing dust. The process for treating mercury-containing exhaust gas comprises: a step of blowing hydrogen chloride into exhaust gas; a step of bringing the exhaust gas into contact with a powdery catalyst to oxidize mercury; a step of subjecting the gas after reaction to dust collection treatment; a step of separating a mixture of recovered dust and used catalyst into dust and catalyst; and a step of circulating at least a part of separated catalyst into a reactor. The process for treating mercury-containing dust comprises: a step of heating the separated dust; a step of separating the heated dust from mercury-containing heated gas by a filter; a step of cooling the dust separated by the filter to produce treated ash; a step of directly and/or indirectly cooling the mercury-containing gas separated by the filter; and a step of storing mercury-containing water resulting from the cooling to form metal mercury. The gaseous mercury can be oxidized in high efficiency and can be incorporated into the dust. The treated exhaust gas is free from mercury and can be dissipated into the air. <P>COPYRIGHT: (C)2008,JPO&INPIT |
