| 摘要 |
There is disclosed a treatment of exhaust gases containing detectable quantities of multivalent heavy metals in high oxidation states by introducing a sulfur reductant into contact with the exhaust gases and maintaining the contact of the sulfur reductant with the exhaust gases under appropriate conditions to favor the reduction of the heavy metal to an harmless, lower oxidation state. Sulfur dioxide is preferred for this treatment. After the treatment with the sulfur reductant, the exhaust gases are treated to remove the excess or residual amounts of the sulfur reductant and the compounds of higher oxidiation states of the sulfur which have been formed by the reduction of the heavy metal. When sulfur dioxide is used, the exhaust gases can be passed into contact with an aqueous alkaline solution which absorbs oxides of sulfur, such as sulfur dioxide and trioxide from the exhaust gases. Suitable solutions for this purpose are aqueous solutions of strong bases such as sodium hydroxide, calcium hydroxide, ammonium hydroxide, etc.
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