Fly ash melting tail gas purification technology

Abstract

The invention relates to a fly ash melting tail gas purification technology which comprises the following steps: fly ash melting furnace tail gas passes through a quenching device firstly to be cooled to 100 DEG C or below and then enters a crystal nucleus agglomeration chamber, heavy metal chlorides in the tail gas form large-particle-size particulate matters and precipitate out under the action of low-frequency sound wave, the large-particle-size particulate matters are separated out by a two-phase separation device, the tail gas subjected to heavy metal chloride removal continuously passes through a graphite falling film absorption tower to remove HCl gas and then passes through an acid gas scrubbing tower to remove acid gas, and finally, clean tail gas is obtained to be exhausted to the external. The purification technology provided by the invention can fully and effectively remove heavy metal chloride salts and the acid gas, prevent the phenomenon of secondary pollution caused by heavy metal salts and greatly lower the waste water treatment cost of the traditional fly ash treatment technology; and in addition, the heavy metal salts obtained by recovery is equivalent to a special heavy metal rich ore and can be used as a metallurgical raw material.

Description

technical field [0001] The invention relates to a purification process of fly ash melting tail gas. Background technique [0002] The fly ash produced in the waste incineration process contains heavy metals and other substances with high leaching concentration. Among them, Pb, Cd, Cu, Zn and other heavy metals in fly ash are volatile during high temperature treatment, and the heavy metal volatiles condense together with the tail gas to form secondary fly ash. Due to the high content of heavy metals in secondary fly ash, if it is not handled properly, it will be more destructive to the natural environment and human health. [0003] The tail gas produced by the melting process is used to treat the fly ash, and the concentration of acid gas and heavy metals is high. Generally, the purification process is divided into dry process, semi-dry process and wet process. [0004] The dry process uses slaked lime or baking soda to react with acid gas. Due to the high concentration of ...

AI Technical Summary

Problems solved by technology

The dry deacidification of the above exhaust gas purification system will still produce a large amount of secondary fly ash, so there is still a problem of secondary pollution

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