METHOD FOR STABILISING HEAVY METAL COMPONENTS BY MEANS OF CAPSULATION EFFECT USING ACCELERATED CARBONATION REACTION OF BIOWASTE INCINERATION BOTTOM ASH

摘要

The present invention relates to a method for stabilising heavy metals by means of capsulation and carbon dioxide fixing and as a result of an accelerated carbonation reaction in a low water-content state of biowaste incineration bottom ash. More specifically, the present invention relates to a method for suppressing elution of harmful heavy metals and particularly chromium (Cr) and fixing CO2 by using an accelerated carbonation reaction in order to capsulate highly alkaline biowaste incineration bottom ash. The invention relates to a technique which alleviates the problem that occurs with bottom ash as a whole due to the very high environmental instability of bottom ash having a particle size of 0.15 mm through such a method, thereby making it possible to reuse the bottom ash as a whole by first separating by particle size and then subjecting bottom ash having a particle size of up to 0.15 mm to carbonation. The aim of the present invention is to provide a method of effectively stabilising harmful heavy metals contained in fine-powder incineration bottom ash having a particle size of up to 0.15 mm and effectively fixing CO2 gas produced following the incineration of biowaste. In order to achieve the above aim, the present invention provides a method of stabilising heavy metals by capsulation and fixing carbon dioxide as a result of an accelerated carbonation reaction in the low-water-content state in the biowaste incineration bottom ash, the method comprising a step of creating incineration bottom ash after incinerating biowaste, a step of mixing the incineration bottom ash with water in a solid-liquid ratio (water/bottom ash, dm3/kg) of 0.3, and a step in which, without processing by mixing a reducing agent into the incineration ash mixed with the water, a 30 vol.% carbon dioxide gas takes part in a carbonation reaction for between 20 minutes and 240 minutes at a rate of 1 l/min, and the present invention provides a technique for the accelerated carbonation of fine-powder bottom ash having a particle size of up to 0.15 mm which has been a problem when reusing bottom ash as a whole through such a method, thereby making it possible to reuse the bottom ash as a whole.