METHOD FOR CARBON DIOXIDE SOLIDIFICATION

摘要

PURPOSE: A carbon dioxide-carbonate fixing method is provided to improve the selective extract rate of Ca, and to minimize the usage of NaOH by increasing the pH of an extraction solution for the effective carbonate conversion reaction. CONSTITUTION: A carbon dioxide-carbonate fixing method comprises the following steps: supplying an ammonium salt solvent to material slag as an extraction solution for extracting alkaline metal components; adding a pH adjustor(NaOH) to the extraction solution for increasing the pH from 8-9 to 12; and producing carbonate precipitates from the extraction solution containing the alkaline metal components, by the carbonate conversion reaction converting carbon dioxide injected into the extraction solution inside a carbonation reactor(20). Ammonium salt in the ammonium salt solvent is selected from ammonium chloride, ammonium nitrate, or ammonium acetate. [Reference numerals] (10) Slag/mineral calcium extraction device; (20) Carbonation reactor pH 8-9 -> 7; (AA) Extraction solution after reaction pH 8-9; (BB) Slag/extraction solution separation(Filtering); (CC) Ammonium salt solvent(pH 6); (DD) Slag/mineral; (EE) Precipitate separation/refinement; (FF) Calcium carbonate(solid); (GG) CO_2 injection; (HH) Recycling-recirculation; (II) Extraction solution pH 6-7