Preparation and characterization of high surface area calcium hydroxide sorbent for SO2 removal

Calcium hydroxides were prepared using novel hydration method and were compared with those obtained by conventional water assisted hydration method and alcohol–water assisted hydration method. In conventional water assisted hydration method and alcohol–water assisted hydration method, raw calcium oxides were hydrated with pure water and alcohol–water solution, respectively, whereas DEG-coated calcium oxides were hydrated with pure water in novel hydration method. Organic coating at the surface of calcium oxide retarded slaking rate and prevented agglomeration during hydration. Calcium hydroxides hydrated with alcohol–water solution and using novel hydration method showed far smaller particle size and less agglomeration than those hydrated with pure water. The specific surface areas of calcium hydroxides hydrated with pure water and alcohol–water solution were 20.13 and 41.23 m2/g, respectively. The specific surface area of calcium hydroxides prepared by novel hydration method was dependent on the contents of water and DEG and ranged from 24.67 to 47.65 m2/g. Through specific surface area and thermo-gravimetric analysis, it was confirmed that the higher the specific surface area of calcium hydroxides, the higher their SO2 reactivity became.