PREPARATION METHOD OF CALCIUM HYDROXIDE HAVING LARGE SPECIFIC SURFACE AREA

摘要

PURPOSE: A method for preparing calcium hydroxide having large specific surface area is provided. Thereby, calcium hydroxide having excellent reactivity and dispersion property as well as high degree of whiteness is prepared. And thus it can be directly used as an absorbant of harmful gas that includes sulfuric oxide or other harmful gases generated from a waste water treating agent or exhaust gas, as a filler in rubber or plastic resin industries, as a coloring agent in paint, and as a soil conditioning agent without further processes. CONSTITUTION: A method for preparing calcium hydroxide(Ca(OH)2) having large specific surface area is characterized by including following steps of: hydrating the caustic lime(CaO) by using 300-1000 wt% of water based on the weight of CaO, at 10 deg.C and for more than 10 minutes; filtering the calcium hydroxide slurry after completing the hydration; drying and milling the filtrate to obtain powdered calcium hydroxide; forming the caustic lime again with using the obtained calcium hydroxide powder by performing pyrolysis at 500-800 deg.C for 10-120 minutes; re-hydrating thus obtained caustic lime as above except adding 0.1-10 wt% of sodium hexametaphosphate to make a calcium hydroxide having a specific surface area of 20-28 m¬2/g.