CUBIC PRECIPITATED CALCIUM CARBONATE PREPARED BY APPLYING CARBONATION METHOD TO LIMESTONE SLUDGE GENERATED FROM IRONWORKS AND PREPARATION METHOD THEREOF

摘要

PURPOSE: A method for preparing a cubic precipitated calcium carbonate and a cubic precipitated calcium carbonate prepared by the method are provided, to obtain a cubic precipitated calcium carbonate having a size of 0.1-0.9 micrometers with a low cost by using limestone sludge. CONSTITUTION: The method comprises the steps of calcining the limestone sludge whose quicklime (calcium oxide) content is 45-55 wt% at a constant temperature for a specific time; pulverizing the calcined lime; mixing the quicklime powder with water to hydrate it; filtering the obtained slaked lime (calcium hydroxide) suspension, drying the filtered one at a temperature of about 95 deg.C and washing the dried one; blowing out carbon dioxide to the calcium hydroxide suspension; and filtering and drying the calcium carbonate obtained by the carbonation to prepare a cubic precipitated calcium carbonate. Preferably the calcination is carried out at 1,000-1,200 deg.C for 1-3 hours; the calcined lime is pulverized into a size of 200 mesh or less; the suspension has a concentration of 4.0-8.0 wt%, the flow rate of carbon dioxide is 0.2-2.0 L/min and a stirring velocity is 500-1,000 rpm in the carbonation; and the carbonation is carried out at 10-20 deg.C.