| 摘要 |
PURPOSE:To obtain calcium carbonate capable of sustaining opacity and paper strength for paper making, by blowing CO2 gas into an aqueous slurry of Ca(OH)2 in the presence of a sulfuric acid compound. CONSTITUTION:CO2 gas is blown into an aqueous slurry of Ca(OH)2 to produce calcium carbonate. In the process, a sulfuric acid compound is added to the above-mentioned aqueous slurry of Ca(OH)2 to afford fusiform calcium carbonate having 0.1-1mu minor axis and 0.6-3mu major axis of the average particle diameter. H2SO4, MgSO4, BaSO4, SrSO4, CaSO4, K2SO4, etc., are cited as the sulfuric acid compound and the MgSO4 is especially preferred. The amount of such sulfuric acid compounds added is 0.05-10.0wt.% based on the calcium hydroxide. The aqueous slurry concentration of the Ca(OH)2 is about 5-40wt.%. The temperature is 5-65 deg.C and gas flow rate of the CO2 is <=50l/min/kg.Ca(OH)2 (expressed in terms of 100% purity of CO2 gas) with about 10-40% CO2 gas concentration. |
