| 摘要 |
PURPOSE:To efficiently obtain a large amount of lamellar calcium carbonate by carbonating Ca(OH)2 with CO2 in the presence of an organic phosphonic acid compound under a reaction condition to form basic CaCO3. CONSTITUTION:CO2 is introduced to lime of milk and carbonation reaction is carried out so as to make basic CaCO3 or a mixed state of basic CaCO3 and Ca(OH)2 to form a carbonation reaction system having <=3.5ms/cm drop in electric conductivity compared with that before the reaction for 40 minutes before exceeding 60% carbonation ratio. Then 0.01-20wt.% calculated as acid of an organic phosphonic acid containing a structural formula shown by the formula (M is H or alkali metal atom) such as nitrilotri(methylenephosphonic acid) is added to the reaction system, and the reaction is continued. Then after the reaction is completed, the reaction mixture is filtered, dehydrated, washed with water' methanol and then dried to give lamellar CaCO3. |
