Study on synthesis and modification of spherical-like nanometer calcium carbonate
The process conditions to prepare spherical-like calcium carbonate by carbonization method from lime slurry and modification conditions of wet process using sodium dodecyl sulfate as modifying agent are studied using D-sodium gluconateas as crystal controlling agent. The XRD and TEM results show that the as-prepared nanometer calcium carbonate is calcite with hexagonal crystal system and spherical-like with uniform diameter of about 50 ~ 100 nm when the temperature is 50 ℃,stirring speed is 800 r / min,crystal controlling agent mass fraction is 1. 5%,Ca( OH)2initial mass fraction is 7%,CO2gas flow rate is 60 mL / min. The results of oil absorption show that when the mass fraction of modification agent is 3. 5%,the temperature of modification is 70 ℃,the modification time is 50 min,the oil absorption of spherical-like nanometer calcium carbonate reaches minimum of about 44 mL /100 g which could meet the first grade standard of national calcium carbonate industry( GB / T 19281—2003)( the oil absorption value should be less than 60 mL /100 g).