Study On Preparing New Technology For Nano Calcium Carbonate

Improving the performance of nano-calcium carbonate and reducing the energy consumption of its process have become an attractive and challenging research project in nano-calcium carbonate industry. It is not only the development direction of calcium carbonate process, but also an important means to improve the economic benefits of calcium carbonate.In this paper, cubic nano calcium carbonate was prepared by normal temperature carbonization. During the nucleation and growth of calcium carbonate, adsorption of crystal control agent on calcium carbonate surface and its mechanism of calcium carbonate morphology control were studied. The effect of carbonization conditions, especially carbonization temperature and high concentration CO2gas, on nucleation, growth, aggregation and morphology of calcium carbonate were discussed. Normal temperature carbonization process was modified to synthesis nano-calcium carbonate with high dispersion, and its application performances were characterized. Finally, feasibility of filtrate’s recycling was analyzed.Morphology of calcium carbonate was controlled as cubic by crystal control agent adsorbed on surface of calcium carbonate, and carbonization temperature made an effect on morphology of calcium carbonate by changing the adsorption rate of crystal control agent. Adsorption rate decreases with increasing temperature, and aggregation of particles intensified, so morphology of calcium carbonate was not controllable. Cubic nano-calcium carbonate can be prepared by increasing concentration of crystal control agent in a high carbonization temperature. High concentration CO2gas was used to prepare cubic calcium carbonate with normal temperature carbonization, and a poor mass transfer and an uneven size distribution of calcium carbonate were resulted in, which can alleviate by a strengthening stirring speed.Cubic nano-calcium carbonate with regular morphology and uniform size distribution were synthesized by a modified normal temperature carbonization process. Its dispersion and other application performances were improved. Industrial test of the modified normal temperature carbonization process was carried out and effect of industrial reactor’s mass transfer was a bit poorer than small scale device while performances of industrial test’s product were agreement with calcium carbonate prepared in laboratory.Finally, filtrate can be used to synthesis nano-calcium carbonate, and method of computing supplement quantity of crystal control agent should be based on the actual concentration of crystal control agent.