Preparation of superfine activated calcium carbonate from calcium carbide residue by the liquid-state method with propionic acid

Processes of extracting calcium from the calcium carbide residue by the liquid-state method with propionic acid were studied, and in order to find optimal craft, the orthogonal array was devised. Results of chemical analyses showed that the extracting calcium yield was 93.4%. The purity of product prepared by this process was 97%, in addition, the whiteness of product was 98.6 and the product could reach the standard of HG/T 2567-2006. The IR spectroscopy and TGA provided evidence to support the existence of the propionic acid unit coating the outside of the calcium carbonate particle. The SEM image proved that the morphology of calcium carbonate was spherical. The DLS confirmed that the diameter of the calcium carbonate particle was about 2.5 mu m.