Study on the preparation of food grade calcium carbonate

Calcium carbonate with different morphologies can be used in different industrial fields. As the food grade calcium carbonate has good smoothness, fluidity, dispersity and wear resistance, it can be used in food, medicine and other industries. At present, there are many methods for the research and industrial production of calcium carbonate at food grade, of which the pilot test method is one of them. The pilot test method adopts the self-made intermittent bubbling carbonization reactor, and has a water bath heating device, a gas distribution tower, a carbonation tower and a temperature control device. A certain amount of quicklime was mixed in 850C hot water at a mass ratio of 1:5, stirring, digesting and holding for 12 hours. After 200 purpose resonance screen filtration and slag refining, a certain concentration of lime milk semen was obtained. Ca (OH) 2 suspension to the concentration of 86g/L, and preheating to 200C~400C, which added to the 1% crystal control agent D, stirring speed is 0.114m/s in gas carbonization reactor, pass into the prepared with CO2 volume fraction is about 30% of the gas mixture by carbonation reaction, paper determination of reaction end point with PH, when PH=7.0, the end of the reaction, to obtain good dispersion and uniform particle size distribution of spherical calcium carbonate. The amount of crystal control agent, air velocity, initial lime concentration and initial carbonization temperature have different effects on the specific surface area and particle size of spherical CaCO3. In addition the limestone from different places due to the formation of age, geology, composition, cause the performance of calcium carbonate products may be different, but by adding crystal control agent D, also can have calcium carbonate crystal form and particle effect is very good, in the global food grade calcium carbonate in the preparation of good adaptability to add control agent D.