Patent ID: 6475459
Filing Date: 2002-11-05
Classification: B82Y,C01F,C01P,C09C

Abstract:
A method for forming calcium carbonate, comprisinga step of reacting a starting material containing calcium oxide with carbonate ions in the presence of water to produce calcium carbonate, and a step of recovering the calcium carbonate, characterized in that the formation is carried out directly from calcium oxide to calcium carbonate without intermediate stages in a three-phase precipitation where calcium oxide is hydrated to calcium hydroxide and the thus formed calcium hydroxide is carbonated to form calcium carbonate attached to a surface of calcium hydroxide particles, wherein the hydration and carbonation are carried out in immediate succession under so intensive agitation that calcium carbonate elements attached to the surface of the calcium hydroxide become detached, the calcium oxide and water being mixed in a fluid containing a gas and a suspension of solid matter and liquid, where the amount of the gas in the fluid is at least 2 parts by volume per one part by volume of the suspension and the amount of the liquid is 1 to 20 parts per one part of solid matter.