Recovering a caustic solution via calcium carbonate crystal aggregates

A method for growing crystalline calcium carbonate solids in the presence of an alkaline carbonate solution in a fluidized-bed reactive crystallizer such that each of at least a portion of the crystalline calcium carbonate solids reach a volume from about 0.0005 mm3 to about 5 mm3, the method comprising:

• reacting, in a slaking process, quicklime (CaO) and a fluid that is substantially free from carbonate to yield a slurry of primarily slaked lime (Ca(OH)2);
• introducing the slurry of primarily slaked lime and an alkaline carbonate solution comprising between 0.1M to 4.0M hydroxide and between 0.1M to 4.1M carbonate into a fluidized-bed reactive crystallizer that comprises a solid bed mass;
• reacting the Ca(OH)2 slurry and the alkaline carbonate solution to deposit a portion of a precipitated calcium carbonate (CaCO3) onto the existing bed of solids that (1) causes the solids to grow in volume, (2) decreases a concentration of dissolved carbonate, and (3) increases a concentration of dissolved hydroxide;
• and
• discharging a portion of the crystalline calcium carbonate solids and the alkaline carbonate solution, the portion of the crystalline calcium carbonate solids comprising particles that each comprise a volume within the range from about 0.0005 mm3 to about 5 mm3.