Recovering a caustic solution via calcium carbonate crystal aggregates

A system for growing crystalline calcium carbonate solids in the presence of an alkaline carbonate solution such that each of at least portion of the crystalline calcium carbonate solids comprise a volume from about 0.0005 mm3 to about 5 mm3, comprising:

• a slaker configured to react quicklime (CaO) and a fluid that is substantially free from carbonate to yield a slurry of primarily slaked lime (Ca(OH)2);
• a fluidized-bed reactive crystallizer configured to enclose a solid bed mass and comprising an input fluidly coupled to the slaker to receive the slurry of primarily slaked lime, an input for an alkaline carbonate solution comprising between 0.1M to 4.0M hydroxide and between 0.1M to 4.1M carbonate, and an output for crystalline calcium carbonate solids that comprise particles each with a volume between about 0.0005 mm3 and about 5 mm3 and the alkaline carbonate solution;
• a dewatering apparatus that comprises an input coupled to the output of the fluidized-bed reactive crystallizer and an output configured to discharge a plurality of separate streams that each comprise a portion of the crystalline calcium carbonate solids and alkaline carbonate solution;
• a seed transfer apparatus configured to deliver seed material into the fluidized-bed reactive crystallizer to maintain a consistent mass of seed material within the fluidized-bed reactive crystallizer;
• and
• a control system communicably coupled to, and configured to control, at least one of the slaker, the fluidized-bed reactive crystallizer, the dewatering apparatus, or the seed transfer apparatus to produce crystalline calcium carbonate solids with a volume from about 0.0005 mm3 to about 5 mm3.