Lime treating process

摘要

Methods of obtaining a solution of calcium ions from lime (e.g. carbide lime) are disclosed. In one aspect the method comprises (i) treating the lime with an aqueous solution of a polyhydroxy compound (preferably sorbitol) having three or more hydroxy groups and a straight chain of 3 to 8 carbon atoms; and (ii) optionally separating insoluble impurities from the solution resulting from (i). In another aspect the method comprises (iii) treating carbide lime with an aqueous solution of a polyhydroxy compound (e.g. sorbitol or sucrose) to extract calcium from the carbide lime; and (iv) separating insoluble impurities from the solution resulting from (i). The solutions obtained may be treated with precipitating agent to obtain a solid calcium containing product. The product may be calcium carbonate obtained by treating the solution with carbon dioxide as the precipitating agent.