In production of cryolite by clay-bittern method,calcium chloride content in its raw material (i.e.industry salt)is high,which causes calcium oxide content in cryolite exceed the allowed figure.

• 黏土-盐卤法生产冰晶石，其原料工业盐中氯化钙含量高，使得冰晶石中氧化钙含量超标。