A process for the preparation of sodium chloride coarse-grained by vacuum evaporation of salt brines

摘要

Common salt is prepared by evaporation of solutions to which have been added small amounts of a soluble salt of carboxy methyl cellulose, preferably in amounts between 1 and 100 mg. per litre of solution. The salt obtained is coarser and harder and less incrustation of the evaporator occurs. The hardness may be further increased by the addition of compounds supplying nitrilotriacetate ions (see Specification 790,457). Examples refer to the evaporation of brine to which has been added 30 mg. of sodium carboxy methyl cellulose per litre of brine and the addition of 30 mg. each of sodium nitrilotriacetate and sodium carboxy methyl cellulose. Specification 617,137 also is referred to.