An improved method of producing voluminous table salt from fused rock salt

摘要

Voluminous table salt is prepared from rock salt by fusing it, allowing the impurities to settle and introducing the melt into water or brine. The brine is obtained as granules and incrustations and may be brought to the desired form by drying and powdering or by bringing it into contact with warm brine, e.g. in a salt pan which is kept in motion. To prevent detonation, the surface of the melt entering the water or brine is increased as much as possible, e.g. by supplying it as a thin jet 3-4 mm. in diameter. The brine to which the salt melt has been added may be transferred to a large collecting vessel in which the salt granules can be converted into common salt with stirring, if necessary, and in which the salt still dissolved crystallizes out on cooling. The brine after adding, e.g. dilute brine to make up for evaporation, is finally led back to the original vessel. The salt may be dried by the waste heat from the melting furnace. To eliminate from the salt calcium sulphate, the brine to which the melt is added is acidified, e.g. with sulphuric or hydrochloric acid; the brine may be regenerated when the dissolved calcium sulphate has become concentrated therein, by adding milk of lime. Brine from salt workings may be used as solvent in the process, and salt obtained therefrom.