Halurgy

a branch of chemical technology devoted to the production of mineral salts.

In the narrow sense of the word, halurgy is the processing of natural salts. Raw materials for industrial halurgy are sea-water, salt deposits formed by the concentration of seawater (a phenomenon in coastal areas with a dry climate), and lake and underground brines. Separate salts are isolated by the processes of evaporation and crystallization under natural (specially created ponds) or industrial conditions. Salt-solubility diagrams serve as the theoretical basis for halurgy. In practice, water solutions of the chlorides and sulfates of sodium, potassium, and magnesium are most important. They were studied by J. H. van’t Hoff and his co-workers in Germany (1897-1908) and by N. S. Kurnakov and his co-workers in the USSR (from 1917). Halurgy typically derives a number of end products from the raw materials. For example, sodium chloride, sodium sulfate, magnesium sulfate, chloride, oxide, and bromine are produced from seawater. The brine of salt lakes yields, in addition to the foregoing, sodium, borax, and lithium salts. Bromine and iodine are extracted from the mineral waters that accompany oil deposits. Magnesium chloride, magnesium sulfate, bromine, rubidium, and cesium salts are produced along with potassium chloride and potassium sulfate in the processing of natural potassium salts.