Ograniczenie rozpuszczalności siarczanów wapnia i magnezu w solance produkowanej metodą otworowego ługowania złóż soli

Abstract

Reduction of the solubility of calcium and magnesium sulphates in brines from borehole leaching of salt depositsA b s t r a c t . Sodium chloride occurring in salt brines is an important raw material for chemical industry. The basic condition for its use in chemical processes is its deep purification from calcium, magnesium and sulphate ions, which are harmful impurities of raw salt brines. The concentration of these ions mainly depends on quality of the exploited salt deposit and also on technology of borehole leaching. Costs of purification of salt brines may be markedly reduced by decreasing concentration of these harmful ions. The Chemkop Study Center in cooperation with the Chemical Company Rokita in Brzeg Dolny, developed a series of inhibitors of solubility of calcium and magnesium sulphates in salt brines, known under the brand name Roksol. The technology of application of these inhibitors in the process of borehole leaching of salt deposits was worked out and tested both on laboratory and industrial scale. This technology is based on adding the Roksol inhibitors into water or solution used for salt deposit leaching , what results in down and decreasing the solubility of the undesirable ions in the brine. The technology allows for considerable reduction of concentration of undesirable ions in the final salt brine. For salt brines obtained from leaching of Zechstein saltss, the concentration decrease is up to 75% for calcium ions, 85% for magnesium ions, and 75% for sulphate ions of the original ones. The simplified assessments of costs of purification of raw salt brines shows (Fig. 1) that decrease in concentrations of calcium, magnesium and sulphate ions in the brine by ca. 30%, 50% and 75% of their original ones may gives monthly savings of costs of salt brine purification of the order of ca. 23 %, 46% and 70%, respectively