Processing potassium containing hard brine comprises precipitating calcium as carbonate from brine containing e.g. sodium chloride, and desulfonating mixture containing Glauber's salt-molten base and epsomite-alkaline chloride

Processing potassium containing hard brine, comprises precipitating calcium as carbonate from brine containing sodium chloride, potassium chloride, magnesium sulfate, calcium sulfate, magnesium chloride and water; desulfonation of a mixture containing Glauber's salt-molten base precipitated from process precursor and epsomite-alkaline chloride mixture by cooling at 5 to -10[deg] C; carrying out multi-stage evaporation of up to 90-110[deg] C and at a temperature nearer to potassium chloride saturation and crystallizing the separated sodium chloride. Processing potassium containing hard brine through multi-stage fractionating evaporation-cool crystallization process, comprises precipitating calcium as carbonate from brine containing sodium chloride, potassium chloride, magnesium sulfate, calcium sulfate, magnesium chloride and water; desulfonation of a mixture containing Glauber's salt-molten base precipitated from process precursor and epsomite-alkaline chloride mixture by cooling at 5 to -10[deg] C, where sulfate and Glauber's salt are removed as sodium sulfate decahydrate; carrying out multi-stage evaporation of up to 90-110[deg] C and at a temperature nearer to potassium chloride saturation and crystallizing the separated sodium chloride; where: the hot solution is cooled up to 25-35[deg] C under potassium chloride crystallization and the crystallized potassium chloride is separated, during further desulfonating the evaporated, cooled solution under deep cooling at 5 to -10[deg] C; and the separated epsomite-potassium chloride-sodium chloride solution was concentrated up to an end concentration of 380-450 g/l magnesium chloride by further evaporation. Durch Auslaugung der löslichen Bestandteile von polymineralischem Hartsalz gewonnene Hartsalzsole lässt sich durch einen mehrstufigen Eindampfungs-Kühlkristallisationsprozess, der polytherm zwischen den Temperaturniveaus von + 100°C bis - 10°C arbeitet, zu den Produkten Kochsalz (NaCl), Kaliumchlorid (KCI), Natriumsulfat (NaSO) und hochkonzentrierte MgCl-Sole aufarbeiten. Durch Konvertierung des Kaliumchlorids mit Natriumsulfat über Glaserit als Zwischenstufe ist auch das chloridfreie Düngemittel Kaliumsulfat (KSO) herstellbar.