method for the purification of magnesiumsul - faat, potassium, sodium and magnesium containing water bearing solutions.

摘要

Multistage process for processing waste liquors containing magnesium sulphate, potassium chloride, sodium chloride and magnesium chloride for utilising the salts contained in these. This involves extracting from the waste liquor in a number of evaporation, crystallisation and desulphation processes, epsom salt in one stage (A), common salt in a second stage (B), and in a final stage (E) a salt mixture consisting of carnallite and common salt which is a starting material for the electrolytic production of magnesium and chlorine. Arranged between the stages (B) and (E) there are three stages (C, D, F); in stage (C) the salt solution isolated in stage (B) is cooled without removing water, a salt mixture consisting of epsom salt and common salt being produced in the process which is returned to stage (A), while the isolated salt solution is further processed in desulphation stages (D, F) with the addition of an aqueous calcium chloride solution and an aqueous barium chloride solution, respectively. The salt solution free of SO4 ions is then passed into the final stage (E). By means of the process it is possible to extract on an industrial scale the abovementioned five products from a waste liquor which has hitherto not been utilised economically. IMAGE