Magnesium chloride precipitation from mixed salt solution using 1,4-dioxan

This paper deals with the preparation of magnesium chloride hydrate from a mixed salt solution containing, besides MgCl2, substantial quantities of undesired substances such as alkali metal chlorides and magnesium sulphate. Magnesium chloride extraction was done using dioxan. In particular, it was found that this salt precipitate as the ternary compound MgCl2·6H2O·C4H8O2. Reaction equilibrium is reached after 40 min. It was shown that solid phase MgCl2·6H2O·C4H8O2 conversion into MgCl2·6H2O is feasible by a drying carried out at constant temperature chosen in the range (70–110 °C). Physico-chemical properties of the final product are determined using XRD, complexometry, potentiometry, gravimetry and FAAS. Prepared MgCl2·6H2O purity is upper than 99%. Its X-ray diffractogram is impurity free.

Research highlights▶ Dioxan addition to mixed salt solution leads to MgCl2.6H2O.C4H8O2 precipitation. ▶ MgCl2.6H2O.C4H8O2 dried at constant temperature (70–110 °C) gives MgCl2.6H2O. ▶ Purity of prepared magnesium chloride hexahydrate salt is more than 99%.