Improving the Dehydration Technology of MgCl2·6H2O and KCl·MgCl2·6H2O

Abstract

The paper summarizes the results of the authors’ studies on the improvement of the dehydration technology of bischofite (MgCl₂·6H₂O) and carnallite (KCl·MgCl₂·6H₂O). Hydrolysis is suppressed by creating excess pressure of hydrogen chloride (HCl) in a dehydration apparatus. An effective technology is the production of slightly hydrolyzed bi-aqueous salts in solid form and their subsequent melting in the presence of HCl-containing gases. A simple and efficient way to produce the latter is the combustion of methane (CH₄) in a mixture of chlorine and air in immersion burners. The kinetics of chlorination of Mg(OH)Cl with HCl-containing gases has been studied. It was found that the reaction rate was limited by the absorption of HCl. The operation of the apparatus for salts dehydration is considered from the point of view of the ideal mixing reactor model. Changes in the apparatus and technological scheme of obtaining magnesium from carnallite are proposed.