Bishophite Chlorination

In order to obtain pure and dry MgCl₂ from bishophite (MgCl₂-6H₂O) hydrogen chloride must be introduced during the final drying step to prevent the decomposition of MgCl₂-H₂O to MgO and HCl. A kinetics study of the chlorination of MgO contained in partially dried bishophite is reported. The two parallel reactions which occur during the HCl treatment were investigated in the temperature range 200-400 °C. With respect to the reactants, the chlorination and dehydration are first-order reactions. The energies of activation for chlorination and dehydration are 2700 and 4700 cal/deg mol, respectively. A time-temperature graph, showing the calculated necessary reaction times, has been constructed.