MgCl2-6H2O, [3] a deficit rather than a credit for chlorine, and [4] the high consumption of graphite. Dow developed this process and uses it exclusively due to the traditional cheap energy on the Gulf Coast. However, the availability of cheap energy may be at an end or will end shortly. It is probably not feasible to reduce the energy of this process markedly. The total energy and electrical energy uses are similar for the anhydrous and Magnetherm processes. The choice of one or the other of these systems in the future will depend in part on which can be developed to require the lesser energy. The energy for the Pidgeon process is high probably because it was operated on a much smaller scale than the Magnetherm process. A retort produced 22.7 kg (50 lb) in an 8-h run. An obvious way to decrease the energy consumed in the bitterns process is to increase the yield of byproduct chlorine. If the chlorine yield is increased to the level of 2.7 kg/kg Mg as anticipated by Norsk Hydro, the total energy consumption would be lowered to 68.3 x 106 kcal/Mton (246 x 106 Btu/Ston) of magnesium. Further reduction can be effected by process improvements in the evaporation step and in the electrolysis. Norsk Hydro has stated that they expect to achieve a level of total energy consumption in their new process of 61 to 67 x 106 kcal/Mton (220 to 240 x 106 Btu/Ston). The Dow Chemical Company also has been reported to have under development a bitterns/electrolytic process which is predicted to lower total energy consumption to 38.9 x 106 kcal/Mton (140 x 106 Btu/Ston) of magnesium. The nature of the process has not been made known other than that the maximum amount of byproduct chlorine will be available for sale or use in other Dow manufacturing processes. However, it can be safely assumed that at least two major technological improvements must be involved: [1] a new and highly efficient method for producing cell feed; and [2] a completely new electrolytic cell with significantly lower resistance and energy requirements. It is known from the patent literature that Dow many years ago developed a bipolar cell for electrolysis of magnesium chloride. Among the
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