Development of solar/thermal energy hybrid furnace and its evaluation for magnesium extraction

This paper reports on the development and evaluation of a hybrid furnace using both electric energy based on solar light energy and thermal energy for the extraction of magnesium (Mg). The solar thermal hybrid furnace was comprised of a solar thermal absorber for absorbing solar thermal energy at the lower portion thereof and an embedded heating coil for electric energy. The developed hybrid furnace was checked thermally by changing the internal temperatures by raising the temperature ranging from 100 to 420 °C using a hot plate at the bottom thereof. The developed furnace took 21 min to increase the internal temperature of the furnace to 700 °C when used the electric energy. Interestingly, on a sunny day outdoors, the internal temperature of the hybrid furnace was increased to 154 °C by solar thermal energy. The heating time of 19 min was needed to increase the internal temperature of the furnace to 700 °C when system was operated by the combination of solar thermal energy and electric energy. In order to evaluate performance of developed solar thermal hybrid system, the extraction of Mg metals was performed by the electrolysis of MgCl₂. Mg was extracted via the developed hybrid furnace by increasing the internal furnace temperature of 700 °C using indoor accumulated electricity. The extracted Mg was extensively characterized by field emission scanning electron microscopy (FESEM), EDX, X-rays diffractions (XRD) and XPS analysis.