One-Step Extraction of Mg-Ca Alloy from Dolomite ＆ Magnesite Ores by Vacuum Aluminothermic Reduction

A novel technique was developed to directly extract Mg-Ca alloy from calcined dolomite and magnesite ores by aluminothermic reduction in vacuum with Al-scraps as reductant.Conical-drum and solid T-cylinder crystallizer/condenser were used.The influence of the condensation conditions,including the reduction temperature,pressure,shape and bottom-height of condenser above sublimation surface,on the depth profiles of Mg and Ca in condensate was investigated with X-ray diffraction scanning electron microscopy and energy dispersive spectroscopy.The results show that at optimized reduction temperature,the height and geometry of condenser had a major impact.For example,when it comes to crystallization of Mg/Ca at optimized height of 16.4 cm,T-cylinder condenser outperformed conical-drum condenser with a descending sequence:Mg>Ca>CaO>CaMg₂.The bottom-up depth profile of Mg decreased and that of Ca increased.The Mg-Ca alloy can be de-oxidizer and/or raw material in metal industry.