Preparation of Al-Sr master alloys by the aluminothermic reduction of SrO using aluminum scrap at pilot plant scale

摘要

Al-Sr master alloys were prepared by aluminothermic reduction of SrO in molten aluminum processed from scrap. The trials were performed at 500 kg pilot plant scale, using a gas operated furnace with a silicon carbide crucible. The effect of temperature, initial magnesium concentration and agitation speed on the aluminothermic reduction rate of SrO powders was studied. Moreover, the microstructure of Al-Sr master alloys prepared has been analyzed by means of optical microscopy, X-ray diffraction (XRD), and scanning electron microscopy (MEB). In this sense, the morphology of secondary constituents and the structure of Al4Sr phase were evaluated. The results showed that the aluminothermic reduction technique is useful for producing Al-Sr master alloys, observing the presence of the Al4Sr intermetallic phase as the main secondary constituent.