Production of Magnesium-Strontium Alloys Through Vacuum Metallothermic Process

Vacuum metallothermic reduction is the main method to produce magnesium (Mg) metal from Mg-containing ores. In the process, a mixture of ore and reductant material is charged in retorts, which provide a vacuum atmosphere of about 100 Pa (1 mbar) in the process. The accounts in the literature stated that the process is viable for the metallothermic reduction of strontium (Sr) as well. The main problem for the reduction of the Sr is the high affinity of Sr to oxygen. Moreover, the Sr is an important metal for Mg alloying. In the present study, production of Mg-Sr alloy from oxide raw materials was studied through the vacuum metallothermic process. Thus, it was aimed to develop a simple and commercially viable method to directly produce Mg-Sr alloys, and the Sr content would be in the form of Mg 17 Sr 2 intermetallic alloy. In the experiments, calcined dolomite ore and SrO were used as raw materials. Investigated parameters were reductant type (FeSi and Al), process temperature, and process time on the recovery ratios of Mg and Sr in produced alloys. The highest recovery ratios, 97.1 pct for the Mg and 81.2 pct for the Sr, were obtained in the experiment conducted at 1250 °C for 480 minutes. The reductant material was the Al, and the Sr-Al addition ratio was 5 wt pct in the experiment.