Laboratory technological research of magnesium intermediates preparation from the dolomites raw materials suitable for magnesium metal production

Abstract

Metallic magnesium has been included in the list of Critical Mineral Raw Materials (CRM) for European Union countries since 2010. The territory of the Slovak Republic has large reserves of mineral raw materials – magnesite and dolomite, which are the initial source of metal Mg. For technological research, the following raw materials (based on chemical analyses of samples) were chosen: dolomite ore from the Sedlice deposit (SED-1), Trebejov deposit (TR-1) and dolomite ore from the Kraľovany deposit (KRA-1). The second deposit is also located near the operation of a potential customer of laboratory results for the production of metal magnesium, OFZ a.s. The aim of the laboratory technological research was to determine the experimental conditions for obtaining suitable Mg intermediates for metal magnesium preparation. For this purpose, there were performed DTA/TG and XRD analyses to study its behaviour, total mass loss and amount of carbon dioxide after calcination process. By optimizing the annealing tests of dolomite, products were obtained that met two conditions for its subsequent use in the sillicothermal process, namely the molecular ratio of CaO/MgO, content of impurities and the content of CO2. The optimization of calcination and repeated annealing pointed at the suitable conditions of dolomite raw sample processing (temperature of 1 050 °C for 2.5 hours, or 1 100 °C for 2 hours).