Factors affecting reduction efficiency in industrial retorts for Mg production by aluminothermic process
(1. Key Laboratory for Ecological Utilization of Multimetallic Mineral (Ministry of Education), Northeastern University, Shenyang 110819, China;
2. School of Metallurgy, Northeastern University, Shenyang 110819, China)
2. School of Metallurgy, Northeastern University, Shenyang 110819, China)
Abstract: Industrial experiments were carried out for Mg production by aluminothermic process in industrial retorts and the factors affecting the reduction efficiency were analyzed. The results show that the main factors reducing the reduction ratio are oxidation and combustion of crystallized magnesium and uneven mixing of raw materials. The latter could result in raw material regions with low Al concentration and MgO redundance, which can promote the formation of 12CaO·7Al2O3 and CaO·Al2O3. For raw material regions with higher Al concentration, both MgO and CaO can be reduced to form the Mg2Ca phase. Radiation and chemical reaction heat are the key factors affecting the reaction rate. Increasing the heating temperature can rapidly increase the bed temperature and obtain sufficient reaction ratio. The higher the magnesium content in the pellets is, the longer the reduction time is required.
Key words: magnesium metallurgy; vacuum aluminothermic reduction; Pidgeon process; heat transfer