Experimental Study of Magnesium (Mg) Production by an Integrated Calcination and Silicothermic Reduction Short Process

Abstract

To promote the innovation of raw magnesium production technology, an integrated calcination and silicothermic reduction short process for magnesium production was experimentally studied on the laboratory scale in this article. The influences of the thermal decomposition temperature, silicothermic reduction temperature, pelletizing pressures and silicon ratio on the characteristics of producing the magnesium by the short process was studied. The crosslinking effect, including reactions between CO 2 decomposed from dolomite and metal elements in ferrosilicon, microstructure change at thermal decomposition and silicothermic reduction stages, was analyzed and discussed. In addition, comparison of the magnesium reduction rate and production efficiency between the new short process and the traditional Pidgeon process was made. The results indicated that the decomposition and reduction temperatures have a more significant influence on the magnesium reduction process than the pelletizing pressure and silicon ratio. A decomposition temperature < 1000°C and reduction temperature > 1100°C was proven to be favorable for improving the magnesium reduction rate and production efficiency of the new short process. It was also found that the integrated short process for magnesium production can reach the same total reduction rate and has lower efficiency compared to the traditional process. The decrease of magnesium production efficiency in the new short process was expected to result from reduction of the contact area and hindering of diffusion between CaOAEMgO molecules and Si(Fe) atoms because of the microstructure change and ferrosilicon consumption by the reactions between CO 2 and metal elements in ferrosilicon. Preparing briquettes with additives of binder or ultrafine particles of raw materials was proposed and considered for further study to improve the production efficiency.

Research on the Process, Energy Consumption and Carbon Emissions of Different Magnesium Refining Processes

“…NaF reacted with active CaCO 3 and converted to CaF 2 . Rongbin Li et al [73] compared the magnesium reduction rate and production efficiency of the short process and the Pidgeon process and studied the effects of thermal decomposition temperature, silico-thermal reduction temperature, granulation pressure and the silicon ratio on the production of magnesium in the short process. They also analyzed the cross-linking effect between the carbon dioxide decomposed from dolomite and the metal elements in ferrosilicon.…”

Novel Approach to Prepare Magnesium and Mg-Al Alloy from Magnesia by Using the Closed Microwave Aluminothermic Method

“…Recently, our result demonstrate that ball milling could lower the reduction temperature of MgO by usi metal as a reducing agent, with ball mill speed and time of 600 r/min and 5 h, respec [22,23]. Therefore, in this article, the reactants are treated by a high-energy ball m process with ball mill speed and time of 600 r/min and 5 h, respectively, in order to e that the reduction of magnesium oxide is carried out at 1273 K. 2 High temperature sealant, 3 graphite flake, 4 sample, 5 Ceramic lid, 6 graphite paper, 7 alumina crucible, 8 Activated carbon powders, 9 ceramic cup.…”

“…Currently, magnesium is mainly prepared using thermal reduction and electrolysis methods [4,5]. As a well-known process, the Pidgeon process is the most mature magnesium smelting method in China, which has the advantage of being a simple technical process, needing less investment to build a factory, having a flexible production scale, and higher purity of magnesium [6][7][8][9][10]. Nevertheless, the disadvantages of high energy consumption and environmental pollution of the Pidgeon process have brought a great challenge to the development of the economy and society.…”

“…(A) is the closed microwave aluminothermic method schematic diagram, (B) is the schematic of reduction process of MgO under microwave irradiation, (C) is the schematic of the experimental equipment. 1 refractory fiber,2 High temperature sealant, 3 graphite flake, 4 sample,5 Ceramic lid,6 graphite paper, 7 alumina crucible, 8 Activated carbon powders, 9 ceramic cup.…”

Effect of nanoclusters formed by metal impurity on magnesium vapor condensation in silicothermic process: a molecular dynamics study

“…The pellets are reduced in retorts under a vacuum of ∼10 Pa and a temperature of ∼1473K. The magnesium vapor released from the reaction zones of retort then diffuses into the crystallizer and condenses to form crowned crystalline magnesium [12].…”