Development of lightweight ferrous alloys that are energy efficient

Sustainability_of_existing_materials and_processes

The aim of this project is to develop process fundamentals for producing lightweight ferrous alloys (Fe-Al-C) directly from the carbothermic reduction of alumina (Al2O3) and iron oxide (Fe2O3) at low temperatures (1500-1600°C), and to determine optimal operating parameters through comprehensive investigations on the formation of various alloy phases.

Aluminium, a key component of these alloys, is produced from the bauxite ore primarily through the electrolytic reduction of alumina using the Hall-Heroult process [1]. This process is ranked among the most energy and CO2 intensive industrial processes [2]. Direct carbothermic reduction of alumina: Al2O3+3C=2 Al +3CO(g), proposed as an alternative process for primary aluminium production, requires temperatures above 2100°C, and suffers from critical design issues such as aluminium carbide and oxycarbide formation, aluminium vaporization and low metal yields

There is a pressing need to discover new ways of producing aluminium based products that are energy efficient, economic and environmentally sustainable. During refractory degradation investigations on the Al2O3-C/Fe system at 1550°C [DP0774100], CIs Khanna and Sahajwalla observed the pickup of metallic aluminium by molten iron. As iron is known to have a high affinity for Al [4], this novel discovery led them to consider the possibility of using molten iron as a "thermodynamic sink" for aluminium. The CIs have performed further pilot experiments which confirm the facile carbothermic reduction of Al2O3 at 1550°C in the presence of molten iron and at atmospheric pressure [5]. The logical extension of these key findings to the direct carbothermic reduction of mixed oxides of aluminium and iron would be an extremely significant development in the field. Fe-Al alloys are used in the automotive sector, for welding electrode manufacture, high temperature gas filters and hard surface coating applications.

This project aims to develop a novel advanced technology to produce lightweight ferrous alloys at lower temperatures (1500-1600°C). This approach will lead to an energy efficient process as the primary production routes for metallic Al and Fe will be replaced by a single system to carry out the simultaneous reduction of mixed oxides (alumina & iron oxide) and the subsequent formation of aluminium based ferrous alloys.