Abstract
The promise of ‘green’ electricity is spurning a potential renaissance of electric furnace smelting, as a means to better meet increasingly stringent decarbonisation targets globally. Assuming that ‘green’ electricity generation addresses some key CO2-e issues, the next sub-element of the system to tackle would be to lower the overall CO2-e associated with electric furnace smelting. This would include improving the consumption of graphite or Söderberg electrodes used for electrical energy input on industrial electric smelting furnaces, to lower still further their contribution to the net CO2-e generation associated with electric furnace smelting.
The historical evolution of electrode carbon consumption, for a broad range of smelted commodities and different electric furnace smelting modes and conditions is surveyed to establish key electrode consumption trends. Contributions of different sources of electrode consumption through oxidation and dissolution reactions, and as distinct from mechanical electrode loss, will be explored for the different electric furnaces and their operation. Opportunities for improvement and lowering of electrode consumption across electric furnace smelting will be explored for each of the primary electrode types.
Comparison of differing consumption by electrode type, is also relevant due to the different carbon-based binder types and sources, used in manufacture of the primary two electrode types, when it is appreciated that the binders are currently largely sourced from coal tar pitch associated with ironmaking coke ovens. The latter units and so primary pitch production are themselves under threat, due to the potential that large-scale conversion to electric furnace ironmaking presents. This magnifies benefits of reduced net electrode consumption in still more efficient electric furnace smelting, in addition to the contribution of inherently lower electrode consumption, to lowering overall CO2-e footprint.