Graphite electrodes are an essential part of the EAF steel production process and comprise a substantial portion of the cost.
Flake graphite from Hexagon's McIntosh Graphite Project in the east Kimberley region of WA was tested in this process, which involved it being treated with a proprietary ingredient and branded as ‘Performance+’.
This work demonstrated a positive and direct correlation between the addition of Performance+ and increased electrical conductivity.
Potential for reduced costs
Managing director Mike Rosenstreich said: “The results for the Performance+ highlight the potential for reduced downtime and lower power consumption leading to reduced costs and smaller carbon footprints in the smelting industry.
“These are essential challenges facing the steel industry and leading to a major transitioning to EAF furnaces in China.
“This strongly endorses our strategy of seeking high-value, deep-market opportunities for our natural graphite as set out in our recent downstream scoping study.”
Increase in conductivity
With Hexagon’s specialised natural-graphite performance additive for EAF graphite electrodes, the company was able to demonstrate reduced energy consumption while minimising electrode consumption in normal EAF operations.
This technical development work demonstrated a consistent increase in electrical conductivity and lower coefficient of thermal expansion, thereby maximising electrical efficiency and reducing energy consumption.
The company manufactured a total of 38 extruded graphite electrodes manufactured with Performance+ additive.
These demonstrated consistent enhanced electrode performance including true density, bulk density and electrical conductivity performance.
Extruded ‘green’ graphite electrodes prior to baking and pitch impregnation
- 12% increase in true density;
- 4.5% increase in bulk density; and
- 25% increase in electrical conductivity.
These results highlight the potential of increasing electrical performance and increasing durability and service lifetime in graphite electrodes to reduce operating costs.
Hexagon’s technical development work indicates a potential substantial new market opportunity for its transformed graphite material, consistent with the outcomes of the Downstream Scoping Study released in May 2019.