ALUMINA QUALITY REQUIREMENTS FOR IMPROVED CELL FEEDING
Andrews, E.W., and Welch, B.J.
Since the inherent problems that smelter cells encounter for stable operation are closely linked with alumina feeding, we have been examining the challenges and obstacles that must be overcome in order to continuously feed cells. This is extending the present feeding technology to its limits. Such an approach has the following advantages:
- Elimination of sludge.
- Better pre-heating of alumina.
- Potential to match feeding with process requirements.
- Ability to maintain a more constant alumina concentration in the electrolyte.
- Minimised thermal disturbances with feeding.
- Feedback information on the flow rate of alumina being added.
Notwithstanding these advantages, the continuous feeding system is likely to be more prone to blockages because of the low flow rates involved and the small openings required to deliver these flow rates. Problems may also occur if the alumina is of such poor quality that it fails to discharge out of the hopper in a consistent fashion.
This paper addresses these issues and identifies what alumina quality factors will need further consideration by alumina refineries and alumina smelters, should a system of this type be adopted in the future.