CAT / Covered Anode Tray
An easy and efficient way to reduce HF emissions from anode butts
How it works
During the production of aluminium in smelters, the anodes used in electrolysis cells have to be replaced frequently. Anode butts are usually placed on anode trays for transportation and cooling in the potroom, a process during which Hydrogen Fluoride (HF) is emitted in large quantities. The ambient air humidity reacts with the fluoride emitted by the hot bath and sticking onto the anode butts, producing HF emissions. HF is particularly toxic for the environment and human beings as well.
With the collaboration of Alcoa Canada, STAS has developed the CAT / Covered Anode Tray, a special tray that reduces HF emissions by 0.055 kg per ton of aluminium, which represents 50% of the HF emitted from anode butts. Considering that the best smelters generate a total of about 0.28 kg of HF per ton of aluminium (for the whole process), the implementing of covered anode trays represents an HF reduction of 20% for a single smelter.
The system, which is very simple, reduces contact between ambient air and the anode butts. A special sealing mechanism around the anode rod ensures an optimum result while minimising the operating costs of the system.
A new crust bin system is also used conjointly with the anode tray cover to further reduce HF emissions during the anode replacement process.
Key features
Productivity Improvement
- Easy to implement and maintain.
- No additional steps added to the anode replacement process.
Safe Operating Environment
- HF reduction in the order of 50 % (0.055 Kg HF /T Al) from the anode tray.
