Fives' Anode Inert Tray
Fives proposes a solution to eliminate emissions coming from hot spent anodes stored in potroom thanks to an Anode Inert Tray (AIT) designed to confine anode butts.
In the electrolysis area of modern aluminium smelters, treatment of pot gas emissions has been drastically improved by the latest generation of dry scrubbing technologies, with efficiency rates close to 99.8%. Therefore, stack emissions now only represent a very small amount of the total fluorides emitted over the entire smelter. Most of the HF is released to the atmosphere directly from the potroom, where in many smelters, no specific treatment is provided to limit emissions related to pot maintenance activities (pot hoods opening, spent anodes removal, etc.).
Fives has developed a system that isolates swiftly spent anode butts, with handling operations reduced to the bare minimum, while maintaining low CAPEX, low OPEX and easy operation. The solution selected consists in sinking the hot butt into a tray containing alumina.
The first trial was performed in 2014 at the ALRO plant in Romania and prototype was validated with ALRO’s operational teams.
After few adjustments and improvements, the industrial version was commissioned at the beginning of 2016 at ALRO. It was designed to entirely replace the pallets used to handle spent anodes and to fit at best in ALRO aluminium smelter. HF emissions in the potline have been monitored on this new AIT industrial system which provides a complete stop of anode butts emissions.
To industrialize the technology both in greenfield and brownfield smelters, Fives’ teams are currently working to improve AIT handling with ECL Pot Tending Machines (PTM). They rely on expertise in anode handling to have an exhaustive overview of all operational constraints related to the implementation of a confinement solution in potrooms. The aim is to have an equipment readily usable by PTM with minimal interference with other pot handling operations.
As reduction of fluoride emissions is a prime concern for aluminium producers, Fives is confident that the Anode Inert Tray technology will soon become a must-have in the aluminium industry when it comes to reducing potroom emissions.