The Pot Tending Machines (PTM) at Qatalum automate the anode changing process. Historically anode changing has evolved from a manual process to a semi mechanised one, still used by smelters today. At Qatalum the process has been moved into the future with the use of a semi-automatic Cover Handling Unit.
The PTM arm with the Cover Handling Unit demonstrating cover removal with precision and speed in a controlled workshop environment
Of all the task done with the PTM, one particular task is the removal and placing of the pot covers during the anode change and anode covering task that shield the exposed portion of the pots. All the PTM's at Qatalum are fitted with a dedicated Cover Handling Unit. Qatalum is the only smelter in the world practicing semi-automatic cover handling. The advantages of this are two fold, increased safety and reduced emissions.
Vehicular and mechanical traffic are the predominant causes of safety related incidents in a potroom, a situation Qatalum has designed to avoid by automating traditionally manual processes.
The covers removed by the PTM Cover Handling Unit within the potroom. All other pots remain closed preventing emissions escaping into the atmosphere
Simply stated, the lack of human interaction on the potroom floor avoids accidents. Additionally, in Qatar's hot conditions it also avoids employee exposure to over 50 degree working conditions. Instead, the whole anode changing process, of which cover handling is one, is executed by a single operator sitting in an air conditioned PTM cabin.
Emissions from pots are drastically reduced when a pot is covered. Logically, by closing the pot, emissions are contained, however, when the covers are removed emissions and particulates can escape into the environment and ultimately get inhaled by attendants. Therefore the efficiency in containing emissions provided by using a PTM significantly reduces the time between opening and closing the pot.
At Qatalum, when covers are removed to facilitate an anode change several factors come into play. There is an inbuilt suction process that is tripled creating a negative atmosphere within the pot. All emissions and dust is sucked into the filtration system creating a dramatically cleaner local environment.
Emissions measured from the potroom roof at Qatalum are currently measured at 0.15 kg of fluorides per tonne of aluminium produced – the lowest in the business and directly associated to cover handlers and the fume suction process.
By automating the cover handling process, Hans Petter Lange, Reduction Manager says that, "Qatalum has set an HSE benchmark allowing for improved working conditions. This is in line with our management directives and mission to become a leading smelter. However, we still have actions in place to reduce emissions and safety even further in the future."