AAPS / Automated Anode Positioning System

A precise and fully automated anode positioning system

In smelters where prebaked anodes are used, huge amounts of anodes need to be replaced continually. The new anodes have to be precisely adjusted in electrolysis cells to ensure good stability to the electrolytic process and to optimize the anode cycle.

Manual positioning methods are still the norm in several smelters. Even with the best trained operating crews, manual positioning – given the number of people involved and the methods that are used – is prone to variability and lack of consistency. In addition, manual positioning exposes the operators to a dangerous environment.

Alcoa and STAS have developed the AAPS / Automated Anode Positioning System, a fully automated system that can be implemented on pot tending machines (PTMs). It both improves health and safety conditions for floor operators and ensures optimal anode positioning. The automatic positioning system is based on laser measurements using as reference the anodic beam instead of the pot tending machine itself.

This automated anode positioning system is also designed to minimize the time when the anode butts are in transition between the electrolysis cell and the anode tray. During this period, HF emissions are very high and loose in the atmosphere. By using the covered anode tray, the reduction of this period of time has a big impact on HF emission (see the description of the covered anode tray).