Cadmium Enrichment Trommel Design


The project involved the design, procurement and fabrication of a trommel for use in Cadmium production at the Nyrstar Port Pirie Smelter. The Trommel consists of a sloping bottom rectangular tank, with soft closing lids and support frame, motor, gear box, shaft, shaft seals, internal rotating cage with cage doors, internal cleaning nozzles and tank instrumentation.

The project involved many unique aspects. Firstly the tank shape itself was sloping along its long axis and short axis to a nozzle at one end. This along with the supporting structure required FEA analysis to design. Secondly the rotating equipment was unique in that custom shaft seals were designed and fabricated.

GPA ensured that Operability, Maintainability and Safety are key requirements in such a project and GPA used these requirements as a guide to the design process. To maximise operability GPA consulted with key Operations staff in the project kick off / design basis meeting, 30% and 90% design reviews. To ensure maintainability, GPA ensured that all components were easily acceptable, for instance, to allow maintenance of the seals, more than 10 x the access space was provided over the replacement units as the Operators advised that the seals cannot be accessed on the current unit without disassembly of the units. To ensure Safety, GPA reviewed safety at design reviews but also undertook guarding risk assessments in accordance with AS4024. To ensure accessibility and safety were met GPA designed a unique tank lid that functions as safety guard rail when open to prevent Operators from falling in the tank and when closed forms the lid of the tank and does not hinder accessibility.