Improvements of a Copper Dry Feed Loss-In-Weight Feed System: RotoFeed® Installation on a Flash Smelting Furnace

Rio Tinto Kennecott smelter personnel identified issues around the dry feed (copper concentrate, slag concentrate, coolant, and flux) loss-in-weight (LIW) screw feeder system feeding the smelter’s flash smelting furnace. Due to properties associated with a finely ground dried concentrate and slag concentrate, the screw feeder system suffered from flushing, which caused excess feed to rush directly through the screw feeder into the furnace’s concentrate burner. Despite multiple “improvements” of the screw feeder system, flushing persisted. Personnel from the Rio Tinto Kennecott’s Projects, Engineering, and Technical teams evaluated replacement options, with a RotoFeed® LIW system chosen as the best choice due to its limited path for feed to flush through the system. This paper will describe the decision process, installation, and the results of changing to the new LIW feed system. This paper will also discuss the additional feed preparation that is required upstream of the system to maintain the RotoFeed® integrity and limit wear. Initial results of the installation showed drastically reduced flushing, and it decreased overall maximum feed rate deviation from ± 15% to less than ± 2% of setpoint. After eight months of operation, the RotoFeed® system performance deteriorated and eventually a replacement RotoFeed® was installed. This paper will discuss the wear found on the original RotoFeed® units and potential RotoFeed® design improvements.