337 348 WG39 Claflin

This paper reviews the evolution of carbon regeneration/reactivation kiln technology through to the Ausenco reactivation design criteria of 2013, and how lessons learned from commissioning and ramp-up of a carbon reactivation kiln designed to those criteria by Nutec Bickley have been captured to modify that technology. A new-generation carbon reactivation kiln can reactivate heavily fouled carbon from a flotation tails carbon-in-leach (CIL) circuit to as good as virgin activity. Despite being heavily fouled by high-molecular-weight frothers and collectors, and with the feed containing approximately 50% w/w contaminants, the kiln successfully heats the carbon to reaction temperatures up to 850°C and achieves 100% reactivation, operating at double the design mass rate and effectively halving the carbon residence time in the kiln. The presented technology is particularly beneficial for gold plants with solution tails losses exceeding 0.04 g Au per ton, with the potential for recovering gold to cover capital costs within months. The collaboration between the client, Ausenco’s engineers, and kiln vendor Nutec Bickley resulted in significant improvements to the kiln design and operation.