Thanks for all the reponses. Sorry if it sounded a bit confused but I was really asking in relation to the two seperate processes, Flotation (spelt it right this time ;-)) and residency/cyanidation. So my initial takeaway from this is that Flotation times are not that critical as there will be other more complex processes in the flow, but that CN residency is critical. Plough could you elaborate a bit more on mass transfer?
Also to clarify, the company that got a 4 hour residency used Oxygen sparging. If I remeber correctly Oxygen is a critical reagent and limiting factor in the cyanide chemical process, so IMHO those results might have been a bit dodgy.
