The influence of microwaves on the leaching kinetics of chalcopyrite

Enhanced recovery of copper was noted for samples leached within the microwave field. Previous work has suggested that this may be due to a “microwave effect”. For the first time this work proves that higher recoveries in microwave systems occur as a result of selective heating of the mineral particle over the solution. It is postulated that the reaction interface has a higher temperature than that of the bulk solution, leading to a higher reaction rate. In addition, it is suggested that high loss leaching solutions will develop a superheated layer close to the periphery of the reaction vessel (due to the small penetration depth) which creates localised heating compared with the measured bulk solution temperature. If leaching takes place within this layer, an apparent rate increase will be noted with respect to the measured bulk temperature.