Impact of microwave irradiation on the processing of a sulfide ore

Microwave pretreatment is one of the emerging technologies that have been reported as having potential economic benefits for the processing of amenable ores. The application of microwave pretreatment to the processing of refractory and finely disseminated ores is of great interest because the technology can potentially reduce high comminution costs and improve mineral liberation. To determine the influence of heating rate on mineral transformation, ground product size distribution and mineral liberation, sized ore samples were subjected to microwave irradiation at power levels varying from 1 to 5 kW over exposure times of between one and six minutes. The microwave-irradiated samples were ground and subsequently floated. A comparison was made with non-microwave-treated samples. Zinc flotation grade and all metal recoveries show a strong dependence on the microwave absorption characteristics of the mineral components of the ore in the following decreasing order: sphalerite, galena and, lastly, chalcopyrite.