Dry comminution and liberation with microwave assistance

Abstract

This paper presents the experimental results obtained from microwave‐assisted comminution/liberation tests on various minerals. The effects of microwave energy intensity and exposure time on microwave heating behaviour and grind‐ability of materials are discussed. The experimental results indicated that particle size has a significant effect. The coarser particles (−9.50 + 4.75 mm) of some minerals (limestone and quartz) were affected by microwave heating to varying degrees, resulting in an increased fineness of the ground product in a subsequent dry ball milling. It was observed that the silicate and carbonate minerals are difficult to heat at lower microwave energy intensities (<7 kW) during a short exposure (<30 min) due to their principally transparent or reflection to microwave energy. The thermal stress fractures in a copper ore in microwave exposure occurred readily, resulting in a better and cleaner liberation of sulphide minerals from the ore matrix.