Patent ID: 8636148

Claim:
A method of sorting mined material to separate mined material into at least two categories, the method comprising the steps of: (a) exposing particles of mined material to microwave energy and heating the particles depending on the susceptibilities and therefore the compositions of the materials in the particles; (b) thermally analysing the particles using the temperatures of the particles as a basis for the analysis to indicate composition differences between particles, with particles containing higher levels of valuable material than other particles falling into one category and particles containing no or uneconomically recoverable concentrations of valuable material than other particles falling into another category, with particles of one category responding differently thermally to particles of the other category to exposure to microwave energy, with the particles in one category being hotter than particles in the other category, the thermal analysis step including thermally assessing particles against a background surface, the thermal analysis step including heating the background surface to a temperature that is between the hotter particles in the one category and the colder particles in the other category to provide a thermal contrast between the particles in each category and the background surface; and (c) sorting particles on the basis of the results of the thermal analysis into the two categories.