Methods and apparatuses for separating metal values, such as nickel and nickel
compounds, from mineral ores, including lateritic ores are disclosed. The method
includes providing a mixture of particles (e.g., crushed and sized ore) that is
composed of at least a first group of particles and a second group of particles.
Group members have similar chemical composition, while particles belonging to different
groups have dissimilar chemical compositions. The mixture of particles is exposed
to microwave/millimeter wave energy in order to differentially heat the first and
second group of particles, thereby increasing differences in magnetic susceptibility
between the first and second group of particles. The mixture of particles is then
passed through a magnetic field gradient, which causes the particles to separate
into magnetic and non-magnetic fractions.
