Ian Wark Research Institute
ARC Special Research Centre
ARC Special Research Centre
Research Area: Chemical engineering, mineral processing, mineralogy
Supervisors:
A/Prof Daniel Fornasiero and
Dr Max Zanin
Description: Value minerals locked in composite particles in
coarse size fractions is the single largest contribution to value
mineral loss from many base metal sulfide flotation plants. The coarse
particle flotation rate is controlled by detachment of particles from
bubbles, which in turn is dependent upon particle hydrophobicity and
flotation cell turbulence. For composite particles, containing regions
of hydrophobic value and less hydrophobic gangue, the bubble may attach
to the hydrophobic region of high contact angle but the expansion of the
three phase line of contact is limited due to the presence of
hydrophilic regions. Hence, the equilibrium contact angle may never be
achieved, and the force of attachment is decreased relative to that
possible for homogenous particles containing only the hydrophobic value
mineral. Studies within the P260E project have revealed that dramatic
increases in the recovery of homogeneous coarse particles can be
achieved by simply increasing the medium viscosity. This project will
further explore the influence of the separating medium (viscosity,
specific gravity) on the detachment of composite particles from bubbles.
The project objective will be to investigate the conditions for
detachment of model composite particles from bubbles under controlled
turbulent and pulp rheological conditions, in particular pulp density.
Expected outcomes: To determine the critical hydrophobicity of
composite coarse particles (including % liberation, distribution and
size of each phase) for a specific size fraction to be floated for a
given power input under different pulp rheological conditions. The
flotation characteristics of synthesis composite particles, eg, lead
borate - silica composite, will be investigated after altering the
medium specific gravity by adjusting either % solids of suspended
particles (ferrosilicon), and/or medium viscosity by addition of
viscosity modifiers.
