Division of Information Technology, Engineering and the Environment
Applied Centre for Structural and Synchrotron Studies
Applied Centre for Structural and Synchrotron Studies
Client: Anglo
Platinum Research Centre
Project duration: 2002-2003
Chief Investigator: Andrea Gerson
Description:
Some metal sulphides can
be floated for separation through the direct surface adsorption of
hydrophobic flotation reagents. In other cases the surfaces of these
minerals need to be activated for reagent adsorption. This
activation is carried out through the surface adsorption of Cu(II)
onto these sulphide minerals.
If Cu(II) is present in process water it can take several forms
after interaction with the water, mineral surfaces and flotation
reagents:
Cu(II) may replace one of the metal ions already present on the sulphide minerals surface and then reduce to Cu(I) thus activating the surface for adsorption of flotation reagents
Depending on the pH of the process water and the concentration of the Cu(II), Cu(II)(OH)2 may precipitate over all mineral surfaces including those of gangue minerals. Cu(OH)2 is hydrophilic and will suppress mineral flotation
On addition of flotation reagents (for instance xanthate or DTP) the Cu(OH)2 may convert to a Cu(I)-flotation reagent complex that can be randomly adsorbed onto all mineral surfaces. This may cause the inadvertent flotation of gangue minerals.
The following were addressed during this project:
Whether pentlandite and pyrrhotite are activated by addition of Cu(II)
The relative kinetics of Cu(I) activation, Cu(OH)2 formation, Cu(I)-flotation reagent complex formation
The amount of Cu(OH)2 surface coverage required to depress mineral flotation
The amount of Cu(I)-flotation reagent surface coverage required for inadvertent mineral flotation
Reagent development/testing for Cu(II) specific hydrophilic reagents and Cu(I) specific hydrophobic reagents.
