Abstract

A "carrier" or "piggy–back" coagulation process was applied to improve the separation efficiency of chromite slimes in wet high–gradient magnetic separation. This was achieved by the addition of a coarse chromite fraction to the slime fraction (< 10 mm). Three coarse chromite fractions were investigated in the present study with size ranges <106>75, <75>53 and <53>38 μm. The results suggested that the <53>38 μm coarse fraction was the most effective in improving the process efficiency. Superior performance was also found to occur between pH 5 and 6. The results were discussed by computing the various components for potential energy of interaction between the slime particles and the "carrier" or "piggy-back" particles at a range of surface potentials in the absence or presence of the magnetic field.