Abstract:
The highly weathered, fragile and low grade manganese ores of Visakhapatnam district of Andhra Pradesh are subjected to wet high intensity magnetic separation (WHIMS) to give beneficiated magnetic fraction. However, the original ore and its non-magnetic fraction contain large quantities of slimy particles which are difficult to separate from their aqueous suspensions. Three different commercial flocculating agents with anionic, cationic and non-ionic characters have been used to improve settling and filtration behaviour of the suspensions. While a small dose of anionic flocculant has been found to be very effective, cationic flocculant is poorly effective even at high dosage. The behaviour of non-ionic flocculant is intermediate between the two. Since extremely fine particles constitute the non-magnetic fraction, it needs higher dosage of anionic flocculant to form large or aggregated flocs which make the filter cake porous even with increasing slurry concentration.