Flocculation of Iron ore Slimes using Synthesised Starch-g-Acrylamide Copolymer

The copolymers synthesised by grafting polyacrylamide chains on starch backbone are found to be efficient
flocculant having appreciable shear and biodegradation resistance. The efficiency of one of the starch-g-poly-acrylamide copolymers has been tested for flocculation
of iron ore slimes. The settling rate following flocc-ulation was measured as function of time. The effect of varying pH, solid concentration of pulp and flocculant dose was studied in the tests. The efficacy of grafted copolymer was established by comparing its performance with a conventional synthetic polymer.
The sedimentation rate increases with increasing flocculant dose upto a certain limiting value after
which the improvement is marginal. The initial solid concentration and pH of suspension have considerable
effect on the settling rate. The settling rate decreases substantially in the alkaline pH range due to the
increased stabilization of the particles in this pH range.