Flocculation of metal-bearing waste waters using cellulose and its graft copolymers

Several types of cellulose (wood pulp) and their graft copolymers with water-soluble monomers were tested for their activity as flocculation aids. They were employed as additives to lime in flocculation experiments involving a simulated mine water containing iron, zinc, and copper salts. The results show that all the cellulosic products had a beneficial effect on the removal of iron, and to a lesser extent on the removal of zinc. The final concentration of ferric ions after 30 min was comparable with that produced by commercial flocculants (Magnifloc, Aquafloc). No improvement of flocculation activity was obtained upon grafting various polar monomers and their mixtures onto dissolving pulp.