Starch graft polymers. I. Graft Co- and terpolymers of starch with 2-hydroxy-3-methacryloyloxypropyl-trimethylammonium chloride and acrylamide: Preparation and evaluation as silica depressants

The title monomers have been grafted onto wheat starch by γ-radiation-induced polymerization in water providing three graft polymers containing poly[2-hydroxy-3-methacryloyloxypropyltrimethylammonium chloride (I)] and two graft polymers containing poly[I and acrylamide (II)]. Characterization is discussed together with their utility as silica depressants in flotation-beneficiation of siliceous ores. Results are provided to illustrate that a starch graft copolymer containing 15% poly(I) graft and a graft terpolymer containing 30% poly(I, II) in the ratio 1:2 are effective as selective depressants for silica in flotation-beneficiation of Florida pebble phosphate ore using special flotation conditions.