The use of high molecular weight polyacrylamides in the selective flocculation separation of a mineral mixture

Abstract Most of the conventional mineral processing separation methods are not effective on mineral mixtures that contain a large percentage of slimes. Selective flocculation is a potentially attractive process for treating such mixtures. The process relies on achieving conditions under which the polymer flocculant adsorbs onto the surface of one mineral and not on the others. In a practical system this selective adsorption would have to be achieved under conditions of fluctuating water quality and mineral composition. Partially hydrolysed polyacrylamides with a molecular weight of around 3 × 10 6 have been used in the selective flocculation separation of a synthetic finely‐divided mixture of haematite and a silicate (100% < 20 μm). It was possible to flocculate selectively from the mixture either the haematite or the silicate by using polyacrylamides of differing anionic character. It was usually necessary to employ a 1:1 electrolyte and a dispersant, in addition to the flocculant, to achieve good selectivity in this system.