Mechanism of Selective Flocculation of Hematite From Quartz With Hydrolyzed Polyacrylamide

Under optimum selective flocculation conditions, most hydrolyzed polyacrylamide (HPAM) adsorbs on the hematite surface by chemical bonding, while only very little (HPAM) adsorbs on quartz by hydrogen bonding and London--van der Waal's forces. The degree of hydrolysis of HPAM affects selective flocculation because of changes in geometry, chemistry, and electrostatic interaction. Pulp pH affects the configuration of HPAM and the homo- and hetero-coagulation of minerals. Ca(II) ion, under optimum selective flocculation conditions, suppresses flocculation of hematite, because it adsorbs on HPAM to lower the chain stretch and adsorbs on hematite to block some of the active sites. 22 ref.--AA