Research On The Selectivity Of Flooculant For Fine Hematite Particle

Fine-grained hematite has the properties of small quality, large surface area, big surface activity, max surface energy and disperses difficultly, which is suitable for adopting flocculation separation process. Based on analysising selective flocculation of fine hematite and combining the characteristics of soluble starch and acrylamide, grafted polymer flocculants of soluble starch- acrylamide was prepared by graft copolymerization.Single-factor conditions on the impact of the starch- acrylamide polymerization were studied in the condition experiment. The level of starch grafting was used to measure the various conditions on the polymerization. The optimal conditions of single-factor were detemined, the concentration of cerium ammonium nitrate was 1mmol/L, the mass ratio of AM/soluble starch was 2:1, the reaction time was 2h, the reaction temperature was 60℃. Under these conditions, the grafting rate of starch could reach 140%. A four factors and three levels orthogonal test was designed in terms of single-factor experiment. The best conditions were investigated, the mass ratio of starch and monomer was 1:2, the concentration of cerium ammonium nitrate was 1mmol/L, the reaction temperature was 65℃, the reaction time was 2h. Under this conditions, the grafting rate of starch was 153.24%. The sanning electron microscopy showed that the morphology of polymer was significantly different from soluble starch and acrylamide after grafting, the higher the grafting yield, the more intensive the branches showed in the sanning electron microscopy. The infrared spectrum indicated that the resulting polymer is compose of starch and acrylamide.The selective test indicated that the prepared starch - acrylamide graft polymer could adsorpte on the surface of pure quartz and pure hematite.From the spectrophotometric method,the graft copolymer adsorped on the surface of quartz was about 9%, while on the surface of hematite it reached 55%. The test of flocculation indicated that the selective flocculation ability of synthesised flocculation was better than modified maize starch and polyacrylamide.