Polyacrylamide Inverse Emulsion And Its Flocculation And Settling Performance Research

In this paper, non-ionic polyacrylamide and cationic polyacrylamide with high molecular weight were synthesized by the means of Inverse Emulsion Polymerization, anionic polyacrylamide emulsion was synthesized by the means of hydrolization of non-ionic polyacrylamide with alkali added in later process.The optimum conditions of preparing non-ionic polyacrylamide using Inverse Emulsion Polymerization was that:reaction temperature 45℃, reaction time 4h, amount of initiator 0.2‰, amount of emulsifier 6%, HLB=6, mass fraction of monomer 40%, the mass ratio of oil to water 1.0:1.0,EDTA-2Na 1.0‰. Unde this condition, the obtained polymer with high molecular weight 1100×104 showed good reproducibility.The above-mentioned emulsion was hydrolyzed at optimum hydrolysis conditions:the hydrolysis agent NaOH, theoretical degree of hydrolization 30%, temperature 60℃, time two hours. Under this condition, Partially hydrolyzed polyacrylamide latex was obtained with DH 24.5% and molecular weight over 660x 104.Cationic polyacrylamide P(DMC-AM) was synthesized with acrylamide(AM) and methacrylatoethyl trimethyl ammonium chloride(DMC) as co-monomers by Inverse Emulsion Polymerization in this paper,the optimal conditions were as follows:amount of initiator 1.4%o, amount of emulsifier 6%, HLB=6, mass fraction of monomer 40%, EDTA-2Na 1.0‰, the molar ratio of DMC to AM 5:95, the mass ratio of oil to water 1.1:1.0, pH=5, reaction temperature 50℃and reaction time 4h. Under above conditions, the molecular weight of the product was 580×104. Through Fourier transform infrared spectrum (FT-IR) measurement, the product was proved to cationic copolymer P(DMC-AM).The flocculation behavior of bauxite forward flotation tailings aqueous system was investigated by the sedimentation test, the experimental result revealed that the flocculation effect of anionic polyacrylamide flocculant was better than nonionic and cationic polyacrylamide, the sedimentation rate was higher,the liquid-solid separating effect was distinct and the up liquid was clear at the best dosage 20g/t.