| The current study investigated the effect of novel organic/inorganic (hybrid) polyacrylamide polymer as ash (slimes) depressant in fine coal flotation for the possibility to enhance the combustible recovery and ash rejection. Raw coal samples contain about 25% of ash-forming minerals were crushed, grinded to -75um and floated in the presence of in-house synthesized hybrid Polyacrylamide (Al(OH)3-PAM or Al-PAM ) at different operational parameters. Denver flotation cell with a 5-Liters capacity was used and the parameters investigated include: Al-PAM dosage, Al-PAM conditioning time, dual use of Al-PAM and a dispersant, impeller rotation speed and pulp's pH. For comparison purposes, commercially available polyacrylamide polymers (PAMs) were also tested.;Results show a significant improvement in both combustible recovery and ash rejection at 0.25 ppm Al-PAM dosage. Further improvement in ash reduction was achieved when flotation was performed using dual dispersant/Al-PAM system. At natural pH, the maximum combustible recovery and ash rejection were obtained at Al-PAM dosage of 0.25 ppm, dispersant dosage of 0.8 ppm, conditioning time of 6 minutes and impeller speed of 1800 rpm. Zeta potential values of both raw coal and concentrates samples showed a large shift to more positive zeta potential values after flotation which indicates a significant depression of ash-forming minerals (slimes) when Al-PAM polymer was used. |
