Effect of reagent blend on characteristics and dispersion of bubbles in a flotation column

The effects of dodecylamine (DDA) and 2-octanol on the characteristics and dispersion of bubbles in a flo- tation column was investigated in this study. Bubble size distribution was measured using the McGill bubble size analy- zer,surface tension was measured using the surface tensionmeter,and aeration rate was researched using the measuring cylinder technique. Furthermore,bubble adsorption density and surface area flux were analyzed. With the increase in reagent concentration,the bubble size decreased until the critical coalescence concentration ( CCC) to 0. 630 3 and 0． 602 0 mm of DDA and 2-octanol,respectively,and the concentrations (CCC99 ),at which bubble size is reduced by 99% from that with water only,were analyzed to be 0. 081 1 and 0. 070 3 mmol / L for DDA and 2-octanol,respective- ly. The bubble size in DDA solution was found to be larger than that in 2-octanol solution with an equal solution con- centration. Surface tension was found to linearly decrease with the increase in reagent concentration,and the surface tension of DDA was lower than that of 2-octanol under the same concentration. Aeration rate increased as the reagent concentration increased,and the aeration rate of DDA was larger than that of 2-octanol. The adsorption density of DDA and 2-octanol at CCC was calculated to be 0. 966 2 and 0. 282 7 μmol / m2 ,and the bubble surface area flux of DDA was smaller than that of 2-octanol while the concentration was above CCC. With the increase of DDA addition in 2-oc- tanol solution,the CCC,constant D32 ,surface tension and adsorption density decreased,but aeration rate and bubble surface area flux increased. With a DDA addition of 0. 032 4 mmol / L,the minimum CCC,constant D32 and adsorption density were obtained at 0. 021 6 mmol / L,0. 583 3 mm and 0. 154 0 μmol / m2 ,respectively,while the maximum bub- ble surface area flux was calculated to be 7. 734 s-1 .