화학공학소재연구정보센터
Minerals Engineering, Vol.122, 179-184, 2018
Importance of collector chain length in flotation of fine particles
Flotation of fine ore is usually carried out with collectors that adsorb specifically, such as the derivatives of carboxylic acids in phosphate processing plants. Industrial flotation processes that use conventional cationic collectors, generally, have a stage of desliming to discharge the fines, as in reverse flotation of iron ore in Brazil. This study aimed to understand why the fines respond well to flotation with oleate (carboxylic collector), but do not have the same performance with usual cationic collectors such as dodecylamine (DDA). The flotation tests were carried out in a modified Hallimond Tube using a pure dolomite sample. DDA, a cationic collector which adsorbs through electrostatic interaction (physical and non-specific adsorption), and sodium oleate (SO), an anionic collector which adsorbs via chemisorption (specific adsorption) were used as flotation collectors. The effect of adding a chain extender was tested and the influence of the size of the amine chain in the floatability of the fines was also observed. The initial results showed that flotation with DDA is strongly affected by particle size. The floatability decreases from 82.6% to 52.6% when d(50) decreases from 74 mu m to 14 mu m. In turn, particle size variation had little effect on the floatability with oleate. The better performance of the fines flotation with oleate was attributed to the hydrophobic aggregation during conditioning which increases the d(50) by 43%. The floatability of fines increases with the hydrophobic aggregate size which, in turn, increases with the chain length of the collector. This explains the better performance of the oleate (17C), if compared with DDA (12C), and suggests the use of long chain collectors for the flotation of fines.