Starch chemical modification for selective flotation of copper sulphide minerals from carbonaceous material: A critical review

The inherent hydrophobicity of carbonaceous graphitic material enables its easy flotation simultaneously with valuable copper sulphides, posing significant flotation separation problems. As widely reported, environmentally benign, cheap and ubiquitous natural polymers such as native starch can be used to depress graphitic carbon. However, starch's macromolecular structural peculiarities and poly-hydroxyl functionalities make it less selective. Nevertheless, with these features, it also means that starch has great physicochemical versatility. Continuous research is prompted to modify starch and eliminate the deficiencies which lower its depressive capacity. This paper reviews the current fundamental knowledge of functional and structural features' influence on underlying binding and depressive mechanisms of native starch and innovative development of specific and efficient starch derivatives. This is in particular view to improving flotation performance of carbonaceous copper sulphide ores.