1 XXVIInternational Mineral Processing Congress (IMPC 2012) Application of Surface Chemical Analysis to the Industrial Flotation Process of a Complex Sulphide Ore

The objective of this study was to achieve Zn activation control in an industrial Cu flotation circuit treating a complex Cu-Pb-Zn-Au-Ag sulphide ore at the LaRonde Division of Agnico-Eagle Mines Limited (Quebec, Canada). In order to provide process relevant results, a laboratory testing methodology was developed to duplicate plant operational parameters. The action mechanisms of ZnSO4, TETA (triethylenetetramine) and NaHSO3 used as depressants in order to limit ZnS activation were examined. Laboratory flotation tests with and without Cu2+ ions (the ions responsible for ZnS activation) were performed. All depressants showed equal or better flotation performance relative to baseline tests. For example, in the presence of Cu2+, the Zn grade reduced from 32.2 % to 17.5 % in the copper rougher concentrate after adding 50 g/t ZnSO4. TOF-SIMS analyses confirmed the relative decrease in surface Cu in the samples treated with ZnSO4 and TETA. For the case with TETA, this indirectly indicates the formation of a copper TETA complex in solution, thereby reducing available Cu for transfer. The TOF-SIMS and XPS data indicate that the addition of ZnSO4 and NaHSO3 resulted in an increase in surface metal hydroxides and SO3 on ZnS grain