Improved azurite sulfurization with ethylenediamine modification and its effects on flotation behaviors: Insight from copper vacancy

Enhanced sulfurization has always been the focus of flotation research on copper oxide minerals. In this study, ethylenediamine (EDA) was used to improve the sulfurization of azurite. ICP-OES, AFM, XPS, Zeta potential, EPR and DFT calculation were applied to reveal the underlying promoting mechanism, and flotation tests were conducted to evaluate the effect of EDA on sulfurization flotation of azurite. ICP-OES, AFM and XPS analyses showed that EDA modification significantly promoted the transformation of the sulfur -containing components to the azurite surface and enhanced the crystallinity of copper sulfide products while their chemical compositions remain unchanged. Zeta potential measurements indicated that EDA modification was accompanied by the increasing copper vacancy on azurite, which supported by EPR test results. Furthermore, DFT calculation showed that copper vacancy enhanced the adsorption stability of sulfurized product on azurite. Therefore, the recovery of azurite with EDA surface modification was increased by more than 12 % during sulfurization-xanthate flotation. This study found that copper vacancy induced by EDA was responsible for the improved sulfurized of azurite, which provided a new perspective for understanding and enhancing the sulfurization of copper oxide minerals.