Adsorption of cupferron on malachite (−2 0 1) surface and implication for flotation

Abstract

This paper investigated the adsorption mechanism of cupferron on the malachite (−201) surface and the implications for flotation via X-ray photoelectron spectroscopy (XPS), Fourier-transform infrared (FTIR) measurements, density functional theory (DFT) calculations, and microflotation tests. The XPS and FTIR analyses confirmed the adsorption of cupferron on the malachite surface. The DFT calculations indicated that the adsorption was mainly due to the reaction between O atoms in cupferron and Cu atoms on the malachite surface. Six different adsorption configurations were discussed, and the Cu3-cupferron anion-O1O2 model was the most stable. The five-membered-ring cupferron-Cu complex was produced under this condition, and the corresponding adsorption energy is −2.092 eV. The density of states (DOS) analysis reveals that the O 2p orbital from cupferron O atoms and the Cu 3d orbital from malachite Cu atom overlapped at −0.7 to 0.3 eV and −2.6 to −0.8 eV around the Fermi level, demonstrating a stable chemical adsorption. The population analysis showed that electron transfer occurred between the Cu and O atoms during the adsorption process. The micro-flotation results showed that cupferron has a strong collecting performance for malachite. This research provides a better understanding of the adsorption mechanism of cupferron on malachite surfaces at the atomic level. It is of great significance for its application in flotation.