Synthesis of thioxopropanamide surfactants for studying the flotation performance and adsorption mechanism on chalcopyrite

Abstract

In this paper, three thioxopropanamide surfactants 3-ethylamino-N-methyl-3-thioxopropanamide (EAMTXPA), N,N-dimethyl-3-(phenylamino)-3-thioxopropanamide (PhATXPA) and 3-ethylamino-N-phenyl-3-thioxopropanamide (EAPhTXPA) were synthesized and introduced as collectors for chalcopyrite flotation for the first time. The chemical reactivity sites of thioxopropanamides was predicted by density functional theory. Micro-flotation tests show that EAPhTXPA possesses better flotation ability to chalcopyrite than EAMTXPA or PhATXPA. The contact angle tests showed that after treatment by the three thioxopropanamides, the contact angle of water drop on chalcopyrite increased. Furthermore, the hydrophobization intensity of EAPhTXPA toward chalcopyrite was stronger than that of EAMTXPA or PhATXPA. The adsorption mechanism of EAPhTXPA onto chalcopyrite was evaluated by adsorption tests and XPS analysis. Adsorption experiments indicate that the adsorption of EAPhTXPA is a spontaneous-endothermic chemisorption process. XPS spectra infer that the S, O and N atoms of EAPhTXPA may bond with the Cu atoms on chalcopyrite surfaces.