A new perspective on copper oxide flotation: Synthesis and mechanism study of a surfactant for sulfide-free flotation

A novel chelating collector, phenylethyl hydroxamic acid (BEHA), was synthesized by hydroxylamine method by increasing the carbon chain on the basis of benzohydroxamic acid (BHA). The application of this reagent could eliminate the sulfurization process and directly floated copper oxide malachite, achieving clean production. Micro-flotation tests were conducted to assess the performance of BEHA in the flotation of malachite (Cu 2 CO 3 (OH) 2 ). In the context of single mineral flotation, BEHA exhibited superior collection performance as compared to BHA. Moreover, in a binary mixed slurry system, BEHA demonstrated efficient separation ability between malachite and quartz under the condition of pH about 8.0. An in-depth investigation into the adsorption mechanism was carried out. The contact angle measurements indicated a significant enhancement in the hydrophobicity of the malachite surface after the treatment with BEHA. The results of scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS) analysis, adsorption testing, Fourier transform infrared spectroscopy (FT-IR) analysis, and X-ray photoelectron spectroscopy (XPS) analysis confirmed that the binding of BEHA to copper active sites on the surface of malachite was chemical and existed in the form of Cu-BEHA.