Flotation Behavior and Adsorption Mechanism of Phenylpropyl Hydroxamic Acid As Collector Agent in Separation of Fluorite from Calcite

The hydroxylamine method involves the synthesis of a new hydroxamic acid collector, i.e., phenylpropyl hydroxamic acid (PHA), from methyl cinnamic hydroxamic acid. Flotation test results show that PHA exhibits good selective collection ability. The adsorption mechanism of PHA is investigated using the zeta potential, Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS). The results show that PHA formed a new Ca-O bond with Ca²⁺ on the fluorite surface via chemical adsorption. A new five-element chelated hydroxamate group may have formed in Ca on the fluorite surface. The PHA selectivity is fully explained via density functional theory (DFT) calculations, and an adsorption model is established.