The synthesis of a novel flotation collector for bastnaesite, 5,5′-methylenedisalicylic acid, based on salicylhydroxamic acid molecular structure

Abstract

In oxide mineral flotation, salicylhydroxamic acid (SHA) is a frequently employed collector renowned for its commendable selectivity. Nevertheless, SHA manifests an insufficient collecting efficacy in bastnaesite flotation. In response, the paper synthesized a novel collector, 5,5′-methylenedisalicylic acid (MDSA), by tethering two SHA molecules with a methylene group. In the flotation separation of bastnaesite and fluorite, MDSA collector exhibits an excellent selectivity. The synergistic application of MDSA collector and sodium alginate (SA) inhibitor effectively accomplishes the flotation separation of these two minerals. Zeta potential experiments and X-ray photoelectron spectroscopic tests consistently reveal that, with same MDSA doses in bastnaesite and fluorite slurries, MDSA possess heightened adsorption capacities on bastnaesite surface in contrast to fluorite. Consequently, in flotation experiments, the use of MDSA collector yields superior recoveries of bastnaesite compared to fluorite. Furthermore, the prior attachment of SA to fluorite interferes with the subsequent MDSA adsorption, whereas the initial SA binding to bastnaesite surface exerts a diminished influence on the subsequent adsorption of MDSA. First-principles calculations elucidate that MDSA can engage with two neighboring surface Ce³⁺ ions of bastnaesite through its two N-hydroxy amide groups, creating two pentacoordinate chelate rings and facilitating its adsorption onto bastnaesite surface. Furthermore, MDSA demonstrates a diminished adsorption energy on bastnaesite in contrast to fluorite.