Flotation separation of bastnaesite from calcite using novel octylmalon dihydroxamic acid as collector

A novel hydroxamic acid collector, octylmalon dihydroxamic acid (OMHA), was designed by introducing the secondary hydroxamic group into octanohydroxamic acid (OHA) and synthesized. OMHA was originally used as the collector in the flotation separation of bastnaesite from calcite. The flotation results revealed that OMHA exhibited better collecting ability and selectivity compared with the conventional hydroxamic acid collector OHA. Effective separation between bastnaesite and calcite can be realized. The concentrate with 69.26% REO grade and 89.49% REO recovery was obtained with 3 × 10−4 mol/L OMHA under natural slurry pH. Zeta potential measurements and FTIR spectra analysis indicated that OMHA was strongly adsorbed on bastnaesite surface but did not interact with calcite. XPS results demonstrated that OMHA was chemically adsorbed on the Ce site of bastnaesite surface. The introduction of the secondary hydroxamic group significantly improved the flotation performance, especially in selectivity.