The floatation of niobite has been studied using different collectors at various reagent dosages and solution pHs. The collectors used in this study included octyl diphosphonic acid (ODA), benzyl arsenic acid (BAA), C7-9 alkyl hydroxamic acid (AHA), alpha-styrolphosphonic acid (SPA), and diisobutyl sulfosuccinate (DSS). Octyl diphosphonic acid was found to be an effective collector for niobite flotation with good selectivity. A flotation recovery of 91.17% was obtained with 140 mg/l octyl diphosphonic acid at pHs less than 5.0. Zeta potential measurements, infrared absorption spectroscopy (IAS) and X-ray photoelectron spectroscopy (XPS) were used to characterize the interactions of niobite with octyl diphosphonic acid. Species distribution diagram of octyl diphosphonic acid and concentrations of various solution species for niobium were determined based on equilibrium constants for various chemical species. A chemical adsorption mechanism of niobite with octyl diphosphonic acid has been proposed. The flotation behavior of niobite with this collector was consistent with the proposed mechanism and the distribution of octyl diphosphonic acid species in aqueous solution as a function of pH. (c) 2004 Elsevier B.V All rights reserved.