The flotation of synthetic fersmite has been studied using different collectors including benzyl arsenic acid, alpha-styrolphosphonic acid, diphosphonic acid, cyclic alkyl hydroximic acid, and alkyl hydroximic acid. The experimental results show that diphosphonic acid is an effective and selective flotation collector for fersmite. Flotation recovery of fersmite ranged from 83.27% to 85.10% with 20 mg/l diphosphonic acid at pH 2.5-5.0. Infrared Absorption Spectrum (IAS) and X-ray Photoelectron Spectroscopy (XPS) were used to analyze the interactions of fersmite with diphosphonic acid. The XPS results indicated that the binding energy Of P-2p of fersmite changed by 3.85 eV after treatment with diphosphonic acid, indicating that diphosphonic acid was chemically adsorbed on the surface of fersmite. (C) 2004 Elsevier B.V. All rights reserved.