The flocculating performance of 1,4-benzoyl hydroxamic acid (PDHA) on ultra-fine bastnasite was studied by individual and artificially mixed minerals flotation tests, and its optimum flocculation conditions including agitation speed, conditioning period and dosage were confirmed as well. Flotation results indicate that PDHA enhances the recovery of ultra-fine rare earth minerals, and it is possible that PDHA could be used as an effective flocculant in the treatment of low grade and finely disseminated rare earth ore. (C) 2014 Elsevier Ltd. All rights reserved.