Leaching kinetics of acid-soluble Cr（VI） from chromite ore processing residue with hydrofluoric acid

摘要

Leaching kinetics of acid-soluble Cr(Ⅵ) in chromite ore processing residue (COPR) using hydrofluoric (HF) acid solution as a leaching agent was investigated for potential remediation of COPR with industrial waste water containing HF. The results show that HF can effectively destabilize the Cr(VI)-bearing minerals,resulting in the mobilization of Cr(Ⅵ) from COPR into the leachate. Particle size significantly influences the leaching of acid-soluble Cr(Ⅵ) from COPR,followed by leaching time,whereas the effects of HF concentration and leaching temperature are slight and the influence of stirring rate is negligible. The leaching process of acid-soluble Cr(VI) from COPR is controlled by the diffusion through the product layer. The apparent activation energy is 8.696 kJ/mol and the reaction orders with respect to HF concentration and particle size is 0.493 8 and-2.013 3,respectively.