Abstract: Chromite ore processing residue（COPR） is a kind of industrial solid waste which is hazardous because it contains an internationally recognized carcinogen，hexavalent chromium（Cr6+）.But it is difficult to determine Cr6+ content of COPR properly and to evaluate its toxicity.Four standard methods for the test of leaching toxicity of solid wastes，i.e.USEPA 3060A，HJ/T 299—2007，HJ/T 300—2007，and GB 5086.2—1997，were checked for Cr6+ extracting efficacy.Under conditions of constant pH，different acids，and combined two-step leaching effects were also compared.Results showed that standard acid leaching method was difficult to effectively leach Cr6+ from COPR and unless COPR phase structure was destroyed，no single method could fully extract Cr6+ .

Key words: chromite ore processing residue, leaching method, hexavalent chromium