DETOXIFICATION TREATMENT METHOD FOR EXTRACTING AND RECOVERING CHROMIUM FROM WASTE RESIDUES CONTAINING HEXAVALENT CHROMIUM

摘要

The present invention discloses a detoxification treatment method for extracting and recycling chromium from hexavalent chromium-containing residues, comprising steps as follows: 1) adding water to the hexavalent chromium-containing residues and mixing uniformly; 2) adding sodium sulfate, sodium chlorate and sulfuric acid to a solution obtained in step 1) and stirring sufficiently to obtain a mixed liquid; 3) treating the mixed liquid by a hydrothermal method or direct heating; 4) after the heating treatment, naturally cooling a solid-liquid mixture to room temperature for holding; 5) separating solid residues and a chromium-containing supernatant, and washing filtered residues with water and then drying; 6) precipitating the supernatant and the water used for washing the filtered residues with a precipitant CaCl 2 , then centrifugally washing, dewatering and drying the precipitates; and 7) recycling a chromium-containing solution for returning to a work section, or for a treatment of recycling chromium. This method may achieve full-residue utilization with simple process, low cost, quick effect, large treating capacity and complete detoxification.