A method for detoxification of chromium-containing waste residue and recovery of chromium

Abstract

The invention belongs to the technical field of solid waste treatment and discloses a toxin removing and chromium recovering method for chromium-containing waste residues. The method comprises steps as follows: the chromium-containing waste residues are subjected to aerobic roasting, naturally cooled, then ground and subjected to ultrasonic treatment, the treated chromium-containing waste residuesare added to a hydrothermal reactor with surface and interface regulating agents and water, after uniform stirring and mixing, a mixture is subjected to a reaction for 0.5-24 h at 30-250 DEG C, an obtained product is cooled and left to stand after the reaction, solid residues and a chromium-containing supernatant are separated, the solid residues are washed and dried, detoxified waste residues are obtained, and the chromium-containing supernatant is subjected to chromium recovering treatment; the surface and interface regulating agents are hydrochloric acid, sodium hydrogen carbonate and sodium carbonate. According to the method, the problems that the leaching treatment of the chromium-containing waste residues is difficult, the cost is high, chromium recovery is difficult, detoxificationis incomplete and the like are solved, and the method has higher social benefit and economic benefit.

Description

technical field [0001] The invention belongs to the technical field of solid waste treatment, and in particular relates to a method for detoxifying chromium-containing waste residue and recovering chromium. Background technique [0002] The methods and technologies currently used for the separation and recovery of heavy metals containing chromium solid waste are mainly hydrometallurgy (including acid leaching, alkali leaching, and salt leaching), thermochemical methods (including smelting, roasting and leaching) and biometallurgy. For example, CN102191390A uses sulfuric acid or hydrochloric acid at normal temperature to leach water-soluble and acid-soluble hexavalent chromium, and then collects the leached chromium resources through reduction and precipitation, but this method needs to adjust the pH three times, consuming a large amount of acid and alkali. CN104726705A uses potassium hydroxide aqueous solution, potassium carbonate aqueous solution, potassium metaaluminate aq...

AI Technical Summary

Problems solved by technology

For example, CN102191390A adopts sulfuric acid or hydrochloric acid to leach water-soluble and acid-soluble hexavalent chromium at normal temperature, and then collects the chromium resources leached through reduction and precipitation, but this method needs to adjust the pH 3 times, consuming a large amount of acid and alkali

CN104726705A uses potassium hydroxide aqueous solution, potassium carbonate aqueous solution, potassium metaaluminate aqueous solution mixed slurry and oxidizing gas to carry out leaching oxidation reaction on chromite, the process is relatively complicated

Chinese patent "a method for recovering hexavalent chromium resources from chromium slag" (CN102191390A) uses sulfuric acid or hydrochloric acid to leach water-soluble and acid-soluble hexavalent chromium at room temperature, which relatively improves the leaching of hexavalent chromium, but from chromium slag Only 60% to 80% of hexavalent chromium resources can be recovered in China, which can neither efficiently recover chromium resources nor completely detoxify chromium slag, and the treated chromium slag still has serious environmental hazards

From the above examples, it can be seen that the current heavy metal recovery methods still have problems such as high cost, complicated operation, and secondary pollution, and there is still a lot of room for improvement.