| 摘要 |
<p>A method for decontaminating waste materials, wherein the residue of water leaching of the roasted chromium mineral containing water soluble hexavalent chromium compounds is wet ground and classified until obtaining such a granulometrical distribution that not more than 5-10% of the particles have an average size larger than 0.4 mm, and 40-60% of the particles have an average size less than 0.8 mm, and is then subjected to wet treatment under vigorous stirring at about 100 DEG C. with sulphur, in an aqueous emulsion of akaline or alkaline-earth sulphide for 1-4 hours, the percentage of solids in the reactor being in the range of 1-60%, preferably 30-35% by weight; and wherein the reacted slurry is thickened and filtered to provide the restored or decontaminated earth and an effluent, which is partly recycled to grinding or to reaction.</p> |
