REDUCTION TREATMENT METHOD FOR SLUDGE, OR THE LIKE, CONTAINING HEXAVALENT CHROMIUM

摘要

PROBLEM TO BE SOLVED: To provide a method for reducing hexavalent chromium to trivalent chromium by mixing sludge or a lumpy object containing hexavalent chromium with organic sludge and incinerating the obtained mixture in a rotary kiln.;SOLUTION: Five tons of the lumpy object obtained by solidifying hexavalent chromium-containing dust by using cement is mixed homogeneously with five tons of a mixture of waste plastics, stand sludge, sawdust, or the like. The obtained mixture is fed to the rotary kiln the temperature of which is managed to be ≥700°C and operated continuously, and is retained in the rotary kiln for 20 minutes, so that hexavalent chromium can be reduced to trivalent chromium. Cinders are made to fall in water from an outlet of the rotary kiln and cooled.;COPYRIGHT: (C)2005,JPO&NCIPI