This study examined the stabilization of Cr electroplating sludge and the recovery of metallic materials using the thermite reaction with Al dross. Samples consisting of a mixture of calcined sludge and dross with aluminum in deficit or excess of -50, -20, -10, 0 (stoicheometric), +10, +20, and +50% were heated in a muffle furnace to start thermite reaction. After the thermite reaction, products were analyzed using ICP-AES and XRD. The metallic products were intermetallic compounds containing mainly Cr and Al mainly. Calculating the amount of Cr in the products after the reaction, the reaction ratio was about 60% except for -50% mixing ratio. When the mixing ratio exceeded -10%, the metallic part of the reaction product aggregated in the crucible was recovered. The mixing ratio of sludge and dross influenced the aggregation of molten slag and molten metal. The Cr(VI) concentration in the sludge and slag of the sample with a mixing ratio of 0% was detoxified based on Japanese soil pollution laws. Therefore this method should improve environmental safety.
展开▼
