Stabilization of copper-contaminated sludge using the microwave sintering.

A sintering with a microwave process was considered to stabilize copper-contaminated sludge and transform it into a sinter because microwave can provide uniform and quick heating. The parameters of addition of iron powder and ferric oxide, crucible modification, and air-forced leading were used in the microwave sintering. The results showed that reduced copper was present and some holes, caused by the high copper-contaminated synthetic sludge passing through the microwave sintering, were distributed throughout the sinters. However, when microwave sintering with the modification of parameters (improved microwave sintering) was used, the phenomena of copper reduction and hole formation were dispelled. Moreover, the improved microwave sintering of synthetic sludge with iron powder at 800W at 30 min formed cuprospinel with peaks of 2theta degrees of 18.508 and 57.05 shifting to 18.9 and 56.55 and the leaching concentration from this sinter passed the limit of toxicity characteristic leaching procedure (TCLP) for copper.