Recovery and safer disposal of phosphate coating sludge by solidification/stabilization

A safer disposal of hazardous phosphate coating sludge by formation of an amorphous calcium phosphate matrix

“…1500-1400 cm In connection with the toxic metals amounts, Cu, Mn, Ni, Cr and specially Zn were the most abundant hazardous metals found in the samples. These results are in good agreement with the results reported in previous works for similar wastes (Dogan and Karpuzcu, 2010;Ucaroglu and Talinli, 2012;Caponero and Tenório, 2000;Pinarli et al, 2005), as PS are mainly composed of zinc phosphates coming from decanter baths of phosphate, very commonly used in the industry responsible for this kind of wastes. Both sludges can be classified as hazardous wastes, due to their reactive and toxic characteristics according to the regulations and cannot be landfilled without a previous S/S process (Ucaroglu and Talinli, 2012).…”

“…The automotive industry originates wastes such as shredder residue (Péra et al, 2004), paint (Arce et al, 2010) or phosphate coating sludge (PS) (Dogan and Karpuzcu, 2010;Ucaroglu and Talinli, 2012). Phosphating is the most widely applied system for metal pretreatment process.…”

“…Of course, different operating parameters and in-process modifications could also render final wastes with diverse compositions and degree of health hazard. Nevertheless, within the field of automotive industry, PS has been often reported to be one of the most problematic varieties of waste, due to the possible leaching of the heavy and/or transition metals which contains (Dogan and Karpuzcu, 2010;Ucaroglu and Talinli, 2012). Accordingly, it has been classified as a hazardous waste by the U.S. Environmental Protection Agency (EPA) and the European Union.…”

“…Regarding the S/S treatment of PS, scarce studies have been reported in the literature. In all of them, authors have used ordinary Portland cement (OPC) as binder (Dogan and Karpuzcu, 2010;Ucaroglu and Talinli, 2012;Pinarli et al, 2005).…”

Modified Zinc Phosphate Coatings: A Promising Approach to Enhance the Anti-Corrosion Properties of Reinforcing Steel

“…Their results showed no damage to the clinkerization process with an addition of up to 7.0% sludge. In addition, According to Ucaroglu & Talinli [60], the phosphate coating sludge after being treated by solidification/stabilization can be used in a matrix of Portland cement. Baldy [61] also studied the possibility of reclaiming this sludge to a zinc-phosphate replenishment solution and other useful products.…”