Stabilisation of Chromium-Containing Electroplating Sludge by Cementation

Electroplating processes and other industrial methods often produce wastes containing heavy metals, such as chromium. If recovery of theses wastes is not feasible, a technical possible remedy can be their immobilisation in cement. At the high pH-value of hardened cement most heavy metals precipitate as hydroxides. Depending on its oxidation state, chromium can either be present as readily soluble chromate (6-valent chromium) or precipitates as chromium-hydroxide (3-valent chromium). Portland cement is usually unsuitable for reducing 6-valent chromium. After being complemented by reducing character additives (such as blast furnace slag, BFS), however, it may be satisfactory. The quantity of safely confinable Cr-load is assessed in this study by pore fluid expression and quasi-dynamic leaching techniques as a function of matrix composition.