Hazardous Wastes Disposal: Stabilization/Solidification of Tannery Residue in the Presence of Chromium
Disposal or reuse of hazardous waste is a major consideration in chemical manufacturing and processing. Waste residuals from the tannery industry can contain high levels of chromium. Considered as a hazardous waste by the Brazilian environmental laws, the chromium-containing waste requires treatment before final disposal. This paper proposes a solution for the disposal of tannery wastes, which are rich in chromium by solidification in a Portland cement matrix using combinations of sodium bentonite and organoclay admixtures. This research is part of a series of experimental studies where Brazilian sodium bentonite, and organoclay materials are used to adsorb both inorganic and organic chromium. The solidified matrix is formed by Type II Portland cement, in which the hydration process stabilizes the tannery waste. Wyoming sodium bentonite and a commercial organoclay are analyzed and compared with the Brazilian clays. X-ray Diffraction is used to characterize the samples and leaching tests are performed to analyze the chromium concentration in the extract solution. In terms of leachate tests, the stabilization by solidification with cement is a process that can be used in the treatment of tannery waste.
Lucio Salgado and Francisco Ambrozio Filho
C. A. Pinto et al., "Hazardous Wastes Disposal: Stabilization/Solidification of Tannery Residue in the Presence of Chromium", Materials Science Forum, Vols. 498-499, pp. 697-703, 2005