Modelagem do processo de difusão de metais pesados presentes em resíduos após o tratamento de estabilização por solidificação (E/S).

Abstract

Materials resulting from the Solidification by Stabilization (S/S) treatment can be landfilled or reused in civil construction for a long period of time in the environment and thus necessary to predict contaminant mobility. The present work aims to treat a Laboratory Solid Waste (RSL) through the Solidification Stabilization technique, and, to analyze the S/S materials for the integrity/durability and immobilization of the contaminants, and to determine the diffusion coefficient of Chromium. To achieve these goals, six steps were performed. In the first stage an experimental design was elaborated, in the second stage the residues and binders were classified and characterized, and in the third stage the specimens were made, which remained 28 days in cure. In the fourth stage, integrity / durability tests and immobilization of contaminants were performed. In the fifth stage, the data were statistically analyzed, and in the sixth stage, the modified chrome diffusion coefficient and the leaching mechanism were determined. With the characterization of RSL it was found that it has a high mass content to be treated, and has an acid character. With the classification it was found that RSL is dangerous belonging to class I. For integrity/durability criteria all S/S materials have been approved. After the treatment it was observed that matrices containing 0, 5 and 10% RSL passed class I waste (hazardous) to class IIa waste (non-hazardous, non-inert), while 20% RSL remained class I. From the modeling of the mass transfer process it was possible to determine the modified diffusion coefficient of chromium, which ranged from 1.86 to 2.86 ppm⁄√h, as well as to verify that the predominant leaching mechanism in the experiments performed , was the surface wash. Given these results, it is possible to conclude that S/S was an effective technique for the treatment of laboratory solid waste with respect to both the integrity/durability and the immobilization of contaminants, since the obtained materials can be disposed of in appropriate landfills or even reused in construction.