STP1240

    Use of the Shrinking Core / Exposure Model to Describe the Leachability from Cement Stabilized Wastes

    Published: Jan 1996


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    Abstract

    Based on physical evidence and observation of the acid dependency of the leaching process, a shrinking core model seems to be an appropriate model for cement stabilized waste. It is argued that for cement stabilized wastes, the bulk diffusion model is likely to be in error. Recent findings will be used to support the concept of a shrinking core model.

    To be able to deal with varying acidities in the leachant, the concept of exposure will be introduced. The model will be derived for a flat surface to illustrate that, as in the ANS 16.1 model, a parabolic leaching behavior can be obtained. Some other characteristics of the model are indicated.

    It is shown that the shrinking core model, using the concept of exposure, adequately takes into account the physical observations as well as adequately correlates the leaching data for a model specimen contaminated with lead. The findings indicate that kinetic factors may play a role in the release of metals. Their relevance for the interpretation of TCLP results is indicated.

    Keywords:

    leaching mechanisms, shrinking core model, dynamic test, solidification, stabilization, leach test, exposure integral, acid leaching


    Author Information:

    Hinsenveld, M
    Research Professor, University of Cincinnati, Cincinnati, OH

    Bishop, PL
    Professor, University of Cincinnati, Cincinnati, OH


    Paper ID: STP14136S

    Committee/Subcommittee: D34.01

    DOI: 10.1520/STP14136S


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