Skip to Main content Skip to Navigation
Theses

CINETIQUES ET MECANISMES DE RELARGAGE DES METAUX LOURDS PRESENTS EN TRACES DANS LES MATRICES CIMENTAIRES.

Abstract : Chemical species contained in a solid matrix may be transferred to the environment through water leaching. Previous studies of trace metals released from building materials (particularly cement-based ones) highlight an important analytical difficulty. The aim of this study is to determine the kinetics and the mechanisms involved in the release of trace heavy metals (Cr, Cu, Ni, Pb, V and Zn) from industrial cement pastes (usually ranging from 20 to 300 ppm).

The development of a dynamic leaching system, named CTG-LEACHCRETE, (used at pH=5, 20°C) which permits the evaluation of the kinetics of trace heavy metals is presented in the first part. Also, innovative solid analysis techniques (ICP-MS-Laser Ablation, local and Grazing Incidence X-rays Diffraction (GIXD) technique) were used to characterise the cement-degraded layers formed during leaching experiments. These techniques enable to monitor the mineralogical evolution and the distribution of trace metals in these areas. The confrontation of these two approaches, kinetic and solid analysis, coupled with a thorough investigation of previously developed models, lead to proposals concerning the mechanisms of release of the trace heavy metals studied.

In all the cement pastes studied (CPA-CEM I, CPJ-CEM II/A and CLC-CEM V/A), chromium is trapped in ettringite by substitution SO42-ÛCrO42- and its release is then controlled by the dissolution of this hydrate. The behaviour of copper, nickel and zinc in degraded areas and in leachates, are correlated to the silicon of the hydrated calcium silicate (CSH), which imply that they are localised there. Lead, was never detected in the leachates. But it is also correlated to the silicon in the degraded layers.
Complete list of metadatas

Cited literature [5 references]  Display  Hide  Download

https://tel.archives-ouvertes.fr/tel-00002509
Contributor : Nathalie Pothier <>
Submitted on : Tuesday, March 4, 2003 - 4:18:09 PM
Last modification on : Thursday, March 5, 2020 - 6:49:20 PM
Long-term archiving on: : Friday, April 2, 2010 - 6:54:37 PM

Identifiers

  • HAL Id : tel-00002509, version 1

Citation

Emmanuel Moudilou. CINETIQUES ET MECANISMES DE RELARGAGE DES METAUX LOURDS PRESENTS EN TRACES DANS LES MATRICES CIMENTAIRES.. Géologie appliquée. Université d'Orléans, 2002. Français. ⟨tel-00002509⟩

Share

Metrics

Record views

1558

Files downloads

7240