Skip to Main content Skip to Navigation
Theses

Stabilisation de rejets miniers pollués à l’arsenic à l’aide de sous-produits cimentaires : étude de l’influence de la cristallochimie sur le risque de mobilisation des polluants

Abstract : The objective of this study is to understand the geochemical behaviour of arsenic in cemented paste backfills. This technique consists in transporting the tailings in the mine openings. Two types of backfills are prepared in the laboratory for this study. First, synthetic cemented paste backfills artificially spiked with arsenic are synthesized, using silica in replacement of the tailings. In parallel, other cemented paste backfill specimens are prepared with arsenic-rich tailings. In the two cases, various types of hydraulic binders are tested. Several types of investigations are conducted on the cemented paste backfill specimens. A mineralogical characterization is carried out with the help of specific tools. At the same time, cemented paste backfill samples are submitted to several complementary leaching tests, to assess the mobility/immobilization potential of arsenic in these matrices. Finally, geochemical modeling is implemented, based on the results of the two previous studies, in order to refine the understanding of the nature and stability of the arsenic compounds. The results show that arsenic is better immobilized in Portland cement and slag-based matrices, rather than in fly ash-based matrices. The variable leaching behaviour from a given matrix to another is due to different arsenic trapping mechanisms. Arsenic can precipitate and form several arsenic minerals, mainly calcium arsenates, but also various other secondary compounds, which are different from a matrix to another. Physical entrapment of the tailings grains by the cementitious minerals can also occur, by formation of a coating around the grains, limiting the oxidation and dissolution of arsenic-bearing sulfides (passivation). These mechanisms are involved in the stabilization/solidification of arsenic by cemented paste backfills.
Document type :
Theses
Complete list of metadatas

https://tel.archives-ouvertes.fr/tel-00740233
Contributor : Abes Star :  Contact
Submitted on : Tuesday, October 9, 2012 - 4:07:16 PM
Last modification on : Wednesday, September 2, 2020 - 3:19:36 AM
Long-term archiving on: : Thursday, January 10, 2013 - 3:41:50 AM

File

these.pdf
Version validated by the jury (STAR)

Identifiers

  • HAL Id : tel-00740233, version 1

Citation

Samuel Coussy. Stabilisation de rejets miniers pollués à l’arsenic à l’aide de sous-produits cimentaires : étude de l’influence de la cristallochimie sur le risque de mobilisation des polluants. Autre. INSA de Lyon; Université du Québec à Abitibi-Témiscamingue, 2011. Français. ⟨NNT : 2011ISAL0077⟩. ⟨tel-00740233⟩

Share

Metrics

Record views

821

Files downloads

2332