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Expression of Cementitious Pore Solution and the Analysis of Its Chemical Composition and Resistivity Using X-ray Fluorescence
Published on: September 23, 2018
Arsenic stability in arsenopyrite-rich cemented paste backfills: a leaching test-based assessment
Samuel Coussy1, Mostafa Benzaazoua, Denise Blanc
1Université du Québec en Abitibi-Témiscamingue, 445 Boul. de l'université, Rouyn-Noranda, QC, Canada. samuel.coussy@uqat.ca
Journal of Hazardous Materials
|November 16, 2010
Summary
Cemented paste backfill (CPB) can stabilize toxic arsenic (As) in mine tailings. Different binders affect As release, with fly ash showing better stabilization at lower pH.
Area of Science:
- Environmental Science
- Geochemistry
- Materials Science
Background:
- Arsenic (As) in mine tailings poses environmental risks due to its high solubility.
- Cemented Paste Backfill (CPB) is a tailings storage method that can immobilize pollutants like As.
- Casa Berardi mine tailings contain significant amounts of As, primarily in arsenopyrite form.
Purpose of the Study:
- To evaluate the effectiveness of different binders in stabilizing arsenic in cemented paste backfill.
- To investigate the mechanisms of arsenic release from CPB under various conditions.
- To compare the performance of fly ash, slag, and Portland cement-based CPB in immobilizing arsenic.
Main Methods:
- Synthesized three types of CPB using Casa Berardi tailings and different binders (fly ash, slag, Portland cement).
- Subjected the CPB samples to various leaching tests after 28 days of curing.
- Conducted accelerated weathering tests to assess sulphide reactivity and its influence on As release.
Main Results:
- Arsenic release was higher in fly ash-based CPB compared to slag- and Portland cement-based CPB under standard conditions.
- Fly ash-based CPB demonstrated superior arsenic stabilization at lower pH levels.
- CPB's neutralizing minerals buffered sulphide reactivity, reducing the oxidation of As-bearing sulphides and influencing As release.
Conclusions:
- The choice of binder significantly impacts arsenic stabilization in CPB.
- Fly ash-based CPB offers potential for arsenic immobilization, particularly in acidic mine environments.
- Understanding As-compound solubility and release mechanisms is crucial for effective tailings management.
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