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Cement based solidification/stabilization of arsenic-contaminated mine tailings
1Department of Civil Engineering, Hanyang University, 17 Haengdang-Dong, Seongdong-Gu, Seoul 133-791, Republic of Korea.
Waste Management (New York, N.Y.)
|January 3, 2009
Summary
Cement effectively stabilized arsenic and lead in mine tailings. A minimum of 7.5% cement content is recommended to significantly reduce arsenic leachability while meeting strength requirements.
Area of Science:
- Environmental Engineering
- Geotechnical Engineering
- Materials Science
Background:
- Abandoned mine tailings pose environmental risks due to heavy metal contamination, specifically arsenic and lead.
- Cement solidification/stabilization (s/s) is a common method for immobilizing contaminants in hazardous waste.
Purpose of the Study:
- To determine the optimal cement content for solidifying/stabilizing arsenic- and lead-contaminated mine tailings.
- To evaluate the physical and chemical characteristics of the solidified/stabilized (s/s) forms.
Main Methods:
- Solidification/stabilization of tailings using cement at varying percentages (5-30wt%).
- Physical characterization using Unconfined Compression Strength (UCS) tests.
- Chemical characterization using Korean standard leaching tests, Toxicity Characteristic Leaching Procedure (TCLP), and Synthetic Precipitation Leaching Procedure (SPLP).
Main Results:
- A cement content of 5% was sufficient to meet the Unconfined Compression Strength (UCS) requirement of 0.35MPa.
- Adding 7.5% cement significantly decreased arsenic leachability from the tailings.
- Lead leachability showed a slight increase with higher cement content due to its amphoteric properties.
Conclusions:
- The study identified optimal cement content ranges for effective stabilization of arsenic and lead in mine tailings.
- Different evaluation procedures yielded varying insights into the performance of solidified/stabilized waste forms.
- Cement stabilization is a viable technique for managing arsenic- and lead-contaminated mine tailings, with specific binder content recommendations provided.
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