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The formation of un...
The formation of unsaturated zones within cemented paste backfill mixtures : Effects on the release of copper, nickel, and zinc
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- Hamberg, Roger (författare)
- Luleå tekniska universitet,Geovetenskap och miljöteknik
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- Maurice, Christian (författare)
- Luleå tekniska universitet,Geovetenskap och miljöteknik
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- Alakangas, Lena (författare)
- Luleå tekniska universitet,Geovetenskap och miljöteknik
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(creator_code:org_t)
- 2018-05-13
- 2018
- Engelska.
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Ingår i: Environmental Science and Pollution Research. - : Springer. - 0944-1344 .- 1614-7499. ; 25:21, s. 20809-20822
- Relaterad länk:
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https://link.springe...
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visa fler...
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https://urn.kb.se/re...
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https://doi.org/10.1...
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Abstract
Ämnesord
Stäng
- Flooding of cemented paste backfill (CPB) filled mine workings is, commonly, a slow process and could lead to the formation of unsaturated zones within the CPB-fillings. This facilitates the oxidation of sulfide minerals, and thereby increases the risk of trace-metal leaching. Pyrrhotitic tailings from a gold mine (CT), containing elevated concentrations of Ni, Cu and Zn, were mixed with cement and/or fly ash (1-3 wt. %) to form CT-CPB-mixtures. Pyrrhotite oxidation progressed more extensively during unsaturated conditions, where acidity resulted in dissolution of the Ni, Cu, and Zn associated with amorphous Fe-precipitates and/or cementitious phases. The establishment of acidic, unsaturated conditions in CT-CBP:s with low fractions (1 wt. %) of binders increased the Cu-release (to be higher than that from CT), owing to the dissolution of Cu-associated amorphous Fe-precipitates. In CT-CPB:s with relatively high proportions of binder, acidity from pyrrhotite oxidation was buffered to a greater extent. At this stage, Zn-leaching increased due the occurrence of fly ash-specific Zn-species soluble in alkaline conditions. Irrespective of binder proportion and water saturation level, the Ni- and Zn-release were lower, compared to that in CT. Fractions of Ni, Zn, and Cu associated with acid-soluble phases or amorphous Fe-precipitates, susceptible to remobilization under acidic conditions, increased in tandem with binder fractions. Pyrrhotite oxidation occurred irrespective of the water saturation level in the CPB-mixtures. That in turn, poses an environmental risk, whereas a substantial proportion of Ni, Cu and Zn were associated with acid-soluble phases.
Ämnesord
- NATURVETENSKAP -- Geovetenskap och miljövetenskap (hsv//swe)
- NATURAL SCIENCES -- Earth and Related Environmental Sciences (hsv//eng)
- NATURVETENSKAP -- Geovetenskap och miljövetenskap -- Geokemi (hsv//swe)
- NATURAL SCIENCES -- Earth and Related Environmental Sciences -- Geochemistry (hsv//eng)
Nyckelord
- Tailings management
- cement
- trace metal leaching
- Applied Geochemistry
- Tillämpad geokemi
Publikations- och innehållstyp
- ref (ämneskategori)
- art (ämneskategori)
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