Response of sulfide-affiliated copper, nickel, and zinc in shale overburdens associated with coals to simulated leaching
Dynamic leaching simulating the hydrogeochemical conditions of the backfilled coal mine spoil bank was conducted to study the behavior of sulfide-affiliated Cu, Ni, and Zn of the black shales during chemical weathering. The black shale samples with total sulfur content ranging from 0.4% to over 3.0% were leached at weekly intervals with distilled-deionized water, synthetic rainwater, and synthetic acid mine drainage respectively. The chemical properties of the leachates were influenced by the chemistry of the leachants as well as by the interactions of pyrite oxidation and carbonate neutralization. Rocks with low sulfur content and high neutralization potential produced alkaline leachates when drained with rainwater, and consequently no trace metals were released. However, when the leachant was a synthetic acid mine drainage, the alkalinity produced by the rock was overwhelmed by the acid introduced by the leachant and the excess acid retained by the rock fragments slowly dissolved trace-metal sulfides. Rocks with moderate to high sulfur content and low neutralization potential were acid-prone and the release of sulfide-affiliated Cu, Ni, and Zn by these rocks is closely related to acid production. In the rock-rainwater system the acid production and the release of trace metals was a slow and time-dependent process. The acid production and the release of trace metals was fast when the acid-prone rocks were leached with synthetic acid mine drainage. The release mechanism of sulfide-affiliated Cu, Ni, and Zn during simulated weathering is explained by the dissolution of their sulfide phase in acid solution. Variations in trace-metal release patterns between samples were primarily due to differences in acid production rates and the uneven distribution of trace-metal sulfides. The abundance of sulfide-affiliated trace metals in the black shale samples follows the order: Cu > Zn > Ni.
- OSTI ID:
- 6039693
- Resource Relation:
- Other Information: Thesis (Ph. D.)
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
54 ENVIRONMENTAL SCIENCES
BLACK SHALES
LEACHING
WEATHERING
COPPER SULFIDES
NICKEL SULFIDES
ZINC SULFIDES
ACID MINE DRAINAGE
COAL MINES
LEACHATES
WATER POLLUTION
BITUMINOUS MATERIALS
CARBONACEOUS MATERIALS
CHALCOGENIDES
CHATTANOOGA FORMATION
COPPER COMPOUNDS
DISPERSIONS
DISSOLUTION
ENERGY SOURCES
FOSSIL FUELS
FUELS
GEOLOGIC FORMATIONS
INORGANIC PHOSPHORS
MATERIALS
MINES
MIXTURES
NICKEL COMPOUNDS
OIL SHALES
PHOSPHORS
POLLUTION
SEPARATION PROCESSES
SOLUTIONS
SULFIDES
SULFUR COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
UNDERGROUND FACILITIES
ZINC COMPOUNDS
010900* - Coal
Lignite
& Peat- Environmental Aspects
520200 - Environment
Aquatic- Chemicals Monitoring & Transport- (-1989)