Evaluation of changes in the chemical equilibria of soils/spoils during wetting-drying cycles using a computer model (REC-1)
When lime reacts with acid mine soils, the dominant reaction product is gypsum (CaSO/sub 4/.2H/sub 2/O). However, depending on the magnesium carbonate content of the lime (dolomite) and occasionally on the presence of certain other magnesium bearing minerals, large quantities of magnesium sulfates (MgSO/sub 4/.XH/sub 2/O) can also be produced. Plant growth will be depressed if soluble salts are too high. It is difficult to predict soluble salt levels by laboratory procedures if two salt compounds with different solubilities are present. Gypsum is substantially less soluble than magnesium sulfate. This computer model (REC-1) uses three major factors that control spoil solution composition and concentration. These factors are the thermodynamic solubility product constant of gypsum, the selectivity coefficient for Ca-Mg exchange on colloid surfaces, and the ion pair stability constants for CaSO/sub 4/ and MgSO/sub 4/ monomers. The model was tested with data from the literature. Its capabilities in predicting solution and exchange phase concentration and composition are very good. The model can be used to predict potential salinity and specific ion toxicity of limed coal-spoils.
- Research Organization:
- Univ. of Kentucky, Lexington
- OSTI ID:
- 5362343
- Report Number(s):
- CONF-821175-
- Journal Information:
- Univ. Ky., Off. Eng. Serv., (Bull.); (United States), Journal Name: Univ. Ky., Off. Eng. Serv., (Bull.); (United States); ISSN UKOBD
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
010800 -- Coal
Lignite
& Peat-- Waste Management
510200* -- Environment
Terrestrial-- Chemicals Monitoring & Transport-- (-1989)
54 ENVIRONMENTAL SCIENCES
ALKALINE EARTH METAL COMPOUNDS
CALCIUM COMPOUNDS
CALCIUM SULFATES
CHEMICAL ANALYSIS
CHEMICAL COMPOSITION
CHEMICAL REACTIONS
CHEMISTRY
COMPUTERIZED SIMULATION
GEOLOGIC DEPOSITS
GROWTH
GYPSUM
LAND RECLAMATION
LIMING
MATHEMATICAL MODELS
MINERALS
MINING
OXYGEN COMPOUNDS
PLANT GROWTH
SALT DEPOSITS
SIMULATION
SOIL CHEMISTRY
SOILS
SPOIL BANKS
SULFATE MINERALS
SULFATES
SULFUR COMPOUNDS
SURFACE MINING