Role of lime in salty spoil genesis
Acid pyritic spoils are often limed to facilitate revegetation efforts. Substantial quantities of soluble sulfate salts are associated with such spoils, before and after liming. Such salts can cause revegetation attempts to fail at seeding and/or during drought stress periods. As magnesium sulfate (MgSO/sub 4/) is more soluble than gypsum (calcium sulfate) under field conditions, MgSO/sub 4/ has more often been associated with soluble salt problems. Since lime reaction chemistry can influence salt genesis in spoils, this was evaluated in a incubation study using calcite and dolomite amendments to an acid, pyritic spoil. Rates of 0, 14.4, and 28.8 meq/100 g (rate equal to total potential acidity) of lime were used. Amended spoils were maintained at 30/sup 0/C and -100 cm moisture tension. Samples were taken periodically and a portion suspended in water at a soil:solution ratio of 1:20 for two hours. Unamended spoil extract pH dropped from 4.8 to 3.2 in nine weeks. Soluble magnesium sulfate doubled (from 2.9 to 6.1 meq/100 g) in the unlimed spoil between weeks one and sixteen. Dolomite amended spoils generated twice as much magnesium salt as calcite amended spoils. Pyrite oxidation, acid generation, i.e., salt genesis, was reduced when calcitic lime was used at the recommended rate based on a measure of total potential acidity. A prompt liming program with calcitic lime can substantially alter the quantity and quality of soluble salts released. The results suggest that dolomite is unacceptable as a liming material for sandy spoils with an appreciable pyrite content.
- Research Organization:
- Univ. of Kentucky, Lexington
- OSTI ID:
- 5305730
- 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
510500* -- Environment
Terrestrial-- Site Resource & Use Studies-- (-1989)
54 ENVIRONMENTAL SCIENCES
ALKALINE EARTH METAL COMPOUNDS
CALCIUM CARBONATES
CALCIUM COMPOUNDS
CARBON COMPOUNDS
CARBONATE MINERALS
CARBONATE ROCKS
CARBONATES
CHALCOGENIDES
DOLOMITE
GEOLOGIC DEPOSITS
GROWTH
IRON COMPOUNDS
IRON SULFIDES
LAND RECLAMATION
LIMESTONE
LIMING
MAGNESIUM CARBONATES
MAGNESIUM COMPOUNDS
MINERALS
MINING
OXYGEN COMPOUNDS
PLANT GROWTH
PRECIPITATION
PYRITE
REVEGETATION
ROCKS
SALT DEPOSITS
SEDIMENTARY ROCKS
SEPARATION PROCESSES
SPOIL BANKS
SULFIDE MINERALS
SULFIDES
SULFUR COMPOUNDS
SURFACE MINING
TRANSITION ELEMENT COMPOUNDS