Static Coal Storage - Chemical Effects on the Aquatic Environment
Abstract
The aqueous leaching of heavy metals from soft coal has been examined under a variety of
conditions. Variables examined were pH, particle size, rate of flow, time of contact and oxygen or
nitrogen atmosphere. Simple leaching of coal from Western mines with pure water does not remove
large amounts of metal. Metal removed was in most cases about 0.1% to 0.5% of the total metal in
the coal. Extended, successive leaches (of about one week duration) and leaches in a mildly acid
(acetic acid-acetate buffer; pH%4.7) tended to remove larger amounts of some metals. Leaching with
a strong complexing agent removes relatively larger amounts of metal. When placed in contact with
water previously spiked with metal ions, the coal actually re duces the aqueous concentration of
many metal ions.
Continuous flow and simple shaker experiments correlate qualitatively with each other.
Considerable variation was found between Eastern and Western coal and also between different
samples of Western coal.
Subject
static coal storage
aquatic environment
leaching
heavy metals