NOTES
Cation Solubilities of Lignite Fly Ashes D. G. Shannon* and L. 0. Fine Plant Science Department, South Dakota State University, Brookings, S . D . 57006
Concentrations of Ca, Na, Mg, and Fe were determined in water extracts of four lignite fly ashes from three Northern Great Plains mines. The main mass of soluble cationic material released was represented by Ca and Na, although considerable variability existed among the four ashes in proportional and absolute amounts solubilized. Mg and Fe generally were solubilized a t rates roughly one to two orders of magnitude less than Ca and Na. As the ratios of Hz0:ash were increased, generally greater relative amounts of Ca, Mg, and Fe and lesser relative amounts of Na were found in solution. Dust collector ash was higher in sulfate than electrostatic precipitator ash, as indicated by these tests. Approximately 50% of the cations solubilized by water from dust collector ashes appeared to exist as sulfates. It is believed that a considerable portion of the Ca, Mg, and Na exists in the ash as oxide, thus giving rise to high p H values for water suspensions.
sume 7000 to 10,000 T/day, and larger plants are being planned. These fuels are moderately high in total ash; one group of samples, ranging from 7-1470 ash, on the dry basis, and with BTU values of 5000-7000/lb, will produce major quantities of ash. Known uses of coal ash include: partial aggregate requirements in asphalt paving, cement in certain concretes, deicing material for streets and highways, and bulk density-ameliorating materials in certain soils. Because of the large quantities of ash, the utility of the ash as an amendment in the amelioration of certain sodic claypan soil properties is being investigated. The possibility exists that some ashes may contain sufficient toxic factors to affect plant growth on certain soils. Ancillary to that investigation and because other potential uses of the ash may also depend on cation solubilities, a study was made of the water-soluble cation composition of some of the major ashes being produced by operating generating plants.
In recent decades, use of lignites and subbituminous coals present in the Tertiary rocks of the Northern Great Plains has been largely limited to local institutional heating plants and moderate-sized (
