Geochemistry of FBC waste-coal slurry solid mixtures. [Quarterly] technical report, March 1--May 31, 1993

Abstract

Three tasks are being conducted in this research project, all related to understanding the chemistry and mineralogy of the co-disposal of fluidized bed combustion (FBC) wastes with coal slurry solid (CSS) from a coal preparation plant. During coal cleaning, pyrite, other heavy minerals, and rock materials are rejected from the coal and discharged in an aqueous slurry to a slurry pond. After dewatering and abandonment of the pond, the pyrite may oxidize and produce acid that may migrate into the underlying groundwater system. If an alkaline product, such as FBC waste, is mixed with the CSS, then the acid will be effectively neutralized as it is produced. In Task 1, soluble components and acid-base reaction products from mixtures of FBC waste and CSS are being extracted for up to 180 days in a series of aqueous batch experiments. The final two sets of extractions, 90- and 180-days, were completed. The extracts and solids from these experiments were submitted for analysis of cations, anions, and mineralogy. In Task 2, 10 L of extracts from three mixtures of FBC waste and CSS were prepared for use in experiments to determine the adsorption/desorption reactions that occur between components of the extracts and three commonly occurring Illinois soils.