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Chemical and physical characterization of western low-rank-coal waste materials. Part 3. Sludges from wet scrubbers using fly ash as a scrubbing reagent. Final report

Technical Report ·
OSTI ID:6624803

The Department of Energy Grand Forks Energy Technology Center has supported development of wet scrubbers that use western fly ashes to supply all or part of the alkalinity requirements of the FGD system. Investigations described in this report address waste characteristics affecting disposal requirements for sludges from these systems. This program has two objectives. One is to determine disposal-related characteristics of sludges from FGD systems using fly ash as a major source of alkalinity. The second objective is to evaluate material-related disposal requirements for these sludges. In this study, two of the sludges were treated to increase physical stability and reduce permeability. Treatment involved application of three commercial fixation processes. And, in addition, fly ash scrubber sludge was treated by adding fly ash from an electrostatic precipitator. Treated and untreated sludges were subjected to a variety of chemical and physical tests. Elemental concentrations were measured in sludge solids and leachates obtained from column studies and sequential batch extractions. The EP extraction was carried out to classify sludges as nonhazardous or hazardous. Other measurements included: moisure content, bulk densities, densities of solids, surface areas, particle size distributions, strengths, and permeabilities. Element concentrations in sludge solids were generally within the expected limits. Calcium concentrations were generally lower in sludges from systems employing fly ash as reagent than would be expected for sludges from systems using limestone or lime. Sodium concentrations were higher in sludges from systems using fly ash from lignite than in sludges from other systems. All materials tested would be classified as nontoxic according to the characteristic of EP toxicity as currently defined.

Research Organization:
Radian Corp., Austin, TX (USA)
DOE Contract Number:
AC18-80FC10200
OSTI ID:
6624803
Report Number(s):
DOE/FC/10200-T4; ON: DE83005165
Country of Publication:
United States
Language:
English