Chemical Characterization of Electrostatic Precipitator Ashes from Pressurized Hydrated-Lime Injection Tests

摘要

Precipitator ashes were collected from four pressure hydrated-lime injection tests at the Hoot Lake utility plant in Minnesota. The commercial feasibility of pressure-hydrated lime SO sub 2 control processes will partially depend on the chemistries of the solid wastes and their disposal requirements. The chemistries of the four precipitator ashes were determined by x-ray fluorescence, x-ray diffraction, and aqueous leaching tests. None of the EP or ASTM batch leachates exceeded RCRA standards; however, once sodium sulfate washed out of the columns barium concentrations in the column leachates increased significantly. Abundant soluble sulfate maintains low barium concentrations in the batch leachates. Most of the barium in the bulk ashes exists as water-soluble barium chloride or other phases. Calcium compounds in the precipitator ashes may reduce arsenic and boron concentrations in the alkaline leachates. The high concentrations of barium in some of the column leachates were not predicted by batch leaching, and is an example of the ability of column leaching to provide complementary data to batch leaching results. (ERA citation 11:038796)