You are here:
EXPERIMENTAL AND THEORETICAL STUDIES OF SOLID SOLUTION FORMATION IN LIME AND LIMESTONE SO2 SCRUBBERS. VOLUME I. FINAL REPORT
Citation:
Jones, B., P. Lowell, AND F. Meserole. EXPERIMENTAL AND THEORETICAL STUDIES OF SOLID SOLUTION FORMATION IN LIME AND LIMESTONE SO2 SCRUBBERS. VOLUME I. FINAL REPORT. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/2-76/273a.
Description:
The report gives results of a theoretical and experimental study to characterize the coprecipitation of calcium sulfate with calcium sulfite hemihydrate. A coprecipitation product had been suggested to explain the mechanism by which sulfate could be precipitated from a scrubber solution subsaturated with respect to calcium sulfate. Lime and limestone SO2 scrubbing systems with oxidation rates below 20% had been operated long-term at steady state with liquors subsaturated with respect to all known calcium sulfate solid forms and yet sulfate was measured in the solids. The existence of a calcium sulfate/calcium sulfite solid solution has been confirmed experimentally and a theoretical formulation has been established. Calcium sulfite hemihydrate was precipitated under controlled laboratory conditions from solutions subsaturated in calcium sulfate. Specific chemical analysis and infrared spectroscopic techniques were used to identify sulfate in the solids. The precipitate's sulfate content was studied as a function of the relative saturation of calcium sulfate and the precipitation rate of calcium sulfite hemihydrate. Also, the effects of high magnesium concentrations and limestone dissolution on the sulfate content of the solids were measured.