Scrubber solids, coprecipitation

The extent of adipic acid coprecipitation is highly influenced by the oxidation fraction of the scrubber solids (sulfite versus sulfate),... 

The batch precipitation tests show dramatic effects of adipic acid slurry concentration and solid phase oxidation fraction on coprecipitation of adipic acid in scrubber solids. Real world scrubbers would probably never operate at adipic acid concentrations as high as those tested and would also not likely ever produce pure phase calcium sulfite hemihydrate. Therefore, the magnitude of the results observed is somewhat a product of the laboratory test conditions. The results do, however, establish the potential importance of adipic acid coprecipitation and, hence, the need for analysis of scrubber solids for adipic acid when determining adipic acid chemical degradation rates by a mass balance calculation approach. 

Large amounts of adipic acid were coprecipitated or occluded in the scrubber solids. The concentration of adipic acid in the solids was a function of both the liquid phase adipic acid concentration and the oxidation fraction in the solids. 

The topics presented in this paper include a description of the bench-scale system, the experimental approach, and the results of degradation testing. Also included are the results of batch precipitation experiments designed to study coprecipitation of adipic acid in scrubber waste solids. 

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