This report is directed toward elucidating the irreversible reactions in the amine-sulfur dioxide system and explores potential methods of chemically recovering the sulfur values. This effort is successful insofar as insight is gained into the reactions of sulfur dioxide in amines at elevated temperatures and a better perspective of the required recovery processes is achieved. Furthermore, in order to gain a perspective of the economics of the modified amine process, engineering cost estimates are carried out for potential process schemes involving chemical recovery. A significant result of this research work was the observation of the disproportionation of the absorbed sulfur dioxide in the amine into di- and polythionates, for example, according to the following overall equation 20 SO2 + 8 H2O yields 6 S2O6(2-) + S3O6(2-) + S5O6(2-) + 16 H(+). This reaction might have ramifications extending to a variety of sulfur dioxide sorption processes in the temperature range of stack gases (200 to 350F). This report, therefore, includes both a discussion of the evidence for this reaction occurring in the amine system and a brief review of some known chemistry of the sulfur species produced. (Author)