A laboratory investigation has been made on those candidate systems for SO2 removal that were developed during a literature search. Emphasis in the investigation was placed on the definition of those parameters which would allow a more definitive engineering evaluation. Of the four candidate systems recommended previously, the non-regenerable limestone-molten nitrate system, and the adduct or complex-forming molten nitrate system have been rejected. The remaining candidate systems - the molten nitrate-calcium oxide system and the tin-lead alloy system-have been investigated in some detail. Comparison studies of the various reactive oxides dissolved or suspended in the molten nitrate solvents have shown that the best reactant is calcium oxide. The complete results of this experimental program are presented in the report.