Abstract: A method is provided for increasing the lifetime of Stretford solution by reducing or eliminating the generation of undesirable thiosulfate salts. The method has three major aspects. First, thiocyanate is added to the Stretford solution. Second, the concentration of sodium sulfate in the solution is maintained at a level below about 100 g/l. Third, the solution should contain little or no thiosulfate at the start of operations. It has been found that little or no thiosulfate is generated when the Stretford unit is operated under these conditions. The concentration of sodium sulfate in the solution is maintained at a level below about 100 g/l by removing sodium sulfate from the solution by cooling a slipstream of the solution to precipitate the sodium sulfate as Glauber's salt.