Abstract: The present invention describes a procedure for the removal of sodium sulphate from a phosphate solution that has been used for absorption of SO2 from flue gases, in which a precipitate forms when the absorption solution is regenerated by evaporation. In this procedure a part of the precipitate is separated from its solution and treated with water and SO2 for transformation of disodium-hydrogen phosphate into monosodium dihydrogen phosphate in the aqueous solution. The sodium sulphate remains undissolved and is removed by filtration. The filtrate is then added back to the main process.

Abstract: The present invention describes a procedure for the removal of sodium sulphate from a phosphate solution that has been used for absorption of SO2 from flue gases, whereby a precipitate forms when the absorption solution is regenerated by evaporation. In this procedure a part of the precipitate is separated from its solution and treated with water and SO2 for transformation of disodium-hydrogen phosphate into monosodium dihydrogen phosphate in the aqueous solution, whereby the sodium sulphate remains undissolved and is removed by filtration, whereafter the filtrate is added back to the main process.

Abstract: Process for removing sodium sulphate from an aqueous citrate, adipate or phosphate buffer solution used for absorption of SO.sub.2 from exhaust gases, by evaporating an aqueous buffer solution at atmospheric pressure at a temperature near its boiling point, thereafter separating the precipitated sodium sulphate and optionally subjecting it to further treatment to recover accompanying buffer salt. The further treatment may consist in a treatment of the precipitated sodium sulphate together with accompanying buffer salt with water at elevated temperature. The solution which is then obtained is mixed with the rest of the buffer solution.

Abstract: SO.sub.2 containing gas is purified by means of an aqueous absorption solution, and SO.sub.2 is regenerated from this solution. There is used an absorption solution containing a phosphate buffer, and SO.sub.2 is removed from the absorption solution together with water by evaporation.

Abstract: Process for removal of sulphur dioxide from exhaust gases by absorption in an aqueous solution containing ions of adipic acid, and stripping of sulphur dioxide with steam. Solid adipic acid is added to the absorption solution before or during the steam stripping in such an amount that all the acid is dissolved at the stripping temperature, and after the stripping the solution is cooled to substantially below the absorption temperature to precipitate solid adipic acid which is separated off and is added again after the absorption which takes place with a solution which is unsaturated with adipic acid.