Abstract: The invention relates to a process for preparing potassium thiosulfate, potassium sulfite or potassium bisulfite comprising the following steps: Step (1a): providing a potassium hydroxide or potassium carbonate solution for neutralizing acid forming components such as dissolving SO2 or H2S; Step (1b): providing an SO2 contacting solution, containing at least some potassium sulfite or potassium bisulfite or potassium thiosulfate; Step (2): providing SO2 gas; Step (3): reacting these to absorb the SO2 gas and to form an intermediate reaction mixture comprising potassium sulfite, or potassium bisulfite or a mixture thereof, and optionally recovering the potassium sulfite, or potassium bisulfite or a mixture thereof, and/or optionally using steps 4 and 5; Step (4): adding sulfur or sulfide containing compound containing sulfur having the oxidation state of 0, ?2 or of between 0 and ?2 to the reaction mixture and optionally potassium hydroxide or potassium carbonate, and reacting the mixture under suitable cond

Abstract: A method for cleaning a contaminated solvent used to treat a gas stream, for example a contaminated glycol or a contaminated amine stream, by vacuum evaporation using a mechanically-maintained horizontally-orientated thin film evaporator, where the contaminant material is recovered from the thin film in solvent-free form, as either a heavy organic material or as free flowing salts.