Sulphur dioxide is a heavy, colourless poisonous gas with a pungent irritating odour. The overarching, dominant use of sulphur dioxide is in the production of sulfuric acid. Sulphur dioxide is an intermediate in the production of sulfuric acid, being converted to sulphur trioxide and then to oleum, which is made into sulfuric acid. Sulphur dioxide for this purpose is made when sulphur combines with oxygen. The method of converting sulphur dioxide to sulfuric acid is called the contact process. Sulphur dioxide is sometimes used as a preservative for dried apricots, dried figs and other dried fruits, owing to its antimicrobial properties and ability to prevent oxidation, it is called E220 when used in this way in Europe. As a preservative, it maintains the colourful appearance of the fruit and prevents rotting. It is also added to sulphured molasses. Sulphur dioxide is also a good reductant In the presence of water, sulphur dioxide is able to decolorize substances. Specifically, it is a useful reducing bleach for papers and delicate materials such as clothes. This bleaching effect normally does not last very long. Oxygen in the atmosphere reoxidizes the reduced dyes, restoring the colour. In municipal wastewater treatment, sulphur dioxide is used to treat chlorinated wastewater prior to release. Sulphur dioxide reduces free and combined chlorine to chloride. Sulphur dioxide is a versatile inert solvent widely used for dissolving highly oxidizing salts. It is also used occasionally as a source of the sulfonyl group in organic synthesis Being easily condensed and possessing a high heat of evaporation, sulphur dioxide is a candidate material for refrigerants. Prior to the development of chlorofluorocarbons, sulphur dioxide was used as a refrigerant in home refrigerants.
We at Spantech provide Sulphur Dioxide gas cylinders with various mixes such as Sulphur Dioxide in Air and Sulphur Dioxide in Nitrogen, in many ppm and % levels, in our Spancan™ A34 litre, A58 litre and A110 litre cylinders.