Process for the manufacture of sulphur which can be recycled
AssigneeCassella Aktiengesellschaft
InventorGeorg Daniek
Life of this patent
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Abstract
The process for recovering recyclable elemental sulfur from a strongly colored solution containing alkali metal sulfides, alkali metal polysulfides, or mixtures thereof comprising (a) mixing said solution at an alkaline pH with a decolorizing amount of an iron or zinc compound which is a hydroxide or the salt of an inorganic acid whereby a precipitate is formed, (b) separating the precipitate to isolate a decolorized solution, (c) precipitating elemental sulfur from the decolorized solution by adding sulfur dioxide or alkali metal thiosulfate under acidic conditions, and (d) separating the precipitated elemental sulfur.
Claims7
A process for recovering elemental sulphur from filtrate solutions from the manufacture of sulphur dyestuffs containing sulphur dyestuffs and alkali metal sulphides or alkali metal polysulphides, or mixtures thereof comprising
- (a) mixing said filtrate solution at an alkaline pH with a decolorizing amount of an iron or zinc compound which is a hydroxide or the salt of an inorganic acid whereby a precipitate is formed,
- (b) separating the precipitate to isolate a decolorized solution.
- (c) precipitating elemental sulfur from the decolorized solution by adding sulfur dioxide or alkali metal thiosulfate under acidic conditions, and
- (d) separating the precipitated elemental sulfur.
Dependencies are inferred from the claim text.