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Foret SA
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Foret SA
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Application filed by Foret SAfiledCriticalForet SA
Priority to ES547563ApriorityCriticalpatent/ES8701131A1/en
Publication of ES8701131A1publicationCriticalpatent/ES8701131A1/en
Publication of ES547563A0publicationCriticalpatent/ES547563A0/en
The process consists of (a) feeding a closed reactor with 8-12% sulphydric acid, 10-18% ammonia and 40-50% of water, (b) allowing to react for 1 hour at 45 deg. C max., maintaining the reaction pressure: (c) introducing anhydrous SO2 in amount of 30-40% until disappearance of the sulphite ion. maintaining the reaction pressure and pH above 7; (d) filtering, decolorising with active carbon and re-filtering.