Process for the brightening of sodium hydrogensulfate
AssigneeGrillo-Werke AG
InventorsKlaus Driemel, Ingo Biertümpel, Horst Kirsch
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Abstract
The process for the brightening of continuously produced sodium hydrogensulfate obtained in the reaction of sodium chloride and concentrated sulfuric acid in molten sodium hydrogensulfate in a circulation reactor, wherein evolved hydrogen chloride and heating gases generated by an immersion burner are withdrawn at various sites and seed crystals are added for a faster conversion of initially formed metastable phases, is that from 0.01 to 0.05% by weight of aluminium oxide and/or from 0.5 to 1.5% by weight of magnesium oxide and/or magnesium sulfate and, optionally, additionally calcium sulfate are added as seed crystals.
Claims4
In a process for continuously producing sodium hydrogensulfate comprising
- reacting sodium chloride and concentrated sulfuric acid in molten sodium hydrogensulfate in a circulation reactor,
- withdrawing evolved hydrogen chloride and heating gases generated by an immersion burner at various sites, and
- adding seed crystals for a faster conversion of initially formed metastable phases, characterized in that the improvement comprises brightening the continuously produced sodium hydrogensulfate (NaHSO4) by
- adding, based on the weight of the NaHSO4, (i) from 0.01 to 0.05% by weight of aluminium oxide and/or (ii) from 0.5 to 1.5% by weight of magnesium oxide and/or (iii) from 0.5 to 1.5% by weight of magnesium sulfate as seed crystals.
Dependencies are inferred from the claim text.