Patent ID: 7067094

Claim:
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 (NaHSO 4 ) by adding, based on the weight of the NaHSO 4 , (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.