Patent ID: 6159382
Filing Date: 2000-12-12
Classification: C01B,C02F,C07C,F28F,Y02P

Abstract:
A method of recovering a sulfuric acid from an aqueous waste stream containing sulfuric acid and an organic impurity comprising the steps of:cooling the aqueous waste stream to a temperature at or near its freezing point to form a slurry of a solid sulfuric acid-rich phase and a liquid phase containing the organic impurity; andseparating the sulfuric solid acid-rich phase and the liquid organic impurity phase on the basis of density;wherein the slurry is formed in a scraped surface freeze crystallizer, the crystallizer comprising a surface onto which the solid phase forms and a scraper for removing the solid phase from the surface to form the slurry of the solid phase and the liquid phase, and wherein the crystallizer is cooled indirectly and is capable of controlling crystal growth in the crystallizer.