Patent ID: 7988942
Filing Date: 2011-08-02
Classification: B01D,C01B

Abstract:
1. A method for recovering dilute and contaminated waste sulfuric acids from nitration processes, where the waste acid from the nitration process which is taken off from the nitration process and, in addition to up to 80% by mass of sulfuric acid and water, contains nitric acid, HNO the production of a highly concentrated nitric acid required in the nitration process from a more dilute nitric acid by extractive rectification with the use of concentrated sulfuric acid as an extracting medium also being coordinated with the nitration process, the sulfuric acid used as extracting medium being diluted during the extractive rectification and being reconcentrated for reuse, wherein the waste acid from the nitration process (F the prepurified sulfuric acid taken off from the bottom of the first stripping column (K