| abstract |
recovery of nitration acid mixtures from nitration processes. of nitric acid mixtures, particularly nitric acid, sulfuric acid and nitric oxides, of the nitrated crude products, which show the nitration of nitrable aromatic compounds after separation of the nitration acid by an acid wash by a multistage extraction process, the extraction process comprising a transverse current extraction with countercurrent extraction attached. The process enables the almost complete recovery of the acids mentioned above, including nitric oxides, at high concentrations, so that the same can be returned to nitration and no longer contaminate the wastewater. |