METHOD FOR PROCESSING AQUEOUS MEDIA CONTAINING METAL NITRATE OR SULPHATE SALTS

摘要

The invention relates to a method for processing an aqueous medium (m) containing at least one type of metal nitrate or sulphate and making it possible to convert said soluble nitrate or sulphate into an insoluble oxide and a nitric or sulphuric acid, wherein the inventive processing method consists (a) in processing said aqueous medium (m) at a temperature ranging from 100 to 700 °C and a pressure of 1-50 MPa and, subsequently in entirely or partially recovering and/or processing the thus obtainable nitric or sulphuric acid. The use of the inventive method for converting soluble metal salts into the insoluble form thereof for purifying aqueous effluents produced by metal nitric or sulphuric acid etching is also disclosed