METHOD FOR OBTAINING OR RECOVERING NITRIC ACID AND HYDROFLUORIC ACID FROM SOLUTIONS OF STAINLESS STEEL PICKLING SYSTEMS

摘要

The invention relates to a method for obtaining or recovering acids, in particular nitric acid and hydrofluoric acid, from solutions and/or from solutions containing metal salts of said acids, comprising the following steps: a) spray drying the solutions at temperatures below the decomposition temperature of the acids, wherein the energy required therefor is introduced by means of a gaseous heat-transfer medium in order to obtain dry metal salts and gaseous acids; b) absorbing the gaseous acids formed in step a); c) separating the dry metal salts formed in step a); optionally d) burning the dry metal salts obtained in step a) at temperatures in the range of 400-900 °C in order to obtain metal oxides and gaseous acids; and e) absorbing the gaseous acids formed in step d).