Process for regenerating exhausted metal-salt- and/or metal-oxide-containing solutions, in particular mixed acids

摘要

The invention relates to a process for regenerating exhausted metal-salt- and/or metal-oxide-containing solutions, in particular mixed acids, in which the solutions are heated and the metal fluorides and metal nitrates are pyrohydrolysed in the course of this, while the water and the free acid vaporise and the acid is recovered from the gases. In order to utilise the advantages of the known process, but simultaneously to avoid its disadvantages, the pyrohydrolysis is performed in a fluidised-bed reactor at a temperature of about 500-1000 DEG C and the metal oxides formed in the fluidised bed are granulated and taken off from the fluidised-bed reactor as dust-free, free-flowing granules, while the gases are dedusted, cooled and then fed to an acid recovery plant. <IMAGE>