Patent ID: 10494258

Abstract:
A method for concentrating an aqueous hydrogen halide starting solution, in particular hydrochloric acid, includes the steps of extractive distillation of the aqueous hydrogen halide starting solution in the presence of an extraction agent in a distillation device, removing hydrogen halide vapor and/or hydrogen halide gas from the upper portion of the distillation device, removing an extraction-agent-containing solution from the lower portion of the distillation device, concentrating the extraction-agent-containing solution which is removed from the lower portion of the distillation device in an evaporation device, and returning the extraction-agent-containing solution which is concentrated in the evaporation device to the distillation device, wherein the extraction-agent-containing solution removed from the lower portion of the distillation device is concentrated in the evaporation device by evaporation at a pressure which is greater than atmospheric pressure.