Metal-contaminated hydrochloric acid is processed to produce near-azeotropic hydrochloric acid product

摘要

Metal-contaminated hydrochloric acid (especially of 3-5% HCl concentration) is processed by evaporating to produce a HCl/water vapor mixture which is then rectified to produce a near-azeotropic HCl product. Processing of metal-containing (especially iron and/or zinc containing) hydrochloric acid (especially with a residual HCl concentration of 3-5 %) comprises: (a) evaporating to produce a concentrated metal chloride which is withdrawn as a bottom product and a HCl/water vapor mixture which is withdrawn as a top product; and (b) rectifying the HCl/water vapor mixture to produce a H2O-enriched product which is withdrawn from the top of the rectifier and a near-azeotropic hydrochloric acid which is withdrawn as liquid from the bottom of the rectifier.