| 摘要 |
The aqueous solution contains from 10 to 30% by weight of iron chloride and from 15 to 25% by weight of hydrochloric acid. The solution is mixed, wholly or partially, with concentrated HCl gas in a crystallization zone at temperatures of from approximately 20 to 60 DEG C, and as a result a concentrated solution is generated which contains crystallized iron chloride and comprises at least 30% strength hydrochloric acid. A first separation device is employed to extract therefrom a salt slurry containing crystallized iron chloride and hydrochloric acid having an HCl content of at least 30% by weight. The remainder of the aqueous solution to be treated is mixed, in an evaporation zone, with flue gas which contains HCl gas and has temperatures of from 750 to 950 DEG C. The flue gas originates from a thermal dissociation process. From the evaporation zone, an HCl-containing gas phase and a liquid phase are drawn off separately. Concentrated HCl gas is extracted from the HCl-containing gas phase and is passed into the crystallization zone. The liquid phase is mixed with the salt slurry from the first separation device, the mixture being separated into a concentrated salt slurry and a liquid phase. The concentrated salt slurry is fed to the thermal dissociation process and the liquid phase is fed to the evaporation zone. |
