Here, "chlorine-containing tail gas, for recovery" refers to process tail gas containing chlorine gas or other chlorine-bearing constituents that is generated during chemical production, electrolytic processes or the manufacture of chlorine-containing chemicals, and is collected and directed into a recovery system prior to emission. After absorption, condensation, purification or conversion, the chlorine resource in such chlorine-containing tail gas can be recovered for the regeneration of chlorine gas, the preparation of chlorine-containing chemicals or use as a raw material in other processes, achieving resource recovery and reducing environmental emissions.