Abstract: Disclosed are a method and apparatus for liquefying chlorine out of a gas mixture containing chlorine gas and noncondensable gases. According to the disclosed method, a multi-stage compression means is utilized for the gas mixture. The gas is compressed as it passes through the compressor series, and then it passes from the last compressor of the series to a condenser. Liquid chlorine and a second gas mixture, containing larger amounts of non-condensables, are recovered from the condenser. A bleed stream of the liquid chlorine is utilized as a refrigerant for the second gas mixture and is passed through a series of individual economizers co-current to the second gas mixture. The flow of the chlorine refrigerant and of the second gas mixture in the economizers may be countercurrent or co-current to the flow of chlorine gas in the compressors.