Abstract: Processes are disclosed which include: (a) providing a gas comprising chlorine, oxygen, and carbon dioxide; (b) feeding the gas to a distillation column having a head, a bottom, a rectifying section and a stripping section, wherein the gas is fed to the distillation column at an introduction point between the rectifying section and the stripping section; (c) distilling the gas in the column at a pressure of 8 to 30 bar and at a column head temperature of ?10° C. to ?60° C., to form liquid chlorine and a head mixture comprising carbon dioxide and oxygen; (d) removing the liquid chlorine from the distillation column at the bottom of the column; and (e) removing a first portion of the head mixture from the head of the distillation column, and refluxing a second portion of the head mixture in the column.

Abstract: Provided are novel methods and systems for separating a mixed gas containing oxygen and chlorine. According to one method in accordance with the invention, the mixed gas and a refrigerant are introduced into a separator unit. At least a portion of the chlorine is condensed from the mixed gas in the separator unit, thereby forming a condensed chlorine-rich liquid fraction and an oxygen-enriched gas fraction. The condensing duty is supplied by the refrigerant, which can be liquid oxygen. The mixed gas and refrigerant can be brought into direct or indirect contact with one another. The invention can be advantageously applied to the treatment of exhaust gases from an ore treatment plant, and can result in enriched oxygen and chlorine streams which may be recycled or used in other applications.

Abstract: The cryopanel of a cryopump can be preferentially defrosted to remove an acid-forming or toxic gas while leaving a second gas substantially condensed upon the cryopanel thereby limiting interaction between the vapor phases of the two gases. The cryopanel is warmed to a temperature within a selective defrost range at which the first gas selectively sublimates from the cryopanel. The temperature of the cryopanel is then maintained at a temperature within this range until the cryopanel is substantially cleared of the first gas leaving the second gas substantially undisturbed as a condensate upon the cryopanel. In a preferred embodiment, the cryopanel is maintained at about 50 to 85K during standard operation before being defrosted.