Method of purifying and recycling argon

#This invention is generally related to a method for purifying a gas. More specifically, this invention is related to a method for purifying and recycling argon.

#Argon is employed in various processes wherein its chemically inert nature, specific physical properties, and a cost that is low relative to those of other noble gases make its use particularly advantageous. For example, argon is used as a blanketing or purge gas, as a heat transfer medium, for degassing of reactive impurities in various metal processes operations, for the atomizing molten steel into the fine powder, and for the production of optical fiber related products.

#While argon is present in air at a much higher concentration than those of the other noble gases, and considerable volumes of argon are available as byproduct of oxygen and nitrogen by air separation, the cost of argon still provides significant incentive toward maximizing recycle usage. Therefore, systems have been commercially implemented to conserve argon by means of pressure, equalization between vessels, recompression and recycle, generally with particulate separation.

#FIG. 1 is a sequence diagram illustrating the purification method of the present invention when the oxygen concentration is less than about 10% in the impure argon.

#FIG. 2 is a sequence diagram illustrating the purification method of the present invention when the oxygen concentration is greater than about 10% in the impure argon.

#FIG. 3 is a schematic flow diagram of one preferred embodiment of the present invention when the oxygen concentration is less than about 10% in the impure argon.

#Other objects, features and advantages will occur to those skilled in the art from the following description of preferred embodiments and the accompanying drawing, in which FIG. 1 provides a schematic diagram of purification method in this invention.

#The following block flow sequences illustrate the preferred way to remove impurities, namely chlorine, nitrogen, oxygen, water, carbon tetrafluoride and carbon dioxide, from an argon rich stream (see Table 1 for concentrations).

#TABLE 1 Concentration ranges Component Molar concentration % Argon 10-98 Nitrogen 0-75 Oxygen 0-20 Water 0-5 Carbon Dioxide 0-1 Carbon Tetraflouride 0-10 Chlorine 0-10