Method for recovering and purifying argon gas from silicon single crystal manufacturing apparatus and apparatus for recovering and purifying argon gas

An argon gas recovering and purifying method comprising:

• introducing a waste argon gas containing nitrogen, oxygen, and carbon monoxide from a silicon single crystal manufacturing apparatus into a waste argon gas storage tank;
• removing solid matters in a pretreatment facility which removes the solid matters in the waste argon gas;
• converting the oxygen into water and converting the carbon monoxide into carbon dioxide by a catalytic reaction;
• and
• removing the water, the carbon dioxide, and the nitrogen to obtain a recovered gas,
• wherein the catalytic reaction is carried out with compression heat alone by arranging a catalyst in a two-stage compressor, then the water is removed by a dryer and then the nitrogen and the carbon dioxide are adsorbed and removed in an ordinary-temperature adsorption tower at the step of obtaining the recovered gas,
• in the converting, auxiliary oxygen is added to the waste argon gas while controlling an additive amount before a first-stage compression unit in the two-stage compressor, then one-stage compressing operation is performed, a temperature of the waste argon gas is increased to 100 to 200° C. by compression heat generated by the compressing operation, and then the carbon monoxide and the auxiliary oxygen are immediately subjected to the catalytic reaction in a first-stage catalytic unit installed behind the first-stage compression unit to convert them into the carbon dioxide,
• the waste argon gas is cooled, and
• hydrogen is then added to the waste argon gas while controlling an additive amount before a second-stage compression unit in the two-stage compressor to perform second-stage compressing operation, a temperature of the waste argon gas is increased to 100 to 200° C. by compression heat generated by the compressing operation, and then the oxygen and the added hydrogen are immediately subjected to the catalytic reaction in a second-stage catalytic unit installed behind the second-stage compression unit to convert them into the water.