A system for recycling vented atmosphere gas discharged from a heat treatment chamber (10) utilizing a protective atmosphere gas therein. The system includes an atmosphere recycling apparatus (15) configured to receive the vented atmosphere gas (16). The atmosphere recycling apparatus includes a gas separator (13) configured to separate the vented atmosphere gas into a purified atmosphere gas stream and an impure stream. The atmosphere recycling apparatus is configured to feed the purified atmosphere gas stream to the heat treatment chamber. A storage vessel (11) can be provided to receive the purified atmosphere gas stream from the atmosphere recycling apparatus, and configured to supplement an atmosphere gas supply to the heat treatment chamber (1) with the purified atmosphere gas stream.