An apparatus for regulating the absolute amount of oxygen and relative percentages of individual gaseous constituents of a gas stream provided to a metallurgical reaction furnace, comprising:
- (a) at least one container;
- (b) each of said containers having molecular screening substances contained therein;
- (c) each of said containers being provided with an ambient air inlet conduit;
- (d) each of said containers also being provided with an outlet conduit for removal, from said container, of an oxygen enhanced gas stream;
- and
- (e) said outlet conduit being connected to a metallurgical reaction furnace.