
128 Aluminum Recycling
amount of energy, ame temperatures are relatively low (<2000°C). When pure
oxygen is mixed with air to create enriched air, the amount of nitrogen brought
into the furnace decreases. With less nitrogen to adsorb heat, the ame temperature
can increase by several hundred degrees (Buchholz and Rødseth, 2011). In addition,
eliminating the nitrogen increases the concentration of CO
2
and H
2
O in the off-gas;
this increases the emissivity of the gas, improving radiative heat transfer still further.
The ame temperature can also be increased by preheating the incoming air (Lucas,
2012; Zhou et al., 2010).
High ame temperatures ...