Continuous flue gas composition measurements (CO, CO2, O2, H2) were made for several rotary aluminum melt furnace heats, with air/oxy/gas combustion. In many cases, during rotary furnace aluminum melting, the furnace atmosphere becomes increasingly reducing (higher CO and H2, lower CO2) as the heat progresses. This suggests that aluminum is being oxidized.
For these heats, the measured flue gas CO, CO2 and H2 compositions were utilized, along with C, H and O balance equations, to calculate instantaneous aluminum oxidation rates throughout the heat.
Measured instantaneous aluminum oxidation rates are compared, for varied burner % O2 participation levels, and for different types of scrap, as a function of flue gas temperature.