Activation of the combustion of low-reactivity solid fuels with metal-rolling production waste

The effect of the addition of different amounts of metal-rolling production waste (metal scale in amount of 1–10 wt%) on combustion characteristics of low-reactive solid fuels (anthracite and semi-coke) was studied. XRD analysis of the metal scale identified Fe 3 O 4 and Mn 3 O 4 phases along with a cubic Fe phase. The characteristics of ignition and combustion of the samples were studied via thermal analysis and high-speed video recording at heating medium temperatures of 600–800 °C (with 100 °C step) using a combustion chamber. It was experimentally found that the addition of a metal scale, regardless of its weight content, increases the fuel reactivity, as evidenced by the drop in temperature of the onset of intense oxidation (ΔT i ) by 2–32 °C and the decrease in the ignition delay time (Δτ i ) by 0.2–2.2 s. The metal scale additive also increases the fuel combustion rate, which was evidenced by the maximum rate of oxidation (Δw max ) increasing by 0.1–2.0 wt%/min and, hence, the temperature of the end of oxidation (ΔT f ) reducing by 13–68 °C. Due to combustion intensification, the carbon content in ash decreased by 55 rel% on average. The amount of CO and NO x contained in gas-phase combustion products diminished as well.