Pyrite roasting in modified fluidized bed: Experimental and modeling analysis

•The modified fluidized bed improves pyrite roasting.•Eulerian model and conservation of chemical species is used to simulate roasting.•The mechanism of the roasting process was determined via isoconversional method.•The conversion rate of pyrite to hematite is high at 950 °C.•Pyrite depletion is determined using kinetics, modeling, and experimentation.