Experimental study on the low to medium temperature oxidation characteristics and kinetics of micro-size iron powder

Micro-size iron powder is a new type of carbon-free energy with great potential. In order to realize large-scale and efficient clean combustion and utilization of metal fuel, it is necessary to master its basic combustion characteristics and chemical reaction kinetics principle. This requires a great deal of research on the chemical kinetics parameters, especially the activation energy. Thermogravimetric analysis (TGA) is the most commonly used tool to obtain kinetic data in experiments, and isotransform kinetic analysis is the most effective method to process the calculation of TGA data. In this paper, six micro-size iron powders of 6, 25, 30, 40, 55, and 120 μm were used to conduct experiments on the thermogravimetric analyzer, and the TGA data are processed and analyzed by Friedman isoconversional method, including the analysis of original TGA data, obtaining conversion data, interpolation of conversion and derivative conversion data, calculating activation energy and conversion function of six kinds of iron powder fitting by Friedman isoconversional method, and comparative analysis of iron powder data with different particle sizes. The results show that in most cases, the smaller the particle size of micro-size iron powder, the more sufficient the reaction is at the same temperature. Before the reaction speed reaches its peak value, the smaller the particle size of iron powder, the faster the reaction speed can get. When the reaction speed reaches its peak value, the smaller the particle size of iron powder, the slower the reaction speed can get. When the conversion is greater than 0.300, for 30, 40, 55, and 120 μm samples, the smaller the particle size of iron powder, the higher the activation energy can get. © 2023 Chemical Industry Press. All rights reserved.