Abstract:

To address the problem of low comprehensive utilization rate of iron-containing dust sludge in steel mills,choline chloride-oxalic acid dihydrate low eutectic solvent（CC-OA DES） was used as the research system,and iron oxide nanoparti-cles were prepared by the thermal decomposition of solid-phase precursors of iron-containing dust treated with CC-OA low eutectic solvent（treated by water washing）.The kinetic analysis of the thermal decomposition of the precursor and the growth of iron oxide grains during the treatment was carried out. It was shown that the precursor obtained during the treatment process was FeC₂O₄·2H₂O,and the kinetics of its thermal analysis was targeted at the second stage of thermal decomposition,the average activation energy of 220.54 kJ/mol for the reaction obtained from the three isotropic methods of the Ozawa,Kissinger-Akahira-Sunose and Starink equations.The optimum conditions for precursor roasting: roasting temperature of 673 K and roasting time of 1 h;the average activation energy for grain growth of iron oxide nanoparticles was calculated to be 39.06 kJ/mol according to the only-image equation,and the relationship between roasting temperature,roasting time and grain size was obtained to achieve the preparation of iron oxide nanoparticles of specific grain size;the iron oxide nanoparticles obtained under the optimum roasting conditions had iron oxide with content of 99.67% and were observed an irregular cubic crystal structure under scanning electron microscopy,with particle sizes mainly in the range of 10~100 nm.

Key words: deep eutectic solvent, iron-containing dust, nanometer iron oxide, kinetics