Kinetics of the low-temperature hydrogen reduction of magnetite concentrates

The hydrogen reduction of natural magnetite concentrates is studied by thermogravimetry in the temperature range 300–570°C. An improved equation of additive retardation time contributions is used to analyze experimental data on the gas reduction rate of powder oxides. A software package is developed to calculate the time contributions of the stages of gas reduction of concentrates and their fractions. The calculated data adequately describe the experimental kinetic curves of the hydrogen reduction of magnetite powders and pellets. It is shown that the derived equations and the developed software package can be used to study the low-temperature hydrogen reduction kinetics of oxides and natural magnetites and to estimate the corresponding technological schemes without using experimental investigations. Calculated curves are presented for the hydrogen reduction of nanosize magnetites.