Please consider the reduction process of magnetite (Fe3O4) in a lab scale furnace equipped with a hydrogen lance. Please consider a case in which a spherical particle 2 mm in diameter reacts with hydrogen, producing iron, which flakes off the surface. Please determine the time required to remove a layer of 1 um thick from the surface at 1000 K and atmospheric pressure. The mass transfer coefficient of hydrogen in the synthetic gas mixture to the magnetite surface is 0.25 m/s and the surface reaction rate constant at the magnetite surface is 0.27 m/s. Molar mass of magnetite is 231.53 g/mol. Density of magnetite is 5.17 g/cm. The environment of the furnace contains 20% hydrogen. Fe3O4(s) + 4H2(g) 3 Fe(s) + 4H2O(g)