How can carbon monoxide reduce hematite to magnetite or iron metal?

Carbon monoxide (CO) acts as a powerful reducing agent in metallurgical processes, including the conversion of iron oxides. When hematite ($F{e}_2{O}_3$), which contains iron in the $F{e}^{3+}$ oxidation state, is heated in the presence of carbon monoxide, the gas facilitates a chemical reduction process.12

This reduction occurs because carbon monoxide effectively removes oxygen from the iron oxide structure at high temperatures. Depending on the conditions and the extent of the reaction, hematite can be reduced to magnetite ($F{e}_3{O}_4$) or further reduced to metallic iron. In industrial applications like blast furnaces, this process is central to iron making, where gases containing carbon monoxide—often generated by burning coke—circulate through the furnace to strip oxygen from the ore, ultimately yielding molten iron.1234

It is important to note that while carbon monoxide is essential for these industrial chemical reactions, it is also an extremely dangerous poison that prevents hemoglobin from transporting oxygen in the human body, posing a severe risk to life if inhaled.2