Sustainable Iron Production by Low Temperature Electrolysis of Fe2O3 Colloidal Electrode

Abstract

Fe is one of the most important metals that has been used in nearly every construction of man. Currently, Fe is manufactured by a carbothermic reduction by which Fe2O3 ores and carbon are reduced at >2000°C in a blast furnace. This conventional method is environmentally hazardous as it emits almost 2 tons of CO2 per every ton of crude iron produced, accounting for 5% of global CO2 emission. With the goal of zero CO2 emission and sustainable development, more advanced technologies of Fe manufacturing are urgently required. Herein, we introduce a novel and sustainable Fe production using a low temperature electrolysis (100°C) of Fe2O3 colloidal electrode. The Fe2O3 colloid with an electronic-ionic conductive network was successfully fabricated which contains Fe2O3 electrochemically active species, carbon and NaOH solution. Carbon acts as an electronic conductor while NaOH solution serves as an ionic conductor. This electrode design helps increase reactive areas for the Fe2O3 reduction process resulting in fast reaction rate. In addition, some organic and inorganic additives were added to enhance an electrolysis efficiency via promoting the reaction and suppressing H2 evolution parasitic reaction. This method can produce high purity Fe powder with a high current efficiency of 95%. Our zero CO2 emission method is much greener, and less energy consumptive than the conventional carbothermic process, which potentially revolutionizes the iron and steel industry that has a history of environmental consciousness for many decades.