7/23/2023 0 Comments Oxidation number of chromium oxideA well-known example is the Hall–Héroult (H–H) cell, though to date this cell relies on a consumable carbon anode, leading to significant process CO 2 emissions along other noxious species (CF 4, C 2F 6, CO and SO 2) 33, 34, 35, 36. In traditional industrial electrolysis, an electrochemical cell is employed in which a direct current passes through a multi-element electrolyte, generating a cell voltage sufficient to drive an otherwise non-spontaneous chemical reaction (i.e., conversion of metal oxide to pure metal) 29, 30, 31, 32. The chemical principle is the production of liquid iron from iron oxide, using the following electrolysis reaction of selective decomposition of Fe oxide (e.g., hematite here): Molten oxide electrolysis (MOE) for iron production is one candidate that is in the category of ultra-low GHG emissions technologies when driven by GHG-free electricity 12. Thus, there remains an imminent need to develop alternative metallurgical technologies that may substantially reduce or even eliminate CO 2 emissions from iron and steel production. Iron and steel production have come under amplified scrutiny over the last decades, however to date the efficiency of current ironmaking technologies is considered optimal, and recycling strategies have already been implemented 7, 8. This corresponds to > 2 billion tonnes of CO 2 emissions annually, or 6–8% of the total anthropogenic greenhouse gas (GHG) produced worldwide 7. Through an integrated blast furnace production route, around 1.8 tonnes of CO 2 are produced for every tonne of steel produced. This can be rationalized considering that it is the reducing power of carbon-containing species (e.g., CO to CO 2 or C nH m to CO 2 and H 2O) that supports the reduction reaction of iron (Fe) oxide (e.g., Fe 2O 3 + 3CO → 2Fe + 3CO 2) 5, 6. The major ironmaking technology employing blast furnaces is not only recognized as being energy intensive, but also emits large volumes of CO 2 2, 3, 4. Iron based alloys, including steels, remain the key structural materials for the numerous technologies that underpin modern civilization, be it pipelines, structures and transportation however, the environmental implications of iron production are vast 1.
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