A new anode material for oxygen evolution in molten oxide electrolysis
A new anode material for oxygen evolution in molten oxide electrolysis
复制标题
DOI：
10.1038/nature12134
复制
发表时间：
2013-05-16
期刊：
影响因子：
64.8
通讯作者：
Sadoway, Donald R.
中科院分区：
文献类型：
--
作者：
Allanore, Antoine;Yin, Lan;Sadoway, Donald R.
熔融氧化物电解（莫伊）是一种电冶金技术，它能够从氧化物原料中直接生产液态金属（1，2），与传统的萃取冶金方法相比，它既大大简化了工艺，又显著降低了能耗（3）。莫伊也被认为是减少炼钢（3-5）、生产无碳金属（6）和为地球外勘探产生氧气（7、8）中二氧化碳排放的一种有前途的途径。到目前为止，莫伊已经使用消耗性阳极材料（与铁合金和钛一起使用的石墨（6，9））或陆地应用无法负担的阳极材料（与铁一起使用的铱（10，11））进行了证明。为了能够在没有工艺碳的情况下进行金属生产，莫伊需要一种阳极材料，该阳极材料在维持氧气析出的同时抵抗耗尽。钢铁生产面临三方面的挑战。首先，工艺温度超过1，538摄氏度（参考文献10）。第二，在阳极极化下，大多数金属在这种条件下不可避免地腐蚀（11-13）。第三，氧化铁在与大多数难熔金属（14）甚至碳接触时发生自发还原。在此，我们表明，包含铬基合金的阳极在通过莫伊的铁提取和氧析出期间表现出有限的消耗。阳极的稳定性是由于形成了铬（III）和氧化铝的电子导电固溶体的结构。这些发现使得对钢铁生产的莫伊进行更大规模的评估变得切实可行，并可能提供一种关键的材料成分，从而能够在生产上级冶金质量的金属的同时减轻温室气体排放。
Molten oxide electrolysis (MOE) is an electrometallurgical technique that enables the direct production of metal in the liquid state from oxide feedstock(1,2), and compared with traditional methods of extractive metallurgy offers both a substantial simplification of the process and a significant reduction in energy consumption(3). MOE is also considered a promising route for mitigation of CO2 emissions in steelmaking(3-5), production of metals free of carbon(6), and generation of oxygen for extra-terrestrial exploration(7,8). Until now, MOE has been demonstrated using anode materials that are consumable (graphite for use with ferro-alloys and titanium(6,9)) or unaffordable for terrestrial applications (iridium for use with iron(10,11)). To enable metal production without process carbon, MOE requires an anode material that resists depletion while sustaining oxygen evolution. The challenges for iron production are threefold. First, the process temperature is in excess of 1,538 degrees Celsius (ref. 10). Second, under anodic polarization most metals inevitably corrode in such conditions(11-13). Third, iron oxide undergoes spontaneous reduction on contact with most refractory metals(14) and even carbon. Here we show that anodes comprising chromium-based alloys exhibit limited consumption during iron extraction and oxygen evolution by MOE. The anode stability is due to the formation of an electronically conductive solid solution of chromium(III) and aluminium oxides in the corundum structure. These findings make practicable larger-scale evaluation of MOE for the production of steel, and potentially provide a key material component enabling mitigation of greenhouse-gas emissions while producing metal of superior metallurgical quality.