Electrolytic Steelmaking: Environmentally Sound Metal Production

据估计，钢铁行业产生的温室气体占人类活动产生的所有温室气体的5%。这是大量使用碳作为还原剂从其矿石中提取金属铁的结果。这项拟议工作的目的是研究电解炼钢的可行性，这是一种直接电解铁水氧化物以生产纯铁和氧气的过程。尽管熔融氧化物中的电化学处理在无碳提取和精炼金属方面具有巨大的潜力，但迄今为止还没有持续努力开发基于这一技术的商业过程，部分原因是数据库的不足。在拟议的调查中正在研究的问题如下：是否有可能设想一种支持所述直接电解过程的化学？为了回答这个问题，我们将研究熔融氧化物溶液的高温物理化学。它们的电学性质将通过电化学阻抗谱(EIS)进行研究。为此目的设计了一种用于测量高活性氧化物熔体电导率的新电池，并正在用Kc1水溶液和NaCl2和Kc1熔体进行测试。将通过电动势测量来研究熔融氧化物溶液的热力学。为此目的设计了参比电极，并将在调查过程中对其进行检查。最后，将在实验室规模的电解槽中进行电解试验，这些槽被设计成在先前采集的数据所指示的参数范围内运行。在经验的基础上，用含有氧化铁和氧化铬的氧化物混合物的原料进行了这种试验，并在铂制成的惰性阳极上观察到了氧气的析出。这证实了法拉第过程可以在这些熔体中运行。随着对基本面的更深入了解，将有可能优化该系统。这项工作的成功完成将使开发一种新的无碳炼钢工艺成为可能，该工艺原则上能够根据不同的原料化学成分进行修改。例如，人们可以通过电解铁和铬的混合氧化物来制造铬铁等铁合金(作为不锈钢的前体)。同样，人们可以通过电解铁氧化物-锰氧化物来生产锰铁。因此，在熔融氧化物中直接电解生产金属不仅将解决钢铁行业面临的一系列环境问题，还将成为跳跃式技术的基础，以加强美国行业的国际竞争地位。

It is estimated that the steel industry generates 5 percent of all greenhouse gases produced by human activity. This is a consequence of the intensive use of carbon as a reductant to extract metallic iron from its ore. The purpose of the proposed work is to examine the feasibility of electrolytic steelmaking, a process of direct electrolysis of molten iron oxide to produce pure liquid iron and oxygen gas. While electrochemical processing in molten oxides has enormous potential for the carbon-free extraction and refining of metals, to date there has been no sustained effort to develop a commercial process based on this technique, in part due to the inadequacy of the database. The question under study in the proposed investigation is the following: is it possible to conceive of a chemistry to support the direct electrolysis process described? To answer this question the high- temperature physical chemistry of molten oxide solution will be studied. Their electrical properties will be investigated by electrochemical impedance spectroscopy (EIS). A new cell for electrical conductivity measurements of highly reactive oxide melts has been designed for this purpose and is being certified in tests with aqueous KC1 solutions and melts of NaC1 and KC1. The thermodynamics of molten oxide solutions will be investigated by emf measurements. Reference electrodes have been designed for this purpose and will be examined during the course of investigation. Finally, electrolysis trails will be conduced in laboratory-scale cells designed to operate in the parameter ranges indicated by the data taken earlier. On an empirical basis, such tests have been conducted with feed consisting of oxide mixtures containing iron oxide and chromium oxide and oxygen evolution has been observed on an inert anode made of platinum. This confirms that faradaic processes can be made to operate in these melts. With a deeper understanding of the fundamentals it will be possible to optimize the system. Successful completion of the work will enable the development of a new carbon-free steelmaking process which in principle has the capability to be modified in accordance with different feedstock chemistries. For example, one could make ferroalloys such as ferrochromium (as a precursor for stainless steel) by electrolysis of the mixed oxides of iron and chromium. Similarly, one could produce ferromanganese by electrolysis of iron oxide-manganese oxide. Thus, metal production by direct electrolysis in molten oxides would not only solve a wide array of environmental problems facing the steel industry but also would serve as the basis for leapfrog technology to strengthen the U.S. industry's international competitive position.