Electrolytic Steelmaking: Environmentally Sound Metal Production

据估计，钢铁工业产生的温室气体占人类活动产生的温室气体总量的5%。这是大量使用碳作为还原剂从矿石中提取金属铁的结果。拟议工作的目的是检查电解炼钢的可行性，这是一种直接电解熔融氧化铁以产生纯液态铁和氧气的过程。虽然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，由于数据库的不足，还没有持续努力开发基于该技术的商业过程。在提议的调查中研究的问题是：是否有可能设想一种化学来支持所描述的直接电解过程？为了回答这个问题，将对熔融氧化物溶液的高温物理化学进行研究。用电化学阻抗谱（EIS）研究了它们的电学性质。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NaC1和KC1熔体进行测试。熔融氧化物溶液的热力学将通过电动势测量来研究。为此目的设计了参考电极，并将在调查过程中进行检查。最后，电解试验将在实验室规模的电池中进行，这些电池被设计成在之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进料进行了这种试验，并在铂制成的惰性阳极上观察到出氧现象。这证实了法拉第过程可以在这些熔体中运行。对基本原理有了更深入的了解，就有可能对系统进行优化。这项工作的成功完成将有助于发展一种新的无碳炼钢工艺，这种工艺原则上有能力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铁合金，如铬铁（不锈钢的前体）。同样，人们可以通过电解氧化铁-氧化锰来生产锰铁。因此，在熔融氧化物中直接电解金属生产不仅可以解决钢铁行业面临的一系列环境问题，还可以作为跨越式技术的基础，加强美国工业的国际竞争地位。

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.