Abstract In this work, the combustion behavior of pulverized sponge iron (PSI), a practical-grade iron product that was proposed as a potential candidate in the metal fuel cycle, was observed directly using high-magnification shadowgraphy and other optical diagnostics techniques. The PSI was combusted in a laboratory-scale, McKenna flat-flame burner. Results suggest that, in agreement with theoretical models, PSI combusted heterogeneously, with most of the particle mass converting to an intact, solid oxide. However, in contrast with previous hypotheses, the formation of a microflame of combusting aerosol that was attached to the particle surface was observed. Results from quantitative shadowgraphy indicated near-instantaneous melting and complex behavior—we attempted to explain these based on the Fe O phase diagram. The analysis of micron- and nano-sized combustion products confirmed that the PSI combusted heterogeneously and a gaseous sub-oxide was formed. Combustion under high excess oxygen was hypothesized to reduce the formation of these oxides.

中文翻译：

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海绵铁粉作为可回收电燃料的燃烧行为

摘要 在这项工作中，粉状海绵铁 (PSI) 是一种实用级铁产品，被提议作为金属燃料循环中的潜在候选产品，使用高倍率阴影成像和其他光学诊断技术直接观察其燃烧行为。PSI 在实验室规模的 McKenna 平焰燃烧器中燃烧。结果表明，与理论模型一致，PSI 燃烧不均匀，大部分粒子质量转化为完整的固体氧化物。然而，与之前的假设相反，观察到附着在颗粒表面的燃烧气溶胶微焰的形成。定量阴影成像的结果表明近乎瞬时的熔化和复杂的行为——我们试图根据 Fe O 相图来解释这些。对微米和纳米级燃烧产物的分析证实，PSI 燃烧不均匀，并形成了气态亚氧化物。假设在高过量氧气下燃烧可以减少这些氧化物的形成。