Researchers from the Microwave Division (DIMAS-ITACA) at the Polytechnic University of Valencia (UPV) have made significant strides in identifying optimal materials and compositions for processing steel residues in microwave reactors. Their study, conducted as part of the Transzerowaste European project involving 12 partners, focuses on the efficient heating of specific materials, alongside the development of transport and thermal insulation solutions compatible with high-temperature microwave environments.
This breakthrough could pave the way for upgrading low-quality iron ores and by-products, improving impurity separation, and boosting recycling rates for lower-grade scrap—an essential step toward climate-neutral and circular industrial value chains.
Efficient Mixtures and Constructive Materials Identified
“We analyzed the compositions to determine which mixtures heat most effectively and under what temperature conditions reactions occur,” explains Beatriz García-Baños, a DIMAS-ITACA researcher. In addition, the team identified materials, such as ceramic tubes for transport and thermal insulation components, that are microwave-compatible and stable under extreme conditions.
Among the key findings, quartz and specific magnesia spinels emerged as ideal materials for use in microwave reactors. These materials ensure the energy is absorbed by the target compositions rather than being wasted, enhancing the overall efficiency of the process.
Microwave Technology for Sustainable Metal Recycling
The research emphasizes the potential of microwave technology to process low-quality iron ore and steel plant residues, including dust and sludge. By using electromagnetic fields, the method offers distinct advantages, such as targeted energy transfer and improved recycling outcomes. However, understanding the behavior of materials at such high temperatures is critical for optimizing the technology.
The design of microwave applicators—a goal of the Transzerowaste project—relies on detailed knowledge of the dielectric properties of raw materials and construction materials within the reactors. These properties determine how materials interact with the electromagnetic field and their ability to absorb microwave energy, making them vital for reactor and process design.
Toward a Circular Economy
This study highlights the transformative potential of microwave technology in advancing sustainable recycling solutions for the steel industry. By enhancing the processing of low-quality scrap and improving resource efficiency, the research contributes to the broader goal of achieving a climate-neutral, circular economy.
