果冻传媒

Iron powder is a promising candidate for seasonal energy storage and long-distance transport due to its high energy density, abundance, safety, and compactness.

Energy is released through the combustion process of (micron-sized) iron powder, while produced iron oxides can be collected and reduced back to iron using clean energy, termed the 鈥渋ron fuel cycle鈥�. For his PhD research, Akmal Irfan Majid looked at the potential of electrolysis for iron powder production.

Experiments

First, Majid conducted experiments to compare the electroreduction of iron oxide suspensions in acidic and alkaline environments.

The alkaline system proved to be more attractive, showing higher electrolysis performance, such as current efficiency, lower energy consumption, easier cleaning, and high-purity iron.

In contrast, acidic conditions face challenges like more hydrogen production and difficulty in rinsing due to strong particle adhesion.

Alkaline conditions

After this, Majid looked at the influence of alkaline conditions using a laboratory-scale cell with parallel plate electrodes in a hematite-alkaline slurry.

The focus was on optimizing parameters that promote dendritic iron deposits, a rough and needle-like depost structure, which are easier to harvest in powder form for direct use in combustion process.

Effects of operating parameters (i.e., current density, hematite mass fraction, powder size, temperature, and alkaline concentration) on current efficiency and deposit morphology were investigated. Results showed different microstructures, including compact layers and various dendrites, with optimal conditions achieving high curent efficiency (鈮� 90%). This research provided insights with regards to controlling dendritic iron powder production and optimizing the powder-to-powder iron electrolysis process for the iron fuel cycle.

Continuous production

Majid also introduced a novel integrated process for continuous electrolytic iron powder production, featuring a fully automated lab-scale prototype with rotating disc electrodes.

Performance tests under varying conditions revealed that dendritic deposits along the disc鈥檚 edge, form at both static conditions and low rotating speeds.

These results demonstrate the potential of the current design for further optimization of continuous iron powder production.

Finally, combustion behavior of electrochemically regenerated iron particles confirmed their combustibility in both single-particle and continuous processes.

The unique features of electrolytic iron powder (non-spherical, rough surfaces, and high surface-to-volume ratio). Additionally, electroreduction of combusted iron powder demonstrated the potential to effectively close the loop in the iron fuel cycle.

Title of PhD thesis: . Supervisors: Niels Deen, Yali Tang, and Giulia Finotello.