An iron ore-based catalyst for producing hydrogen and metallurgical carbon via catalytic methane pyrolysis for decarbonisation of the steel industry

13 pags., 11 figs., 1 tab.Experiments to investigate the catalytic pyrolysis of methane using an iron ore-based catalyst were carried out to optimize catalytic activity and examine the purity of the carbon produced from the process for the first time. Ball milling of the iron ore at 300 rpm for varying times – from 30 to 330 min – was studied to determine the effect of milling time on methane conversion. Optimal milling for 270 min led to a five-fold increase in methane conversion from ca. 1%–5%. Further grinding resulted in a decline of methane conversion to 4% shown by SEM to correspond to an increase in particle size caused by agglomeration. Data from Raman and Mössbauer spectroscopy and H2 temperature programmed reduction indicated a change in phase from magnetite to maghemite and hematite (at the particle surface) as the grinding time increased. Analysis of the carbon produced as a byproduct of the reaction indicated a highly pure material with the potential to be used as an additive for steel production.Funding to support this work was provided by UK Research and Innovation (UKRI) grant EP/S023909/1 and the Offshore Renewable Energy (ORE) Catapult. The authors acknowledge use of the facilities and the assistance of Sam Davis in the Loughborough Materials Characterisation Centre. The authors also thank British Steel Ltd for provision of the iron ore used in this study. Financial support from grants RTI2018-095303-BC51 (funded by MCIN/AEI/10.13039/501100011033 and “ERDF A way of making Europe”) and S2018-NMT-4321 (funded by the Comunidad de Madrid and “ERDF A way of making Europe”) is gratefully acknowledged.Peer reviewe