High-purity hydrogen gas from the reaction between BOF steel slag and water in the 473–673 K range

A novel method for producing hydrogen with water and BOF steel slag was developed. The steel slag was reacted with water during 2–57 days at 50 MPa for temperatures ranging from 473 to 673 K. The quantitative evolution of the slag and gas compositions indicated that the main H2 producing reaction is:  H2O → Fe3O4 + H2  K, approximately 5 NL of H2 per kg of slag were produced in 3 days. The reaction rate was only 1.5 times faster when the slag was crushed down to an initial particle size below 50 μm. The H2 production has been also tested on slags carbonated beforehand at 0.142 ± 0.002 kg of CO2 per kg of slag. The reaction was found to be thermally activated. A high purity hydrogen (99.995%) is produced with non-carbonated steel slag below 573 K whereas CH4 production was measured in all the other experiments.