CO2 and H2O gas conversion into CO and H2 using highly exothermic reactions induced by mixed industrial slags

•Conversion of CO2 and H2O into CO and H2 by synthetic slags is reported.•Synthetic slags represents a mixture of metallurgical and gasification slags.•Conversion is promoted by forming orthovanadate between CaO and V2O3.•Extra heat is produced by exothermic reaction.•Potential reduction of CO2 emissions is discussed.

This communication reports conversion phenomena in which CO2 and H2O gases are transformed into CO and H2, respectively, when exposed to a mixture of molten CaO-rich metallurgical slag and V2O3-rich gasifier slag. On reaction, CO2 and H2O are thermodynamically driven to become CO and H2, respectively, by giving up oxygen over the formation of calcium orthovanadate in the slag. The concept was experimentally investigated with a synthetic slag heated to 1500 °C (an assumed slag tap-out temperature in the metallurgical industry) in a CO2 saturated atmosphere. On heating, a rapid drop in oxygen partial pressure occurred between 1405 °C and 1460 °C, where 97% of CO2 transformed to CO. Potential industrial applications with the H2O-to-H2 conversion are then explored using detailed process computations. If the process is made economically viable, CO2 and H2O could be converted into products that are environmentally and industrially attractive and that have the potential for energy savings and greenhouse gas reduction in a process.