Abstract
Substituting natural gas with hydrogen in the copper industry is proposed for decarbonization but may risk copper product quality. In addition, care should be taken in choosing the combustion atmosphere to maintain SiC refractory linings, both aspects being relevant to copper cathode melting furnaces. Thermodynamic calculations were performed for combustion atmospheres of hydrogen and natural gas fuel mixtures (up to 100% H₂) and combustion indexes (λ < 1) at 1120°C and oxygen-free electronic copper (Cu-OFE). These were followed by laboratory-scale tests for Cu-OFE samples under gas-lance top-blown crucible furnace conditions. Copper samples from crucible tests were water-quenched to trap dissolved hydrogen. Copper-refractory interactions were studied with sessile drop tests. Simulations suggest that hydrogen dissolution in copper increases with fuel hydrogen content and temperature, for a constant air ratio λ. Visible porosity was demonstrated by copper samples exposed to hydrogen-rich atmospheres. Furthermore, pure SiC presented potential reaction with Cu-OFE under vacuum, whereas composite SiC refractories did not.