Mining colossus Rio Tinto and aluminium and renewables company Hydro have announced that they will partner to identify suitable carbon capture technologies for the aluminium electrolysis process.

Their partnership agreement provides for the sharing of certain information, results and costs covering specific R&D activities from lab tests with external suppliers to larger, on-site pilots. Together, they expect to invest approximately $45 million over five years, with most of the work conducted at Rio Tinto’s facilities in Europe and Hydro’s facilities in Norway. Beyond this collaboration, both companies will continue to pursue substantial decarbonisation efforts independently.

Anode consumption during the electrolysis process accounts for approximately three-quarters of a smelter’s direct CO₂ emissions. For several years, scientists from Rio Tinto and Hydro have been exploring different carbon capture technologies as complementary solutions to help each company meet their climate targets. This is in addition to the development and scaling up of carbon-free aluminium smelting technologies such as Hydro’s HalZero technology and Rio Tinto’s participation in the ELYSIS joint venture.

Capturing carbon from aluminium smelter flue gas, with CO₂ concentrations around 1% (vol.), requires adapting direct air capture technologies for higher concentrations or point source technologies for lower concentrations. In both cases, the current technology readiness level is low and requires significant development efforts to mature from laboratory to commercial scale. The collaboration between Rio Tinto and Hydro aims to speed up this development process to abate greenhouse gas emissions from smelters.