Decarbonization of mineral processing operations: Realizing the potential of carbon capture and utilization in the processing of ultramafic nickel ores

Abstract

Mining and mineral processing operations are responsible for 4 to 7 percent of greenhouse-gas emissions globally and are under a huge pressure to reduce their emissions. Decarbonization through CO2 capture and utilization is a lucrative option only when the captured CO2 can be utilized to bring down the costs such as in oil recovery from reservoirs where the injected CO2 increases the recovery. Unfortunately, in mining operations, the captured CO2 doesn’t have any utilization so far which is a primary reason of mining industry’s sluggish response for decarbonization commitments. Herein, we provide a first proof of CO2 capture and utilization in nickel mineral processing industry by using CO2 as a conditioning agent prior to froth flotation resulting in the conversion of monohydroxide complexes to carbonates which increases electrostatic repulsion between the valuable mineral and the gangue leading to enhanced froth flotation recovery. The inclusion of CO2 to the froth flotation improved the nickel recovery and grade by an extra 10% and 4%, respectively while permanently storing the CO2 at the same time. The study provides a strong motivation for decarbonatization in the industry through CO2 utilization.