Mineral carbonation for serpentine mitigation in nickel processing: a step towards industrial carbon capture and storage

Abstract

TBC

Fizzy ore processing sequesters CO 2 while supplying critical metals

“…A previous study by Khan et al. ( 16 ) explored the use of ex situ carbon mineralization to convert serpentine minerals into magnesite during ore processing. The authors’ motivation was to prevent formation of slimy coatings (the technical term is, in fact, “sliming”) of serpentine on nickel sulfide grains because this adversely affects nickel recovery and decreases concentrate grade during froth flotation.…”

“…A preliminary technoeconomic analysis done by Khan et al. ( 16 ) suggests that building ex situ carbonation reactors of the sort used by Wang and Dreisinger ( 7 ) into ore processing circuits can reduce the cost of froth flotation as well as pumping and dewatering of process slurries. Wang and Dreisinger’s ( 7 ) work in PNAS is compatible with the froth flotation methods that are currently used for recovery of nickel- and cobalt-bearing sulfide minerals, which means it could be integrated into ore processing plants at new mines and potentially used to retrofit plants at existing mines.…”

Cellulose Nanocrystals’ Role in Critical Mineral Beneficiation: Dual Aggregate-Dispersant Behavior Supports Environmentally Benign Nickel Processing

“…Acid attack disintegrates serpentine during grinding before collectorless flotation. , CO 2 conditioning prior to air-based froth flotation converts monohydroxide complexes to carbonates that increase electrostatic repulsion between serpentine and pentlandite and improve nickel recovery and grade . The most commonly used technique to mitigate slime coating is to introduce dispersants into the flotation pulp to alter steric and electrostatic interactions and thus colloidal interactions between particles. ,,, Valuable minerals can be effectively separated from gangue using selective dispersants. Krivoshapkina et al.…”

“…However, high-grade Ni-sulfide ores are depleted, and Ni-bearing laterite ore processing is challenging and expensive. , Abundant, low-grade ultramafic sulfide ores represent a significant alternative Ni resource. For example, the Pipe deposit in Manitoba, Canada, is estimated to contain >3 million tonnes Ni worth more than US$84 billion (US$28,062/tonne in May 2022) .…”

“…At the froth flotation pH of 10, positively charged, hydrophilic serpentine coats negatively charged, hydrophobic pentlandite, which prevents bubble-particle attachment: the bubbles preferentially collide with hydrophilic surfaces, leading to low Ni recovery also known as serpentine slime coating on pentlandite . Serpentine also negatively affects unit operations in mineral processing by increasing the pulp viscosity and yield stress, lowering comminution grinding efficiency and mixing efficiency, causing high turbulence damping, cavern formation, and bubble coalescence and leading to the high recovery of unwanted mineral (gangue) during froth flotation . High yield stress also leads to higher energy requirements for pumping operations for mineral slurries.…”