Atmospheric Carbon Mineralization in an Industrial-Scale Chrysotile Mining Waste Pile

Abstract

Magnesium-rich minerals that are abundant in ultramafic mining waste have the potential to be used as a safe and permanent sequestration solution for carbon dioxide (CO). Our understanding of thermo-hydro-chemical regimes that govern this reaction at an industrial scale, however, has remained an important challenge to its widespread implementation. Through a year-long monitoring experiment performed at a 110 Mt chrysotile waste pile, we have documented the existence of two distinct thermo-hydro-chemical regimes that control the ingress of CO and the subsequent mineral carbonation of the waste. The experimental results are supported by a coupled free-air/porous media numerical flow and transport model that provides insights into optimization strategies to increase the efficiency of mineral sequestration at an industrial scale. Although functioning passively under less-than-optimal conditions compared to laboratory-scale experiments, the 110 Mt Thetford Mines pile is nevertheless estimated to be sequestering up to 100 tonnes of CO per year, with a potential total carbon capture capacity under optimal conditions of 3 Mt. Annually, more than 100 Mt of ultramafic mine waste suitable for mineral carbonation is generated by the global mining industry. Our results show that this waste material could become a safe and permanent carbon sink for diffuse sources of CO.

Converting Chrysotile Nanotubes into Magnesium Oxide and Hydroxide Using Lanthanum Oxycarbonate Hybridization and Alkaline Treatment for Efficient Phosphate Adsorption

“…High-efficiency removal of phosphate is urgently needed in wastewater. , Chrysotile clay is a magnesium-rich silicate which has been used as a safe, low cost, and permanent sequestration solution for CO 2 capture from the atmosphere on an industrial scale . Unlike other synthetic nanostructures which are exorbitantly expensive, such as carbon nanotubes (US$500 000 per kg), natural ChNT clay costs substantially less, at US$0.27 per kg, and its global supply exceeds 2 × 10 6 tons per year .…”

Controls on CO2 Mineralization Using Natural and Industrial Alkaline Solids under Ambient Conditions

“…Our results are applicable for passive CO 2 mineralization strategies. In such applications, an unlimited source of CO 2 (i.e., atmosphere) is present and the rate and extent of CO 2 mineralization is limited simply by the reactivity of the solid reactants (and the availability of sufficient moisture). − The objective of using pure CO 2 in our experiments is not to highlight a specific application but rather to ensure sufficient dissolved carbon such that mineral dissolution is rate-limiting. Thus, our conditions are selected to accelerate passive carbonation by supplying sufficient amounts of reactants while maintaining ambient temperature and pressure to not alter the mechanisms of CO 2 mineralization reactions.…”

Recovery of Magnesium from Industrial Effluent and Its Implication on Carbon Capture and Storage

“…2− ] to 2.0 resulted in lower TR and CR as the excess of Mg 2+ ions would The excess of Mg 2+ ions would promote discrete precipitation, leading to the formation of fines and thus lowering granulation efficiency. 41 Yet, it should be noticed that there was a need for discrete precipitates (at the reactor's bottom) for starting homogeneous nucleation. However, as these precipitates could help form fine particles in the reactor, they should be monitored throughout the experiment in order to prevent the formation of fine particles.…”

“…The excess of Mg 2+ ions would promote discrete precipitation, leading to the formation of fines and thus lowering granulation efficiency . Yet, it should be noticed that there was a need for discrete precipitates (at the reactor’s bottom) for starting homogeneous nucleation.…”