ACEME: Direct Aqueous Mineral Carbonation of Dunite Rock

Abstract

This research explores the use of serpentinized dunite (which is comprised of 61% lizardite) as a feedstock for aqueous mineral carbonation. In initial experiments, dunite was heat‐activated (630°C, 4 h), adopting a procedure which is similar to that used for serpentinite to enhance their carbonation reactivity. Heat‐activation converts crystalline lizardite mineral into an amorphous, reactive phase, and the carbonation of this heat‐activated material resulted in a magnesite yield of 55% compared to 27% obtained with raw dunite under the same reaction conditions. The formation of silanol nests occurred during carbonation of heat‐activated dunite as deduced through FTIR and TGA‐MS analyses. Samples of dunite were also heat‐transformed at high temperatures (800°C, 3 h) to convert lizardite into forsterite, and these samples were also studied as potential feedstocks for mineral carbonation. Heat‐activated dunite was found to engender much higher magnesite yields compared to heat‐transformed dunite (forsterite rich) and raw dunite. This study suggests that during heat‐activation of dunite, as it is for lizardite, conditions should be maintained to avoid forsterite formation. © 2018 American Institute of Chemical Engineers Environ Prog, 38:e13075, 2019

Magnesium Leachability of Mg-Silicate Peridotites: The Effect on Magnesite Yield of a Mineral Carbonation Process

“…A temperature of 650 • C is sufficient for lizardite to complete dehydroxylation [36]. In our previous publication, we established that heat-activated dunite provided higher magnesite yields compared to that of heat-transformed dunite (forsterite rich) and raw dunite [4]. The aim of this work was to confirm these magnesite yield results through a second approach, i.e., Mg extraction using acid dissolution experiments.…”

“…Warming of 2 • C would release billions of tons of soil carbon [2]. Geological storage, oceanic storage, and recently mineral carbonation, are among different candidates for CO 2 sequestration to prevent its emissions to the atmosphere [3,4]. Mineral carbonation, mainly using naturally abundant Mg-silicates, can offer safe storage of CO 2 in the form of mineral carbonates for many centuries [5,6].…”

“…Single stage [4,[6][7][8][9][10][11][12] and two-stage carbonation [13][14][15][16][17][18][19] are different processes that are being extensively studied for CO 2 capture, utilization, and storage. Initial studies on mineral carbonation showed relatively slow reaction kinetics [20].…”

“…Compared to other magnesium silicate minerals that have been studied for mineral carbonation, dunite is more complex as it is usually a mixture of minerals. One example that has previously been studied contains 61%-62% lizardite, 30%-33% olivine, 3.8%-8.3% brucite, and 0.6% magnetite [4]. Heat activation can be used to convert the lizardite present in dunite into more reactive amorphous Mg-silicate phases.…”

Opportunities for Mineral Carbonation in Australia’s Mining Industry

“…Their research and technical facilities are centred at the University of Newcastle, Australia. MCi's suite of projects includes fundamental theoretical and laboratory research [66,[95][96][97][98][99][100] as well as one of the world's first mineral carbonation pilot plant facilities [101,102]. MCi's project has primarily been studying the carbonation of serpentine, which as mentioned above is an abundant mineral in New South Wales (NSW), Australia and globally [102].…”