Fate of transition metals during passive carbonation of ultramafic mine tailings via air capture with potential for metal resource recovery

Abstract

This is a repository copy of Fate of transition metals during passive carbonation of ultramafic mine tailings via air capture with potential for metal resource recovery.

Solubility of the hydrated Mg-carbonates nesquehonite and dypingite from 5 to 35 °C: Implications for CO2 storage and the relative stability of Mg-carbonates

“…Dypingite and nesquehonite are common weathering products of ultramafic rocks (Wilson et al, 2006(Wilson et al, , 2014Power et al, 2007;Beinlich and Austrheim, 2012;Garcia del Real et al, 2016;Lin et al, 2017), and are documented CO 2 sinks that can be used to store CO 2 (Power et al, 2007(Power et al, , 2013a(Power et al, , b, c, 2016Pronost et al, 2011;Bea et al, 2012;499 Assima et al, 2012499 Assima et al, , 2014cHarrison et al, 2013aHarrison et al, , 2015Harrison et al, , 2016Harrison et al, , 2017Wilson et al, 2014;McCutcheon et al, 2014;Morgan et al, 2015;Hamilton et al, 2016Hamilton et al, , 2018Gras et al, 2017). 501…”

“…Ultramafic rock such as serpentinite contributes disproportionately to the release of chromium globally during natural weathering processes compared to other rock-types, owing to its high reactivity and high chromium content (McClain and Maher, 2016;Beinlich et al, 2018). It has recently been observed that secondary Mg-carbonate minerals formed during the weathering of ultramafic rock can help to mitigate the release of metals such as chromium, due both to incorporation of the metals into the carbonate minerals, and trapping of particulates within carbonate cement (Hamilton et al, 2016;Hamilton et al, 2018). The relative stability and mechanism of phase transformations is highly relevant to the cycling of potential contaminants like chromium in both natural and engineered ultramafic weathering environments.…”

Insights on Structure and Threshold Detection Limits of Stichtite (Magnesium-Chromium Carbonate-Hydroxide) by Fourier Transform Infrared Analysis

“…It has been puzzling for early researchers why stichtite occurs in only a few chromite-rich serpentinites, if it is indeed only a surface weathering product. It is now reported that stichtite and other hydrotalcite minerals will form as a surface weathering product when ultramafic mine tailing pore water has pH 8.4 to 9.1 [38] and 8.8 to 9.4 [43]. It is also known that stichtite can form in active deep-sea submarine serpentinizing systems with pH 9 to 12.5 conditions [10,11,44,45].…”

“…While it is possible that these compositional trends may reflect the abundance of reactants within the serpentinizing system, it is also possible that this compositional variation is a record of serpentinizing fluid pH. In host material with high porosity and permeability, such as ultramafic mine tailings, it has been demonstrated that stichtite can form as a weathering product, and exchange ions with the pore waters [42,43]. Future workers should explore the possibility of mapping spatially this potential fossil pH record for specific deposits, and examine the ion exchange capacity of this mineral, and specifically which sites may be prone to exchange, and which may bind ions more tightly.…”

Opportunities for Mineral Carbonation in Australia’s Mining Industry

“…Other research groups at the University of Queensland and Monash University, Australia have been working on different aspects of mineral carbonation, field studies and the use of waste materials [103][104][105][106][107][108][109][110]. Recent research investigated ultramafic mine tailings as feedstock because they contain abundant Mg-rich silicate and hydroxide minerals and have a smaller grain size and increased reactive surface area due to ore processing [106,107]. Table 2 presents a summary of research on mineral carbonation in Australia.…”