A combination process of mineral carbonation with SO2 disposal for simulated flue gas by magnesia-added seawater

Mineral carbonation is known to be among the most efficient ways to reduce the anthropogenic emissions of carbon dioxide. Serpentine minerals (Mg3Si2O5(OH)4), have shown great potential for carbonation. A way to improve yield is to thermally activate serpentine minerals prior to the carbonation reaction. This step is of great importance as it controls Mg2+ leaching, one of the carbonation reaction limiting factors. Previous studies have focused on the optimization of the thermal activation by determining the ideal activation temperature. However, to date, none of these studies have considered the impacts of the thermal activation on the efficiency of the aqueous-phase mineral carbonation at ambient temperature and moderate pressure in flue gas conditions. Several residence times and temperatures of activation have been tested to evaluate their impact on serpentine dissolution in conditions similar to mineral carbonation. The mineralogical composition of the treated solids has been studied using X-ray diffraction coupled with a quantification using the Rietveld refinement method. A novel approach in order to quantify the meta-serpentine formed during dehydroxylation is introduced. The most suitable mineral assemblage for carbonation is found to be a mixture of the different amorphous phases identified. This study highlights the importance of the mineralogical assemblage obtained during the dehydroxylation process and its impact on the magnesium availability during dissolution in the carbonation reaction.

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Feasibility of a Mineral Carbonation Technique Using Iron-Silicate Mining Waste by Direct Flue Gas CO2 Capture and Cation Complexation Using 2,2′-Bipyridine

Minerals ◽

10.3390/min11040343 ◽

2021 ◽

Vol 11 (4) ◽

pp. 343

Author(s):

Javier F. Reynes ◽

Guy Mercier ◽

Jean-François Blais ◽

Louis-César Pasquier

Keyword(s):

Flue Gas ◽

Energy Demand ◽

High Energy ◽

Mining Waste ◽

Mineral Carbonation ◽

Co2 Uptake ◽

Co2 Removal ◽

Main Challenge ◽

Positive Balance ◽

Iron Complexation

Mineral carbonation is gaining increasing attention for its ability to sequester CO2. The main challenge is doing it economically and energy-efficiently. Recently, many studies have focused on the aqueous reaction of carbon dioxide with the alkaline earth minerals such as serpentine, Mg-rich olivine and wollastonite. Nevertheless, Fe-rich olivines have been poorly studied because of their high energy demand, which make them unfeasible for industrial implementation. This article describes the feasibility of an indirect mineral carbonation process using silicic, Fe-rich mining waste with direct flue gas CO2 via iron complexation using 2,2′-bipyridine. The overall process was performed in three main steps: leaching, iron complexation, and aqueous mineral carbonation reactions. The preferential parameters resulted in a recirculation scenario, where 38% of Fe cations were leached, complexed, and reacted under mild conditions. CO2 uptake of 57.3% was achieved, obtaining a Fe-rich carbonate. These results are promising for the application of mineral carbonation to reduce CO2 emissions. Furthermore, the greenhouse gas balance had a global vision of the overall reaction’s feasibility. The results showed a positive balance in CO2 removal, with an estimated 130 kg CO2/ton of residue. Although an exhaustive study should be done, the new and innovative mineral carbonation CO2 sequestration approach in this study is promising.

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Glycine-Induced Synthesis of Vaterite via Direct Aqueous Mineral Carbonation of Flue Gas Desulfurization Gypsum

10.21203/rs.3.rs-1050584/v1 ◽

2021 ◽

Author(s):

Xuemin Liu ◽

Zhihe Pan ◽

Huaigang Cheng ◽

Zhien Zhang ◽

Fangqin Cheng ◽

...

Keyword(s):

Growth Mechanism ◽

Greenhouse Effect ◽

Flue Gas ◽

Economic Benefit ◽

Flue Gas Desulfurization ◽

Mineral Carbonation ◽

Glycine Concentration

Abstract Mineral carbonation of flue gas desulfurization gypsum (FGDG) can not only sequester CO2 to mitigate the greenhouse effect, but also produce CaCO3 to generate economic benefit. A mixture of calcite and vaterite CaCO3 was produced by FGDG carbonation in our previous study. Nevertheless, the production of uniform crystalline CaCO3, especially for vaterite, still maintains a big challenge via carbonation of FGDG. Herein, nearly pure vaterite was synthesized via FGDG carbonation in the presence of glycine was reported firstly. The results show that the content of vaterite increased from 60% to 97% with increasing glycine concentration and then kept a constant value, indicating that glycine can promote the formation of vaterite and inhibit the growth of calcite. Additionally, the investigation of vaterite growth mechanism in the presence of glycine demonstrated that the formation of intermediate, glycinate calcium, played an important role to stimulate the growth of vaterite. This study provides a new insight to produce a high-valued vaterite CaCO3 during the direct mineral carbonation of FGDG.

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