CO₂ Sequestration by Aqueous Red Mud Carbonation at Ambient Pressure and Temperature

Abstract

An analysis of carbonation was carried out with the aqueous fresh red mud suspension at a liquid-to-solid ratio of 10 kg/kg, as well as in the leached-hydrated matrixes and leachates isolated from this red mud suspension after three successive leachings, to evaluate their intrinsic carbonation potential at ambient conditions (temperature of 20 ± 1 °C and atmospheric pressure). The carbonation assays were performed at 20 °C using a CO2 concentration of 15.00 vol% at a flow rate of 5 mL/min. The red mud matrix has a great leaching capacity of Na−(hydr)oxide, which is the principal hydroxide that seems to be implicated in the carbonation of leachates that have half-carbonation capacity of red mud. Moreover, the carbonation of the red mud suspension also involves a portlandite-containing matrix. The carbonation of the red mud suspension and leachates implicates a complete neutralization of their content in Ca− and Na−(hydr)oxides. Although the leached hydrated-matrixes seem to be partially carbonated, it preserves a carbonation capacity near to that of leachate after three successive leachings. Moreover, three leached hydrated-matrixes and leachates have a carbonation capacity (7.09 g of CO2/100 g of red mud) higher than the carbonation capacity obtained for the red mud suspension, which is evaluated to 4.15 g of CO2/100 g of red mud. Taken together, these results suggest that the carbonation of the red mud may be enhanced by the use of leached hydrated-matrixes and leachates obtained from multiple leaching.

Sequestration of carbon dioxide (CO2) using red mud

“…Carbonation capacity (5.3 g of CO 2 /100 g) of RM II at l/s ratio 0.35 when compared to the results (4.15 g of CO 2 /100 g at l/s ratio 10.0) of other investigator [30], it was found that higher l/s ratio did not yield higher CO 2 capture efficiency. …”

Production of nanostructured magnetic composites based on Fe0 nuclei coated with carbon nanofibers and nanotubes from red mud waste and ethanol

“…1.0-1.5 t of RM which represents worldwide over 66 million ton. Red mud waste has been investigated for different applications such as production of ceramics [1], recovery of iron [2], production of composites with polymers [3], production of hydrogen [4], as catalyst [5], for the CO 2 sequestration [6] and to produce coagulants [7,8]. Krimpalis et al described the reduction of iron from RM to produce the magnetic phase maghemite ␥-Fe 2 O 3 [9].…”

Neutralization of red mud using CO2 sequestration cycle

“…Various methods have been used for neutralization of red mud by adding liquid carbon dioxide [12,14], saline brines or seawater [15], Ca and Mg-rich brines, soluble Ca and Mg salts, acidic water from mine tailing, fly ash, carbon dioxide gas [16,17]. The NRM is utilized for environmental benefits.…”