Work

Aqueous Mineral Carbonation of Red Mud for CO2 Permanent Sequester

Year: 2025
Type: article
Abstract: Red mud is a solid waste (slurry) produced during the extraction of alumina, containing minerals such as cancrinite, sodalite, tricalcium aluminate (TCA), and katoite. Due to the use of NaOH in alumina extraction, red mud has a high alkalinity (pH 12–13). Currently, the storage and management of red mud are suboptimal, as it is directly disposed of in landfills without treatment, leading to soil and water contamination and posing environmental risks. Indonesia produces a significant volume of red mud, amounting to 4.4 million tons per year, necessitating effective treatment methods to reduce its danger. One of the solution is mineral carbonation, which neutralizes red mud and serves as permanent CO2 sequestration by injecting CO2 into the red mud slurry. This process dissolves the minerals in red mud into the liquid phase, where they react with CO2 to form mineral carbonates, especially calcium carbonate. The carbonation product of red mud can subsequently be used in cement, brick, tile, and fertilizer production.The red mud used in this research was sourced from Tayan mining in West Kalimantan, Indonesia. Initial characterization of the red mud using XRD and XRF revealed a CaO content 2.936%. The sequestration capacity of red mud, with various liquid/solid (L/S) ratios (1:1–5:1) at ambience temperature of 30°C, was analyzed using TIC (total inorganic carbon) over an observation period of 80 minutes. The optimal L/S ratio was determined to be 1:1, with a conversion rate of 23.886%, while the best CO2 capture capacity is also at a 1:1 ratio with a capacity of 0.551 kg CO2/kg red mud, with neutralization occurring at the 15-minutes. This method neutralizes red mud and provides sustainable CO2 sequestration
Language: English
Open Access status: diamond
OpenAlex ID: W7220075492
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