title: Bauxite residue neutralization with simultaneous mineral carbonation using atmospheric CO2.
abstract: Simultaneous carbon mineralization during neutralization of bauxite residue, a caustic alkaline by-product of alumina refining, was tested using laboratory batch and a field pilot study in contact with atmospheric CO2. Since CO2sequestration is limited by the Ca concentration in the bauxite residue, extra Ca sources were added in a semi-soluble mineral and salt form (flue gas desulfurization gypsum or CaCl2) to verify whether this Ca addition accelerated and enlarged the CO2sequestration obtained as a consequence of neutralization. The results of 55 days of batch and longer-term field tests were in good agreement, and the neutralization rate was accelerated through the addition of both Ca sources. Without the addition of the extra Ca source, atmospheric CO2contributed to neutralization of pore water alkalinity alone, while Ca addition induced further neutralization through mineral carbonation of atmospheric CO2to CaCO3. This simple addition of environmentally benign Ca to bauxite residue may provide a feasible bauxite residue management practice that is cost-effective and easy to apply in the field.
authors.affiliation: Korea Institutes of Geoscience and Mineral Resources, Gwahang-no 124, Yuseong-gu, Daejeon, Republic of Korea. Electronic address: yshan@kigam.re.kr.
authors.forename: Young-Soo
authors.initials: YS
authors.lastname: Han
authors.affiliation: Korea Institutes of Geoscience and Mineral Resources, Gwahang-no 124, Yuseong-gu, Daejeon, Republic of Korea. Electronic address: swji@kigam.re.kr.
authors.forename: Sangwoo
authors.initials: S
authors.lastname: Ji
authors.affiliation: Korea Institutes of Geoscience and Mineral Resources, Gwahang-no 124, Yuseong-gu, Daejeon, Republic of Korea. Electronic address: pklee@kigam.re.kr.
authors.forename: Pyeong-Koo
authors.initials: PK
authors.lastname: Lee
authors.affiliation: Korea Institutes of Geoscience and Mineral Resources, Gwahang-no 124, Yuseong-gu, Daejeon, Republic of Korea. Electronic address: ocd11333@kigam.re.kr.
authors.forename: Chamteut
authors.initials: C
authors.lastname: Oh
keywords: Bauxite residue; Carbon sequestration; Mineral carbonation; Neutralization