TY - JOUR
T1 - Fixed bed column studies for decontamination of acidic mineral effluent using porous fly ash-basic oxygen furnace slag based geopolymers
AU - Sithole, N. T.
AU - Ntuli, F.
AU - Okonta, F.
N1 - Funding Information:
The authors would also like to thank ArcelorMittal (South Africa) for providing the BOFS, Eskom (South Africa) for providing the fly ash and the National Research Foundation (South Africa) for providing financial assistance to conduct this work.
Publisher Copyright:
© 2020 Elsevier Ltd
Copyright:
Copyright 2020 Elsevier B.V., All rights reserved.
PY - 2020/8/1
Y1 - 2020/8/1
N2 - This paper presents column studies conducted to evaluate and assess the potential use of Fly Ash (FA). Basic Oxygen Furnace Slag (BOFS) based geopolymers to remove metals, sulphates and acidity from Acid Mine Drainage (AMD). Geopolymers were prepared using NaOH, Fly ash (FA) was used as source of silica additive to supplement BOFS. The blending ratio was fixed to 10% FA and the S/L ratio was kept 20%. The H2O2 was used as a blowing agent to increase the porosity of the FA/BOFS based geopolymer at four different percentages (1.5%, 1%, 0.5% and 0%). The four different geopolymers with distinct porosities were employed in different columns respectively. It was found that over 99% removal efficiency of metals and sulphates was achieved in the first 60 days of column studies. The dissolution of Ca(OH)2 was the main constituent responsible for the removal of acidity in AMD. Characterization revealed that precipitation was the main mechanism for removal of metals. Gypsum was the main byproduct formed with precipitated metals presented by goethite, spertite and manganite.
AB - This paper presents column studies conducted to evaluate and assess the potential use of Fly Ash (FA). Basic Oxygen Furnace Slag (BOFS) based geopolymers to remove metals, sulphates and acidity from Acid Mine Drainage (AMD). Geopolymers were prepared using NaOH, Fly ash (FA) was used as source of silica additive to supplement BOFS. The blending ratio was fixed to 10% FA and the S/L ratio was kept 20%. The H2O2 was used as a blowing agent to increase the porosity of the FA/BOFS based geopolymer at four different percentages (1.5%, 1%, 0.5% and 0%). The four different geopolymers with distinct porosities were employed in different columns respectively. It was found that over 99% removal efficiency of metals and sulphates was achieved in the first 60 days of column studies. The dissolution of Ca(OH)2 was the main constituent responsible for the removal of acidity in AMD. Characterization revealed that precipitation was the main mechanism for removal of metals. Gypsum was the main byproduct formed with precipitated metals presented by goethite, spertite and manganite.
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U2 - 10.1016/j.mineng.2020.106397
DO - 10.1016/j.mineng.2020.106397
M3 - Article
AN - SCOPUS:85084261069
SN - 0892-6875
VL - 154
JO - Minerals Engineering
JF - Minerals Engineering
M1 - 106397
ER -