Effects of Activator Properties and Curing Conditions on Alkali-Activation of Low-Alumina Mine Tailings
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In: Waste and biomass valorization, Vol. 11.2020, No. September, 13.08.2019, p. 5027–5039.
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TY - JOUR
T1 - Effects of Activator Properties and Curing Conditions on Alkali-Activation of Low-Alumina Mine Tailings
AU - Falah, Mahroo
AU - Obenaus-Emler, Robert
AU - Kinnunen, Paivo
AU - Illikainen, Mirja
N1 - Publisher Copyright: © 2019, The Author(s).
PY - 2019/8/13
Y1 - 2019/8/13
N2 - The mining industry generates a notable amount of mine tailings (MTs). Disposal of MTs creates environmental impacts such as air pollution and the release of heavy metals into surface and underground water. The European Union (EU)-funded project “Integrated mineral technologies for more sustainable raw material supply” (ITERAMS) includes an effort to produce eco-friendly backfill materials to enhance operation and mine safety and covers for surface deposits of tailings based on geopolymerization technology. This paper investigates the effects of activator concentration, curing temperature and time on alkali-activated materials based on low-alumina MTs from the Cu/Ni mine in Northern Finland. Alkaline activators containing sodium silicate solution (Na2SiO3) at different concentrations were used and two different curing temperatures, 40 °C and 60 °C, for periods of 7, 14, and 28 days were considered. Scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM/EDS) and X-ray diffraction (XRD) were performed to investigate the structure, morphology and phase compositions of the alkali-activated products. The effect of curing temperature and alkaline solutions on mechanical strength and water absorption were investigated. The results indicate that the alkalinity and curing temperature affect the mechanical and microstructural properties of the compositions of alkali-activated MTs. The 30 wt% Na2SiO3 addition enables the alkali activated MT to improve the compressive strength with a highest value of 6.44 and 15.70 MPa after 28 days of curing at 40 °C and 60 °C, respectively. The results of this study deliver useful information for recycling and utilization of MTs as sustainable material through the alkali activation.
AB - The mining industry generates a notable amount of mine tailings (MTs). Disposal of MTs creates environmental impacts such as air pollution and the release of heavy metals into surface and underground water. The European Union (EU)-funded project “Integrated mineral technologies for more sustainable raw material supply” (ITERAMS) includes an effort to produce eco-friendly backfill materials to enhance operation and mine safety and covers for surface deposits of tailings based on geopolymerization technology. This paper investigates the effects of activator concentration, curing temperature and time on alkali-activated materials based on low-alumina MTs from the Cu/Ni mine in Northern Finland. Alkaline activators containing sodium silicate solution (Na2SiO3) at different concentrations were used and two different curing temperatures, 40 °C and 60 °C, for periods of 7, 14, and 28 days were considered. Scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM/EDS) and X-ray diffraction (XRD) were performed to investigate the structure, morphology and phase compositions of the alkali-activated products. The effect of curing temperature and alkaline solutions on mechanical strength and water absorption were investigated. The results indicate that the alkalinity and curing temperature affect the mechanical and microstructural properties of the compositions of alkali-activated MTs. The 30 wt% Na2SiO3 addition enables the alkali activated MT to improve the compressive strength with a highest value of 6.44 and 15.70 MPa after 28 days of curing at 40 °C and 60 °C, respectively. The results of this study deliver useful information for recycling and utilization of MTs as sustainable material through the alkali activation.
KW - Mine tailings
KW - Alkali-activation
KW - Curing condition
KW - Mechanical strength
KW - Microstructure
UR - http://www.scopus.com/inward/record.url?scp=85070967902&partnerID=8YFLogxK
U2 - 10.1007/s12649-019-00781-z
DO - 10.1007/s12649-019-00781-z
M3 - Article
VL - 11.2020
SP - 5027
EP - 5039
JO - Waste and biomass valorization
JF - Waste and biomass valorization
SN - 1877-2641
IS - September
ER -