TY - JOUR
T1 - Hydrotalcite and hydrocalumite as resources from waste materials of concrete aggregate and Al-dross by microwave-hydrothermal process
AU - Abd-El-Raoof, F.
AU - Tawfik, A.
AU - Komarneni, S.
AU - Ahmed, S. E.
N1 - Funding Information:
The authors acknowledge the United States Agency of International Developments ( USAID ) for funding a part of this research.
Publisher Copyright:
© 2019 Elsevier Ltd
PY - 2019/5/20
Y1 - 2019/5/20
N2 - Hydrotalcite (HT) and hydrocalumite (HC) were synthesized from active MgO, CaO and Al 2 O 3 in the presence of K 2 CO 3 using microwave-hydrothermal (M−H) process at 100 °C/1 h. The above active oxides were prepared via HCl leaching of dolomite (fine waste of concrete aggregate) and Al-dross waste, precipitated as hydroxides and then activated by calcination. The prepared materials were characterized via XRD, FTIR and TEM. Results showed that chemical recycling of Al-dross and dolomite wastes produced aluminum, magnesium and calcium hydroxides from which their active oxides produced at 600, 900 and 1000 °C, respectively. The M−H treatment of MgO/Al 2 O 3 (4:1) slurry of the active oxides for 1 h at 100 °C resulted in Mg 2 Al(OH) 7 in amorphous plate-like shape while the CaO/Al 2 O 3 (4:1) slurry under the same conditions provided semi-crystalline multi-phases. These phases were identified through X-ray diffraction (XRD) analysis as Katoite [Ca 3 Al 2 (OH) 12 ] and calcium aluminum hydroxides [Ca 2 Al(OH) 7 ·3H 2 O]. In the presence of K 2 CO 3 , MgO/Al 2 O 3 and CaO/Al 2 O 3 slurries produced nano-sized crystalline hydrotalcite or hydrocalumite as deduced from XRD, FTIR and TEM results.
AB - Hydrotalcite (HT) and hydrocalumite (HC) were synthesized from active MgO, CaO and Al 2 O 3 in the presence of K 2 CO 3 using microwave-hydrothermal (M−H) process at 100 °C/1 h. The above active oxides were prepared via HCl leaching of dolomite (fine waste of concrete aggregate) and Al-dross waste, precipitated as hydroxides and then activated by calcination. The prepared materials were characterized via XRD, FTIR and TEM. Results showed that chemical recycling of Al-dross and dolomite wastes produced aluminum, magnesium and calcium hydroxides from which their active oxides produced at 600, 900 and 1000 °C, respectively. The M−H treatment of MgO/Al 2 O 3 (4:1) slurry of the active oxides for 1 h at 100 °C resulted in Mg 2 Al(OH) 7 in amorphous plate-like shape while the CaO/Al 2 O 3 (4:1) slurry under the same conditions provided semi-crystalline multi-phases. These phases were identified through X-ray diffraction (XRD) analysis as Katoite [Ca 3 Al 2 (OH) 12 ] and calcium aluminum hydroxides [Ca 2 Al(OH) 7 ·3H 2 O]. In the presence of K 2 CO 3 , MgO/Al 2 O 3 and CaO/Al 2 O 3 slurries produced nano-sized crystalline hydrotalcite or hydrocalumite as deduced from XRD, FTIR and TEM results.
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U2 - 10.1016/j.conbuildmat.2019.02.105
DO - 10.1016/j.conbuildmat.2019.02.105
M3 - Article
AN - SCOPUS:85061800044
SN - 0950-0618
VL - 207
SP - 10
EP - 16
JO - Construction and Building Materials
JF - Construction and Building Materials
ER -