Characteristic Studies of Critical Rare
Earths Scandium and Yttrium
from Circulating Fluidized Bed Coal Fly
Ashes
Quang Tuan Lai, Thenepalli Thriveni, and Ji Whan Ahn
Abstract Globally, coal is the largest primary source of electricity. As per the global
demand for coal production, coal ash has also subsequently increased. The coal by
products such as fly ash and bottom ashes are the main sources for rare earth and
other metals. The tremendous benefits of recycling these ashes have wide energy
applications. In this paper, we reported characteristic studies of critical rare earth
such as scandium and yttrium from the circulating fluidized bed combustion fly
ashes. The preliminary study investigated the performance of three reagents, HCl,
H 2 SO 4 , and HNO 3 on rare earth leaching from a Korean circulating fluidized bed
combustion fly ash. Hydrochloric acid was selected as the proper reagent used for
subsequent experiments. The variables including reagent concentration, leaching
time, and temperature in the range of 1.5–4 mol/L, 5–120 min, and 25–80 °C were
optimized. The leaching efficiency of scandium and yttrium were at 48 and 45%
under the optimized conditions.
Keywords Characteristics · Critical rare earths · Circulating fluidized bed
combustion · Fly ash · Leaching
Q. T. Lai
Department of Resources Recycling, University of Science & Technology, 217 Gajeong-ro,
Yuseong-gu, Daejeon 34113, Republic of Korea
Tectonic and Geomorphology Department, Vietnam Institute of Geosciences and Mineral
Resources (VIGMR), 67 Chienthang Street, Hadong District, Hanoi 151170, Vietnam
Q. T. Lai · J. W. Ahn (B)
Mineral Resources Division, Center for Carbon Mineralization, Korea Institute of Geosciences and
Mineral Resources (KIGAM), 124 Gwahak-ro, Yuseong-gu, Daejeon 34132, Republic of Korea
e-mail: ahnjw@kigam.re.kr
T. Thriveni
Department of Chemistry, Sri Venkateswara University, Tirupati, Chittoor (Dt) 517502, Andhra
Pradesh, India
© The Minerals, Metals & Materials Society 2021
A. A. Baba et al. (eds.), Energy Technology 2021, The Minerals, Metals
& Materials Series, https://doi.org/10.1007/978-3-030-65257-9_2
13
Earths Scandium and Yttrium
from Circulating Fluidized Bed Coal Fly
Ashes
Quang Tuan Lai, Thenepalli Thriveni, and Ji Whan Ahn
Abstract Globally, coal is the largest primary source of electricity. As per the global
demand for coal production, coal ash has also subsequently increased. The coal by
products such as fly ash and bottom ashes are the main sources for rare earth and
other metals. The tremendous benefits of recycling these ashes have wide energy
applications. In this paper, we reported characteristic studies of critical rare earth
such as scandium and yttrium from the circulating fluidized bed combustion fly
ashes. The preliminary study investigated the performance of three reagents, HCl,
H 2 SO 4 , and HNO 3 on rare earth leaching from a Korean circulating fluidized bed
combustion fly ash. Hydrochloric acid was selected as the proper reagent used for
subsequent experiments. The variables including reagent concentration, leaching
time, and temperature in the range of 1.5–4 mol/L, 5–120 min, and 25–80 °C were
optimized. The leaching efficiency of scandium and yttrium were at 48 and 45%
under the optimized conditions.
Keywords Characteristics · Critical rare earths · Circulating fluidized bed
combustion · Fly ash · Leaching
Q. T. Lai
Department of Resources Recycling, University of Science & Technology, 217 Gajeong-ro,
Yuseong-gu, Daejeon 34113, Republic of Korea
Tectonic and Geomorphology Department, Vietnam Institute of Geosciences and Mineral
Resources (VIGMR), 67 Chienthang Street, Hadong District, Hanoi 151170, Vietnam
Q. T. Lai · J. W. Ahn (B)
Mineral Resources Division, Center for Carbon Mineralization, Korea Institute of Geosciences and
Mineral Resources (KIGAM), 124 Gwahak-ro, Yuseong-gu, Daejeon 34132, Republic of Korea
e-mail: ahnjw@kigam.re.kr
T. Thriveni
Department of Chemistry, Sri Venkateswara University, Tirupati, Chittoor (Dt) 517502, Andhra
Pradesh, India
© The Minerals, Metals & Materials Society 2021
A. A. Baba et al. (eds.), Energy Technology 2021, The Minerals, Metals
& Materials Series, https://doi.org/10.1007/978-3-030-65257-9_2
13