Geology Reference
In-Depth Information
Table 8.2 Energy, water consumption and GHG emissions derived from the production of 1 kg of
REE (Koltun and Tharumarajah, 2008)
REE
Electr.,
Heat
Exergy
GHG
Water
MJ
energy,
MJ
cost, MJ
emissions,
kg CO
2
eq
consumption,
kl
Lanthanum
91.817.8
127.627.0
357.171.5
39.64.35
43.511.0
Cerium
154.729.8
199.541.5
586.2116
67.67.11
75.719.1
Praseodymium
91.917.9
128.227.3
358.072,1
40.54.33
43.411.0
Neodymium
173.133.3
218.945.2
651.6128,4 75.57.88
85.521.4
Gadolinium
996.4191.0 1166235.0
3657.0712.5 423.643.4
522.3131.7
Yttrium
331.563.6
424.486.8
1253.1245.8 144.915.0
180.745.9
Bouorakima (2011) also undertook a LCA of REO production in Bayan Obo,
and another Chinese mine with similar ores, Maoniuping in Sichuan province. These
two accounted for 48% and 24% respectively of the 2010 REO Chinese production,
which is almost exclusively dedicated to light REE. The investigation provides
data regarding the mining, comminution, beneficiation and hydrometallurgical pro-
cessing of REO at the Bayan Obo site of Baotou Steel Rare Earth Group Hi-Tech
Co
32
.
Due to a lack of publically available data, some processes were estimated. Bouo-
rakima (2011) approximated that some 470.3 GWh (44.3 for mining and 426 for
beneficiation) were consumed as fuel and electricity to produce the 2010 net 62,400
tonnes of the total (REO) at a rate of 16,200 tonnes of ore per day. This accounts
for a direct energy use of 27.1 MJ/kg of TREO (2.55 mining and 24.55 benefi-
ciation), without taking into consideration the energy consumed in producing the
chemicals used in the process. The production of waste rock was 58.2 tonnes/t of
TREO which contained 14.2 kg of radioactive ThO
2
. Wastewater was estimated
at 75 m
3
/t of TREO. The overall emissions for the whole process including the
separation of REO was 6.45 kg CO
2
eq=kg of TREO plus an acidification poten-
tial of wastewater and the atmosphere of 0.559 kgSO
2
e=kg of TREO and 0.124
kgSO
2
e=kg of TREO, respectively. A tonne of original ore also produces 351
kg of metallic co-products (Fe and Nb), 60 kg of bastnaesite and 589 kg of tailings
(Schüler et al., 2011). Kara et al. (2010) reports from the Ecoinvent database, an
environmental impact for producing 1 kg of each REO of 8.5 kg CO
2
e/kg of
La
2
O
3
; 7.59 kg CO
2
e/kg of Ce
2
O
3
; 34.35 kg CO
2
e/kg of Nd
2
O
3
; 36.85 kg
CO
2
e/kg of Pr
2
O
3
; 2.32 kg CO
2
e/kg of Sm
2
O
3
; 46.79 kg CO
2
e/kg of
Eu
2
O
3
; and 0.30 kg CO
2
e/kg of Gd
2
O
3
.
32
The Tailing Dam is 11 square kilometers wide and six meters above the ground. About 10 million
tonnes of wastewater are discharged each year containing iron slag, fluorine, chlorine, sulphates and
other toxic chemicals plus waste slurries of rare earth minerals including the radioactive elements
Th and U. The dam is 11km close to Baotou village.
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