Geology Reference
In-Depth Information
duced. Thus, whilst the deposit occurs at 33.0% iron ore, this contributes to only
9% of the mine's economic value, meanwhile REO constitute 6% of the volume but
proportion 86% of the revenue stream.
Table 8.2 shows data from the same paper which was used to estimate the
consumption of water, electricity, fuel energy and the corresponding GHG emissions
generated in the production of 1 kg of every type of REE.
Table 8.1 Energy, water consumption and GHG emissions from mining to sepa-
ration of 1 kg of REO (Koltun and Tharumarajah, 2008)
Process
Electr.,
Heat
GHG
Water
MJ
energy, MJ
emissions,
kg
consumption,
kl
Mining and
1.6
6.2
2.5
3.05
beneficiation
REO extraction from
5.6
90
10.5
19.09
bastnaesite
REO extraction from
55.6
11.9
18.3
18.15
monazite
Light REO
12.6
0
3.3
0.58
separation
Medium REO
5.2
0
1.3
0.16
separation
Heavy REO
15.5
0
5.5
8.52
separation
Overall production
96.118.4 108.121.6
41.44.2
49.5512.4
for 1kg of REO
The figures of Table 8.1 for the separation of light REO (La;Pr;Nd) are
calculated considering a solvent extraction process with mono-2-ethylhexyl ester
HEH(EPH) as an extractant in a HCl medium. Something similar occurs with
medium REO (Sm;Eu;Gd) but the process requires a considerable number of
extraction and scrubbing stages. The heavy REO (Tb;Dy;Ho;Er;Y b;Y ) is sep-
arated using an ion exchange process with a 2-ethylhexyl-hydrogen 2-ethylhexyl
phoshonate, PC-88A resin with the reduction calculated based on the fused fluo-
ride salt electrolysis for La;Pr and Nd, including mischmetal, in a Reno cell. The
medium and heavy RE metals are metallothermically reduced with calcium over
the anhydrous fluoride at about 1000
o
C in a tantalum crucible.
Koltun and Tharumarajah (2008) provide the electrical and fuel energy con-
sumption separately (see Table 8.2). Thus based on this report and assuming an
average Chinese electric grid mix of 75% produced from coal power stations and
25% from hydro, the primary fuel consumption (exergy cost) calculated by the au-
thors of this topic for the overall exergy consumption per kg of REE is among the
highest of all metal productions.
Search WWH ::
Custom Search