Rare Element Resources
Bear Lodge Project
Canadian NI 43-101
Technical
Report
October 9
th
, 2014
10135-200-46 - Rev. 0
17-17
The reaction extent varies with feed composite. Testing results have shown that
the thorium oxide compound is partly leached by hydrochloric acid under the
current leach unit operating conditions and, therefore, requires additional
processing to remove it.
Uranium Oxide Leaching Reaction
U
3
O
8
+ 4*HCl → 2*UO
2
Cl
2
+ UO
2
+ 2*H
2
O
Reaction Extent: 61-67%
Testing results have shown that uranium oxide is partly leached by hydrochloric
acid. The most recent test data indicate maximum uranium content will be below
35 g/ton in the final product.
Other Elements
Other elements such as Aluminum, Potassium, Magnesium,
Manganese, Lead, etc., are present in the pre-concentrate and are
partly leached by hydrochloric acid. See Table 17.1 for reaction
extents of various other elements.
17.4 Process Description Unit 300 – Precipitation & Calcination
The Precipitation Unit is designed to selectively precipitate the rare earths as oxalates
from the leach solution by the addition of oxalic acid.
The Pregnant Leach Solution (PLS) is pre-heated to 85°C in a heat exchanger (200-
HTX-002) using reclaimed heat energy and a secondary steam heat exchanger (200-
HTX-001), (used mainly for startup). The PLS and Oxalic Acid are combined in the
first of four agitated precipitation reactor tanks operated in series (300-REA-
001,2,3,4). The reactants flow through the reactors by overflow. After the first tank,
the temperature is raised to 90°C using steam coils in the first three tanks. Any one
of the four reactor tanks may be taken out of service and bypassed for maintenance.
The remaining three tanks are sized to provide the required residence time of three
hours. See Table 17.2 for precipitation test results.
