Rare Element Resources
Bear Lodge Project
Canadian NI 43-101
Technical
Report
October 9
th
, 2014
10135-200-46 - Rev. 0
17-15
The leach reactors will operate at 45
o
C. Most of the energy to maintain this
temperature will come from the already hot acid and water additions coming from the
HCl recovery circuit. The leach reactor tanks are equipped with steam coils to pre-
heat the reactors on start-up and maintain temperature as needed during operation.
The leach reactors are vented to a common condenser to remove most of the acid
vapor and return the condensate to one of the leach reactors, and thus minimize the
consumption of neutralizing reagents in the neutralizer scrubber (500-SCR-001).
A neutralization scrubbing system (500-SCR-001) is used to prevent harmful gases
from being released to the atmosphere. The scrubbing system is designed to remove
any chlorine gas, ammonia gas, or hydrochloric and oxalic acid gas from the
ventilation systems of the various reactors and chemical storage tanks.
The scrubbing system uses a solution of sodium hydroxide to neutralize the acidic
vapors. Trace ammonia gasses will also react with chlorides and sulfates to form
soluble ammonia salts. The high pH aqueous bleed from the scrubber is sent to the
metal carbonate reactor #1 (350-REA-001) and eventually to tailings disposal through
that process.
Instrumentation will be installed in the Hydromet plant to provide quantitative
information on the plant operation (flow rates, temperatures, pH, production rate, etc.)
Chemistry
17.3.1
A) Leach reactors
Rare Earth Oxides Leaching Reaction
RE
2
O
3
+ 6*HCl → 2*RECl
3
+ 3*H
2
O
Reaction Extent: 85-92% TREE
In the above reaction, RE is a rare earth element or Yttrium present in the
pre-concentrate.
Table 17.1 presents leach efficiency by element for various ore composites.
