Direct Extraction Metallurgy
Recognizing the importance of leveraging the
cost advantages provided by the physical location of our FOXTROT Resource,
Search Minerals committed early to look at its extraction metallurgy as an
opportunity to do more to position as a low-cost supplier. Under the leadership of
Dr. David Dreisinger, Search V.P. of Metallurgy, and
with investment garnered from Federal and Provincial Government programs,
Search developed its breakthrough Direct Extraction Metallurgical Process
(Patent Pending). After processing over 3.0 tonnes of material representative of the Foxtrot Deposit, the pilot plant testing has clearly demonstrated the ability to produce a high purity mixed rare earth oxide (REO) concentrate. In addition, the pilot plant testing has successfully demonstrated the ability to bring uranium, thorium, zinc, and iron levels below those thresholds expected by refineries that separate mixed REO concentrates into individual rare earth elements (REEs). As important, this proprietary process significantly reduces CAPEX and operational costs while offering a more environmentally conscientious solution for managing waste residue.
Simpler is Better
Search's Direct Extraction process provides a high purity rare earth oxide concentrate simply by crushing and treating the mineralized rock. This process effectively eliminates the grinding and wet flotation stages of a more conventional extraction processes, reducing the amount of capital equipment required and the amount of electricity and chemical reagents used in operations.
An additional advantage is the elimination of a wet tailings pond. The waste material from this process is in the form of a dry stackable residue which reduces the overall mine footprint and provides the opportunity to return tailings to the open pit area at the time of remediation.
How Direct Extraction Works
The mill feed is finely crushed and treated with relatively small amounts of sulfuric acid in a kiln at 180°C (low temperature) to render the REE water-soluble. After water leaching, the REE solution is purified by neutralizing the remaining acid. The REE are then precipitated into a concentrate using sodium carbonate. The rare earth carbonate is then re-dissolved in hydrochloric acid to reject remaining impurities. The REE are then precipitate again as a high- grade 98.99% oxide concentrate.