Search Minerals Provides Pilot Plant Optimization Update
Search Minerals Provides Pilot Plant Optimization Update
VANCOUVER, British Columbia, Oct. 23, 2019 -- Search Minerals Inc. (“Search” or the “Company”) (TSXV: SMY) is
pleased to provide an update of the current pilot plant optimization being carried out by SGS Canada in Lakefield, Ontario. The
SGS Minerals test program designed to optimize the Search Minerals Direct Extraction Process for Rare Earth Element
Recovery is nearing successful completion.
HIGHLIGHTS:
• The absence of acid during material heating is favourable for equipment selection and maintenance as acid
corrosivity was significantly reduced
• Gains in rare earth recovery can be obtained by fine crushing of the primary material
• Process flowsheet simplification by placing uranium removal in the much smaller re-leach circuit
• Re-leaching of the rare earth carbonate was optimized to permit high rare earth recovery and minimum co-
extraction of impurities
• Removal of thorium from the re-leach solution by selective solvent extraction
Greg Andrews, President and CEO stated; “We are receiving significant improvements and efficiencies to our proprietary direct
extract process flowsheet during this optimization program. The data and information gathered during the program will be used
to prepare a preliminary economic assessment for capital and operating costs along with engineering plans to build a
demonstration plant in St. Lewis, Labrador. These processing advancements along with our recent DEEPFOX resource
estimate announcement well positions Search to become a crucial player in the creation of a secure North American rare
earth element supply chain.”
The Direct Extraction Process involves the following unit operations.
1. Material Crushing
2. Sulfuric Acid Treatment of the Crushed Material at ~190 °C for 4 hours
3. Water Leaching of the Acid/Material Mixture at 90 °C for 24-36 hours
4. Iron and Impurity Removal by Magnesium Carbonate Addition to pH 3-3.5
5. Filtration and Washing of the Leach Residue and Iron Precipitate
6. Uranium Removal by Ion Exchange
7. Precipitation of a Mixed Rare Earth Carbonate by Addition of Sodium Carbonate
8. Re-Leaching of the Mixed Rare Earth Carbonate with Sulfuric Acid and Filtration of Un-Leached Residue
9. Thorium Removal by Precipitation
10. Zinc Removal by Precipitation as Zinc Sulfide
11. Rare Earth Oxalate Precipitation and Calcination to Produce a Mixed Rare Earth Oxide of High Purity (+99% REO) for
Refining
The SGS Program funded by Search Minerals with significant support from the Newfoundland and Labrador Department of
Tourism, Culture, Industry and Innovation (“TCII”) and from the Atlantic Canada Opportunities Agency (“ACOA”) was designed
to optimize the process in the areas of hot sulfuric acid treatment, water leaching, uranium removal, re-leaching of the mixed
rare earth carbonate and thorium removal. A composite sample of material from the Foxtrot deposit was used for all testing.
The analysis of the rare earth oxide content was 1.10% TREO consistent with prior work.
Rare Earth Oxide Analysis (%)
La2O3 0.188
Ce2O3 0.399
Pr6O11 0.049
Nd2O3 0.175
Sm2O3 0.031
Eu2O3 0.002
Gd2O3 0.032
Tb4O7 0.0048
Dy2O3 0.027
Ho2O3 0.0054
Y2O3 0.150
Er2O3 0.015
Tm2O3 0.002
Yb2O3 0.013
Lu2O3 0.0018
Total 1.10
The significant results achieved to date include the following:
1. A pilot plant test of material heating followed by hot acid mixing was completed. The use of material heating ahead of
acid treatment did not impact rare earth extraction in the subsequent water leaching. The absence of acid during
material heating is favourable for equipment selection and maintenance as acid corrosivity was significantly reduced.
2. A study of material crush size on rare earth extraction showed that a significant increase in REE extraction could be
achieved by crushing the material to 0.5 mm prior to acid treatment and water leach at 90 °C and 10% solids for 24
hours. The water leach extractions for the key elements were 89% Pr, 89% Nd, 78% Tb and 77% Dy. These results
indicate further gains in rare earth recovery can be obtained by fine crushing of the primary material.
3. Uranium removal was demonstrated on the primary leachate after iron removal or from the re-leach solution (formed by
acid leaching of the rare earth carbonate). The uranium can be removed by conventional ion exchange in either location
in the process to below detection limit. These results allow process flowsheet simplification by placing uranium
removal in the much smaller re-leach circuit.
4. The re-leaching of the rare earth carbonate was optimized to permit high rare earth recovery and minimum co-extraction
of impurities.
5. A pilot plant test was performed on removal of thorium from the re-leach solution by selective solvent extraction. The
pilot plant test treated rare earth leachate in two stages of extraction with a primary amine solvent, followed by two
scrub stages with dilute sulfuric acid and finally two strip stages with dilute hydrochloric acid. The thorium content of
the solution was reduced from 4.83 mg Th/L to 0.03-0.07 mg Th/L representing approximately 99% removal efficiency
with negligible extraction of rare earth elements. The low level of thorium in solution will result in < 5 g Th/t in the mixed
rare earth oxide from the process to meet all rare earth refinery specifications. The small amount of thorium and minor
amounts of rare earths in the strip solution will be directed to the main water leach circuit for precipitation of thorium
into the final leach residue and recovery of the rare earths. The demonstration of this thorium control process was a
major achievement of the SGS program.
The SGS group will complete the program by treating the thorium – free solution containing rare earths with (1) sulfide ion to
precipitate zinc and (2) oxalate to precipitate a mixed rare earth oxalate. The rare earth oxalate will then be calcined to form a
mixed rare earth oxide. The mixed rare earth oxide is anticipated to have a purity of +99% rare earth oxide content, consistent
with previous work.
The SGS Minerals program has resulted in significant optimization of the Search Direct Extraction Process with respect to
process simplification, increased operating flexibility, reduced chemical consumption and more robust management of minor
element impurities.
Qualified Person :
Dr. David Dreisinger, Ph.D., P.Eng., is the Company's Vice President, Metallurgy and Qualified Person for the purposes of NI
43-101. Dr. Dreisinger has reviewed and approved the technical disclosure contained in this news release as applicable. The
company will endeavour to meet high standards of integrity, transparency, and consistency in reporting technical content,
including geological and assay (e.g., REE) data.
About Search Minerals Inc.
Led by a proven management team and board of directors, Search is focused on finding and developing resources within the
emerging Port Hope Simpson Critical Rare Earth Element (“ CREE”) District of South East Labrador (the “ District”). The
Company controls a belt 70 km long and 8 km wide including its 100% interest in the FOXTROT and DEEP FOX Projects,
which are road accessible and at tidewater. Exploration efforts have advanced “Fox Meadow” as a significant new CREE
prospect very similar to and in close proximity to FOXTROT and DEEP FOX. The FOXTROT Project has a low capital cost to
bring the initial project into production ($152 M), a short payback period and is scalable due to Search’s proprietary processing
technology.
The FOXTROT preliminary economic assessment is preliminary in nature and includes inferred mineral resources that are
considered too speculative geologically to have the economic considerations applied to them that would enable them to be
categorized as mineral reserves, and there is no certainty that the preliminary economic assessment will be realized. The
preliminary economic assessment includes the results of an economic analysis of mineral resources. Mineral resources are
not mineral reserves and do not have demonstrated economic viability.
All material information on the Company may be found on its website at www.searchminerals.ca and on SEDAR at
www.sedar.com
For further information, please contact:
Greg Andrews
President and CEO
Tel: 604-998-3432
E-mail: [email protected]
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Venture Exchange) accepts responsibility for the adequacy or accuracy of this release.
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