Independent Studies Further Validate the American Rare Earths’ (ARR) Halleck Creek Project
06 Maggio 2024 - 2:03PM
American Rare Earths (ASX: ARR | OTCQX: ARRNF and AMRRY)
(“ARR” or the
“Company”) is
pleased to announce results from a metallurgical study on leaching
extraction of REE from Halleck Creek ore by low temperature, direct
acid leaching. The U.S. Department of Energy’s Office of Energy
Efficiency and Renewable Energy (“EERE”) awarded a three-year
(2022-2025) research contract to Phinix, LLC with American Rare
Earth and Virginia Tech as team members. This metallurgical study
was carried out by researchers at the Department of Mining and
Minerals Engineering at Virginia Tech. These positive results
further confirm the findings of the metallurgical testwork carried
out by Wood PLC1 which were previously announced by ARR.
Donald Swartz, Chief Executive Officer of American Rare
Earths commented: “We’re extremely pleased with the
leaching results which further validate the recent scoping study
assumptions and our optimism around the project. High REE recovery
at low temperatures with short duration indicate low(er) operating
costs and effective extraction of rare earths. ARR is pleased that
we have been able to work with the Department of Energy, Phinix and
Virginia Tech on this project and look forward to continuing the
relationship in the next phases of the EERE project.”
Dr. Wencai Zhang, of Virginia Tech, commented on the
results: “The low-crystallinity characteristic of the
allanite can significantly reduce the extraction costs of REEs from
the deposit. I am very excited about our recent findings.”
Technical SummaryUnder the direction of Wencai
Zhang, Ph.D., Dr. Wei Liu and doctoral candidate Zhongqing Xiao
performed leaching testwork and published the results (Liu, et.
al., 2024) at Virginia Tech for the project. Virgnia Tech used
finely ground sample material from the Halleck Creek Project, p80 =
47.9 µm, that was concentrated using magnetic separation to produce
a mixed rare earth concentrate (“Concentrate”). The leaching
testwork compared the effects of a variety of acids, acid
concentrations, temperatures, solid/liquid ratios, and particle
sizes, collectively known as “leach kinetics”, on the
recoverability of REE from the Concentrate. Virginia Tech
demonstrated that approximately 80% of REE were extracted from the
Concentrate using 1 M sulfuric acid at 75° C for 2 hours.
Importantly, this work shows that the REE can be successfully
recovered using mildly acidic, readily available chemicals at low
temperatures which might decrease capital and operating costs and
potentially reduce environmental impacts of the project. The study
also demonstrated that the amorphous crystalline structure of the
Halleck Creek allanite due to the metamictization of the allanite
over geologic time further enhances the leachability of the
ore.
This phase of testwork focused on the leaching kinetics of the
Concentrate. During this stage of the EERE project, Virgnia Tech
did not attempt to isolate discrete rare earth elements. As the
project continues, Virginia Tech will focus on isolating discrete
REE.
Allanite is the primary REE bearing mineral at the Halleck Creek
project. Importantly, allanite is less refractory than monazite or
bastnaesite, as monazite and bastnaesite cannot be leached using
low-temperature acid tank leaching. No significant silica gel
formation was observed during leaching. Allanite from Halleck Creek
exhibits “metamict”, amorphous texture, resulting from
decomposition of the crystalline structure of the mineral due to
low-level decay of uranium and thorium over a 1.4-billion-year
period. The amorphous nature of the Allanite appears to enhance REE
leaching. Virginia Tech performed leach tests on allanite
concentrates at elevated temperatures. Figure 4, below, illustrates
that REE recovery decreases with increased temperature particularly
when exceeding 900° C. Virginia Tech hypothesizes that allanite
recrystalizes at higher temperatures, and reduces the ability to
leach REE from the Concentrate. A novel, comprehensive allanite
review paper prepared by leading researchers on allanite leaching
supports this hypothesis and highlights the potential of allanite
as an REE ore mineral (Xiao and Zhang, 2024). The allanite review
paper also suggests that future metallurgical research focusing on
separation and leaching is needed (Xiao and Xhang, 2024). We would
encourage readers to review this paper, which is the most
comprehensive review and summary of allanite to date.
Figure 1. The effect of roasting on the recovery
of REE from the allanite feed sample. The allanite feed sample was
roasted in a muffle furnace for two hours. Leaching conditions: 1 M
H2SO4, d80 = 47.9 µm, 75 ˚C, S/L ratio = 25 g/L, and 2 h.
ReferencesLiu, W., Xiao, Z., Das, S., &
Zhang, W. (2024). Mechanism and kinetic study of rare earth
extraction from allanite by direct acid leaching. Minerals
Engineering, 205, 108489.
Xiao, Z. & Zhang, W. (2024). Review of allanite: Properties,
occurrence and mineral processing technologies. Green and Smart
Mining Engineering, 1, 40-52.
This market announcement has been authorized for release to the
market by the CEO of American Rare Earths.
See here for
additional technical details and the full technical
studies.
Competent Persons Statement:
This work was reviewed and approved for release by Mr. Kelton
Smith (Society of Mining Engineers #4227309RM) who is employed by
Tetra Tech and has sufficient experience which is relevant to the
metallurgical testing and type of deposit under consideration and
to the activity which he is undertaking to qualify as a Competent
Person as defined in the 2012 JORC Code. Mr. Smith consents to the
inclusion in the report of the matters based upon the information
in the form and context in which it appears.
About American Rare Earths
Limited: American Rare Earths (ASX: ARR | OTCQX: ARRNF and
AMRRY) owns the Halleck Creek, WY and La Paz, AZ rare earth
deposits which have the potential to become the largest and most
sustainable rare earth projects in North America. American Rare
Earths is developing environmentally friendly and cost-effective
extraction and processing methods to meet the rapidly increasing
demand for resources essential to the clean energy transition and
US national security. The Company continues to evaluate other
exploration opportunities and is collaborating with US
Government-supported R&D to develop efficient processing and
separation techniques of rare earth elements to help ensure a
renewable future.
Further information
Head OfficeAmerican Rare Earths
Ltd1658 Cole Blvd, Suite G30Lakewood, CO,
80401info@americanree.comwww.americanree.com
Susan AssadiMedia
Relations USsassadi@americanree.com347 977 7125
Beverly JedynakInvestor Relations
USBeverly.jedynak@viriathus.com312 943 1123
A photo accompanying this announcement is available at
https://www.globenewswire.com/NewsRoom/AttachmentNg/76e39d49-56ea-4bb8-aa02-3edc795565fc
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