Mr. Chris Grove reports
COMMERCE RESOURCES CORP. ACHIEVES 98% NDPR RECOVERIES INTO SOLUTION FROM SULPHATION CRACK OF ITS HIGH-GRADE CONCENTRATES
Commerce Resources Corp. has provided an update on the progress of its metallurgical program to produce samples of mixed rare earth carbonate (REC) concentrate to satisfy several requests by global processors. As part of this program, continued bench-scale flow sheet development, ahead of scale-up and bulk processing, has resulted in the highest rare earth element (REE) recoveries to date into the combined high-grade monazite mineral concentrate (1) as well as into the subsequent sulphation crack water-leach liquor phase (for example, the pregnant leach solution or PLS). Highlights include:
- Monazite mineral concentrate (1) grade of approximately 40 per cent rare earth oxide (REO) at 82-per-cent recovery and 3.2-per-cent mass pull (recovery and mass pull with reference to unprocessed whole rock);
- Recoveries of 98 per cent neodymium, 98 per cent praseodymium, 95 per cent terbium and 90 per cent dysprosium into the PLS (with reference to the mineral concentrate (1));
- Combined overall NdPr (neodymium and praseodymium) recovery of approximately 78 per cent into the PLS (with reference to unprocessed whole rock).
The flow sheet for the Ashram REE/fluorspar deposit, developed by Hazen Research, uses conventional unit processes to produce a high-grade rare earth mineral (monazite) concentrate (1) that is comparable with active global hard-rock REE producers. Specifically, the Ashram flow sheet utilizes a flotation -- HCl leach -- magnetic separation process approach to achieve high-grade (over 40 per cent REO) monazite concentrates (1) at high recovery comparable with active global producers.
In the current work, flotation concentrate produced from the 2015 pilot plant operation was used as feed to the subsequent HCl leach and magnetic separation stages, which were completed at bench scale and resulted in monazite concentrate (1) grades of approximately 40 per cent REO at 82-per-cent overall recovery. The monazite concentrate (1) was then mixed (in about 50-gram batches) with concentrated sulphuric acid (H2SO4) and heated to about 220 C in a stirred pot over an about three-hour period to convert the contained REEs into soluble rare earth sulphates (for example, the sulphation crack), which were then dissolved in a water leach to bring the REEs into solution (for example, the PLS). The recent test work resulted in the highest recoveries of REEs achieved to date in the sulphuric acid -- water leach stage, at 98 per cent for NdPr, as well as the highest overall recoveries achieved to date from unprocessed rock into the PLS, at approximately 78 per cent NdPr.
All major hardrock REE mines globally produce mineral concentrates of at least 35 to 40 per cent REO, which are then placed into solution and processed downstream into marketable products. Such high grades of mineral concentrate considerably reduce the downstream processing cost and risk through lower reagent use, fewer deleterious elements entering solution and a smaller hydrometallurgical plant requirement by comparison. With respect to the Ashram deposit, test work has now demonstrated that over 80 per cent of the REEs in the unprocessed deposit material can be effectively concentrated (recovered) into just 3 to 4 per cent of the original mass, resulting in a significant upgrade factor of over 21 times the original head grade. In addition, the recent work has now demonstrated that 98 per cent of the NdPr contained in this concentrate can be put into solution for downstream recovery. These results are also a strong improvement on the 90 to 95 per cent REE recoveries into solution achieved in prior test programs.
Company president Chris Grove comments: "The ongoing work on the Ashram flow sheet has demonstrated that very high-grade monazite concentrates (1) at high recoveries have been produced, and there is still room for improvement. Moreover, the prior bench-scale work has demonstrated that producing high-grade monazite concentrates (1) at high REE recoveries is repeatable, and now, the current test program has demonstrated that high REE recoveries into solution at the sulphuric acid water-leach stage, are also repeatable. Our metallurgical results to date continue to solidify our belief in Ashram as a potential low-cost leader for mixed REC/NdPr supply to the global market."
In the next steps of the process flow sheet the leach liquor produced from the sulphuric acid water leach stage will be treated by solvent extraction (SX) to reject thorium followed by SX to purify and concentrate the REEs. A mixed REC, high in NdPr, will then be precipitated from the SX strip liquor. This test work is currently being completed on the bench scale and in parallel to the scale-up of the sulphuric acid pot digestion stage from 50 g batches to 2.5-kilogram batches. The test work will continue to scale up until approximately 2.5 kilograms of on-spec mixed REC is produced.
(1) Concentrate refers to the recovered REE minerals into the magnetic fraction of the magnetic separation stage (about 70 per cent of the overall REEs) as well as the REEs that have been precipitated and recovered from the HCl leach liquor fraction (about 12 per cent of the overall REEs). Collectively, the combined concentrate accounts for over 80-per-cent overall REE recovery through this stage, which is then fed together into the sulphation crack stage.
National Instrument 43-101 disclosure
Darren L. Smith, MSc, PGeo, Dahrouge Geological Consulting Ltd., a permit holder with the Ordre des Geologues du Quebec and qualified person as defined by National Instrument 43-101 -- Standards of Disclosure for Mineral Projects, supervised the preparation of the technical information in this news release.
About Commerce Resources Corp.
Commerce Resources is a junior mineral resource company focused on the development of the Ashram rare earth and fluorspar deposit located in Quebec, Canada. The company is positioning to be one of the lowest cost rare earth producers globally, with a specific focus on being a long-term supplier of mixed rare earth carbonate and/or NdPr oxide to the global market. The Ashram deposit is characterized by simple rare earth (monazite, bastnaesite, xenotime) and gangue (carbonates) mineralogy, a large tonnage resource at favourable grade, and has demonstrated the production of high-grade (over 45 per cent REO) mineral concentrates at high recovery (over 70 per cent) in line with active global producers. In addition to being one of the largest rare earth deposits globally, Ashram is also one of the largest fluorspar deposits globally and has the potential to be a long-term supplier to the met-spar and acid-spar markets.
We seek Safe Harbor.
© 2021 Canjex Publishing Ltd. All rights reserved.