Heavy Liquid and Dense Media Separation tests in China on bulk samples from the North Aubry lithium deposit, provide viable support to the potential commerciality of the projectDiversified minerals explorer and developer Ardiden Limited (
- Metallurgical testwork program continues to demonstrate robust recoveries on the bulk sample obtained from the North Aubry Lithium deposit at Ardiden's 100%-owned Seymour Lake Lithium Project in Ontario, Canada.
- Additional Heavy Liquid Separation (HLS) testwork on the bulk spodumene sample improves previous Yantai results, producing very high-grade lithium concentrate of up to 7.01% Li2O using a liquid density of 2.95g/ml and achieving a very impressive 91.63% recovery rate.
- Initial Dense Media Separation (DMS) testwork on the spodumene sample produces high-grade lithium concentrate of up to 6.92% Li2O, with a recovery of 81.74%, and a concentrate of 6.05% with recovery of 85.58%
- Positive results obtained from the bulk sample with coarse spodumene particles of up to 6.0mm and an average head feed grade of 1.29% Li2O.
- Extensive metallurgical testwork programs continue on the bulk samples.
- The overall results from this testwork program will assist in the development of a suitable commercial process flow design for the Seymour Lake lithium processing facility.
Ardiden confirms the Yantai metallurgical test results have provided further confirmation the spodumene crystals from the North Aubry Lithium deposit, liberate extremely well at a very coarse particle size of up to 6.0mm, confirming the previous testwork results. The 500kg spodumene sample had a solid average head grade of 1.29% Li2O (refer Table 1 in link below).
The comprehensive testwork on the bulk sample is to develop a commercial process flowsheet design for the Seymour Lake lithium processing facility.
COURSE SPODUMENE PARTICLE SIZES
The bulk sample feed material was collected from the North Aubry deposit using a large rock breaker and excavator. This sample did not have a natural particle size distribution (PSD) resulting from the typical drill and blast and crushing process that would normally occur on site.
Ardiden confirms the large rocks were hand broken and homogenised, then using a number of high controlled staged crushing and sample preparation procedures, Yantai artificially generated a typical feed for processing units. 500kg sample and the top size of 6mm was selected for the first stage of testwork. 6mm is the topical size limit for lithium chemical plant. The crushed head sample size distribution and grades are shown in Table 1 (see link below), with 86.46% of the particle sizes ranging from 0.5mm to 6.0mm and having an average head grade of 1.37% Li2O. There was only 13.54% of the particles that were below the 0.5mm produced with an average head grade of 0.84% Li2O.
The aim of these metallurgical tests is to create the commercial process flow design which will increase the quantity of coarse material produced during the crushing phase, without the need to use a roller crusher, which in turn reduces the quantity of fine material generated and potentially assisting Ardiden with reduced crushing and processing times, which in turn are likely to reduce the costs of producing a lithium concentrate.
HEAVY LIQUID SEPARATION (HLS) TESTWORK
The HLS float and sink test results have continued to provide further evidence of the high-quality nature of the spodumene material from Seymour Lake.
The HLS tests on the North Aubry spodumene material shows that, with the heavy liquid density of 2.95g/ml, a very impressive spodumene concentrate of up to 7.04% Li2O, with a recovery of 91.63% is produced (Refer to Table 2 in link below).
DENSE MEDIA CYCLONE SEPARATION TEST WORK
The Dense Media Cyclone mineral separation tests were conducted on 0.5mm to 6mm size fractions, under a number of different operating conditions (refer to Table 3 in link below).
The testwork results indicate that with recovery rate of 85.58%, a lithium concentrate grade of 6.05% Li2O can be achieved. Ardiden notes as shown in Table 3 in link below, that should it be needed the lithium concentrate grades can be improved with an increase in feed pressure, but the recovery rate is likely to be decreased.
Different medium densities were also tested, as shown in Table 4 (see link below). A lithium concentrate grade of 6.92% Li2O with a strong recovery rate of 81.74% was achieved. The most encouraging results occurred when using:
- Feeding density of 2400kg/m;
- Ore feeding pressure 0.045Mpa;
- Ratio of ore and medium at 1:6; and
- Feed size of 0.5mm to 6.0mm.
The metallurgical test results support that gravity separation is viable method to produce commercial grade lithium concentrate from the Seymour Lake spodumene. Testwork on bulk sample is continuing.
COMMERICAL PRODUCTION POTENTIAL
These latest metallurgical testwork results obtained from Yantai confirm that the North Aubry spodumene quality is world-class and appears to contain only traces amounts of deleterious minerals (announced 12 April 2017). High grade lithium concentrates with excellent recovery rates can also be achieved.
The Company anticipates the development of a robust commercial process flowsheet from the bulk sample testwork program.
Unlike some lithium deposits found in Australia, the North Aubry lithium deposit does not appear to have any issues with iron. Higher content of iron in spodumene will negatively impact the down-stream processing, and hence the commercial value of the lithium concentrate produced.
Ardiden considers these latest metallurgical testwork results from Yantai to be extremely encouraging. The HLS having achieved high-grade lithium concentrate of up to 7.01% Li2O, combined with impressive recovery rates of up to 91.63%, the Company looks forward to advancing the development of an optimal process flowsheet to produce a commercial grade lithium concentrate.
Ardiden confirms that as these are still only preliminary testwork results and further work is underway for the development of the process flowsheet as part of the feasibility studies being conducted at the Seymour Lake Lithium Project.
The Company looks forward to providing further updates as they come to hand.
To view tables and figures, please visit:
About Ardiden Ltd
Ardiden Limited (ASX:ADV) is an emerging international strategic metals company which is focused on the exploration, evaluation and development of four 100 per cent owned projects located in the established mining jurisdiction of Ontario, Canada.
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