This report details the proposed processing route for recovering battery-grade lithium carbonate from lithium-bearing clay at the Nevada North Lithium Project.
Report context
This technical report, dated 23 July 2025, describes the recovery methods proposed for the Nevada North Lithium Project. The information presented is based on metallurgical test results described in Section 13 of the report, with the processing flowsheet employing industry-standard, commercially available equipment. This section serves as the basis for the capital and operating cost estimates presented in Section 21. The project proposes two construction phases, with a total mine life of 42 years and the process plant operating 24 hours per day, 365 days per year at 92% availability.
Processing route
Beneficiation
Run-of-mine mineralized material will be crushed and mixed with water before being fed to unit operations designed to liberate lithium-bearing clay from gangue material. The process uses wet attrition scrubbing followed by multi-stage classification to remove coarse material with low lithium content, referred to as coarse gangue. The coarse gangue will be separately stockpiled. The clay fines will then be sent to a first dewatering stage (thickening) and a second dewatering stage (decanter centrifuging), producing a slurry feed for the processing plant.
Leaching and neutralization
The dewatered slurry will be mixed with sulfuric acid from the acid plant to leach lithium and other constituents into pregnant leach solution (PLS). Acid availability primarily determines leach feed rates, which in turn determine mineralized material mining rates. The report notes that acid consumption variability has been low among mineralized material tested to date, so tonnage adjustments beyond this are minor. The free acid contained in the resultant leached residue will be progressively neutralized with a slurry of ground limestone, lime, and a magnesium hydroxide slurry recycled from the magnesium precipitation circuit.
Counter current decantation and filtration
The neutralized slurry will be sent to a counter current decantation (CCD) circuit to recover residual lithium-bearing solution, then fed to recessed chamber filter presses. The filter cake will be conveyed to the clay tailings filter stack as waste material for stacking.
Magnesium and calcium removal
The PLS overflow or filtrate will be sent to magnesium and calcium removal circuits. First, the solution will be concentrated via water removal. The bulk of the magnesium will be crystallized as MgSO₄·xH₂O salts, removed via centrifugation, and conveyed to the clay tailings filter stack. Any remaining magnesium in the brine will be precipitated with milk-of-lime and separated by recessed chamber membrane filter presses. The precipitated solids will be repulped and recycled back to neutralization, eventually leaving the process with the neutralized filter cake. Calcium in the liquor will be removed via soda ash addition, with an ion exchange polishing step bringing divalent cation concentration to very low levels.
Lithium carbonate production
The purified lithium-bearing brine will be fed to the lithium carbonate production circuit. Soda ash will be used to precipitate lithium carbonate. A bicarbonation step will be used to further remove impurities from the lithium carbonate crystals. The circuit includes first stage lithium carbonate crystallization, bicarbonation, second stage lithium carbonate crystallization, and sodium sulfate and potassium sulfate crystallization for zero liquid discharge.
Key reported parameters
| Parameter | Value | Basis |
|---|---|---|
| Parameter | Value | |
| :— | :— | |
| Phase 1 design capacity | 43,000 t/a Li₂CO₃ | |
| Phase 2 design capacity | 86,000 t/a Li₂CO₃ | |
| Peak annual LCE production | 109,100 t/a | |
| Process plant availability | 92% | |
| Mine life | 42 years | |
| Total material processed (dry) | 443.3 Mt | |
| Processed material (dry) | 204.8 Mt | |
| Waste material (dry) | 238.4 Mt | |
| Peak annual throughput (dry) | 13.0 Mt | |
| Plant operating schedule | 24 h/d, 365 d/a | |
| Clay types processed | Multiple, blended from two stockpiles | |
| Acid consumption variability | Low among material tested |
Project website: https://surgebatterymetals.com/project
Technical qualifications
The proposed flowsheet is based on metallurgical test results described in Section 13 of the report and has not been demonstrated at commercial scale. The process parameters for acid consumption variability are reported from testwork conducted on mineralized material samples, with the report noting that mineralized material tonnage adjustments beyond an initial range are minor. No historical operating data from a commercial-scale plant at this project are presented.
Source: Nevada North Lithium Project , Form 43-101F1 Technical Report, 23 July 2025, Section 17 Recovery Methods.
