The PEA designs a lithium carbonate production route that uses solar evaporation ponds and a chemical plant, with liming to remove magnesium and sulphates before processing.
Report context
The Preliminary Economic Assessment (PEA) for the Advantage Lithium Project, located in the Cauchari Salar, Jujuy Province, Argentina, is based on a technical report dated with the document number N° 209020-00053-000-GE-TEN-0001_3. The report describes the proposed design for production wells, evaporation ponds, and a processing plant to produce 20,000 tonnes per year of Battery and Technical Grade Lithium Carbonate (Li2CO3).
Processing route
Brine extraction and evaporation ponds
Brine is extracted from production wells divided into north and south zones within the Cauchari Salar. The brine is pumped to halite evaporation ponds where solar energy and wind cause water evaporation, precipitating mainly halite salts and concentrating lithium. The area required for the evaporation ponds is calculated based on local evaporation rate and rainfall, which depend on solar radiation, relative humidity, wind speed, temperature changes, and brine chemistry.
At a defined point, the brine is sent to a liming plant where calcium hydroxide (Ca(OH)2) reacts with magnesium (Mg) and sulphates (SO4) in a reactor, precipitating magnesium hydroxide and calcium sulphate. The pulp is sent to a decantation pond, and the brine is transferred to further solar evaporation ponds. A back-up stage liming plant is installed to remove remaining magnesium. After decantation, the concentrated brine is pumped to final ponds where halite and some potassium salts crystallize. When the brine reaches suitable lithium concentration for processing, it is stored in reservoir ponds.
Ponds are constructed with local material and lined with geomembranes over geotextiles to prevent leakage. Salts deposited in ponds are harvested when they reach a defined height and transported to discard stockpiles. The estimated mass operational value for treated brine in the ponds is 14 million tonnes per year.
Lithium carbonate plant
The lithium carbonate plant receives brine concentrate from the solar ponds and removes final impurities through chemical processes.
In the first stage, remaining Mg and Ca are removed by reacting the brine with mother liquor (recovered from belt filtration), soda ash, and slaked lime, precipitating Calcium Carbonate (CaCO3) and Magnesium Hydroxide (Mg(OH)2). The pulp is pumped to a re-pulping tank and then to a discard pond. The brine is then pumped to an Ion Exchange (IX) stage that adsorbs minor impurities and delivers purified brine to the carbonation stage.
In the carbonation stage, lithium carbonate precipitates at high temperature through the addition of soda ash. The lithium carbonate is separated from solution using a belt filter. At this point, the product can be dried and sold as technical grade lithium carbonate or further processed to battery grade.
For battery grade production, the lithium carbonate is re-pulped with water and reacted with carbon dioxide to produce a more soluble lithium bicarbonate solution. The solution is filtered to remove insolubles, then passes through an Ion Exchange stage to remove all di- and tri-valent metals and boron. The solution is heated to release and recover carbon dioxide and crystallize pure lithium carbonate. The solids are thickened, filtered, dried, sized, and packaged.
Reagents
Calcium hydroxide is the main reagent, used in both the liming plant at ponds and the lithium carbonate plant, with total consumption of 58,700 TPY. Soda ash (Na2CO3) is used for Ca/Mg removal and lithium carbonate precipitation, with total consumption of 35,000 TPY, prepared as a 28% w/w solution. Other reagents include caustic soda (280 TPY for IX), sulphuric acid (150 TPY for equipment cleaning), and hydrochloric acid (1,400 TPY for IX).
Water and waste management
Fresh water for the process comes from a fresh water well and is treated in a reverse osmosis plant before injection into the lithium carbonate plant. Process water is reutilized, including product washing water used for soda ash solution preparation.
Equipment is periodically cleaned using 18% sulphuric acid solution, with the cleaning solution sent to the discard pond.
Solid discards from the lithium carbonate plant , Mg(OH)2 and CaCO3 , are pumped directly to a discard pond after re-pulping, where solids decant and liquid may be reused in evaporation ponds.
Key reported parameters
| Parameter | Unit | Value | Basis |
|---|---|---|---|
| Lithium carbonate production target | TPY | 20,000 | Design |
| Brine treated in ponds (estimated operational) | TPY | 14,000,000 | Design estimate |
| Lime consumption (primary liming) | TPY | 55,400 | Design |
| Lime consumption (secondary liming stage) | TPY | 3,300 | Design |
| Soda ash consumption (total) | TPY | 35,000 | Design |
| Caustic soda consumption | TPY | 280 | Design |
| Sulphuric acid consumption | TPY | 150 | Design |
| Hydrochloric acid consumption | TPY | 1,400 | Design |
| Halite/Potash salt generation from ponds | TPY | 3,925,826 | Design estimate |
| Mg(OH)2 and CaCO3 discards from plant | TPY | 310,178 | Design estimate |
Project website: https://www.northernminer.com/company/advantage-lithium/
Technical qualifications
This article is based solely on the recovery methods sections (Section 17) of the Preliminary Economic Assessment technical report for the Advantage Lithium Project (Technical Report N° 209020-00053-000-GE-TEN-0001_3). The information presented represents the proposed design described in the PEA. No historical operating data or testwork results are included in the source material. The report does not provide detailed mass balances, energy requirements, capital or operating cost estimates, economic analysis, or project ownership information. Flow sheet details, performance data, and current project status beyond the described design are not available from this source.
Source: Preliminary Economic Assessment of the Advantage Lithium Project, Jujuy Province, Argentina, Technical Report N° 209020-00053-000-GE-TEN-0001_3, Section 17: Recovery Methods.
