After the evaporation ponds, the brine is fed to the Li2CO3 plant, where, through a series of purification processes, solid lithium carbonate is obtained, to be shipped according to the final customer requirements. The lithium carbonate plant is a chemical facility that receives the concentrated brine from the evaporation ponds and, through a series of chemical processes, generates lithium carbonate battery grade in a solid form. All impurities that are still left in the brine after the evaporation ponds are removed in the lithium carbonate plant, through specific stages. The first stage of the lithium carbonate plant is the calcium and magnesium removal stage. A solution of soda ash and slaked lime are added to the concentrated brine from the evaporation ponds in an agitated reactor. Mg and Ca will precipitate as magnesium hydroxide (Mg(OH)2) and calcium carbonate (CaCO3). The slurry is then filtered, and the Mg and Ca free brine is sent to the next stage. The solids obtained from the filtering stage are re-pulped and sent directly to the first sludge pond. The lithium rich brine is fed to an ion exchange stage, to remove remaining calcium, magnesium, and any other di/tri valent metals in the brine. The impurity free brine is then sent to carbonation reactors. Here the addition of a soda ash solution and high temperatures result in lithium carbonate precipitating (technical grade), which is filtered on a belt filter, repulped and centrifuged. This can be directly dried and sold as technical grade. In order to obtain battery grade, the pulp is transported to another purification stage. The mother liquor generated from the belt filter is recycled to the ponds in order to recover the remaining lithium. The purification stage consists of the generation of lithium bicarbonate through the reaction in agitated reactors of the solid lithium carbonate and gaseous CO2 at low temperature. The lithium bicarbonate is much more soluble in water than lithium carbonate, allowing the separation from any residual soluble and insoluble impurities. With the use of an IX stage utilizing a specific selective resin, any boron and/or di/tri valent metals left in the solution are removed, and a highly pure bicarbonate solution is fed to a desorption stage. With the increase of temperature (up to 80°C) the CO2 is desorbed, and solid lithium carbonate is re-precipitated.
The slurry is centrifuged, dried, reduced in size (milled) and packaged in maxibags, to be finally transported to clients. The brine production wellfields will be located on two sectors of the Salar de Cauchari, one in the Archibarca area, near and among the initial evaporation ponds and another located south-east of this location. Initially, and up to year four (4) of the operation, the evaporation ponds will cover an area of approximately 10.5 million m2. The brine lithium concentration decreases from 580 mg/l to 545 mg/l by Year 5 of the operation, and an increase to 11.3 million m2 in pond area is required. By Year 10, the average brine lithium concentration decreases to 491 mg/l and requires the final increase of the evaporation ponds area to 12.2 million m2. Project CAPEX for 25,000 tpa lithium carbonate is estimated to be USD 659 million. Costs estimates and economic assessments for the 25,000 tpa processing facility are at a AACE Class 4 +30% /- 20% level with no escalation of costs. The Cauchari Project is at Pre-Feasibility Study phase. The capital cost estimate was prepared by Worley Chile S.A. and Worley Argentina S.A. (collectively, Worley) in collaboration with Allkem. The estimate includes capital cost estimation data developed and provided by Worley, Allkem, and current estimates. Exploration and mining activities are subject to regulatory approval following an environmental impact assessment ("EIA"), before initiating disturbance activities. The CPs understand that Allkem (previously Advantage Lithium) obtained all required approvals for the exploration drilling and testing programs in the Salar. Allkem is currently in the process of renewing and maintaining required exploration-related permits while awaiting approval of exploitation permitting. Further permits will be required once exploitation is initialised.