Production Process:
Evaporation Ponds: The ponds are lined with a polymer-based material laid
over a protective geosynthetic material and engineered granular bedding. The
ponds’ configuration includes provision for uninterrupted production during
salt harvesting and maintenance work. Brine will be transferred between the
successive evaporation ponds using self-priming pumps.
Production Wells: Screened wells target the largest lithium brine aquifers.
Submersible electric pumps are proposed for brine pumping. These pumps send
the brine to evaporation ponds through a network of pipelines and mixing
pools.
Hydrogeology: The Cauchari and Olaroz Salars are classified as “Silver
Peak-type” or “sulfate-type” brine deposits characterized by restricted
basins within deep structural depressions filled with sediments
differentiated as inter-bedded units of clays, salt (halite), sands and
gravels. In the Cauchari and Olaroz salars, a lithium-bearing aquifer has
developed during arid climatic periods. On the surface, the salars are
presently covered by carbonate, borax, sulfate, clay, and sodium chloride
facies.
Process: The production process involves two distinct steps and is generally
consistent with other established brine operations. The first step uses a
solar evaporation process to concentrate lithium in the brine and
precipitate competing salts in large-scale ponds. The ponds at
Cauchari-Olaroz are based on SQM’s design criteria used in their Atacama
operation, and involve the use of shallow ponds where the precipitated salt
is annually harvested from the flat pond base. The second step uses
processing facilities to transform the concentrated lithium brine into
battery-grade lithium carbonate while ensuring the removal of impurities
from the end-product.