The average lithium content in the Earth’s crust is estimated at about 0.007%. Despite this, lithium is considered abundant and widely distributed, with significant extraction from various sources. Notably, the brines in the Salar de Atacama are highlighted for their high lithium concentration ~1800 mg/L. Lithium is currently recovered from these brines through a solar evaporation process. The brine is transferred through a series of ponds, increasing the lithium concentration from 0.2% to 6% over 18 months, while decanting other minerals like potassium, magnesium, and boron. This method is the most efficient and cost-effective globally due to the Salar de Atacama’s high lithium concentration of approximately 1800 ppm and the region’s intense solar radiation, which facilitates evaporation at no economic cost. This manuscript describes in detail the lithium and potassium extraction processes used in the Salar de Atacama.

In the mining industry, key unit operations such as grinding, flotation, thickening, and tailings transport are negatively affected by the presence of clay minerals, which impart complex rheological behaviors to mineral suspensions by increasing their rheological properties. This deterioration arises from specific physicochemical characteristics of clay minerals such as fine particle size, anisotropic character, laminar morphology, and swelling capacity. This work reviews the effects of various rheology-modifying reagents on clay suspensions including kaolinite, illite, and montmorillonite. The reviewed reagents include inorganic salts, pH modifiers, polymers, surfactants, and nanoparticles. Their mechanisms of interaction with solid particles are analyzed, highlighting their influence on the degree of dispersion or aggregation. Furthermore, this review proposes research opportunities focused on the formulation of hybrid reagents, modified biopolymers, and the development of reagents effective under adverse conditions such as high salinity or elevated temperatures. This review provides a comprehensive basis for optimizing the use of rheological additives through more efficient and sustainable strategies for managing clay-rich suspensions in the mining industry.

High-molecular-weight anionic polyacrylamide was used to analyze the effect of kaolin on the structure of particle aggregates formed in freshwater and seawater. Batch flocculation experiments were performed to determine the size of the flocculated aggregates over time by using focused beam reflectance measurements. Sedimentation tests were performed to analyze the settling rate of the solid–liquid interface and the turbidity of the supernatant. Subsequently, a model that relates the hindered settling rate to the aggregate size was used to determine the mass fractal dimension ($D_f$). Flocculation kinetics revealed that greater amounts of kaolin generated larger aggregates because of its lamellar morphology. The maximum size was between 10 and 20 s of flocculation under all conditions. However, the presence of kaolin reduced the settling rate. The fractal dimension decreased with the increase in the kaolin content, resulting in the formation of irregular and porous aggregates. By contrast, factors such as the flocculation time, water quality, and quartz size had limited influences on the fractal dimension. Seawater produced a clearer supernatant because of its higher ionic strength and precoagulation of particles. Notably, the harmful effect of clays in seawater was reduced.

This study analyzes the behavior of sodium polyacrylate (NaPA) as a rheological modifier for clay-based tailings. Special emphasis is placed on the impact of calcium and magnesium ions in industrial water, which are analyzed through rheograms, zeta potential measurements, and molecular dynamics simulations. The results are interpreted as electrostatic interactions, steric phenomena, and cation solvation. This interpretation integrates experimental studies with microscopic analyses, employing molecular dynamics simulations to elucidate the underlying mechanisms. In all cases, a decrease in the yield stress of synthetic slurries is observed as the dosing of NaPA increases due to greater repulsion between tailings particles through an increase in electrostatic repulsion and larger steric forces that hinder agglomeration. However, efficiency is reduced in the presence of divalent cations as zeta potential measurements suggest a reduction in the electrical charges of the particles and the polymer, making its application more challenging. The differences obtained in the presence of calcium compared to magnesium are explained in terms of the solvation of these ions and their impact on the polymer conformation in solution and adsorption on the mineral surfaces. This explanation is reinforced by molecular dynamics studies, which indicate that polymer adsorption on minerals depends on the type of mineral and type of ion. Particularly for quartz, the highest adsorption of NaPA occurs in the presence of calcium, whereas for a kaolinite surface, the highest polymer adsorption is obtained in the presence of magnesium. The competitive effect of these phenomena leads to the rheological behavior of the tailings being dominated by the effects originating in the clay.

The growing demand for lithium for lithium-ion batteries and energy storage systems has driven the exploitation of natural brines in the “Lithium Triangle” (Chile, Argentina, Bolivia). However, the presence of boron, which is highly soluble and exhibits amphoteric behavior, poses a critical challenge to achieving battery-grade purity standards (<5 ppm). This element interferes with the crystallization and morphology of lithium carbonate (Li₂CO₃), reduces recovery efficiency, and affects the chemical stability of lithium phases. Due to its molecular characteristics and strong affinity for water, boron is difficult to remove using conventional methods. This work presents a critical review of current technologies for its removal from lithium-rich brines, including ion exchange with functionalized resins, adsorption, liquid–liquid extraction, and electrochemical methods. Their principles, efficiencies (60%–95%), selectivity towards Li⁺ and Mg²⁺, sustainability, reusability, and industrial feasibility are analyzed. A comparison shows that ion exchange and adsorption offer high selectivity and reusability, liquid–liquid extraction stands out for its efficiency but has lower sustainability, and electrochemical methods exhibit high sustainability with variable efficiency. The choice of the most suitable technology will depend on the specific composition of the brine and the operating conditions of the plant.