Although the main cause of hydrometallurgical plant closures is the depletion of oxidized copper minerals reserves, the lack of new hydrometallurgy projects also contributes to these closures. One solution is to be able to process copper sulphide ores hydrometallurgically. However, it is widely known that sulphide copper ores—and chalcopyrite in particular—have very slow dissolution kinetics in traditional leaching systems. An alternative to improve the extraction of copper from sulphide ores is the use of a pretreatment process. Several investigations were developed evaluating the effects of pretreatment, mainly in the extraction of copper from chalcopyrite in chloride media. This study presents a review of various pretreatment methods prior to heap leaching to aid in the dissolution of copper from sulphide ores. Different variables of pretreatment that affect the extraction of copper were identified, including the type of salts used in agglomeration, curing time, and curing temperatures. Successful cases such as the implementation of the CuproChlor^® process (use of calcium chloride), and various pilot studies using sodium chloride and temperature, show that pretreatment is an alternative that aids in the dissolution of copper from sulphide ores.

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.