Investigating the geochemical behavior and exploration potential of lithium in brines; a case study of Bam salt plug, Zagros Zone, southern Iran.

Lithium (Li) is a scarce and technologically important element; the demand for which has recently increased due to its extensive consumption, particularly in manufacturing of Li-ion batteries, renewable energy, and electronics. Li is extracted from brines, pegmatite, and clay minerals; though extraction from brines is economically preferred. More than 200 salt plugs are in the Zagros Mountains which represent potential sources for Li exploration. This preliminary study collected first data on the abundance of Li in the salt plugs in southern Iran, and investigated Li distribution during evaporation of halite-producing brine ponds. The XRD analysis of powdered samples showed that gypsum and halite are the dominant solid phases in the ponds in which Li is concentrated in gypsum, while halite is depleted of Li. ICP-MS and ICP-OES analyses showed that Li in brines is concentrated during the evaporation by factors up to 28 with total contents up to 40 mg kg‒1. The Mg/Li ratio was higher than 70, which makes the brine unsuitable for conventional evaporation extraction techniques which require Mg/Li ratios of less than 6. Considering that 25 mg kg‒1 is a suitable concentration of Li for exploration purposes, the results of this study suggest that with the advancement of extraction techniques, the depletion of presently used high-grade Li reserves, the increasing demand for lithium, the need for extraction from diverse sources, and the exploration of new resources, the salt plug brines have an exploratory potential for Li in the future.