Lithium in the Waters of the Mangystau Region, Kazakhstan: Distribution, Geochemical Controls, and Extraction Potential

This study presents a hydrogeochemical assessment of formation waters from the Karazhanbas, Zhetybay, and Uzen oil fields in the Mangystau Region of Kazakhstan, with the objective of elucidating the distribution of lithium, identifying the geochemical factors governing its accumulation, and evaluating its extraction potential. The investigation considered key physicochemical parameters, ionic composition, lithium concentrations, and the relationships between Li, total dissolved solids (TDS), pH, and major cations. Major ions were determined by standard hydrochemical methods, while lithium concentrations were analyzed via inductively coupled plasma optical emission spectrometry (ICP-OES). Results indicate that all investigated waters belong primarily to the calcium-chloride type according to Sulin’s classification. In terms of TDS, the sequence of increasing salinity is Uzen > Zhetybay > Karazhanbas. Specifically, TDS values for Karazhanbas range from 3,725.9 to 40,891.3 mg/dm³, for Zhetybay from 110,800.1 to 150,104.8 mg/dm³, and for Uzen from 130,387.4 to 163,107.1 mg/dm³. Lithium content varies from 0.30-0.70 mg/dm³ in Karazhanbas waters to 1.40-1.85 mg/dm³ in Zhetybay, while Uzen waters reach concentrations of 1.51 mg/dm³. Positive correlations were established between Li and Ca²⁺, Mg²⁺, and Na⁺+K⁺, suggesting that lithium accumulation is linked to the overall salt matrix and water-rock interaction processes. The data demonstrate that maximum mineralization does not always correspond to maximum lithium content. Zhetybay is identified as the most promising site for further lithium-oriented research. The formation waters of the Mangystau Region may be considered a potential secondary hydromineral resource; however, their industrial feasibility requires further geochemical, technological, and environmental evaluation.