ABSTRACT

Lithium minerals, petalite (Li[AlSi₄O₁₀]) and lepidolite (K₂(Li, Al)_5-6[Si_6-7Al_2-1O₂₀](OH, F)₄), were reacted with seawater and NaCl solutions for 240 hours at 150 to 250°C and with a water/mineral ratio of 25 by weight, to clarify the role of dissolved salts on the enrichment of lithium in natural saline waters such as coastal thermal waters and fossil seawaters. Lithium leaching from the minerals was enhanced with increasing salt concentration and temperature. It was proved from the experiments using various salt solutions that NaCl solution and seawater are effective for the leaching of lithium from rocks and that even the altered seawaters containing low magnesium have the ability to extract lithium from rocks. This investigation suggests that the non-volcanic saline waters of high lithium content (e.g. fossil seawater) can be produced by a long term seawater-rock interaction at relatively low temperature without a contribution from the so-called “magmatic emanation”.