Effect of mechanical activation on lithium and alkali cation release from dolomitic clay wastes of boron processing plant

With the significant increase in lithium demand and production, alternative resources such as lithium-bearing clays have increasingly attracted attention and have been considered as a potential source. In addition to conventional Li recovery methods such as acid treatment and roasting, more economical and environmentally friendly techniques such as mechanical activation followed by water leaching are also being considered. In Türkiye, wastes from boron processing plants, containing approximately 900 ppm of lithium and mainly of dolomitic clays and unrecovered boron minerals (~10-13% of waste), are considered as a potential lithium source. However, due to high dolomite and boron mineral contents, the waste material may release significant amounts of alkaline earth ions such as Na+, K+, Mg2+, Ca2+, and B2O3 during leaching, which may interfere with lithium extraction from the solution. In this study, the leaching behavior of lithium, alkali ions, and other possible elements (e.g., B2O3, Fe3+, and Al3+) from both raw clay waste and mechanically activated forms of this waste material was investigated in detail. The results showed that water leaching without sodium salt of activated waste samples achieves about 44.7–57.7% lithium recovery, yielding high lithium concentrations (80–115 ppm), low levels of alkali ions (4430 ppm Na+, 114 ppm K+, 20 ppm Ca2+, and 7 ppm Mg2+), and almost no detectable Fe3+ (<0.2 ppm) or Al3+ (0.07 ppm) ions. On the other hand, a single problem was encountered where 0.95 % of B2O3 concentrations did not decrease in water leaching at even room temperature.