The investigation of lithium extraction by roasting with sulfating agent and water leaching from nepheline syenite rocks

In this study, the extraction of lithium from zinnwaldite concentrate containing 0.25% Li was investigated. The run-of-mine ore originated from nepheline syenite rocks in Kırşehir, Turkey, and contained 216.3 ppm Li. Firstly, the ore was beneficiated by a flotation process to increase the lithium content. Then, it was subjected to roasting and water leaching processes, respectively. In the roasting process, calcite and gypsum were used as additives to form dissoluble lithium sulfate for the next process. Additionally, the effect of roasting temperatures (750, 850, 950, and 1000oC) and times (30, 60, 90, 120, and 240 min) was examined along with different ratios of additives to concentrate to find the optimal conditions. Accordingly, the calcined product from the roasting process was dissolved in water by determining the optimal leaching temperature, time, and water/solid ratio. Consequently, a lithium product was obtained from the concentrate with 93.3% extraction efficiency. Finally, the mother liquor contained 30 mg/dm3 Li, the production of Li2CO3 from mother liquor will be investigated in case of production of the sample at the optimal conditions of roasting and leaching in further studies.