Process and Mechanism of Sulfate Roasting-Water Extraction of Lithium from Lithium Mica Ore

This is an essay in the field of metallurgical engineering. Taking a lithium mica ore in Jiangxi as raw material, the roasting-leaching, mixed acid ripening, direct acid leaching and alkali pressure cooking process were explored. Finally, the sulfate roasting-water leaching method was used to extract lithium from lithium mica ore. At the same time, the effects of roasting temperature, roasting time, additive type, additive amount, liquid-solid ratio and leaching temperature on lithium leaching rate were studied. The results show that roasting temperature has a great influence on lithium leaching rate, and the leaching effect of lithium is better in the appropriate roasting temperature range. 40% potassium sulfate, 20% sodium sulfate and 20% calcium oxide were added to the lithium mica ore, calcinated at 900 ℃ for 1 h, and the calcine was leached at room temperature for 1 h according to the liquid-solid ratio of 1∶1. The lithium leaching rate reached 94.87%. This shows that the effect of using sulfate as an additive to roast and extract lithium is better. Through the study of the roasting mechanism, it can be seen that the mineral structure is reconstructed after the addition of sulfate after high temperature roasting. The sodium and potassium ions in the ore are replaced with lithium ions in the lithium mica, so that they are separated from the insoluble aluminum silicate minerals to generate soluble lithium sulfate, which is then immersed in water and then into the solution.