A study on the lithium extraction from the clay-type lithium ore by using the activation-roasting and water leaching technique

With the increasing demand for lithium resources, the development technology of clay-based lithium ore has become the focus of attention in the industry. This paper takes a clay-type lithium deposit in Yunnan as a case study. For example, the utilization of lithium resources in clay-type lithium ore is realized through thermal-chemical activation roasting and water leaching of lithium. In this paper, the hot chemical activation roasting of clay lithium ore is studied.The effects of additives, calcination temperature and time on the extraction of lithium were investigated. The effects of leaching temperature, time and liquid-solid ratio on the activated product water were investigated.The process of dissolution and diffusion of soluble substances in water leaching was analyzed. The amount of sodium sulfate is 30%, the roasting temperature is 700 ℃, and the roasting time is 60 min.Under the conditions of 60 min, leaching temperature and leaching time were 30 ℃ and 1 min respectively, and the liquid-solid ratio was 1 mL/g, the leaching rate of lithium was 89%. The XRD, XPS and TOF-SIMS analytical results of the calcined samples show that the clay-type lithium ore had reacted with lithium chlorite, kaolinite and montmorillonite to have produced sillimanite and albite through the action of sodium sulfate, and the lithium in the ore has been converted into the soluble lithium sulfate. Based on the time-of-flight ion mass spectrometry and XPS analytical results, the extraction mechanism of lithium from the ore has been explored. The thermochemical action of the clay-type lithium ore led to the collapse and defects of structures of silica-aluminum minerals, then resulted in the formation of soluble lithium sulfate through the reaction of free lithium on the surface from the structure of mineral, and the additive of sodium sulfate. The green and efficient extraction of lithium has been realized through the dissolution-diffusion of lithium into the solution in the water leaching process of the clay-type lithium ore.