Development of typical lithium minerals roasting for high lithium extraction

As a new type of energy and strategic resources, more and more attention has been paid to the exploitation and utilization of lithium resources. The main ways for obtaining lithium containing compounds are the extractions of lithium from brine and from ores. The development trend of lithium extraction from lithium ores is to further reduce production cost and to decrease energy consumption through technological innovation of lithium extracting technology. This review summarizes the development of main lithium extracting techniques, and the main lithium extraction methods is evaluated from the aspects of roasting conditions, lithium recovery, energy consumption of roasting and scale of equipment. Compared to the limestone roasting method, extractions of lithium by sulfuric acid roasting, sulfation roasting, chlorination roasting and alkali digestion methods have the advantages of low energy consumption and high lithium extraction efficiency. It is found that the high temperature roasting of lithium ore is an indispensable and a critical step whatever lithium extraction process is adopted. On this basis, it makes a detailed comparison between the widely used rotary kiln roasting technology and the fluidized roasting technology. Although the rotary kiln roasting technology has become mature, there are still some problems such as high energy consumption, non-uniform roasting ores and melting ring at high temperature. This provides a development space for the fluidized roasting of lithium ore. Compared to rotary kiln roasting, fluidized roasting has the advantages of high defluorination/transformation efficiency, large capacity and low power consumption, but it also faces great challenges. The development of lithium ore fluidized roasting is important for improving the roasting efficiency and production capacity of lithium minerals and reducing the energy consumption of roasting process.