Clay-type lithium ore extraction technology

At present, the degree of attention paid to the selection and processing technology of clay-type lithium ore is not enough, the lithium extraction process is not mature, and the separation and extraction technology of clay-type lithium ore is still in the exploratory stage. The main extraction technologies currently studied can be divided into sulfuric acid leaching, roasting-leaching, external field enhanced leaching and acid-base combined method.

1 Sulfuric acid leaching method

The sulfuric acid leaching method uses acid solution as a leaching reagent to directly extract lithium from the ore. The mechanism is that sulfuric acid reacts with metal ions in the ore to form soluble lithium sulfate, thereby converting the lithium ions fixed in the ore into the solution.

2 Roasting-leaching method

The roasting-leaching method is to activate the clay lithium ore by roasting or roasting with additives, and then use water, acid or salt solution to leach and extract lithium. Among them, the roasting-acid leaching method is to roast the ore sample first, and then use acid leaching to form a soluble metal lithium salt to convert the lithium in the ore into the solution.

The additive roasting-water leaching method is to mix the ore sample with a certain amount of additives, roast the mixed material, and then leaching the roasted mixture with water. Common additives include natural materials such as limestone and gypsum and compounds such as sulfates, carbonates, hydroxides, and chlorides. Its mechanism is to add additives to react with lithium-containing minerals in the ore during the roasting process to form soluble metal lithium salts, and then convert the lithium in the ore into the solution through water leaching.

The roasting-ion exchange leaching method is to first decompose and activate the lithium-containing minerals in the ore by roasting, and then react with the ore sample through a salt solution. The cations in the salt solution exchange ions with the lithium in the ore, and then form soluble metal lithium salts to convert the lithium in the ore into the solution. This method is more suitable for carbonate-type lithium resources, because the lithium in carbonate-type lithium resources is adsorbed between the layers of the mineral structure and is easier to exchange.

3 External field enhanced leaching method

The external field enhanced leaching method mainly uses ultrasound, electrolysis or microwave to mature the minerals, break the stable state of lithium in the ore, promote lithium leaching, and thus convert the lithium in the ore into the solution.

4 Acid-base combined method

The acid-base combined method is mainly used in alumina production. This method combines the processes of alkali and acid. Some researchers have improved this method and applied it to lithium extraction.

The acid-base combined method has simple operation, low equipment requirements, low energy consumption, controllable process parameters, small amount of residue, and low production cost, which has opened up a new way for the development and utilization of lithium-rich clay.

Clay-type lithium ore is currently in the initial stage of development. In the future, the deep development of clay-type lithium ore requires further optimization of the existing extraction process, improving the leaching rate and comprehensive recovery rate of lithium, and reducing energy consumption and cost.