With the explosive development of the new energy industry, the price of lithium electric materials has skyrocketed. At present, lithium element has become the most valuable resource in waste lithium batteries. Therefore, how to realize efficient lithium recovery from waste lithium batteries is the most valuable technology for lithium electric recovery.

Because the wet process process is too long, lithium loss is too large, conventional process has the shortcomings of low lithium recovery and high operating cost, so front-end lithium extraction is a prerequisite for realizing efficient lithium recovery. At present, there are many process routes on the market, which are briefly introduced as follows:

1, carbothermal reduction method

Using carbon (coke, activated carbon or graphite) as reducing agent, in low oxygen or nitrogen atmosphere, at a high temperature (550-700 degrees) for reduction reaction, and then it is soaked in water to get lithium rich solution, and further purification, concentration to get lithium leaching solution, the follow-up can be made according to customer requirements of the corresponding specifications of lithium carbonate products.

The advantages of this method are high reliability of equipment, simple and controllable process, high energy consumption, and comprehensive recovery of lithium up to 85-88%.

2, hydrogen reduction method

Using hydrogen (pure hydrogen or nitrogen-hydrogen mixture) as reducing agent, solid phase reaction is carried out at a low temperature (500-600 degrees), and then it is immersed in water to get Li-rich solution, and further purified to get Li-containing leaching solution, which can then be made into the corresponding specifications of lithium carbonate or lithium hydroxide products according to customer requirements.

The advantages of this method are high reaction efficiency, high lithium and low impurity in the purification liquid, low energy consumption, comprehensive recovery of lithium up to 88-92%, and certain requirements on the source of hydrogen.

3. Natural gas reduction method

Using natural gas as reducing agent and nitrogen as protective atmosphere, gas-solid reduction reaction is carried out at a high temperature (600-700 degrees), and then it is immersed in water to get Li-rich solution, and further purified to get Li-containing leaching solution. Subsequently, lithium carbonate products of corresponding specifications can be made according to customer requirements.

The advantages of this method are simple raw material acquisition, high reaction efficiency, low energy consumption and comprehensive recovery of lithium up to 85-90%.

4. Ammonia reduction method

Ammonia gas is used as reducing agent, gas solid reaction is carried out at a high temperature (800-1000 degrees), and then it is soaked in water to get Li-rich solution, and further purified to get Li-containing leaching solution. Subsequently, lithium carbonate products with corresponding specifications can be made according to customer requirements.

The advantages of this method are simple raw material acquisition, high reaction efficiency, low energy consumption and comprehensive recovery of lithium up to 85-88%.

5, sulfuric roasting

Using sulfuric acid as the transformation agent, roasting at a high temperature (500-700 degrees), lithium is converted into easily dissolved lithium sulfate, nickel, cobalt, manganese and other impurity elements mainly exist in the form of metal oxides, and then after water leaching to obtain Li-rich solution, and further purification to obtain Li-containing leaching solution, the follow-up can be made according to customer requirements of the corresponding specifications of lithium carbonate products.

The defects of this method are high corrosiveness of equipment, high fineness requirement of raw materials, high impurity content of liquid containing lithium, difficulty in removing impurities, high energy consumption, lithium comprehensive recovery rate of about 85%.