With the rapid development and application of lithium-ion batteries, a large amount of waste lithium-ion battery materials have emerged. It is understood that waste lithium-ion batteries contain high-value metals such as cobalt and lithium, and the anode copper (approximately 35%) is a widely used primary production material, which can be used as an additive in plastics, rubber, etc. Therefore, the useful separation of waste lithium-ion battery anode materials is crucial for maximizing the capitalization of waste lithium-ion batteries and eliminating their corresponding environmental impact. In the future, the recycling and processing of lithium-ion batteries, in addition to recovering valuable resources, will inevitably require the proper disposal of substances that can adversely affect the environment. Furthermore, based on the development of lithium-ion batteries and future environmental requirements, future lithium-ion battery crushing equipment production lines will develop towards integration and diversification.
Mechanical processing technology is currently a crucial technology for metal recovery from waste lithium-ion batteries. Therefore, its recycling has progressed alongside the development of crushing technology, with shredding and crushing separation technology being relatively mature. This technology is already being applied in lithium-ion battery recycling. With increasingly stringent environmental requirements, this technology is bound to be widely used in lithium-ion battery recycling. Jixin has developed a lithium-ion battery crushing and recycling equipment line. Waste batteries are fed into a shredder for shredding, and then into a specialized crusher for further crushing. This crushing breaks down the positive and negative electrode plates and separator paper inside the battery. The broken material is then fed into a collector by an induced draft fan, and then a pulse dust collector collects and purifies the dust generated during crushing. The material entering the collector then passes through an airlock and enters an airflow separator. Airflow and vibration collect the separator paper from the positive and negative electrode plates, while also collecting the dust generated by the airflow separator. Finally, the mixture undergoes a combined process of hammer crushing, vibrating screening, and airflow separation to separate and recover the positive and negative electrode components of the waste lithium-ion batteries. The metal grades of the experimental samples and the separated enriched products were analyzed using ICP-AES. The results showed that after crushing and sieving, the copper and aluminum grades in the crushed material with a particle size greater than 0.250 mm were 92.4%, while the grades in the crushed material with a particle size less than 0.125 mm were 96.6%, both of which can be directly recovered. In the crushed material with a particle size of 0.125~0.250 mm, the copper and aluminum grades were lower, and air separation could be used, with an operating airflow velocity of 1.00 m/s.
After pretreatment, the resulting crushed products from waste lithium-ion batteries are generally complex in composition, including the battery casing, positive electrode material, negative electrode material, copper current collector, aluminum current collector, separator, and electrolyte, requiring further separation and processing. The main metal recycling processes for waste lithium-ion batteries include physical sorting, pyrometallurgical methods, and hydrometallurgical methods. Regarding the uses of waste lithium-ion batteries, we understand that cobalt, lithium, copper, and plastics found in them are all valuable resources with extremely high recycling value.
Waste lithium-ion batteries mainly consist of a casing, positive electrode, negative electrode, electrolyte, and separator. The positive electrode is formed by coating lithium cobalt oxide powder onto both sides of an aluminum foil current collector using PVDF, which acts as a binder. The negative electrode has a similar structure, consisting of carbon powder bonded to both sides of a copper foil current collector. Common methods for recycling waste lithium-ion batteries include hydrometallurgy, pyrometallurgy, and mechanical-physical methods. Compared to hydrometallurgy and pyrometallurgy, the mechanical-physical method using lithium-ion battery shredders eliminates the need for chemical reagents and consumes less energy, making it an environmentally friendly and efficient method.
(1) Physical sorting method
Physical sorting methods are based on differences in material properties such as particle size, density, and magnetic properties. Key methods include screening, gravity separation, flotation, and magnetic separation. First, a vertical shearing machine, a pneumatic shaking table, and a vibrating screen are used to classify waste lithium-ion batteries, yielding positive electrode materials, negative electrode materials, separators, and current collectors after crushing and sorting. The positive and negative electrode materials are then heat-treated at 500℃, followed by flotation to separate lithium cobalt oxide and graphite. This process achieves a lithium cobalt oxide recovery rate of up to 97%.
(2) Pyrometallurgical method
Pyrometallurgical methods involve pre-treating waste lithium-ion batteries by removing the battery casing and then reducing and roasting the mixed materials. Organic substances such as binders escape as gases, while most of the low-boiling-point lithium oxide escapes as vapor, which is then absorbed and recovered using water. Other metals (copper, nickel, cobalt, etc.) form metal alloys, which are subsequently processed using hydrometallurgical techniques. Fluorine and phosphorus in the electrolyte are solidified in the slag. Umicore International Ltd. owns a waste battery recycling plant in Oren, Belgium, with an annual processing capacity of 7,000 tons.
my country's new energy vehicles primarily adopt pure electric power, making the disposal of expired lithium-ion batteries a key government concern. The lithium-ion battery recycling industry is of great significance, and this pilot program for the recycling and utilization of power lithium-ion batteries will accelerate the improvement of the market's power lithium-ion battery recycling system.
