Principle and equipment characteristics of automatic crushing and separation of lithium battery positive and negative recovery equipment

Lithium battery battery is a coating composed of particles. In the process of electrical preparation, a uniform wet slurry is coated on the metal collector, and then the solvent in the wet coating is removed by drying. It is often necessary to add polymer binder or dispersant, as well as carbon black and other conductive agents into the electric slurry. Although the solid content is generally greater than 30%, during the drying process, when the solvent evaporates, the coating will always experience certain shrinkage, and the solid substances are close to each other in the wet coating, forming a porous dry electrical structure.

Lithium battery has rapidly occupied the power source market of portable electronic and electrical equipment since its commercialization due to its significant advantages such as high voltage, large specific capacity, long service life and no memory effect, and its output has increased year by year. Lithium battery is an electronic consumable with a service life of about 3 years. If the discarded lithium battery is improperly disposed, the lithium hexafluorophosphate, carbonate organic compounds, cobalt, copper and other heavy metals contained in it will inevitably pose a potential pollution threat to the environment.

In addition, cobalt, lithium, copper and plastics in spent lithium batteries are valuable resources with high recovery value. Therefore, scientific and effective treatment and disposal of spent lithium batteries has not only significant environmental benefits, but also good economic benefits. Lithium battery is mainly composed of shell, positive and negative, electrolyte and diaphragm. It is formed by coating lithium cobalt oxide powder on both sides of the aluminum foil collecting fluid through PVDF which plays a bonding role; The negative structure is similar to the positive structure, which is composed of carbon powder bonded on both sides of the copper foil. At present, the research on the recycling of spent lithium batteries mainly focuses on the recovery of high-value positive and noble heavy metals cobalt and lithium, while the separation and recovery of negative materials are relatively small. In order to alleviate the increasingly serious resource shortage and environmental pollution caused by the rapid economic development. Therefore, the effective separation of the negative component materials of spent lithium batteries can promote the realization of waste lithium battery resource utilization in a large extent and eliminate its corresponding environmental impact. The commonly used methods for recycling spent lithium batteries include hydrometallurgy, pyrometallurgy and mechanical physics. Compared with the wet method and the fire method, the mechanical physical method does not need chemical reagents, and has lower energy consumption. It is an environmentally friendly and efficient method. Based on the negative structure characteristics of lithium battery, Xingmao Machinery adopts the combined process of crushing and screening and air separation to conduct separation and enrichment research on it, so as to realize the separation and recovery of negative copper, aluminum and carbon powder of waste lithium battery.

Working principle of waste lithium battery positive and negative recovery equipment:

Based on the positive and negative structure of lithium battery and the material characteristics of its constituent materials, copper and carbon powder, a combined process of hammer crushing, vibration screening and air separation was used to separate and recover the negative constituent materials of spent lithium battery. The results show that after crushing and screening, the grade of copper in the crushed material with particle size greater than 0.250 mm is 92.4%, while the grade of carbon powder in the crushed material with particle size less than 0.125 mm is 96.6%, which can be directly recovered; In the crushed material with particle size of 0.125~0.250 mm, the grade of copper is relatively low, and the effective separation and recovery of copper and carbon powder can be realized through air separation; In the process of air separation, when the operating air velocity is 1.00 m/s, the recovery rate of copper reaches 92.3% and the grade reaches 84.4%.

Characteristics of waste lithium battery positive and negative recovery equipment:

1. The combined process of hammer crushing, vibration screening and air separation can realize the resource utilization of copper and carbon powder in the negative material of waste lithium battery;

2. The negative material can be effectively separated from the carbon powder and copper foil by hammering and crushing, and then the copper foil and carbon powder can be initially separated by vibrating and screening based on the size difference and shape difference between particles. The results of hammering stripping and screening separation showed that copper and carbon powder were enriched in the particle size range of more than 0.250 mm and less than 0.125 mm, respectively, with the grade of 92.4% and 96.6%, which could be directly sent to downstream enterprises for recycling;

3. For the broken particles with particle size of 0.125~0.250 mm and low copper grade, the effective separation between copper and carbon powder can be achieved by air flow separation. When the air flow velocity is 1.00 m/s, a good recovery effect can be achieved. The recovery rate of metal copper can reach 92.3% and the grade can reach 84.4%