The significance of recycling used batteries primarily lies in the fact that improper disposal or improper stacking for extended periods can lead to the dispersal of harmful substances such as mercury, nickel, lead, and chromium. The damage these harmful substances cause to groundwater sources and soil is **severe**, as the leachate from a single AA battery is enough to render 1 square meter of soil unusable for agriculture, and a single button battery can contaminate 600,000 liters of water (which is the water consumption for a person's entire life). The lead in rechargeable batteries can damage the circulatory, digestive, and nervous systems, while cadmium can cause kidney damage and osteomalacia among other serious conditions.

Battery recycling: If discarded batteries are not disposed of properly, they can contaminate our water sources, erode the crops and land we depend on for survival, and threaten our living environment. Therefore, it is necessary to recycle and reuse used batteries. This not only prevents environmental pollution but also allows for the reuse of valuable components, conserving resources.

Battery Recycling, Why Recycle Used Batteries:

Disposable batteries, when discarded in large quantities into the environment, can affect the pH of soil and water systems with their acidic or alkaline electrolyte solutions, leading to acidification or alkalization. Heavy metals like Hg and Cd, when absorbed by organisms, enter the human food chain through various pathways, accumulating in the human body and causing deformities or mutations, and even leading to more severe consequences. A single button battery can contaminate 600,000 liters of water, equivalent to an individual's lifetime water consumption. A single battery left in the ground can render one square meter of land unusable. Among the five substances that pose the greatest threat to the natural environment, batteries contain three.

Battery Recycling, Features of Lithium-ion Batteries:

1. High open-circuit voltage: The single battery cell voltage typically reaches 3.6V, which is three times that of a standard nickel-hydrogen or nickel-cadmium battery.

2. High Energy Density: Taking the UR18650 battery as an example, its energy density by weight and volume can reach 125Wh/kg and 300Wh/cm³, respectively.

3. High output power, suitable for high current charging and discharging.

4. Excellent cyclic performance, no memory effect.

5. Self-discharge rate low: At room temperature, the self-discharge rate is less than 12%, with nickel-cadmium batteries (about 25%/month) and nickel-metal hydride batteries (about 15%/month). Due to the formation of a solid electrolyte interface (SEI) layer on the carbon negative surface during the charging and discharging process, this layer allows ions to pass through but not electrons, effectively preventing the self-discharge process.

6. Recharge/Discharge: The Coulomb efficiency can reach after cycles.

7. Wide operating temperature range: -25 to +45°C; if the thermal stability of the positive material and electrolyte can be improved, the operating temperature range can be expanded to -40 to +70°C.

8. Eco-friendly Chemical Energy: Lithium-ion batteries are free of pollutants and serve as an extremely environmentally friendly chemical energy storage device.

9. Long cycle life: With 80% discharge depth, the cycle life exceeds 1200 cycles; with a shallower discharge depth, the cycles can reach over 5,000.

10. Excellent processing flexibility, capable of producing batteries in various shapes, such as cylindrical and soft-pack. Consequently, lithium-ion secondary batteries offer superior advantages compared to traditional secondary batteries.

Battery Recycling Methods: What are the ways to recycle used batteries?

1. The method for heat treatment involves grinding the old batteries and sending them to the furnace for heating. During this process, the emitted Hg can be extracted. When the temperature is higher, zinc also evaporates, which is also a precious metal. The melted iron and manganese combine to form the manganese iron alloy required for steelmaking.

2. Wet Processing: In this wet processing unit, all types of batteries, except for lead-acid batteries, are dissolved in sulfuric acid. Various metals are then extracted from the solution using ion exchange resins. The raw materials obtained through this method are purer than those from the heat treatment process, and thus, they command a higher market price. Moreover, 95% of the substances contained in the batteries can be extracted. Wet processing eliminates the sorting step (since sorting is a manual operation, it increases costs).

3. Vacuum Heat Treatment Method: First, sort out nickel-cadmium batteries from the waste batteries. Heat the waste batteries in a vacuum, where Hg rapidly evaporates, allowing for recovery. Then, grind the remaining material and use a magnet to extract iron. Nickel and manganese are then extracted from the remaining powder. The processing cost for one ton of waste batteries is less than 1500 marks (approximately 6,345.18 yuan today)!!

Battery recycling, the process of recycling and handling used batteries generally includes the following points:

1. Category: By smashing recycled batteries, removing the zinc casing and battery bottom iron, extracting the copper cap and graphite rod, the remaining black material consists of manganese dioxide and other mixtures as the battery core. After separately collecting these materials and processing them, we can obtain some useful substances. The graphite rods can be washed, dried, and reused as electrodes.

2. Zinc Shot Production: After cleaning the peeled zinc shell, place it in an iron pot and heat it, then maintain the temperature for 2 hours. Remove the floating slag on top, pour it out to cool, and then drip it onto an iron plate. Wait until it solidifies to obtain zinc shot.

3. Copper Sheet Recycling: We can flatten the copper caps, wash them with hot water, then boil them in a solution of 10% sulfuric acid for 30 minutes to remove the surface oxidation. After removing and washing, dry them to obtain copper sheets.

4. Recycling: We place the black material into the tank and then add 60°C warm water, stirring for an hour to dissolve it completely. After that, we allow it to settle, filter, and wash the filter cake twice, collecting the mother liquor.

5. Manganese Dioxide Recovery: We wash the filtered sludge with water three times, filter it, then dry the filter cake in a pot to remove some carbon and other impurities. After that, we immerse it in water and stir thoroughly for 30 minutes, filter it again, and then dry the filtered cake at 100-110°C. This process allows us to obtain manganese dioxide.