How Car Batteries are Recycled
Because of the materials that comprise a typical automotive (lead-acid) battery, there are three main “streams” in the recycling process for this particular product. Most of today’s battery cases are made of polypropylene, which is easily recycled into new plastic products. Before plastic found it’s way into the market, all batteries were made from hard rubber, the same material that makes up bowling balls.
Step One – Separate
After the obsolete batteries are collected, they are sent to a facility for sorting and processing. According to Battery Council International, the batteries are first placed in a machine called a “hammermill,” which crushes the batteries into small, nickel-size pieces. These pieces then are placed in a tank, where the dissimilar densities of the materials cause some to sink (lead), some to float (hard rubber and plastic) and liquids to go into solution (battery acid). From here, the materials are separated and treated individually.
Step Two – Lead and Plastic
The lead from the tank is melted in furnaces and then poured into molds called “ingot” molds. These molds can range in weight from 65 to 2,000 pounds. While the lead is still in a molten form, impurities (also known as “dross”) float to the top of the mold and are skimmed off to further purify the lead. Once the lead is cooled, it is shipped to battery manufacturers for reuse in new batteries.
After being scooped from the tank, battery plastic is separated from the hard rubber and recycled in a similar manner to most other plastics. It is washed and dried, then sent to a recycling facility where it is placed in an extruder. An extruder is a machine that uses heat and pressure to melt plastic. The plastic is cut into homogeneous pellets and sent to be made again into new batteries. Rubber cases cannot be recycled, but it makes a good carbon additive in the secondary lead smelting process.
Step Three – Battery Acid
The third main material, battery acid, can be reused. This method involves adding a neutralizing agent to the acid, breaking it down into water and a salt compound. The water is then tested for cleanliness and is typically released into a public sewer system.
To recycle car batteries in your area, use Earth911′s recycling locator.
