So let’s say you do your part—you recycle, sort out plastic bottles from aluminum, pick up old newspapers, and rummage through the trash looking for misplaced recyclable items. But have you ever wondered what happens to all that material? Where does it go? How is it recycled into a new product? Read on to take a crash course on the process of recycling!
At the curb, a large truck picks up items at specific locations and transports them to the materials recovery facility (MRF). As they are all clumped together, they need to be separated. The first step in the separation process is the V-Screen, which is a series of fast-moving rotators that isolate the paper and cardboard from the rest.
Next, strong magnets pick up metallic items (like steel and other ferrous metals), segregating them to be sent to a smelter, which will melt them down into their essential parts for reuse. Aluminum, on the other hand, is not magnetic, and continues along with other non-magnetic metals to an eddy current rotor. Eddy currents make strong fields of energy around non-magnetic metals, and thus separate the aluminum items.
Then, an optical scanner shoots hard blasts of air at plastics, knocking them off the conveyor belt into a separate bin. The final objects, glass, fall off the end of the conveyor belt into a large bin. This is just the sorting process. The real magic happens at the specific destination factories.
Paper is shipped to a mill and placed into a de-inker. The type/ink is essentially lifted directly off the paper! The inkless paper (now called “pulp slurry”) is then mixed with water into a mush by a machine, the pulper. A washing machine then spins the pulp slurry at a high speed with more water to remove contaminants. The cleaned pulp slurry is then pressed, which removes all water and any remaining ink. By this point, it’s hard enough to be cut by steam-heated rollers, which flatten it into a continuous roll of paper. Since paper degrades each time it’s recycled, it can be used in insulation, paper towels, and even toilet paper!
Metals, similarly, are sent to a mill; however, they are melted at extremely high temperatures into a molten liquid. The liquid is pressed into metal bars, called ingots. Once the ingots are cool enough, they are shipped to other manufacturers who remake them into other objects, like cans, file cabinets, and even components for cars and airplanes.
Plastics, unlike metals and paper, go to a reclaimer, which sorts the plastics based on density (ever see those numbers on the bottom of a container? They direct the reclaimer as to which plastics go where). Once the reclaimer sorts the plastics, they are sent to a grinder and ground up into little plastic flakes. They are then cleaned, and thrown into a furnace, which breaks them down into their more basic elements (carbon and hydrogen). The molten plastic can then be molded and shaped into the final desired item, like t-shirts, plastic bottles, and lawn chairs.
Glass is crushed at its reclaimer by a crushing machine. It is then referred to as cullet, and can be either sent to manufacturers to be mixed with virgin materials or melted into molten glass for reshaping. Items made from recycled glass include kitchen tiles, glassphault (an alternative to asphalt for paving streets), and glass sand, which cuts down on beach erosion.
There you have it: the short (and long!) of recycling, from your home back to store shelves. So the next time you toss a water bottle into a recycling bin, you can have the satisfaction of knowing exactly where it came from, and exactly where it will end up.