Recycling
The man grabbed his soda and guzzled the last drops down. He playfully shot it into the recycling can like a basketball. (Did you know that an aluminum can is able to power a TV for three hours?) Luckily, he didn’t throw it into the garbage. The can landed with a hollow plunk. Flies buzzed around each day, attracted to the sweet smell. Soon, the can was crushed from all the other recyclables that were piling onto it.
One cold winter day a garbage truck rolled onto the curb. A large shaggy man with a poorly shaved beard in a dirt-smeared greenish uniform jumped out from the back of the truck. He picked up the bin and dumped all the materials into the back. Suddenly, he pulled a large lever and there was a grinding sound at the back. Everything was immediately smashed flat. He opened the door, and the garbage men drove away into the distance. Every time they went on any speed bump, all the garbage at the back would be thrown up and down. The garbage was thrown back and forth once more when the driver made a sharp turn into the entrance of a facility and screeched to a halt. He began to back up while red lights in the back flashed repeatedly. Another man to his right gave the driver the signal that he was backed up enough, and the driver pulled down the lever, opening up the back of the truck. The man picked up a sleek black walkie-talkie and gave a brief message. Suddenly, the gate of the port opened up. Inside, there was a large container connected to a giant conveyer-belt. A lever was pulled and down came the garbage, flying down in a flurry. If you pictured it in your mind, it would look like geese in flocks suddenly seeing bread on the ground and coming down in waves. Workers each had material to sort, which included newspaper, cardboard, aluminum, steel can, glass, and plastic.
Garbage tumbled down a chute landing in a giant tray. The workers pushed the cans into the eddy current separator. The eddy current separator uses eddy currents, which is the actions of something containing movable electric charges exposed to a changing magnetic field. There are many forces created by this: propulsion, attraction, repulsive, and drag affects. The eddy current separator uses propulsion and repulsion. Repulsive forces are used to separate the metals and the non-metals. Then the eddy current separator uses propulsion by launching the metals off the belt, while the non-metals fall due to the effect of gravity. This is like when two poles are pushed against each other in two magnets, except all they do is push away from each other. The same concept is shown here, except the poles don’t make a difference. The aluminum can face any way and be launched off the belt.
Next, the cans are cut into equal blocks so the machines have an easier time doing their job. Then they chemically and mechanically clean the blocks of aluminum to minimize oxidation losses. Oxidation is the act when oxygen combines with another element, particularly metal. The effect of this is a chemical reaction: if aluminum oxidizes, it might become flaky or weaker.
The orange flames danced back and forth, as blocks of aluminum rolled into the furnace. They crackled while the blocks began to degrade into mush. The crisp wavy smoke rose to the ceiling, finding its way out of the furnace. This is the next step in recycling aluminum. Temperatures inside start from 1202 degrees and can reach up to 1562 degrees Fahrenheit. Dross is a mass of solid substances in a confined amount of liquid, gas, or solid on a molten metal. It is usually found on low-melting-point metals.
Dross actually is fairly easy to skim off. Moreover, the dissolved hydrogen is then removed, typically by chlorine and nitrogen gas. Aluminum is the most recyclable material; it only takes 5% of its own energy to recycle it.
Scientists take samples of the aluminum for spectroscopic analysis – they do this to test if they need to add more high purity aluminum, zinc, copper, manganese, silicon, or magnesium ,depending on the final product wanted. Recycled aluminum can be formed into ingots, billets, and rolls of sheets.
In addition, aluminum is the biggest saver out of all: it saves 64,300 kilowatt hours per ton of material reclaimed. Aluminum is so efficient that 75% of aluminum cans that are in use today were created in 1988!
A brand new can rolled fresh out of the line and then it took another long journey. One day, a man walked up to a sleek vending machine. He inserted a crumpled dollar and the machine responded with a whir. The thud of the can dropping, echoed, and the man took it slowly, sipped it, drained it, and threw it into the recycling bin.