Recycling

=Recycling= a page by Adrian Boyarsky and Russell Bray == = = =How is Paper Recycled?= 1.Break paper down Using water and chemicals, paper is broken down int cellulose fibers. This happens in a pulper, which chops the paper. Heat breaks down the paper further. The old paper becomes a mushy substance known as pulp. 2. Removal of not paper contaminants

Pulp is pushed through a screen which filters out bits of plastic and glue. The paper is then spun to remove things like staples and other heavy contaminants.

3. Removal of ink

Ink is removed by first washing the paper with water. Then, air bubbles and soap are used to force the rest of the ink from the paper. A frothy layer forms on top of the pulp containing the ink. This layer is removed.

4. prepare paper for processing

The pulp is mixed with discoloring chemicals. If the paper is going to be white, the pulp is mixed with a bleaching agent. Any large bundles of fibers are seperated and the fibers are caused to swell by beating them.

5. Making of New Paper

The watery pulp is poured onto a flat screen that moves through a series of presses. The water begins to drain and the paper fibers begin to bond together. The paper is moved through heaters to dry it out completely. A coating can be applied to make glossy paper. Finally, the paper is wound into giant rolls to be shipped. Resources:

[|http://www.tappi.org]/paperu/... /earth_answers/ EarthAnswers_Recycle.pdf [|www.paperrecycles.org]. []

= = =How Is An Aluminum Can Recycled?= 1. Condensing the aluminum cans Cans are crushed and condensed into bales that weigh over 1200 pounds. The bales are sent to aluminum manufacturing companies for processing.

2. Shredding the bales of aluminum The aluminum companies shred the condensed cans into small pieces of aluminum about the size of a potato chip

3. Removing Decorations The decorations on the cans are removed through a burning process.

4. Melting the aluminum The aluminum pieces are melted in a furnace. The molten aluminum is then poured into huge 25 foot long ingots.

5. Rolling into Sheets The large ingots are fed into rolling mills. The rolling process flattens the aluminum into sheets that are one-hundredth of an inch thick. New aluminum is usually blended with the recycled aluminum during this process. At this time the aluminum cools.

6. Packaging for shipping The sheets of aluminum are coiled and shipped to can makers.

Resources [] [|http://www.uoregon.edu/~recycle/after_collection.html] [] []

=How is glass recycled?= Glass is made with silica (sand) but can be combined with other substances to make colored glass. Blue Glass is made by adding cobalt compounds to the molten glass during the manufacturing process. Brown glass is made by adding Nickle, Sulfur and Carbon. Green Glass is made by adding metals like iron, chromium and copper.

During recycling, colors can not bbe mixed together. Each color glass must be separated. Some states do not recycle colored glass at all. 1. Removal of contaminated glass Any glass that has had color mixing will not be melted down. Instead this glass will be used mainly in insulating material or concrete.

2. Glass is crushed All glass is crushed into tiny pieces with are collectively known as cullet

3. Glass is melted The cullet is melted. The reason recycled glass is important is because it melts at a lower temperature than the raw materials which saves energy in the manufacturing process.

4. Molten glass used to form new products The cullet is molded into desired shaes such as jars and bottles and sent to companies for filling and labeling.

Resources: [] []

=Recycling Plastics= Traditional recycling of plastics are similar in process to glass or aluminum, yet plastics have been difficult and expensive to recycle because these methods do not produce a pure, high quality material as an end product. There is a shift towards going "greener" as more and more users are recycling their plastics and this in turn is pushing industry into making a cost effective solution to recycling.

Akio Kamimura and Shigehiro Yamamoto report invention of an efficient new method to depolymerize polyamide plastics that does not require costly pressure chambers, extreme temperatures, or high energy inputs. The method relies on ionic liquids that change nylon-6 into captrolactam, its component compound and could be recycled and reused multiple times. Their results were published in the ACS Publication Organic Letters entitled [|An Efficient Method To Depolymerize Polyamide Plastics: A New Use of Ionic Liquids]

A branch of previously un-recycled products are thermosets (such as computer circuit boards and electrical insulation). These plastics are very hard and heat resistant, yet have many addititves that are difficult to extract from the usuable polymers. Antonio Broekhuis and colleagues describe development of another thermosetting plastic that can be melted and remolded without losing its original heat-resistance and strength in their ACS Publication [|'Self-healing' Polymer May Facilitate Recycling Of Hard-to-dispose Plastic].