Plastic recycling is the process or recovering waste or scrap plastics and reprocessing the material into other, useful products, completely different from their original state at times. For example, plastic bottles once used for soft drinks are recycled and turned into a park bench. Recycling is met with mixed reviews. Some say that more energy and money are put into the recycling effort than what you’ll ever get out. And others say that recycling is a very effective way to stop pollution, conserve landfill space, and help our planet recover from excess carbon emissions. Regardless of opinions, plastic recycling continues to be big business, and many of the recycled items can be commonly found in millions of homes, parks, schoolyards, etc.

Plastic polymers require greater processing to be recycled than glass or metal materials. Plastics have very low entropy of mixing, which is due to the high molecular weight of their large polymer chains. A macromolecule interacts with its environment along its entire length, so its enthalpy of mixing is quite large in comparison to that of an organic molecule with a similar structure. Heating the plastic alone is not enough to dissolve such a large molecule. And because of this, plastics must often be nearly identical in composition to mix efficiently.

When different types of plastic are melted together, they tend to undergo phase-separation, similar to oil and water, and set in these different layers. The phase boundaries cause structural weakness in the material, and the polymer blends are only useful in limited applications. Another barrier to recycling is the widespread use of dyes and fillers and other additives in plastics. The polymer is too viscous to efficiently remove fillers, and would be damaged by many of the processes that could cheaply remove added dyes.

The use of biodegradable plastics is increasing rapidly. If some of these get mixed in with other plastics during the recycling process, the final product becomes less valuable. Many of these problems can be solved using an elaborate monomer recycling process, in which a condensation polymer undergoes the inverse of the polymerization reaction used to manufacture it. This yields the exact same mix of chemicals that formed the original, which can be purified and used to synthesize new polymer chains of the same type.

Another potential option is the conversion of various polymers into petroleum by a much less precise thermal depolymerization process. This process would be able to accept almost any polymer or mix of polymers, including thermoset materials like vulcanized rubber tires, and biopolymers in feathers and other agricultural waste. Like natural petroleum, the chemicals produced can be made into various fuels and polymers. A pilot plant of this type exists in Missouri, using turkey waste as input material. A new process has recently been developed in which many kinds of plastic tubing can be used as a carbon source in the recycling of scrap steel.

If you’ve ever recycled in your life, then you know it’s a way to make some cash in a pinch. Recycling not only puts a few dollars in your pocket, it also helps out our environment. Metals, plastics, and other harmful substances line our streets. Often times in big cities, we’ll see the homeless with their collection of cans, bottles, copper wiring, etc.

They’re not the only people who are doing this. Many ordinary people from average communities go to great lengths to recycle old aluminum cans and glass bottles. It may look strange to walk alongside the road picking up cans, but you’re helping the environment and earning cold hard cash.

Recycling is one of the easiest things in the world to do. There is a lot of junk to be found in any town or city you live in. By taking a simple walk around the block, you can probably spot an entire shopping cart worth of junk just lying around. Cans are always the most common lying around, but you’ll also see bits of wire, hubcaps, bottles, countless plastic items, etc. (more…)

Paper recycling is the process of recovering waste paper and then remaking it into new paper products. There are three categories of paper that can be effectively used as feed stocks for making recycled paper.

The first is mill broke, followed by pre-consumer waste, and then post-consumer waste. Mill broke is paper trimmings and other paper scrap leftover from the manufacturing of paper, and is recycled internally in a paper mill.

Pre-consumer waste is material that was discarded prior to consumer use. And post-consumer waste is material discarded after consumer use, such as OM (old magazines), OTD (old telephone directories), and RMP (residential mixed paper). Any paper that is suitable for recycling is referred to as scrap paper.

Over 90% of paper pulp is made from wood, holding paper production accountable for around 35% of felled trees. Recycling of newsprint saves around 1 ton of wood while recycling 1 ton of printing paper saves a little more than 2 tons of wood.

(more…)

Steel, aluminum, and other types of metal are very common materials found across the globe. Every year they’re produced in vast quantities and used in multiple applications. The usefulness of metal was discovered thousands of years ago. And since then, technology has combined metals, making them stronger and more reliable than ever.Longevity, malleability, conductivity, and strength are the reasons they have been used over the years to provide us with many of the goods we use today. Various metals can be found in cars, computers, buildings, utensils, etc. Metals can remain viable products, even decades after they’re discarded.

Metals can be recycled indefinitely without losing any of their properties over time. One of the most recycled metals is aluminum. Like most metals we use, aluminum is an ore. The bauxite, a reddish clay-like ore, rich in aluminum compounds, is mined for the metal. The tricky thing about processing the aluminum is that it only exists in combination with other elements, usually oxygen.

(more…)