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The Paper Milling and Re-Use Process
The History of Paper
The Egyptians are generally credited with producing the earliest form of writing substrate more than 3,000 years ago, known as papyrus, but in 105 AD the Chinese began the process of papermaking as we know it today.
In the United States, papermaking began in the early 1600’s, and a few of the original mills continue to produce a very small amount of paper; for demonstration purposes. Some of the American mills still operating today are the same mills that produced paper used during the Civil War. And the oldest operating corporation in the world, the huge Swedish papermaker Stora-Enso, has been in operation for more than 700 years.
In the face of the internet and the digital age, paper remains a constant, reliable vehicle as the most commonly used surface upon which images and words may be reproduced, and in which almost every product may be packaged. And paper is still made from the Earth’s only renewable resource; trees!
How Paper is Produced Today
The modern paper manufacturing process today differs from ancient methods, only in the size of and technological advances in the machinery used in modern paper mills. The raw material, trees, is the still the same raw material that was used 2,000 years ago. Today, responsible paper manufacturers around the world take even greater care in protecting this natural resource as stewards of forests and timberland; harvesting at proper growth cycles and replanting and reforesting this valuable land for future use.
Paper mills operate in a linear production-flow. Harvested trees are debarked, chipped and pulped into a lava-like material. This material then flows into huge vats, filled with various chemicals that begin to bleach it to a lighter shade, and whitening agents are added to the mix. The pulped material continues to flow onto huge conveyer screens and then through a series of huge rolling cylinders, smoothing the flow to paper-like substance. The flow continues through a series of dryers and is wound onto heavy iron cores, to be further processed and then sent to the mill’s rewinding and finishing station.
A large mill will produce thousands of tons of white paper, every day. Paper is shipped from a mill in two forms; rolls and sheets. Rolls are destined for end-users whose presses are referred to as web or roll-fed. Sheets can be as small as letter-size writing paper or as large as 56 x 80”. Common items produced on paper are newspapers, books, magazines, envelopes, posters and folding cartons.
Papermaking and Recycling
Paper mills that own and cultivate forests and timberland are called integrated mills. Mills that do not own such land are called non-integrated mills. Non-integrated mills produce paper in the same fashion as integrated mills, but must turn to the marketplace to purchase their raw materials. For such mills that raw material is called pulp. Pulp is available in various forms and is usually made from virgin fibers or is made with recycled fibers. Pulp made from recycled fibers can contain a minimum of 10% of post-consumer waste or as much a 50% post-consumer waste.
Most integrated mills do produce recycled paper, and do so by adding a percentage of recycled pulp to the production. All mills can make paper made from 100% virgin fibers but no mill can make paper from only recycled fiber and must add some percentage of virgin fibers to maintain the structure of the paper.
Metropolitan Recycling is a major contributor to the manufacture of pulp and paper made with post-consumer waste. Most of the paper processed by Metropolitan Recycling reaches our facility after it has been used by business-consumers. It is then processed and returned, to be re-used up to seven more times again.