How To Make Paper From a Tree
Everybody knows that paper is made from trees, bees make honey and ants make sugar (hang on…) but have you ever thought about the actual process that goes into making it?
First, workers harvest trees, mostly from special tree-growing areas called tree farms. After the trees are removed, more trees are planted in their place. While they are growing, the young trees produce lots of oxygen, and provide great habitat for deer, quail, turkeys and other wildlife.
The logs are transported to the paper company where they get a bath to rinse away dirt and other impurities before being turned into small chips of wood. The chips are then sorted according to size, and moved to the pulping operation, where they will be turned into pulp for making paper.
In the pulping stage, the individual wood fibers in the chips must be separated from one another. This can be accomplished using one or more pulping techniques. The type of paper that’s being made determines the pulping process that is used. The finished pulp looks like a mushy, watery solution. But if you look at it under a microscope, you will see that the individual wood fibers have all been separated.
Now it’s time to make paper out of our pulp. That mainly means getting the water out of the wood-fiber soup, since this papermaking stock is about 99% water. The first area in which this takes place is called the wet end of the papermaking machine.
First, papermakers spray the stock onto a long, wide screen, called a wire. Immediately, water begins to drain out the bottom of the wire. This water is collected so that it can be reused over and over again. Meanwhile, the pulp fibers are caught on the top side of the wire, and begin to bond together in a very thin mat. The fiber mat remaining on the wire is then squeezed between felt-covered press rollers to absorb more of the water.
Even when this wet end work is over, the pulpy stuff on the wire is still about 60% water. But now it’s time for the dry end.
In the dry end, huge metal cylinders are heated by filling them with steam. The wet paper, which can be up to 30 feet wide, passes through these hot rollers – sometimes dozens of them, and often in three to five groups. Heating and drying the wet sheet seals the fibers closer and closer together, turning them gradually from pulp into paper.
When you look at a piece of paper, can you find any difference in thickness in that single sheet? Probably not, thanks to a part of the paper machine called the calender – big, heavy cast iron rollers that press the drying paper smooth and uniform in thickness.
Sometimes the paper is coated, often with fine clay, to make it glossier and easier to print on.
A bit more drying, then rolled onto a big spool or reel, the pulp – a miraculous mat of fibers from trees – has become paper, ready for a thousand different uses.
Picture from pdtissues.com
Edited from an artivcle – paper college