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Paper production: how paper is produced. Here are all the stages of paper production starting from virgin wood or recycled paper.
It takes 2 tons of wood to produce a ton of pulp which will create a further reduced amount of paper.
Phases of paper production starting from virgin wood
The wood arrives at the factories and is conveyed in a sort ofcentrifugewhich removes the barks. This instrument is called "drum" but we have nicknamed it "debarker".
Generally, the "drum" is powered by a turbine driven in turn by the steam produced by the combustion of the same barks. This phase, therefore, even if it causes loss of oxygen (felling of trees, deforestation) and harmful emissions (even the combustion of organic matter such as bark produces CO2) does not yet require an energy expenditure.
The bark is discarded because it is excessively rich in lignin, waxes and substances not useful for paper production. For the production of carta are employed cellulose fibers, substance that constitutes the wall of the plant cell.
The trunks, devoid of bark, are transferred to a kind ofgrinders able to reduce them into very small wood fragments (wood chips). The wood chips are further processed to become a pulp, virgin paper pulp. The stages of this transformation are different:
Massive use of water resources.
2. Alkaline cooking
For several hours and at a temperature of 158 ° C with high energy expenditure.
3. Lava wood
In the wood boiler it reaches 1,000 ° C and becomes a kind of wooden lava. Various chemicals are recovered from the boiler and come out melted in the form of lava. This phase produces a black waste, which will be burned to produce steam and electricity.
4. Second wash
The wooden lava is washed and bleached to then be conveyed to a machine called a thinner where the paper pulp is formed.
In an alkaline extraction tower, thepaper pulpit is bleached with chlorine dioxide. The pulp takes on the classic white color of the paper. The pulp is then partially dehydrated so as to allow the loss of part of the water absorbed with the second wash.
The pasta is placed in storage containers where it will still lose some water. The complete removal will take place by means of two rotating rollers that process over 1000 meters of paper per minute. In this phase, the percentage of water contained in the paper goes from 95 to 5%.
7. Sheets of paper
The presses shape the first sheets of paper. The presses are accompanied by analyzers capable of identifying any anomalies.
The sheets are then rolled up into huge rolls. Imagine a huge roll of blank paper. A roll contains more than 60 km of paper and weighs approximately 60 tons. The rolls are then cut into smaller coils ready for large distribution. Before distribution, some rolls are further cut.
9. A4 sheets
Some of the rolls are conveyed - by automatic robots on rails - to cutting machines in order to produce printing sheets in the classic A4 format. Production reaches 55,000 sheets per minute.
How paper is produced
For paper production starting fromrecycled paper pulpyou can read the in-depth article dedicated toPaper recycling.
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