-The logs of coniferous trees are saturated with water and de-barked.
- The wood is ground down, which softens the ligin, and the mechanised forces separate the fibres to form 'groundwood pulp'.
- This pulp is screened to accept 1-2mm pieces, with larger pieces being re-circulated for additional screening.
-The resulting pulp can only be used for low-grade paper such as newspaper, so the pulp is bleached with peroxide or sodium hydroxide.
-This is the most widely used method in the UK for producing wood pulp.
- After de-barking, the hard- and softwood logs are cut into 2cm chips along the grain.
- These are pounded into fragments and screened.
- The resulting pulp is stored and treated with either an acid or and alkali to break down the lignin.
- Most chemical pulp is made by the alkaline kraft process, or sulphate process, which uses caustic soda and sodium sulphate to 'cook' the wood pulp.
- The amount of fibre produced is lower than with mechanical methods, but the fibres are longer, stronger and contain fewer impurities.
- Recycled paper and board used for waste pulp is often used for lower grades of paper, as its strength, durability and colour are not as good as virgin fibres.
-Waste pulp is often mixed with virgin fibres to produce better quality papers as fibres become shorter and weaker and lose their papermaking qualities.
- Manufacturers blend a variety of…