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Details

Graphics- wood pulping
mechanical, chemical, waste
6
Art/Design
12th Grade
05/07/2009

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Cards

Term

mechanical pulp

advantages

Definition
  • provides 90% yield as it uses the whole log, except for the bark
  • mechanical pulp mills are relatively cheap in comparison to other types of mills
  • well suited for bulk grades of paper. e.g newspaper and packaging
  • can be bleached to provide higher value paper
Term

mechanical pulp

disadvantages

Definition
  • lower strength characterisitics than softwood chemical pulps
  • paper can go yellow when exposed to light due to containing a big amount of 'lignin'
Term

chemical pulp

advantages

Definition
  • higher quality wood pulp produced, with longer so therefore stronger fibres with fewer impurities
  • produces chlorine free disposable products
  • waste lignin can be burnt as fuel, often supplying power to the national grib or steam to local heating plants
Term

chemical pulp

disadvantages

Definition
  • lower yield than mechanical methods due to the lignin being completely disolved and spearated from the fibres
  • no chemical pulp is produced in the UK
Term

waste pulp

advantages

Definition
  • makes use of recycled paper
  • well suited for bulk grades of paper e.g newspaper and packaging
Term

waste pulp

disadvantages

Definition
  • cannot be recycled indefinately ue to pulp losing its quality- new pulp needs to be added
  • does not save any energy in processing than in any other methods
  • requires considerable processing and addititives to produce good quality paper
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