Pulps

advantages and disadvantages on types of method pupling

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  • Created by: Alia
  • Created on: 09-05-12 11:03

Mechanical Pulping

Advantages:

. provides a 90% yield from teh pulpwood as it uses the whole of the log except for the bark.

. investment costs for mechincal pulp mills are realtively low in comparsion with other types of mill.

. well suited for 'bulk' grades of paper; i.e newsprint and packaging boards.

. can be bleached to produce higher value-added products.

Disadvantages:

. lower strength characteristics than softwood chemical pulps

. paper can 'yellow' when exposed to bright lights due to high lighin content.

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Chemical Pulping

Advantages:

. higher quailty wood pulp produced with longer, stronger fibres that contain fewer impurities.

. produces 'chlorine-free' disposable products.

. waste lighin from the process can be burnt as a fuel oil substitue, often supplying power to the national grid or steam to local domestic heating plants.

Disadvantages:

. lower yeild than mechanical methods as the lighin is completely dissolved and separated from the fibres.

. no chemical pulp is produced in the UK, therefore it must be imported

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Waste Pulping

Advantages:

. makes use of recycled papers, which are a sustainable resource.

. well suited fro 'bulk' grades of paper; i.e. newsprint, tissue and packaging boards.

Disadvantages:

. cannot be recylced indefinite;y as pulp loses quailty - virgin pulp needs to be added.

. does not save any more ebergy in processing than other methods

. requires considerable processnig and additives to produce good-quailty paper.

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