Rio Tinto | Minerals and Metals for the world

It's worth the minerals it's written on
Graham Ellicott explores the invisible world of the ingredients of paper production.

Think paper and you see a newspaper, book or magazine, or the pristine white sheets in the feed tray of the computer's printer.

You don't see minerals, but there they are.

They are incorporated into paper to enhance its properties and to make its production more efficient. Indeed, without minerals the choice of paper that you use in your everyday life would be far more limited.

Paper is made by using an acid or alkali based process to break down a fibrous material, such as wood, to form a pulp. This suspension of individual fibres is then put into porous moulds and the liquid drains away to leave a sheet of wet paper. The remaining liquid is extracted from these wet sheets by hydraulic pressing. Finely ground particles of minerals are used at every stage of the papermaking process from the production of the pulp to the finishing of the paper surface.

During the breakdown of wood to individual fibres, resinous tacky pitches are released and these tend to form agglomerates, known as "stickies", which gum up the paper production equipment. Talcs can be used to remove the pitch by enveloping it; the resultant mixture is then removed before it can cause damage to paper rollers or other processing equipment.

Industrial minerals can also be used to reduce the cost of production of printing paper as they are more economical on a weight for weight basis than wood pulp. In the main a higher mineral addition, of say limestone, will result in a lowering of the cost of the finished sheet of paper.



It's worth the minerals it's written on Graham Ellicott explores the invisible world of the ingredients of paper production. Think paper and you see a newspaper, book or magazine, or the pristine white sheets in the feed tray of the computer's printer. You don't see minerals, but there they are. They are incorporated into paper to enhance its properties and to make its production more efficient. Indeed, without minerals the choice of paper that you use in your everyday life would be far more limited. Paper is made by using an acid or alkali based process to break down a fibrous material, such as wood, to form a pulp. This suspension of individual fibres is then put into porous moulds and the liquid drains away to leave a sheet of wet paper. The remaining liquid is extracted from these wet sheets by hydraulic pressing. Finely ground particles of minerals are used at every stage of the papermaking process from the production of the pulp to the finishing of the paper surface. During the breakdown of wood to individual fibres, resinous tacky pitches are released and these tend to form agglomerates, known as "stickies", which gum up the paper production equipment. Talcs can be used to remove the pitch by enveloping it; the resultant mixture is then removed before it can cause damage to paper rollers or other processing equipment. Industrial minerals can also be used to reduce the cost of production of printing paper as they are more economical on a weight for weight basis than wood pulp. In the main a higher mineral addition, of say limestone, will result in a lowering of the cost of the finished sheet of paper.
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Review is published by Rio Tinto, 6 St James' Square, London SW1Y 4LD, England Telephone +44 (0)20 7930 2399 Editor: Cherry DeGeer