Georgia-pacific France

Arjo Wiggins Limited

Christian Richard

Didier Joisson

Cyrille Schu

Gilbert Schohn

The invention relates to a method for producing a sheet of paper () comprising paper fibres and calcium carbonate mainly in the form of calcite crystals linked directly to the paper fibres. The inventive method is characterised in that it comprises the following steps:&#x2014;(i) an aqueous composition comprising calcium bicarbonates () and/or hydrated and/or dissolved carbon dioxide () and (ii) an aqueous composition comprising calcium hydroxide () are mixed in an aqueous medium in such a way as to precipitate the calcium carbonate in the form of vaterite crystals;&#x2014;paper fibres (') are immediately added;&#x2014;the vaterite crystals are left to transform into calcite crystals on contact with the fibres;&#x2014;said mixture containing the calcite crystals which are fixed to the fibres is subsequently sent on the conveying wire of the papermaking machine (M) for drainage and so that the sheet of paper can be formed;&#x2014;the sheet of paper () thus obtained is treated, if necessary, and dried.

Method for producing a sheet of paper comprising calcite

The invention relates to a method for affixing a mineral filler onto an aqueous cellulose-fiber suspension. In this invention, the method uses as its reaction medium an aqueous cellulose-fiber suspension which is derived from papermaking and which includes at least hydrogen carbonates, carbonates or silicates of alkali and/or earth alkali metals, and the invention adds to the reaction medium a hydroxide of the filler mineral in order to precipitate the mineral filler's carbonates or silicates onto the fibers. In particular, the invention applies to papermaking.

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Chambery, France

Christian Richard