Paper manufacturing process including a step for fixing of mineral fiuller on cellulosic fibres

摘要

To bond a charge of a mineral material to the cellulose fibers in a suspension, the fiber suspension as a papermaking pulp contains at least hydrogen carbonates, carbonates or alkaline metal silicates and/or alkaline earths together with a reagent. The bonding material for attachment to the fibers is added as a mineral hydroxide for precipitation of its carbonates or silicates on to the fibers. The fiber suspension contains sodium hydrogen carbonates and also calcium hydrogen carbonates and/or magnesium hydrogen carbonates. The alkali content is completed at 2-30 degrees F. The fiber suspension contains ions of sodium (N+) at a rate of 20-1000 ppm, or ions of calcium (Ca<2> (+) ) at a rate of 5-200 ppm and/or magnesium ions (Mg<2> (+) ) at a rate of 5-200 ppm. The hydroxide mineral charge is a calcium hydroxide either as a concentrated milk or in solid form with a particle size of ≤ 6 mu m. After the mineral material has precipitated on to the fibers in the suspension, a gas is injected into the suspension containing a carbon dioxide to neutralize and stabilize the pH value of the cellulose fiber suspension. The fiber suspension used is supplied as a pulp of chemically bleached or unbleached fibers, a mechanical pulp, a thermomechanical pulp, or mixtures of pulp types. An Independent claim is included for the production of paper sheets from the pulp of a fiber suspension where mineral materials have been deposited on to the fibers. The wet pulp is fed to a papermaking machine, and the wet sheets are dried.