DE715832C - Process for the production of a paper filler and size - Google Patents

Description

Process for the manufacture of a paper filler and sizing material des Tatents 693 3S6 is that a silica minerals made of silica, e.g. B. from German clay or kaolin, obtained from the known digestion with sulphurous acid Silica-containing residue can be used as a paper filler, because as a result the dissolving out of the coloring inorganic constituents of the raw material, in particular of iron, and as a result of the bleaching effect of the digestion of sulfuric acid, the residue Satisfies all requirements that a paper filler has to meet, in particular with regard to the color purity.

But it would now also be recognized that when you break down the above-mentioned Minerals with sulphurous acid are a very beneficial option residue that can be used as a paper filler without the use of another substance, thus from the digested raw material itself, through appropriate management of the digestion process km to incorporate a material particularly suitable for paper sizing in the same work step, -so that. the mixture of substances for filling paper and at the same time for paper sizing Use f @ ndn bann.

The following process is used for this purpose: _ The silicic acid Clay mineral, e.g. B.

Kaolin is digested in a known manner with aqueous sulphurous acid. The clay and iron content of the deer substance is dissolved. Out of the solution the aluminum and iron sulfites are now undissolved without prior separation Alumina residue precipitated. This can e.g. B: in a known way by: happening, that nvan by removing the SO2, be @es by heating or suction, one hydrolysis initiator. The iron sulfite remains in solution. You have it with you in the hand, the entire alumina content or just part of the alumina content, depending on your requirements de @ solution to fail. Because the clay that was excreted on the back later in paper sizing and the insoluble residue left on acid digestion to be used for paper filling, it will depend on the case of the treated Minerals depend on insoluble substances and on digestible clay, up to the extent to which the clay dissolved in the digestion is to be precipitated again, with it the amounts of paper filler and size precipitant to each other in one technical appropriate and economically favorable relationship.

After the precipitation, which has been carried out to a greater or lesser extent, is complete the dissolved clay becomes the precipitate along with the insoluble digestion residue from the overlying solution separated by filtering and washed out.

The precipitate obtained in the process described here can now for the purposes of filling and sizing paper in a moist or dry state be used in such a way that it is either in the pulp slurry, with simultaneous supply of acid, which dissolve the clay precipitate and so that the aluminum salt required for gluing is to be produced, stirred, or that the precipitate is added to the pulp slurry for the purpose of Solution of clay treated with seams. Example of slurried iron-containing kaolin with a whiteness of only 55% was annealed at about 600 °. 1oookg of this annealed kaolin, which is 34% o A12 O @ and 3.5% Fee 0s contained 100 parts of A12 0.3 for 24 hours at about 6o ° treated with 20% strength aqueous sulphurous acid with stirring. Afterward the temperature was increased to 100 ° and at the same time the sulfurous Letting acid escape. After no more sulphurous acid escaped, was the mother liquor containing practically all of the iron with the exclusion of air from the booth body separated and washed this.

The washed residue contained all of the digestion residue 240 kg of pure iron free clay in the form of a sulphurous acid, in Acid readily soluble hyd @ ates. Its whiteness was only 82%. The residue mixture was stirred with water, and into this slurry were 450 kg of gaseous Sulphurous acid introduced to convert the clay into the soluble salt. The mixture would be used for filling and as a precipitant in paper sizing.

The use of the aluminum sulfite alone for the sizing of paper is not the subject of the patent.

Claims (1)

PATENT CLAIM: Process for the production of a paper filler, which at the same time contains a substance suitable for paper glue, characterized in that that on the in a known manner from alumina mineral by treatment with aqueous sulphurous seams restrained by the acid digestion as Sulphite dissolved alumina by known measures; separated from the solution again and is in the mixture after the iron-containing solution has been separated off by means of acid soluble salt transferred -cnrd. .