GB2037340A

GB2037340A - Utilizing waste paper

Info

Publication number: GB2037340A
Application number: GB7927549A
Authority: GB
Original assignee: VYZK USTAV PAPIERU CELULOZY
Current assignee: VYZK USTAV PAPIERU CELULOZY
Priority date: 1978-12-06
Filing date: 1979-08-07
Publication date: 1980-07-09
Also published as: CS220858B1; IT7923964A0; IT1125398B; ES483485A1; DD145293A1; NL7904845A; FR2443528A1; DE2926185A1; JPS5580588A

Abstract

Short fibers obtained by fractionating waste paper reduce in the course of processing of waste paper the bonding properties of long fiber fractions. According to this invention the short fiber fractions are first separated from the long fiber fractions, the long fiber fractions regenerated by milling, advantageously by fibrillation milling, and subsequently at least part of the earlier separated short fiber fraction added to the regenerated long fiber fraction for further processing.

Description

SPECIFICATION Method for utilizing waste originating by fractionizing waste paper in the paper manufacture DESCRIPTION The invention relates to a method for utilizing waste originating by fractionizing waste paper in the paper manufacture.

One of principle negative effects in the course of processing paper stuff obtained from collected waste paper are fine and very fine particles. They not only contribute to an increase of the degree of milling, cause a worse dehydration but they mainly prevent a correct processing of fibers by milling and thus their full regeneration, which is for fibers obtained from waste paper the major condition required for a following processing by a paper machine.

As follows from evaluations of up to now obtained results, it is obvious, that fine particles of fibers lower the mechanical strength of the paper in that they fill gaps between individual fibers increasing.

thus distances between fibers capable of bonding. A consequence thereof is a required increased degree of milling and a reduced capability of dehydration. The fine fractions of fibers increase due to their high stiffness the required milling pressure in the course of milling. A consequence thereof is a further increase of the amount of fine fractions, as due to the high pressure in the course of milling long fibers are disintegrating. The regeneration of long fibers is thus very impaired as for this purpose a rather smooth, mostly highly fibrillation milling is required, which proceeds at lower milling pressures.

In order to enable a maximum regeneration of fibers obtained from waste paper, the fractionizing of waste paper is very advantageous.

By fractionizing, two fractions are obtained, one with long fibers the second with short fibers waste. This waste consists of fine fractions of fibers and of fillers, of an amount up to 30 per cent. The separated long fibers are processed independently by fibrillation milling, increasing thus the bonding properties of fibers showing in increased mechanical strengths of paper sheets obtained from these fibers.

The processing of waste paper by fractionizing found however up to now no industrial application as there was no industrial utilization for the short fiber fraction, of which up to 30 per cent is originating.

Thus considerable economical losses are occuring due to the necessity of liquidation of a large amount of waste, due to worsening of environmental conditions and high requirements on power.

It is an object of this invention to provide a method leading to utilization of this waste in the paper industry. According to this invention the separated waste represented by a mixture of short fibers and of fillers is in the course of the proceeding process returned to the fraction of long fibers which has been prior to this mixing with the waste processed by milling advantageously by fibrillation milling, to required mechanical values whereby the amount of returned waste from fractionizing can be within 10 to 100 per cent of the separated waste. The separated waste can be also utilized for some other suspension of material than from which it has been fractionized in order to reduce the content of fillers or in order to obtain from the final mixture new properties for the paper.

The attached drawing indicates diagrammatically the whole process according to this invention.

With reference to the drawing, waste paper is disintegrated in a pulper 1, wherefrom it is discontinously or continuously removed to a storage bin 2, wherefrom it is conveyed by a stream of water to a separator 3 of contaminants, where the not fiberized fractions and contaminants of higher and lower specific weight are removed. The material rid of contaminants is brought to a storage bin 4 wherefrom it is pumped to a fractionizer 5. Here fine fractions of fibers and fillers are separated at an amount up to 30 per cent of the overall amount of paper stuff. The stream of long fibers passes from the fractionizer 5 to a storage bin 7.From this storage bin 7 the long fiber fraction is pumped over a thickening vessel 8 and another storage bin 9 to mills 10, where it undergoes a fibrillation milling and is collected in a mixing vessel 1 The bonding properties of fibers are regenerated by this milling and their specific surface is increased. Due to the increase of the specific surface the contact surfaces of individual fibers are increased in the course of formation of the paper sheet and fine fiber fractions the waste -- which represents due to its morphology a dead not active part of the paper stuff forms some kind of filler and does not prevent to such an extent as was the case at not regenerated fibers the creation of bonds and it is possible to return it at the whole extent back into the suspension and start its processing together with the other fractions.

The short fiber fraction -- the waste from the fractionator 5 passes to a storage bin 6, wherefrom it is pumped to the mixing vessel 11 or alternatively to this mixing vessel 11 by way of a thickening vessel 1 2. From the mixing vessel 11 the mixed material passes for processing to a paper machine. By the amount of added short fiber fraction -- of the waste - into the mixing vessel 11 can be adjusted the dehydration, the degree of milling, the amount of fillers and other properties of the paper while maintaining high mechanical strength obtained by correct regeneration of the long fiber fraction. See also the following table.

Dehydration Length of fracture Stress Tearing .SR km kPa mN 500 ml 700 ml 800 ml waste paper, classical technology 44.05 98.9 148.3 55 2.85 120 665 waste paper, short fibers removed 7.6 17.2 26.0 20 2.4 110 950 waste paper. short fibers removed. milled 24.2 53.9 83.7 39 3.9 150 495 to milled material 10% of short fibers added 27.9 62.9 93.6 42 4.0 130 455 to milled material 30% short fibers added 31.3 70.1 104 47 3.95 130 470 to milled material 80% short fibers added 39.3 90.3 133.7 54 4.15 140 490 to milled material 50% short fibers added 35.0 80 118.3 50 4.0 140 505 to milled material 100% short fibers added 33.7 76.9 114.3 59 4.1 140 490

Claims

1. A method of utilizing waste originating by fractionizing waste paper in the paper industry wherein the collected waste paper undergoes fractionizing, separating the long fiber fraction and the waste the short fiberfraction and fillers regenerating the long fiber fraction by milling to required mechanical values and returning thereafter at least a part of the earlier separated waste to the long fiber fraction, whereby the amount of returned waste from fractionizing is within 10 to 100 per cent of the separated waste.

2. A method as claimed in claim 1, wherein the milling step is fibrillation milling.

3. A method as claimed in claim 1 or 2 wherein the separated waste from fractionizing waste paper is added to a suspension other than that from which it has been fractionized in order to reduce the amount of fresh fillers.

4. A method as claimed in claim 1 or 2 wherein the separated waste from fractionizing waste paper is added to a suspension other than that from which it has been fractionized in order to obtain new properties of the final mixture.

5. A method for utilizing waste originating by fractionizing waste paper in the paper industry, substantially as herein before described with reference to the accompanying drawing.