FI119382B - Process for processing paper and fibrous material - Google Patents

Description

119382

Method for treating paper and fibrous material

Background of the Invention

The invention relates to a process for treating paper, especially recycled paper, and fibrous material, particularly paper fiber, prior to pulping.

Recycled paper is rich in impurities: bio-waste, metals, glass, stone and various fine fractions, among other things. sand, broken glass and dust. Impurities cause malfunctions, wear and high costs if they get into the pulper. Also, the quality of the recycled paper varies widely in terms of dry-grade properties and compactness, with pulping time and end result varying. In the future, paper pulp will also be recovered from commercial and industrial waste and household waste, making careful removal of impurities from the raw material before pulping.

There are various methods for purifying impurities produced by pulper. We use eg. raggers that collect bale yarns and plastic films from pulper. For washing the reject, there are eg. various floatation devices to separate heavy bodies. There are several methods of protecting the pulper from wear caused by hard objects entering the pulper. Biological activity of recycled paper fibers; ; ·; expensive chemicals are used to contain it. Different types of screening and washing processes are used to clean the pulp from the pulp.

• · •. ·. Most methods cause extremely high operating costs, · · · ”1 / s, maintenance downtime, slowing down pulping and therefore limiting the use of pulp ** ·; * 25 recoverable raw materials to the purest raw materials.

• · · * ;;; Impurities cause heavy wear on the expensive parts of the pulper and: ···: at worst, stop the whole process without warning.

SUMMARY OF THE INVENTION • ·; ***. The object of the present invention is to solve the above mentioned problems. 30 avoiding or substantially reducing them. This object is achieved by a process according to the invention, characterized in that the material is: ···: homogenized to a selected ejection size of about 50-200 mm before pulping:: *: using a crusher which at the same time fluffs the material and feeds it. Further, the impurity separation means and that the homogenization and separation of the impurities is carried out dry.

119382 2

Most contaminants are removed from the material to be treated already in the crusher.

Magnetics, gravity and / or Eddy-current technology can be used to separate impurities. It is wise to separate the separated materials and recycle them.

Although the material can now be dispensed directly from the pre-treatment to the pulper at constant capacity, the material pre-treated in the manner of the invention may also be stored.

In view of the above, the advantages or features of the method of the invention may be as follows:

Pulpper wear is significantly reduced when stones and metal are removed before pulping. At the same time, a more economical structure can be used as a pulper, with fewer or no impurities removal equipment; for example, no so-called. ragger for collecting iron-15 yarns and plastic films. The smaller particle size also increases the efficiency of pulping, reducing the energy consumption per pulp produced.

On the other hand, it is now possible to use a fiber raw material containing more impurities than normal. This also means that cheaper paper raw materials can be used in paper making. If the raw material is baled on arrival at the paper mill, there is no longer: separate bale removers are needed, but the yarns are only separated after crushing.

• ·:. *. Purification of the pulp produced by the pulp from the fine fraction and. ···, 25 other impurities is easier and the purification process produces less rejection. The reject, which is largely composed of plastic membranes, is more homogenous and purer, e.g. ** ** · * as a recycled material or energy is easier.

When the proportion of bio-waste and other organic matter is lower, v: 30 requires less chemicals and processing to stop the biological activity (like · robien) in the paper.

The throughput time in the pulper is reduced because of the material to be pulverized. has been crushed to dissolve faster. The pulping rate increases especially when handling • packagings that are otherwise difficult to dissolve.

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The process produces a homogeneous crush that is easy to store prior to pulping and dispensing into pulper as needed. Pulpper's efficiency is enhanced by the constant availability of ready-made raw materials.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will now be described, by way of example, with reference to a block diagram of the accompanying drawing, which illustrates the flow of the method according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

As shown in the block diagram of the drawing, the waste paper containing the impurities 10 or the corresponding fibrous raw material R is first directed to the crusher 1, then to the screening means 2, then to the impurity separating means 3 and then to the pulpers 4.

In crusher 1, the raw material R is crushed to a homogeneous crumb, to a mass of about 50 to 200 mm (at least 100 to 200 mm). At the same time, the crushing will flush the raw material R, making it possible to separate the impurities. A piece size of about 100 mm allows ferritic material to be removed by magnets and also aluminum to be removed. Largest impurities, such as large rocks, are automatically removed by the crusher 1 itself before the impurities separator means 2 and 3. As a crusher. . ·. Conventional known crushers may be used.

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After crushing, the fines are separated from the raw material R; . * in crushing equipment 2. Crushing to the correct and even ejection size is important for fine separation of fine particles and other impurities.

After screening, stone, metals, hard plastics 25 and bio-waste are separated from the crushed material, for example, by means of an air separator in separating means 3. A homogeneous size of • • · air also requires efficient operation of the air classifier. These separating means 3 may also be conventional devices for separating materials.

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Following the process steps described above, ··· 30 mechanically cleaned, dry and frothy light fractions are obtained which can be delivered to a pulper with a constant capacity of · · · '*] *'. Alternatively, the final product or part of it can be stored for later use. for. Pulpper 4 efficiency and! : *: The utilization rate can be increased when continuously prepared raw material is available.

·: ··: As a pulper 4, simpler solutions can be used compared to conventional structures, since they do not now require equipment for the removal of impurities.

The above description of the invention is intended only to illustrate the basic idea of the invention. Thus, a person skilled in the art can implement the details of the invention in many ways without departing from the scope defined by the appended claims.

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Claims (6)

119382 A process for treating paper and fibrous material prior to pulping, characterized in that the material is homogenized to a particle size of about 50 to 200 mm before pulping by means of a crusher (1) which at the same time fluffs the material and feeds it to contaminant separators (2, 3) that the homogenization and separation of impurities is carried out dry. Method according to Claim 1, characterized in that the largest contaminants are removed from the material to be treated already in 10 crushers (1). Method according to one of the preceding claims, characterized in that magnetization, gravity and / or Eddy-current technology are utilized in the separation of impurities. Method according to one of the preceding claims, characterized in that the separated materials are kept separate and recycled. Method according to one of the preceding claims, characterized in that the treated material is fed to the pulper (4) at a constant capacity. A process according to any one of claims 1 to 4, characterized in that the treated material is stored prior to pulping. * t * · • · · ··· • i · • · · • • • • • • • • • • • • • · · · · · · · · · · · · · · • · • · · · ♦ · · If If If If If If If If If If M M M M M M M M M M M M M M M M M. • · · • M «« II ·· • · 119382