KR0151110B1 - Method of de-inking waste paper materials - Google Patents

Abstract

The present invention is a process of dispersing ink particles from the raw material by pulping the paper material in the hydra pulper (1) to produce a fibrous raw material, and adding a substance in the form of a mixture of sodium phosphate salt and sodium carbonate salt to the fibrous raw material It is related with the deinking method of the waste paper material which consists of. In order to remove the ink particles from the fibrous raw material, the raw material and the dispersed ink particles are passed through the washing steps (4), (7) and (8) in the centrifugal washing machine (3).

Description

Deinking Method of Waste Paper

The present invention relates to a de-inking method of waste paper material.

In the paper and cardboard sector, it is well known to use secondary fibers obtained by recycling waste paper materials and dispersing and separating ink particles from waste paper materials and their secondary fibers recycles the waste paper, in particular newspaper printing, This step is necessary to make paper for tissue and fine paper.

In known recycling processes, the waste paper or feed is usually placed in a hydrapulper, wherein the waste paper or feed is water and the following chemicals, namely (1) caustic soda or other deodorizing chemicals, (2) sodium metasilicate as buffer, and (3) hydrogen peroxide or other bleach.

In hydrapulper, the feed is broken down into fibrous pulp and then demulsified and bleached by the added chemical.

A series of dumps of fibrous pulp or slushed fibers with 15% (when pulping at high roughness) or 5 to 6% (for mills not pulping at high roughness) from a hydrapper Or dump into a storage box, where the slushed fibers are diluted to about 1.5% roughness.

Subsequently, the raw or diluted slushed fibers are passed through a desorbing device consisting of a floating sorting vessel or a washing screen or a combination thereof to remove dispersed ink particles from the slushed fibers.

In a method using a flotation vessel, the defrosting vessel is allowed to flocculate the dispersed ink molecules and then float on the bubble (which is generated at the base of the flotation vessel and then rolled out) to the surface of the vessel. Collector soap is added to the raw material.

In the deinking method, a large amount of water is used to wash away the dispersed ink particles from the system by passing the raw material through a rotating decker, sidemill screen, screw press or similar device.

Such known deinking methods require the addition of numerous different deinking chemicals. In addition, some chemicals are only valid for one of two different methods: flotation and washing, and cannot be used for other methods. Moreover, caustic soda, most commonly used in fairly large quantities as a deodorant chemical, can corrode fibers and is not considered environmentally safe as it flows from wheat to external water sources.

It is therefore an object of the present invention to provide a method for deinking waste paper, which almost overcomes the above mentioned problems associated with known methods.

Therefore, the present invention is to pulp the paper material to produce a slush-like rough fibrous raw material; A specific substance is added to this fibrous raw material to disperse ink particles from the raw material; In the deinking method of waste paper material comprising the steps of removing the dispersed ink particles from the fibrous raw material, the specific material used to disperse the ink particles is a mixture of sodium phosphate and sodium carbonate salts, where the mixture is at ambient temperature. It is effective to provide an ink dispersing agent).

Preferably, the material consists of 1 to 75% by weight sodium carbonate and 25 to 99% by weight sodium phosphate.

The material may also comprise 1 to 2% by weight metasilicate and / or 0.5 to 2% by weight caustic soda.

In addition, the material may include an absorbent salt together with a non-magnetic booster or may include a hygroscopic salt.

If necessary, for example, 0.25 to 5% by weight of a bleaching compound such as hydrogen peroxide or other suitable bleach may be added.

In the following, the invention will be described in more detail by examples with reference to the drawings, which diagrammatically illustrate one aspect of the invention.

Referring to the figures, the figures show that the process steps themselves are well known to those skilled in the art, except that the known deoiling material is replaced with a material as used according to the invention. The process diagram of is shown.

In the illustrated method, when the waste paper is fed to the hydral pulp 1, the waste paper is pulverized into slush rough fibrous pulp or fibrous raw material. Water is added to the raw material together with the substance to disperse the ink particles from the raw material. From this, raw materials and dispersed ink particles are passed into the centrifugal washer 2 to remove grit, pins, clips and the like, and to remove particles of too large size through the screen 3.

The raw material then passes through a first washing step 4 consisting of a concentrator 5 and a fine threshing or dispersing machine 6, thereby sufficiently defiberizing the raw material, which is fairly clean and contains no ink marks but very small ink particles. Is generated. From this, the raw material passes through the second and third washing steps 7 and 8, respectively, each step comprising a vertical screen 9, where dilution water is added to the raw material. The fourth washing step 10 consists of another concentrator 11, where the clean raw material is passed from the concentrator 11 into the crystallizer and papermaking machine.

According to an aspect of the present invention, the material added to disperse the ink particles consists of a mixture of 1 to 75% by weight sodium carbonate and 25 to 99% by weight sodium phosphate, a typical composition of 8% by weight sodium carbonate and 92% by weight sodium phosphate Is done.

The material may also include small amounts of metasilicate (eg 1-2 wt%) and / or caustic soda (eg 0.5-2 wt%). The composition may be further enhanced by using hygroscopic salts with non-invasive boosters and may also include hygienic agents. A bleach, for example hydrogen peroxide, may be added at 0.25 to 5%.

As another alternative to the washing method of the deinking method mentioned above, the material may also be used in known flotation methods to disperse the ink particles.

The use of these materials in deinking methods has the following advantages over the commonly used chemicals:

(1) Unlike other desorption products which were effective only in one of the conventional methods, they are effective ink dispersants for both conventional deinking methods (i.e., flotation and washing methods).

(2) Through its formulation, it can be used as a one-shot ink dispersant in hydrapper without adding a buffer or any other chemicals to the hydrapper.

(3) Since it is effective as an ink dispersant even at low temperatures (e.g., 9 ° C), the power required to heat the contents of the hydrapulper to 50 to 60 ° C, which is required by known methods using other deodorizing chemicals, Can be saved.

(4) Unlike caustic soda, it does not corrode fibers, making stronger paper products, and can be used as caustic soda substitutes in hydrapulper.

(5) As ink dispersant, not only the collector soap is necessary in the flotation deinking method, but also high temperature (60 ° C.) is not required even when the collector soap is used, which brings additional economic advantages in use.

(6) more stable in the environment, ie much less toxic to aquatic organisms, much lower and more acceptable biological oxygen at this point than other desorption products (eg caustic soda or bleach) when flowing from wheat to an external water source Demand demand (BOD) and chemical oxygen demand (COD).

(7) In the mill test, it was found to have excellent forming agent properties in that the fibers were evenly distributed on the processed paper to provide a better final product.

Furthermore, mill machine processes using the material for deinking and further experimentation have revealed the following additional advantages: (a) Depending on the waste paper mixing ratio in the feed used, the recycled product has a strength of 5-30%. Significantly increased; (b) produce better and less stained products when used to degrease office-grade waste paper (ie, waste paper that does not contain wood) that has been graded to be better off so far with better grades; (c) not only can successfully process laser prints, dried photographic prints, and novel FLOXO inks that have been known to be difficult to desorb so far, but also produce higher brightness than standard deodorizing products; (d) The ability to pass less than 85% of viscous materials or rubber allows to overcome most of the major bulk problems, such as expensive machine downtime caused by paper recycling.

While certain aspects of the invention have been described, various modifications may be considered without departing from the scope of the invention as defined in the appended claims.

Claims (4)

Pulping the paper material to produce a fibrous raw material of slush-type roughness; Dispersing the ink particles from the fibrous raw material by adding an ink dispersible composition; And in the de-inking method of waste paper comprising the steps of removing the ink particles thus dispersed from the fibrous raw material, wherein the ink dispersible composition consists only of a mixture of sodium phosphate and sodium carbonate salts, or meta Characterized in that it consists only of a mixture of sodium phosphate and sodium carbonate salts containing a small amount of silicate, caustic soda or both. The method of claim 1, wherein the ink dispersible composition is used to disperse the ink particles at a low temperature of about 9 ° C. The method of claim 1, wherein the ink dispersible composition consists of about 8% by weight sodium carbonate and about 92% by weight sodium phosphate. The method of claim 1 or 2, wherein the ink dispersant comprises about 1 to 2 weight percent metasilicate, 0.5 to 2 weight percent caustic soda or both.