JP2005230721A - Treatment method of paper waste - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an industrial-scale method providing effectively paper waste containing aluminum component to a material cycle, the aluminum component being recovered as effective matter available as a compound for paper manufacturing raw material, or as a water treatment agent, causing no trouble of apparatus in thermal recycling. <P>SOLUTION: Aluminum component is extracted from the paper waste by bringing the waste having aluminum foil into contact with an aluminum dissolving extraction agent, to recover the aluminum component as variable matter. As the aluminum dissolving extraction agent, dilute hydrochloric acid, dilute sulfuric acid, or alkali hydroxide aqueous solution is given. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention provides a paper waste material having at least an aluminum foil, for example, a paper pack waste material obtained by laminating paper, an aluminum foil and a plastic film, or a so-called pulper scum after taking out a paper component from such a paper pack waste material. The present invention relates to a method for separating and recovering as a valuable material, for example, an aluminum compound and a water treatment flocculant that can be effectively used in the manufacturing process of paper.

  In the paper manufacturing process, it is industrially performed to extract a paper component from a paper pack waste material used as a disposable container for food or the like and use it as a raw material pulp. On the other hand, an aluminum compound is also mixed as a papermaking auxiliary material in the papermaking process.

  The paper pack waste material for raw material pulp extraction is mainly made of paper having a water resistance performance by laminating a plastic film such as polyethylene. Recently, however, functions required for such containers have been diversified. For example, as a sake pack container, a paper container in which a plastic film and an aluminum foil are laminated has been widely used.

  For this reason, the need for what laminated | stacked aluminum foil as a paper pack waste material for raw material pulp extraction has increased.

  When a paper component is extracted from a paper pack waste and reused as a raw material pulp, the paper component is usually dissolved and separated and recovered using a crusher called a pulper. Then, the waste plastic film after extracting the paper components is incinerated, and is thermally recycled as a waste heat boiler in the form of a waste heat boiler or the like. However, when aluminum components are contained in the order of several percent or more in the plastic film to be incinerated, aluminum oxide dust by-produced by incineration causes troubles such as blocking the heat exchanger for heat recovery. . Also, aluminum, which is a valuable resource, is not used at all and discarded.

  In view of the above points, an object of the present invention is to effectively use a paper waste material containing an aluminum component for material recycling, and the aluminum component can also be effectively used as a compound that can be effectively used as a papermaking raw material or a water treatment agent. An object of the present invention is to provide a method which can be carried out on an industrial scale, which is recovered as a valuable material such as a compound and does not cause any trouble in an apparatus during thermal recycling.

  The above problem can be solved by bringing a paper waste material provided with an aluminum foil into contact with an aluminum dissolution extractant, extracting the aluminum component from the paper waste material, and separating and recovering the aluminum component as a valuable material. . As the aluminum dissolving and extracting agent, dilute hydrochloric acid, dilute sulfuric acid, alkaline hydroxide aqueous solution and the like can be considered.

The extraction rate of the aluminum component is a rate at which the aluminum component is dissolved in the extractant. Various tests have shown that the factors that make this rate constant are:
(1) The paper waste material and the extractant are sufficiently mixed so that all aluminum laminated plastic film surfaces are in contact with the extractant evenly:
(2) The rate at which the extractant permeates the aluminum foil and plastic film laminated surface is made constant, that is, all the aluminum laminated plastic films that are in contact with the extractant are of equal dimensions:
(3) Keeping the temperature of the extractant brought into contact with the paper waste material constant.

In order to satisfy the above, the present inventors have found that it is very effective to contact the extractant after cutting the paper waste material to a size of 50 mm or less.
Further, since the pulper debris without any pretreatment (for example, after the paper is extracted by the pulper) is bulky, it is preferable to cut it to increase the volume efficiency of the actual apparatus.

  Moreover, the extraction agent brought into contact with the paper waste material can increase the extraction speed of the aluminum component as its temperature increases. However, when the extraction is performed at a temperature exceeding 40 ° C., the wax component or the like impregnated in the paper is fluidized to reduce the purity of the aluminum compound to be extracted, and the filterability is deteriorated. Cause inconvenience. Therefore, it is preferable to extract at a temperature of 40 ° C. or lower.

  In addition, when using an aqueous sodium hydroxide solution as an alkali hydroxide extractant that is brought into contact with paper waste, if the concentration is 5 to 15% by weight, preferably 8 to 12% by weight, the dissolved aluminum component is replaced with the sodium component. It can be separated and separated as precipitated aluminum hydroxide. When the concentration exceeds 15% by weight, the solubility of aluminum decreases at a temperature higher than a low temperature, or the region where the precipitate is separated as sodium aluminate rather than as aluminum hydroxide becomes large. In addition, the sodium hydroxide concentration as the extractant is preferably lower in consideration of the efficiency of washing the waste paper material after extraction and the safety factor of the device crotch due to the viscosity of the liquid. There is a problem in that aluminum hydroxide cannot be precipitated and separated even when cooled to a cooling lower limit temperature of 0 ° C. or lower.

  FIG. 1 shows a flow in the case of performing extraction using dilute hydrochloric acid as an extracting agent. In the treatment process equipment, it is necessary to select a corrosion-resistant material for the liquid contact part. In obtaining a flocculant as a valuable material, concentration or dilution or multistage extraction can be considered as a method for adjusting the concentration.

The chemical reaction of aluminum chloride synthesis by this hydrochloric acid extraction is as follows.

  FIG. 2 shows a flow in the case of performing extraction using dilute sulfuric acid as an extractant. In the treatment process equipment, it is necessary to select a corrosion-resistant material for the liquid contact part. Periodic purging of the circulating acid must also be considered. In obtaining a flocculant as a valuable material, specific gravity control or the like can be considered as a method for adjusting the concentration.

The chemical reaction of aluminum sulfate synthesis by this sulfuric acid extraction is as follows.

  FIG. 3 shows a flow in the case of performing an extraction process using an aqueous sodium hydroxide solution as an extractant. In the treatment process equipment, unlike the acid extraction described above, the material of the liquid contact portion does not need to consider corrosion resistance, and may be stainless steel. Also, in the washing, unlike the acid extraction, the load is small, and in some cases, it is possible to incinerate without washing. Periodic purging of the aqueous sodium hydroxide solution to be circulated must also be considered. In obtaining a flocculant as a valuable material, specific gravity control or the like can be considered as a method for adjusting the concentration.

The chemical reaction of aluminum extraction with this aqueous alkali hydroxide solution is as follows.

In any dissolution reaction, a local battery reaction between hydrogen ions and metal aluminum is a main reaction, and hydrogen gas is generated.
The aluminum laminated plastic film used as a raw material is composed of an aluminum foil and a plastic film, and these are in close contact with each other, so that it has been imagined that it is difficult to dissolve and extract aluminum. However, it has been found that the extraction proceeds unexpectedly and promptly by generating hydrogen gas on the laminated surface and assisting the separation of both.

  As an embodiment of the extraction operation or the washing operation, there are existing methods such as a mixing tank method in which the paper waste material cut into the extractant or the washing water is added and stirred, and a method of bringing the circulating extractant into contact with the paper waste material as a fixed layer The method is applicable.

  As a method for filtering the paper waste material after extraction or washing of the aluminum component, it is preferable to perform pressure filtration because the paper waste material is bulky.

(Example 1)
2 kg of 19.8 wt% hydrochloric acid was brought into contact with 2 kg of pulper residue containing an aluminum laminated plastic film cut so that the maximum dimension of each sample piece was 5 cm or less, and the aluminum foil was dissolved in hydrochloric acid. The pulper residue was put into a tank equipped with a stirrer to form a slurry and stirred for about 3 hours. When the pulper residue in the tank was visually observed, the aluminum foil was completely dissolved.

  After the above operation, the mixture was filtered while squeezing hydrochloric acid and pulper residue. The aluminum component in hydrochloric acid was 61 g / liter, and the total chlorine component was 201 g / liter.

  When the above-mentioned pulper residue after pressure filtration was washed with 40 liters of water and then filtered again, the aluminum component adhering to the pulper residue was 0.05% and the chlorine component was 0.5%. .

(Example 2)
To 700 g of pulper debris containing an aluminum laminated plastic film cut so that the maximum dimension of each sample piece is 5 cm or less, 2 liters of 9 wt% sodium hydroxide was contacted to dissolve the aluminum foil in an aqueous sodium hydroxide solution. . The pulper residue was put into a tank equipped with a stirrer to form a slurry and stirred for about 4 hours. When the pulper residue in the tank was visually observed, the aluminum foil was completely dissolved.

  After the above operation, when the sodium hydroxide aqueous solution and pulper residue were filtered, the aluminum component in the sodium hydroxide aqueous solution was 22 g / liter, and the sodium component was 52.7 g / liter.

  When the sodium hydroxide aqueous solution obtained by the above operation and dissolved in aluminum was cooled to 8 ° C. and aluminum hydroxide was precipitated and filtered, the aluminum component in the sodium hydroxide aqueous solution after filtration was 21.3 g / liter. The sodium component was 53.7 g / liter. This was again contacted with 45 g of pulper residue and repeatedly used for extracting the aluminum component in the pulper residue.

  The aluminum hydroxide obtained by filtration by the above operation was dissolved in contact with dilute hydrochloric acid to obtain an aluminum chloride aqueous solution.

When the pulper residue after press filtration was washed with 15 liters of water and then subjected to press filtration again, the aluminum component adhering to the pulper residue was 0.07%, and the chlorine component was not detected.

It is a flowchart in the case of performing extraction processing using dilute hydrochloric acid as an extracting agent. It is a flowchart in the case of performing extraction processing using dilute sulfuric acid as an extracting agent. It is a flowchart in the case of processing using aqueous alkali hydroxide solution as an extractant.

Claims (8)

  A method for treating paper waste, comprising: bringing a paper waste material having at least an aluminum foil into contact with an aluminum dissolution extractant, extracting an aluminum component from the paper waste material, and separating and recovering the aluminum component as a valuable material.   The method for treating paper waste materials according to claim 1, wherein the aluminum-dissolving extractant is selected from the group consisting of dilute hydrochloric acid, dilute sulfuric acid and an aqueous alkali hydroxide solution.   2. The paper waste material processing method according to claim 1, wherein the paper waste material is a pulper waste comprising an aluminum foil and a plastic film.   The paper waste material processing method according to claim 1, wherein the paper waste material is cut into a size of 50 mm or less and then contacted with an extractant.   The method for treating a paper waste material according to claim 1, wherein the temperature of the extractant to be contacted is 40 ° C or lower.   An aqueous alkali hydroxide solution is used as the aluminum dissolving extractant, and the aqueous alkali hydroxide solution after cooling and separating the aluminum hydroxide after the aluminum component extraction is repeatedly brought into contact with a paper waste material provided with another aluminum foil. The processing method of the paper waste material of Claim 1.   The paper waste material treatment method according to claim 1, wherein a 5 to 15 wt% aqueous sodium hydroxide solution is used as the aluminum dissolution extractant.   The paper waste material after the aluminum component is extracted and separated by the method according to any one of claims 1 to 7 is washed with 5 times or more of water as a weight ratio to the paper waste material, and then subjected to pressure filtration. A method for treating paper waste materials, comprising incinerating after the aluminum component contained in the waste paper material after washing is 0.3% or less and the chlorine component is 2% or less.

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