Neutral deinking method for waste newspaper and waste book and periodical paper

Abstract

The invention relates to a neutral deinking method for waste newspaper and waste book and periodical paper, which is characterized by comprising the following steps of: 1) treating the waste newspaper and the waste book and periodical paper into fragments, and adding the fragments and water into a pulper for mixing; 2) adding a neutral deinking agent into the container after mixing, diluting with hot water, and fully mixing and crushing; (3) adding water into the crushed paper pulp for dilution, and carrying out flotation by using a flotation machine; (4) pouring the paper pulp subjected to flotation into a pulp bag, washing through a filter screen, and carrying out roll forming, squeezing and drying on the filtered pulp to finish neutral deinking; the neutral deinking agent for the waste newspaper and the waste book and periodical paper is widely applicable to deinking of the waste newspaper and the waste book and periodical paper, and is particularly applicable to deinking of waste paper printed matters of which the ink drying mode mainly depends on permeation drying; the process is simple and easy to implement; the deinking effect is good, environmental protection and energy saving are achieved, and the deinking wastewater pollution load is low.

Description

Technical Field

[0001] The invention relates to the technical field of neutral deinking methods for paper, in particular to a neutral deinking method for waste newspapers and waste book and periodical paper. Background Art

[0002] With the increasing shortage of plant resources and the emphasis on environmental protection, the recycling of regenerated fibers has attracted great attention from countries around the world. Deinking is an important step in the recycling of waste paper. Using good deinking technology to remove printing ink from paper is the key to the recycling of waste paper. At present, domestic waste paper deinking mainly adopts flotation and washing methods. Since the washing method consumes more papermaking water, flotation deinking is valued. Flotation deinking technology mainly includes alkaline deinking, neutral deinking, and enzymatic deinking. Alkaline deinking uses chemicals such as sodium hydroxide and sodium silicate to deink at a pH of 9-11. However, the addition of alkaline chemicals increases the discharge of BOD and COD, and makes the mechanical pulp fibers in the ingredients yellow due to the decolorization of lignin, resulting in the phenomenon of "alkaline blackening". Neutral deinking is a new type of chemical deinking technology developed in recent years, which can effectively reduce the diffusion of ink particles, reduce the generation of anionic garbage, prevent the re-precipitation of ink particles, reduce the cost of deinking and wastewater treatment, and reduce the degree of pollution. Neutral deinking agents are only composed of surfactants, mainly anionic surfactants and nonionic surfactants. Anionic surfactants have good detergency, good foaming properties, fine and stable foam, and low price; nonionic surfactants have good dispersing and emulsifying effects, low critical micelle concentration, and can achieve good deinking effects at low concentrations, but the foam they produce is less and unstable. In addition, since the hydrophilic base of nonionic surfactants is composed of a certain number of oxygen-containing groups and is not ionized in aqueous solution, it has good compatibility with other types of surfactants;

[0003] Compared with the current abundance of alkaline deinking agents, there are still few neutral deinking agents, which are in urgent need of development. Therefore, it is proposed to conduct a neutral deinking compound system experiment with a suitable surfactant, and to obtain optimized process conditions in order to obtain high whiteness and low residual ink concentration of old newspaper regeneration pulp, which is of great significance for the recycling of waste newspapers and waste book and periodical paper. Therefore, a neutral deinking method for waste newspapers and waste book and periodical paper is proposed. Summary of the invention

[0004] In view of the above existing technical problems, the present invention provides a neutral deinking method for waste newspapers and waste book papers, which is characterized by comprising the following steps:

[0005] 1) Processing waste newspapers and waste book and periodical paper into pieces and adding them into a pulper together with water for mixing;

[0006] 2) Add neutral deinking agent to the mixed container, dilute with hot water, and mix and crush thoroughly;

[0007] 3) Dilute the shredded pulp with water and use a flotation machine for flotation;

[0008] 4) After flotation, the pulp is poured into a pulp bag, washed through a filter screen, and the filtered pulp is rolled into shape, pressed, and dried to complete neutral deinking;

[0009] The neutral deinking agent includes, by weight, 20-25 parts of sodium polyoxyethylene fatty alcohol ether sulfate, 20-30 parts of coconut acid diethanolamide, 10-20 parts of polyoxyethylene myristic acid ether, 10-20 parts of sodium dodecyl sulfonate, 10-15 parts of sodium stearate, 15-20 parts of dodecyl fatty alcohol, 20-30 parts of ethanol, and 20-30 parts of water;

[0010] In step 2, add water to dilute, mix and crush thoroughly, dilute to 1.2% to 2% of the pulp, keep the temperature at 40 to 50°, and take 30 to 50 minutes;

[0011] In step 3, water is added to dilute to 1% to 1.8% of the original pulp;

[0012] In step 3, the flotation temperature is 50-60°C, the flotation time is 20-30 minutes, and 0.2-0.4% of CaCl2 is added in the absolute dry pulp;

[0013] In step 4, the filter screen is a 100-150 mesh copper screen.

[0014] Beneficial effects of the present invention:

[0015] The present invention avoids the problems of strong alkaline (usually pH value is about 12), high corrosiveness, and great environmental pollution caused by the use of strong alkaline chemicals such as sodium hydroxide in the conventional alkaline deinking process. At the same time, it also greatly reduces the difficulty of treating deinking wastewater, and has very important practical significance in the fields of energy conservation, emission reduction, and green environmental protection. The neutral deinking agent for waste newspapers and waste books and periodicals is widely applicable to the deinking of waste newspapers and waste books and periodicals, and is particularly applicable to the deinking of waste paper printed products whose ink drying method mainly relies on penetration drying; the process is simple and easy to implement; the deinking effect is good, environmental protection and energy saving are achieved, and the pollution load of deinking wastewater is low. DETAILED DESCRIPTION

[0016] The following will be described clearly and completely in conjunction with the technical solution of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0017] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0018] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected" and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal connection of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances. In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0019] Example 1

[0020] Step 1, weighing 20 parts of fatty alcohol polyoxyethylene ether sodium sulfate, 20 parts of coconut acid diethanolamide, 10 parts of myristic acid polyoxyethylene ether, 10 parts of sodium dodecyl sulfonate, 10 parts of sodium stearate, 15 parts of dodecyl fatty alcohol, 20 parts of ethanol, and 20 parts of water by weight;

[0021] Step 2, pouring the components weighed in step 1 into a reaction kettle, heating to 50° C., stirring at a speed of 120 r / min until completely dissolved, standing and cooling naturally, to obtain a neutral deinking agent sample A for the neutral deinking method of waste newspapers and waste book papers of the present invention;

[0022] Step 3, cutting the waste newspapers and waste book and periodical paper into pieces of 1.5 cm×1.5 cm, mixing them evenly, and putting them into a container, wherein the weight ratio of the waste newspapers to the waste book and periodical paper is 6:4;

[0023] Step 4, adding a neutral deinking agent into the container, and diluting with hot water to a pulp concentration of 1.5%, wherein the temperature of the hot water used is 50°C;

[0024] Step 5, placing the container in a constant temperature water bath at a temperature of 45°C, keeping it warm for 40 minutes, taking it out, diluting the pulp with water to a pulp concentration of 1.5%, using a flotation machine for flotation, wherein the flotation temperature is 50°C, and the flotation time is 25 minutes, pouring the flotated pulp into a pulp bag for washing, and rolling the filtered pulp into shape, pressing, and drying to complete the deinking process.

[0025] Example 2

[0026] Step 1, weighing 20 parts of fatty alcohol polyoxyethylene ether sodium sulfate, 20 parts of coconut acid diethanolamide, 12 parts of myristic acid polyoxyethylene ether, 12 parts of sodium dodecyl sulfonate, 10 parts of sodium stearate, 15 parts of dodecyl fatty alcohol, 18 parts of ethanol, and 18 parts of water by weight;

[0027] Step 2, pouring the components weighed in step 1 into a reaction kettle, heating to 50° C., stirring at a speed of 120 r / min until completely dissolved, and standing to cool naturally, thereby obtaining a neutral deinking agent sample B for the neutral deinking method of waste newspapers and waste book papers of the present invention;

[0028] Step 3, cutting the waste newspapers and waste book and periodical paper into pieces of 1.5 cm×1.5 cm, mixing them evenly, and putting them into a container, wherein the weight ratio of the waste newspapers to the waste book and periodical paper is 6:4;

[0029] Step 4, adding a neutral deinking agent into the container, and diluting with hot water to a pulp concentration of 1.5%, wherein the temperature of the hot water used is 50°C;

[0030] Step 5, placing the container in a constant temperature water bath at a temperature of 45°C, keeping it warm for 40 minutes, taking it out, diluting the pulp with water to a pulp concentration of 1.5%, using a flotation machine for flotation, wherein the flotation temperature is 50°C, and the flotation time is 25 minutes, pouring the flotated pulp into a pulp bag for washing, and rolling the filtered pulp into shape, pressing, and drying to complete the deinking process.

[0031] Example 3

[0032] Step 1, weigh 20 parts of fatty alcohol polyoxyethylene ether sodium sulfate, 20 parts of coconut acid diethanolamide, 14 parts of myristic acid polyoxyethylene ether, 14 parts of sodium dodecyl sulfonate, 10 parts of sodium stearate, 15 parts of dodecyl fatty alcohol, 16 parts of ethanol, and 16 parts of water by weight;

[0033] Step 2, pouring the components weighed in step 1 into a reaction kettle, heating to 50° C., stirring at a speed of 120 r / min until completely dissolved, standing and cooling naturally, to obtain a neutral deinking agent sample C for the neutral deinking method of waste newspapers and waste book papers of the present invention;

[0034] Step 3, cutting the waste newspapers and waste book and periodical paper into pieces of 1.5 cm×1.5 cm, mixing them evenly, and putting them into a container, wherein the weight ratio of the waste newspapers to the waste book and periodical paper is 6:4;

[0035] Step 4, adding a neutral deinking agent into the container, and diluting with hot water to a pulp concentration of 1.5%, wherein the temperature of the hot water used is 50°C;

[0036] Step 5, placing the container in a constant temperature water bath at a temperature of 45°C, keeping it warm for 40 minutes, taking it out, diluting the pulp with water to a pulp concentration of 1.5%, using a flotation machine for flotation, wherein the flotation temperature is 50°C, and the flotation time is 25 minutes, pouring the flotated pulp into a pulp bag for washing, and rolling the filtered pulp into shape, pressing, and drying to complete the deinking process.

[0037] Example 4

[0038] Step 1, weighing 20 parts of fatty alcohol polyoxyethylene ether sodium sulfate, 20 parts of coconut acid diethanolamide, 16 parts of myristic acid polyoxyethylene ether, 16 parts of sodium dodecyl sulfate, 10 parts of sodium stearate, 15 parts of dodecyl fatty alcohol, 14 parts of ethanol, and 14 parts of water by weight;

[0039] Step 2, pouring the components weighed in step 1 into a reaction kettle, heating to 50° C., stirring at a speed of 120 r / min until completely dissolved, standing and cooling naturally, to obtain a neutral deinking agent sample D for the neutral deinking method of waste newspapers and waste book papers of the present invention;

[0040] Step 3, cutting the waste newspapers and waste book and periodical paper into pieces of 1.5 cm×1.5 cm, mixing them evenly, and putting them into a container, wherein the weight ratio of the waste newspapers to the waste book and periodical paper is 6:4;

[0041] Step 4, adding a neutral deinking agent into the container, and diluting with hot water to a pulp concentration of 1.5%, wherein the temperature of the hot water used is 50°C;

[0042] Step 5, placing the container in a constant temperature water bath at 45°C, keeping it warm for 40 minutes, taking it out, diluting the pulp with water to a pulp concentration of 1.5%, using a flotation machine for flotation, wherein the flotation temperature is 50°C, the flotation time is 25 minutes, pouring the flotated pulp into a pulp bag for washing, rolling the filtered pulp into a shape, squeezing, and drying, completing the deinking process,

[0043] The comparison of the deinking effect of the neutral deinking method for waste newspapers and waste book papers in the above embodiment and the conventional alkaline deinking method is shown in the following table:

[0044]

[0045] It can be seen from the above table that in terms of deinking effect, the deinking effect of the deinking agent used in the neutral deinking method for waste newspapers and waste book papers of the present invention is similar to that of conventional alkaline deinking. After deinking, the whiteness of the pulp is increased by 10%, and the removal rate of ink particles can reach more than 90%.

[0046] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. The various components mentioned in the present invention are common technologies in the existing field. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only to illustrate the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention to be protected. The scope of protection claimed by the present invention is defined by the attached claims and their equivalents.

Claims

1. A neutral deinking method for waste newspapers and waste book papers, characterized in that: The following steps are involved: 1) Processing waste newspapers and waste book and periodical paper into pieces and adding them into a pulper together with water for mixing; 2) Add neutral deinking agent to the mixed container, dilute with hot water, and mix and crush thoroughly; 3) Dilute the shredded pulp with water and use a flotation machine for flotation; 4) After flotation, the pulp is poured into a pulp bag and washed through a filter screen. The filtered pulp is rolled into shape, pressed, and dried to complete neutral deinking.

2. The neutral deinking method for waste newspapers and waste book papers according to claim 1, characterized in that: The neutral deinking agent includes, by weight, 20-25 parts of sodium polyoxyethylene fatty alcohol ether sulfate, 20-30 parts of coconut acid diethanolamide, 10-20 parts of polyoxyethylene myristic acid ether, 10-20 parts of sodium dodecyl sulfonate, 10-15 parts of sodium stearate, 15-20 parts of dodecyl fatty alcohol, 20-30 parts of ethanol, and 20-30 parts of water.

3. The neutral deinking method for waste newspapers and waste book papers according to claim 2, characterized in that: In step 2, water is added for dilution, and the mixture is fully mixed and crushed to 1.2% to 2% of the pulp. The temperature is maintained at 40 to 50° and the time is 30 to 50 minutes.

4. The neutral deinking method for waste newspapers and waste book papers according to claim 3, characterized in that: In step 3, water is added to dilute the mixture to 1% to 1.8% of the original pulp.

5. The neutral deinking method for waste newspapers and waste book papers according to claim 4, characterized in that: In step 3, the flotation temperature is 50-60°C, the flotation time is 20-30 minutes, and 0.2-0.4% of CaCl2 is added in an absolute dry pulp amount.

6. The neutral deinking method for waste newspapers and waste book papers according to claim 5, characterized in that: In step 4, the filter screen is a 100-150 mesh copper screen.

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