JP6251576B2 - Method for suppressing adhesion of calcium carbonate scale and method for producing waste paper pulp - Google Patents

Description

  The present disclosure relates to a method for suppressing adhesion of calcium carbonate scale and a method for producing waste paper pulp in a waste paper pulp manufacturing process.

  In the paper industry, neutral paper has become the mainstream of production instead of acid paper. Neutral paper is mainly blended with calcium carbonate such as wet heavy calcium carbonate and light calcium carbonate, which could not be blended with acidic paper, as a filler. As the proportion of such neutral paper containing calcium carbonate as recovered paper increases, a portion of this calcium carbonate elutes into the process water in the used paper pulp manufacturing process, and the process water is recycled and reused. Therefore, the calcium concentration in the process water tends to increase compared to the conventional method.

On the other hand, sodium hydroxide is used as a disaggregation aid in the disaggregation process of waste paper. This is because sodium hydroxide has a weak alkalinity in the system to promote disaggregation and an ink saponification effect. In the waste paper bleaching process, hydrogen peroxide bleaching is generally performed, and sodium hydroxide is used because an alkaline environment is required. Furthermore, since sodium silicate is blended as a hydrogen peroxide stabilizer, the pH of the process water is usually alkaline, for example, 8 to 10, and calcium ions in the process water react with carbonate ions. It is easy to form a calcium carbonate scale. In addition, the sodium silicate may react with calcium ions or colloidal silica derived from water, and silicate-silica composite scale may be precipitated.
These scales deposit and adhere to various places such as pipes, washing / dehydrating devices, screens, etc. in the waste paper pulp manufacturing process, resulting in problems such as blockage of pipes, poor washing, and poor dehydration. When substances that clogged due to clogging that were actually attached to the screen of the used paper pulp manufacturing process were analyzed, more than 90% of them were inorganic substances, which were hard scale substances mainly composed of calcium carbonate.

  The scale removal operation is usually performed by periodically suspending operation and mechanically peeling and removing, or by immersing piping and devices in the cleaning liquid and circulating the cleaning liquid. In the waste paper pulp manufacturing process, this operation is performed at a frequency of once every 3 to 6 months, and 1 to 2 days are required for one operation. Even if such periodic peeling / removal is performed, the scale suddenly adheres, the pipes become clogged, the throughput decreases due to clogging of the screen, and the wire of the dehydrator (extractor etc.) equipped with a wire mesh. Countermeasures to scale are an important issue because it may hinder operations such as causing dehydration failure due to clogging.

Therefore, the use of a scale inhibitor that suppresses the adhesion of scale in the process for the purpose of stabilizing the operation and reducing the scale removal work has been proposed, for example, a method of adding organic phosphonic acids to the process circulating white water [ [Patent Document 1], a method of using organic oxycarboxylic acids and phosphonic acids in the waste paper pulp manufacturing process [Patent Document 2], maleic acids and (meth) acrylaminomethylpropanesulfonic acid ( There are a method of using a copolymer with (meth) acrylic acid [Patent Document 3] and a method of adding a water-soluble copolymer containing methylpropanesulfonic acid and an ethylenically unsaturated carboxylic acid [Patent Document 4].
However, such a method has not yet satisfactorily suppressed the scale generation.

  On the other hand, in the papermaking process, it is known that bacteria and microorganisms propagate in papermaking process water and pulp slurry to produce slime using cellulose, saccharides and the like derived from wood as a raw material as nutrients. It has been well known that this slime is mixed into a papermaking raw material to cause a decrease in production efficiency due to a piece of paper, or to reduce the quality of a paper product. For this reason, in order to prevent generation | occurrence | production of slime, the method of disinfecting papermaking process water using, for example, sodium hypochlorite aqueous solution and ammonium sulfate aqueous solution is proposed (for example, refer patent document 5).

  In Patent Document 6, calcium carbonate is agglomerated by mixing a small amount of slime adhering to a neutral papermaking system into the system, resulting in spots on the paper, a reaction product of an oxidizing agent and an ammonium salt. It is disclosed that it is possible to completely prevent adhesion of slime in the system and to prevent aggregation of calcium carbonate due to a small amount of slime.

Japanese Patent No. 2526924 JP-A-3-161585 JP-A-4-356580 Japanese Patent No. 4373591 Japanese Patent No. 4914146 JP 2008-121167 A

  In recent years, the reuse of waste paper has increased in the paper industry. For this reason, in a used paper pulp manufacturing process, it is calculated | required to supply a used paper pulp stably by stable operation. On the other hand, in the manufacturing process of waste paper pulp, the water quality fluctuates drastically depending on the type of waste paper used as a raw material, so it is difficult to control calcium-based scales mainly composed of calcium carbonate. Screen clogging and wire clogging occur. When such a problem occurs, not only the cleaning efficiency and the dewatering efficiency are lowered, but also the operation stop is required for cleaning the attached scale, so that stable operation cannot be performed.

  The present disclosure provides a method for suppressing adhesion of calcium carbonate scale and a method for producing waste paper pulp in the waste paper pulp production process.

  In one aspect, the present disclosure provides a method for suppressing the adhesion of calcium carbonate scale in a used paper pulp manufacturing process, which comprises adding hypochlorite and ammonium sulfate and / or ammonium chloride to white water circulating in the used paper pulp manufacturing process. About.

  In one aspect, the present disclosure adds hypochlorite and ammonium sulfate and / or ammonium chloride to white water circulating through a waste paper pulp manufacturing process having a disaggregation process, a dust removal process, a dehydration process, and an aging (bleaching) process. The present invention relates to a method for producing waste paper pulp.

  According to this indication, adhesion of a calcium carbonate scale can be controlled in a used paper pulp manufacturing process.

FIG. 1 is a schematic configuration diagram of an example of a used paper pulp manufacturing process.

  As described above, Patent Document 6 discloses that calcium carbonate is aggregated by mixing a small amount of slime adhering to a neutral papermaking system into the system, resulting in spots on paper, an oxidizing agent and an ammonium salt. It is disclosed that the slime adherence in the system can be completely prevented by using the reaction product, and that calcium carbonate can be prevented from agglomerating due to a small amount of slime. That is, Patent Document 6 merely discloses prevention of aggregation of calcium carbonate accompanying generation of slime under conditions where microorganisms can propagate. On the other hand, the present disclosure has a high pH compared to the papermaking process such as neutral papermaking system, raw material system, and recovery system, and is usually used in the recycled paper pulp manufacturing process where the microorganisms are not capable of breeding. The invention of the present application that adhesion of calcium carbonate scale can be effectively suppressed by adding hypochlorite such as sodium hypochlorite and ammonium sulfate and / or ammonium chloride to white water circulating in the water Based on the findings found by the people. In addition, the present disclosure relates to a case where hypochlorite such as sodium hypochlorite and ammonium sulfate and / or ammonium chloride are used in combination as compared with the case where sodium hypochlorite and ammonium bromide are used together. This is based on the finding found by the present inventors that the adhesion of calcium carbonate scale can be effectively suppressed.

  In the present disclosure, the “waste paper pulp production process” refers to a process of producing a pulp (also referred to as waste paper pulp, deinked pulp, or DIP) that is a raw material of paper from waste paper. In one or a plurality of embodiments, Included in waste paper, a disaggregation process where pulp waste is mixed with water while mixing raw paper used as raw material, a rough selection process that removes foreign substances contained in the waste paper, a deinking process that removes ink components by adding a deinking agent A selection process for separating foreign matter and pulp content with a screen, a washing process for washing the deinked pulp slurry, a dehydration process for dehydrating the pulp, and a bleaching process for bleaching the pulp.

  One or a plurality of non-limiting embodiments of the used paper pulp manufacturing process will be described with reference to FIG. FIG. 1 is a schematic configuration diagram of an example of a used paper pulp manufacturing process. The used paper pulp manufacturing process shown in FIG. 1 includes a disaggregation process using a pulper 11, a rough selection process using a rough selection screen 12, a selection process using a selection screen (primary, secondary and tertiary) 13, a preflow. First-stage deinking process using theta 14, Washing process using first-stage extractor 15, Dehydration process using first-stage thickener 16, Bleaching process using bleach tower 17, Second-stage deinking process using post-flowtater 18, It includes a selection process using primary, secondary and tertiary selection screens 19, a cleaning process using post-stage extractor 20, and a dehydration process using post-stage thickener 21.

  In the present disclosure, “white water circulating through the used paper pulp manufacturing process” refers to all water used in the used paper pulp manufacturing process, and in one or a plurality of embodiments, used in the rough selection process, the selective selection process, and the like. Including shower water and white water. In the present disclosure, the white water that circulates the used paper pulp manufacturing process may include those that are recycled or reused.

[Method of suppressing adhesion of calcium carbonate scale]
In one aspect, the present disclosure provides a method for suppressing the adhesion of calcium carbonate scale in a used paper pulp manufacturing process, which comprises adding hypochlorite and ammonium sulfate and / or ammonium chloride to white water circulating in the used paper pulp manufacturing process. About.

  In one or more embodiments of the present disclosure, “suppressing the adhesion of calcium carbonate scale” means, in one or a plurality of embodiments, slits or screens in a rough and / or selective process of a used paper pulp manufacturing process, wires or pipes in a dehydration process It includes inhibiting, reducing, or preventing the scale containing calcium carbonate from adhering to the above.

  In one or more embodiments of the present disclosure, hypochlorite includes sodium hypochlorite, potassium hypochlorite, calcium hypochlorite, and the like.

  In one or a plurality of embodiments, the method for suppressing adhesion of calcium carbonate scale and the method for producing waste paper pulp according to the present disclosure includes adding hypochlorite and ammonium sulfate, and adding hypochlorite and ammonium chloride. And at least one selected from the group consisting of adding hypochlorite, ammonium sulfate and ammonium chloride.

  In the method for inhibiting adhesion of calcium carbonate scale and the method for producing waste paper pulp of the present disclosure, hypochlorite and ammonium sulfate and / or ammonium chloride may be added after reacting in advance or separately. Also good. In one or a plurality of embodiments, hypochlorite and ammonium sulfate and / or ammonium chloride are preferably added to shower water in a rough selection step, a selection step, a washing step, and / or a dehydration step.

  The addition of hypochlorite and ammonium sulfate and / or ammonium chloride, in one or more embodiments, comprises hypochlorite and ammonium sulfate and / or ammonium chloride as a molar ratio of residual chlorine to nitrogen. You may carry out by adding so that it may become 1: 1-1: 2. Further, in one or a plurality of embodiments, the molar ratio of hypochlorite to ammonium sulfate and / or ammonium chloride (molar ratio of residual chlorine amount to nitrogen) is 1: 1.1-1: 2, : 1.2 to 1: 2 or 1: 1.2 to 1: 1.6. In the present disclosure, the “residual chlorine amount” includes bound chlorine and free chlorine. The amount of residual chlorine may be calculated from the effective chlorine concentration of the hypochlorite aqueous solution to be used, and may be measured by a conventionally known method or a method developed in the future.

  In this indication, hypochlorite is added to white water which circulates a used paper pulp manufacturing process so that it may become 3-20 mg / L as effective chlorine concentration in one or a plurality of embodiments. In one or a plurality of embodiments, ammonium sulfate and / or ammonium chloride is added to white water circulating in the used paper pulp manufacturing process so that the molar ratio is 1: 1 to 1: 2 with respect to available chlorine.

  In one or a plurality of embodiments, addition of hypochlorite and ammonium sulfate and / or ammonium chloride can be performed using a hypochlorite aqueous solution, an ammonium sulfate aqueous solution, and an ammonium chloride aqueous solution.

  In this indication, pH of white water which circulates a used paper pulp manufacturing process is 9-12, or 10-11 in one or a plurality of embodiments.

[Method of inhibiting aggregation of calcium carbonate]
In one aspect, the present disclosure relates to a method for suppressing aggregation of calcium carbonate in a used paper pulp manufacturing process, which comprises adding hypochlorite and ammonium sulfate and / or ammonium chloride to white water circulating in the used paper pulp manufacturing process. . In the calcium carbonate aggregation suppression method of the present disclosure, the addition, molar ratio, concentration, and the like of hypochlorite and ammonium sulfate and / or ammonium chloride are the same as those of the calcium carbonate adhesion suppression method of the present disclosure.

[Method for producing waste paper pulp]
In one aspect, the present disclosure relates to a method for producing waste paper pulp from waste paper, comprising adding hypochlorite and ammonium sulfate and / or ammonium chloride to white water circulating in the waste paper pulp production process. According to the method for producing used paper pulp of the present disclosure, the used paper pulp is produced by adding hypochlorite and ammonium sulfate and / or ammonium chloride to white water circulating in the used paper pulp producing process. In one or a plurality of embodiments, it is possible to prevent the calcium carbonate scale from adhering in the process and / or to suppress the aggregation of the calcium carbonate. Therefore, in one or a plurality of embodiments, the shutdown due to washing of the adhering scale is reduced, and the used paper pulp is stably produced. it can. In one or a plurality of embodiments, the method for producing waste paper pulp according to the present disclosure is a method for producing waste paper pulp including performing the method for suppressing adhesion of calcium carbonate according to the present disclosure or the method for inhibiting aggregation of calcium carbonate according to the present disclosure.

[Paper manufacturing method]
In one aspect, the present disclosure is a method for producing paper using a raw material containing waste paper pulp, and includes a waste paper pulp production process in which white water added with hypochlorite and ammonium sulfate and / or ammonium chloride is recycled. Including a manufacturing method. According to the paper manufacturing method of the present disclosure, since it includes a waste paper pulp manufacturing process in which white water added with hypochlorite and ammonium sulfate and / or ammonium chloride is recycled, the calcium carbonate scale in the waste paper pulp manufacturing process is included. Since the adhesion can be prevented and / or the aggregation of calcium carbonate can be suppressed, the used paper pulp manufacturing process can be performed stably. In one or a plurality of embodiments, the paper manufacturing method of the present disclosure is a paper manufacturing method including performing the calcium carbonate adhesion suppression method of the present disclosure or the calcium carbonate aggregation suppression method of the present disclosure.

  The present disclosure will be described based on the following examples and comparative examples, but the present disclosure is not limited thereto.

(Preparation Example A) Preparation of a mixture of sodium hypochlorite and ammonium sulfate A sodium hypochlorite solution (residual chlorine content: 140 g / L) was diluted with deionized water so that the residual chlorine content was 5 g / L After that, 30% ammonium sulfate aqueous solution (ammonium sulfate (manufactured by Kishida Chemical Co., Ltd.) 30 g was dissolved in deionized water to make the total amount 100 g) and the molar ratio of residual chlorine amount and nitrogen was 1: 1.2. It was prepared as follows.

(Preparation example B) Preparation of mixed liquid of sodium hypochlorite and ammonium sulfate Prepared in the same manner as in Preparation example A, except that the molar ratio of the residual chlorine amount and nitrogen was 1: 1.6.

(Preparation Example C) Preparation of a mixture of sodium hypochlorite and ammonium bromide Sodium hypochlorite solution (residual chlorine content: 140 g / L) was deionized water so that the residual chlorine content was 5 g / L. 1% sodium hydroxide aqueous solution was added at 30 ml / L, and 30 g ammonium bromide aqueous solution (ammonium bromide (manufactured by Kishida Chemical Co., Ltd.)) was dissolved in deionized water to make a total amount of 100 g ), The residual chlorine amount and nitrogen molar ratio was 1: 1.2.

(Preparation example D) Preparation of sodium hypochlorite aqueous solution A sodium hypochlorite solution (residual chlorine amount: 140 g / L) was diluted with deionized water so that the residual chlorine amount was 5 g / L.

(Preparation Example E) Preparation of a mixture of sodium hypochlorite and ammonium chloride A sodium hypochlorite solution (residual chlorine content 140 g / liter) was diluted with deionized water to a residual chlorine content of 5 g / liter. Thereafter, a 20% ammonium chloride solution (20 g of ammonium chloride (manufactured by Kishida Chemical Co., Ltd.) dissolved in deionized water to make the total amount 100 g) has a molar ratio of residual chlorine to nitrogen of 1: 1.2. Mixed.

(Preparation Example F) Preparation of a mixture of sodium hypochlorite and ammonium chloride Hypochlorous acid as in Preparation Example E, except that the molar ratio of residual chlorine to nitrogen was 1: 1.6. A mixture of sodium and ammonium chloride was prepared.

(Test Example 1) Confirmation of adhesion suppression effect of calcium carbonate 29.4 g / L calcium chloride aqueous solution (calcium chloride dihydrate (manufactured by Kishida Chemical Co., Ltd.) dissolved in deionized water), 16.8 g / L Sodium bicarbonate aqueous solution (sodium bicarbonate (made by Kishida Chemical Co., Ltd.) dissolved in deionized water) and 56.8 g / L sodium metasilicate aqueous solution (sodium metasilicate nonahydrate (made by Kishida Chemical Co., Ltd.)) Was dissolved in deionized water).

  After adding 40 ml of deionized water, 5 mL of 29.4 g / L calcium chloride aqueous solution, and 5 mL of 16.8 g / L sodium bicarbonate aqueous solution to a 10 ml glass screw tube, immediately add to this mixture (pH 10.0). Each of the preparations A to D was added so as to have the concentration shown in Table 1 below, and then 3 ml of 56.8 g / L sodium metasilicate aqueous solution was added.

  This was stirred at 40 ° C. for 3 hours, then allowed to stand and allowed to cool at room temperature for 1 hour. The screw tube was washed with water to remove the non-adhered scale and dried at 70 ° C. After visually observing the adherence state of the screw tube wall surface, the adhering matter was dissolved with dilute hydrochloric acid and neutralized with an aqueous sodium hydroxide solution, and the total amount was put into a 100 ml volumetric flask to make 100 ml with deionized water. The amount of calcium in the aqueous solution was measured using a lambda-9000 manufactured by Kyoritsu Riken and using the phthalate complexone method as a measurement principle. The results are shown in Tables 1 and 2 below.

Table 1 shows the visual evaluation results. Visual evaluation was performed in the following four stages based on the amount of the screw tube with no drug added.
++++: Adhering amount of screw tube without addition of drug ++: Adhering amount less than that of screw tube without addition of drug +: Less adhering amount −: No adhesion

Table 2 shows the adhesion rate of calcium carbonate adhering to the screw tube. The adhesion rate (%) of the calcium carbonate scale was calculated using the following formula. In addition, the amount of calcium with no drug added was 3960 mg / L.
Adhesion rate of calcium carbonate scale (%) = (calcium amount (mg / L) of sample added with each drug / calcium amount without addition of drug (mg / L)) × 100

  As shown in Tables 1 and 2, Test Examples 1-1 and 1-2 to which sodium hypochlorite and ammonium sulfate were added had a small amount of scale attached to the screw tube wall surface at any concentration. Compared with Test Example 1-3 in which sodium chlorite and ammonium bromide were added and Test Example 1-4 in which only sodium hypochlorite was added, the amount of calcium carbonate scale adhered was small. Sodium hypochlorite and ammonium chloride in Test Examples 1-5 and 1-6, the scale amount attached to the wall surface of the screw tube was small at any concentration, and sodium hypochlorite and ammonium bromide were added. As compared with Test Example 1-3 and Test Example 1-4 to which only sodium hypochlorite was added, the amount of calcium carbonate scale attached was small.

(Test example 2) Confirmation of adhesion suppression effect of calcium carbonate using on-site sample Shower water (pH 10.7) circulating in the waste paper pulp manufacturing process It filtered with 2 filter papers (made by Advantech Toyo Co., Ltd.). After adding 40 ml of this filtrate, 5 ml of 29.4 g / L calcium chloride solution, and 5 ml of 16.8 g / L sodium hydrogen carbonate solution to a 100 ml glass screw tube, this mixture (pH 10.4) was immediately added. Each agent of Preparation Examples A, C, D, and E was added so as to have concentrations shown in Table 3 below. This was stirred at 40 ° C. for 3 hours, then allowed to stand and allowed to cool at room temperature for 1 hour. The screw tube was washed with water to remove the non-adhered scale and dried at 70 ° C. The deposit on the wall surface of the screw tube was dissolved with dilute hydrochloric acid and neutralized with an aqueous sodium hydroxide solution, and the total amount was put into a 100 ml volumetric flask and made up to 100 ml with deionized water. The amount of calcium in the aqueous solution was measured using a lambda-9000 manufactured by Kyoritsu Riken. Using the amount of calcium obtained, the adhesion rate (%) of the calcium carbonate scale was determined using the equation of Test Example 1 above. The results are shown in Table 3 below. The amount of calcium with no drug added was 185 mg / L.

  As shown in Table 3, in Example 1, to which sodium hypochlorite and ammonium sulfate were added, the amount of calcium carbonate scale deposited was small compared to Comparative Examples 1 and 2 at any concentration. Further, in Example 2 to which sodium hypochlorite and ammonium chloride were added, the amount of calcium carbonate scale deposited was small compared to Comparative Examples 1 and 2 at any concentration.

(Test Example 3) Change in size of fine particles in on-site sample White water (pH 11.7) collected from an extractor in the used paper pulp manufacturing process It filtered with 2 filter papers (made by Advantech Toyo Co., Ltd.). 40 ml of this filtrate was added to a 100 ml glass screw tube, and each of the preparations A, D and E was added so as to have the concentrations shown in Table 4 below, and the mixture was stirred at 40 ° C. for 3 hours. 300 μl of a sample in the screw tube was collected, diluted with 100 ml of deionized water, and then immediately measured for fine particle size using a desktop fine particle counter / high sensitivity turbidimeter NP500T manufactured by Nippon Denshoku Industries Co., Ltd. The number of fine particles having a size of 0.5 μm or less and 1 to 3 μm was measured, and the ratio before and after the addition of the drug was determined using the following formula. The results are shown in Table 4 below. The filtrate was dried and subjected to fluorescent X-ray analysis and IR analysis. As a result, it was confirmed that the scale was mainly composed of calcium carbonate.
Fine particle ratio (%) = [number of fine particles one hour after addition (number) / number of fine particles before addition (number)] × 100

  As shown in Table 4, in Example 3 to which sodium hypochlorite and ammonium sulfate were added, the proportion of fine particles having a size of 0.5 μm or less increased compared to Comparative Example 3 and 1 The proportion of fine particles of ˜3 μm decreased. In Example 4 to which sodium hypochlorite and ammonium chloride were added, the proportion of fine particles having a size of 0.5 μm or less increased compared to Comparative Example 3, and the proportion of fine particles of 1 to 3 μm. Decreased. By adding sodium hypochlorite and ammonium sulfate in the waste paper pulp manufacturing process, it is possible to remain in the water system while the size of the particles formed is fine, so that the reduction in dehydration efficiency is suppressed and stable operation becomes possible Guessed.

(Test Example 4) Actual Machine Example As Example 5, a mixture of sodium hypochlorite and ammonium sulfate was connected to a pipe line (pH 10.0) connected to the upstream and downstream extractor shower water in the waste paper pulp manufacturing process shown in FIG. (Mole ratio of residual chlorine to nitrogen is 1: 1.2) was added 24 times a day for 15 minutes so as to be 9 to 12 mg / L as residual chlorine to produce used paper pulp. The number of continuous operation days and the number of replacements of the front and rear screens were counted. Further, as Comparative Example 4, waste paper pulp was produced in the same manner as in Example 5 except that phosphonic acid-based scale inhibitor was used instead of sodium hypochlorite and ammonium sulfate, and Comparative Example 5 showed sodium hypochlorite and Waste paper pulp was produced in the same manner as in Example 5 except that ammonium sulfate was not added. The results are shown in Tables 5 and 6 below.

  As shown in Table 5 and Table 6, Example 5 to which sodium hypochlorite and ammonium sulfate were added had a longer continuous operation day than the case where no additive and a phosphonic acid-based scale inhibitor were added. The number of exchanges was small. Moreover, the continuous operation days were long compared with the case where a phosphonic acid scale inhibitor was added. Therefore, it was confirmed that stable operation was possible by adding sodium hypochlorite and ammonium sulfate.

Claims (5)

  Waste paper pulp production comprising adding hypochlorite and ammonium sulfate and / or ammonium chloride to white water circulating through the waste paper pulp production process having a disaggregation process, a dust removal process, a dehydration process, and an aging (bleaching) process Method for suppressing adhesion of calcium carbonate scale in the process.   The adhesion suppressing method according to claim 1, wherein hypochlorite and ammonium sulfate and / or ammonium chloride are added so that the molar ratio of the residual chlorine amount to nitrogen is 1: 1 to 1: 2.   The adhesion suppression method according to claim 1 or 2, wherein the pH of white water circulating through the used paper pulp manufacturing process is 9-12.   A mixture of hypochlorite and ammonium sulfate and / or ammonium chloride is added to white water circulating through the waste paper pulp manufacturing process so that the effective chlorine concentration is 3 to 20 mg / L. 4. The method for suppressing adhesion according to any one of items 1 to 3.   A waste paper pulp comprising adding hypochlorite and ammonium sulfate and / or ammonium chloride to white water circulating through a waste paper pulp manufacturing process having a disaggregation process, a dust removal process, a dehydration process, and an aging (bleaching) process. Production method.

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