JP2010236158A - Filler for papermaking - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a filler for papermaking, reusable for internal filling of paper by using a burned ash as a raw material, and treating the burned ash by a comparatively simple process because the reduction of an industrial waste is strongly sought from a view point of environmental protection, and especially the treatment of the burned ash becomes a problem; to provide a method for producing the filler; and to provide the paper containing the filler for the papermaking. <P>SOLUTION: The filler for the papermaking exhibiting excellent wire abrasion resistance can be obtained by heat-treating the raw material at a temperature of 700-800°C, and regulating the pH by using sulfuric acid and/or aluminum sulfate. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a papermaking filler obtained from incinerated ash and a method for producing the same. In particular, the papermaking filler of the present invention is suitable as a papermaking filler to be internally added during papermaking because it does not easily wear the wire of a papermaking machine. The present invention also relates to a paper containing the papermaking filler.

  In recent years, reduction of industrial waste has been strongly demanded from the viewpoint of environmental conservation. The reduction of industrial waste is a request to all companies and local governments that are engaged in power generation and waste incineration, and the paper and pulp industry is no exception.

  Under such circumstances, handling of incinerated ash has become a major social problem. At present, some of the incineration ash is effectively used as recycled materials such as cement raw materials, iron-making antioxidants, admixtures, etc., but the rest are often landfilled as industrial waste. It is considered that the reason why reuse is not so advanced is that even if incinerated ash is discharged from the same equipment, the constituent elements are not constant, so the product quality of the reused product is not constant. Another possible cause is that the generation amount is enormous.

  However, on the other hand, the development of methods for reusing incineration ash is also progressing. The methods are broadly divided into (1) a method for reusing incineration ash as a raw material, and (2) some processing for incineration ash. There are two methods: a method of performing and reusing as a raw material after improving a specific property.

  As the former method, a method of reusing it as artificial soil by mixing cement raw materials, antioxidants for iron making, snow melting agents, organic sludge, etc. and incinerated ash has been studied and commercialized (Patent Literature) 1).

The latter method is more complicated because of the processing. As an example, Patent Document 2 discloses a porous material produced by carbonizing papermaking sludge and papers in a non-oxygen atmosphere at 650 ° C. or lower, and further hydrothermally synthesizing them in an alkaline aqueous solution. ing. Patent Document 3 discloses a regenerated particle aggregate obtained by using deinked floss as a main raw material, and subjecting the main raw material to dehydration, drying, combustion, and pulverization operations, including gehlenite (Ca ₂ Al ₂ SiO ₇ ) and A regenerated particle aggregate that suppresses the total content of hard substances such as anorthite (CaAl ₂ Si ₂ O ₈ ) to 2.0 mass% or less is shown. Furthermore, Patent Document 4 discloses a method for producing an inorganic material while applying heat treatment at 600 to 800 ° C. to an aqueous slurry discharge containing organic matter and inorganic particles, and suppressing decomposition of calcium carbonate in the discharge. Yes.

  Both the former and the latter are common in that incinerated ash is not used as waste, but has some added value and is used again as a raw material, and is considered to reflect the current social background.

  On the other hand, in order to reuse these products using incinerated ash, a lot of costs and energy may be required, or the quality of the reused product often does not reach the required quality. Also, from the viewpoint of life cycle assessment, the cost and energy required to recycle incineration ash and the quality of the obtained reused product are comprehensively judged and are not practically practical. There are also many. For example, as in Patent Document 2, enormous energy is required to perform carbonization treatment in a non-oxygen atmosphere and hydrothermal treatment in an alkaline aqueous solution, and the process becomes complicated. In Patent Document 3, since it is preferable to perform a plurality of stages of combustion using a plurality of combustion furnaces, it also consumes a large amount of energy and also requires a large amount of equipment space. It may be disadvantageous in terms of cost from the viewpoint of use. As described above, in order to perform various pretreatments for reusing incineration ash, a lot of costs and labor are required, which are often difficult in practice. This is also one of the reasons why recycling of incineration ash cannot be actively promoted.

Japanese Patent Laid-Open No. 09-121684 JP 2004-277272 A JP 2008-190049 A JP-A-10-29818

  The main problem of the present invention is to provide a papermaking filler that can be reused for the internal addition of paper by using the incinerated ash as a raw material and processing the incinerated ash by a relatively simple process, and a method for producing the same. is there. It is also an object of the present invention to provide a paper comprising such a papermaking filler.

  By this invention, the manufacturing method of the filler for paper manufacture which uses incinerated ash after heat-processing at the temperature of 700-800 degreeC as a raw material is provided. According to the present invention, it is possible to efficiently obtain a papermaking filler with greatly improved wire wear. In the present invention, the raw material incineration ash may be one or more selected from the group consisting of paper sludge incineration ash, coal incineration ash, waste incineration ash containing paper, biomass incineration ash, and combined fuel incineration ash. More preferably, paper sludge and / or incineration ash of coal is used. In addition, the method for producing a papermaking filler of the present invention includes a step of dispersing incineration ash to form a slurry, and adding sulfuric acid and / or sulfate to the incineration ash slurry to adjust the pH to 7 to 10, and incineration It is preferable to further include a step of pulverizing the ash to adjust the average particle size to 0.1 to 10 μm.

  In another aspect, the present invention is a papermaking filler made from incinerated ash after heat treatment at a temperature of 700 to 800 ° C. The papermaking filler of the present invention preferably uses papermaking sludge and / or coal incineration ash as the raw incineration ash. Further, the paper filler of the present invention preferably has a whiteness of 10% to 60%, more preferably 30% to 60%.

  In another aspect, the present invention is a paper containing the above papermaking filler.

Although not limited to this, this invention includes the following invention.
(1) a step of incinerating a raw material containing at least one selected from the group consisting of papermaking sludge, coal, paper-containing waste, biomass, and composite fuel at a temperature of 700 to 800 ° C. to obtain incinerated ash; A method for producing a papermaking filler, comprising: dispersing the obtained incinerated ash into a slurry, and adding sulfuric acid and / or sulfate to the incinerated ash slurry.
(2) The manufacturing method of the filler for paper manufacture as described in (1) which further includes the process which grind | pulverizes the said incineration ash and sets an average particle diameter to 0.1-10 micrometers.
(3) A paper filler obtained by the method according to (1) or (2).
(4) The papermaking filler according to (3), wherein the whiteness is 10% to 60%.
(5) A paper comprising a papermaking filler obtained by the method according to (1) or (2).

  INDUSTRIAL APPLICABILITY According to the present invention, a papermaking filler excellent in suitability as a papermaking filler using incinerated ash discharged from combustion equipment such as a boiler as a raw material and a method for producing the same are provided. The papermaking filler of the present invention has characteristics that make it difficult to wear the wire of the paper machine by adjusting the temperature at which the incinerated ash used as a raw material is heat-treated within a predetermined range, and is excellent as an internal filler. . In addition, the papermaking filler of the present invention can be produced by a relatively simple method using incinerated ash as a raw material, and is therefore extremely advantageous and practical from the viewpoint of energy and cost.

FIG. 1 is a result of analyzing the crystal composition of the incinerated ash material obtained in Example 1 and Comparative Example 1 by X-ray diffraction.

  Hereafter, the details of the filler for paper manufacture which uses incineration ash by this invention as a raw material, and its manufacturing method are described.

Papermaking Filler The papermaking filler of the present invention uses incinerated ash obtained by subjecting a raw material to a heat treatment at a temperature of 700 to 800 ° C. In general, incineration ash is mainly composed of various metals and inorganic substances such as oxides, sulfides, and chlorides thereof, but the composition thereof is very complicated and varies depending on the incinerated products and the production area. Incinerated ash may contain halogens and heavy metals in addition to inorganic oxides such as SiO ₂ , Al ₂ O ₃ , CaO, and MgO, organic substances in combustion raw materials such as unburned carbon. As described above, the composition of incineration ash varies depending on the location and season, but in order to reuse industrially stably, such incineration ash with a non-constant composition is used as a raw material for a certain level of papermaking. It is required that the filler can be manufactured stably. Under such circumstances, the inventor has surprisingly found that the wire wear degree of the incineration ash is improved by controlling the incineration temperature when obtaining the incineration ash to 700 to 800 ° C. . That is, according to the present invention, it is possible to stably produce a paper filler with excellent wire wear properties from various raw materials regardless of combustion conditions such as the time for heat treatment and the shape of combustion equipment. . As demonstrated in the examples described later, by burning the raw material in the presence of oxygen at a heat treatment temperature of 800 ° C. or lower, the wire wear resistance is remarkably reduced and it can be suitably used as a filler for papermaking. become. On the other hand, when the heat treatment temperature is lower than 700 ° C., the combustion efficiency is lowered, and many unburned components mainly composed of unburned carbon remain, which is not preferable. From the viewpoint of combustion efficiency and the like, in a more preferred embodiment, the combustion temperature of the present invention is 750 to 800 ° C.

In general, the temperature at which the incineration raw material is heat-treated is set according to the specifications of the incineration equipment so that the raw material is sufficiently incinerated and has desired effects in energy recovery, volume reduction, and the like. In recent years, in order to suppress the generation of dioxins during incineration, it is common to incinerate raw materials at temperatures exceeding 800 ° C. However, when incineration is carried out at a temperature exceeding 800 ° C., aluminum calcium silicate typified by gehlenite (Ca ₂ Al (AlSi) O ₇ ) is produced. When the incinerated ash containing gehlenite or the like is used as a filler for papermaking, the papermaking wire of the papermaking machine is significantly damaged. Although the details of the mechanism by which the filler for papermaking excellent in wire wear resistance is obtained by the present invention are not clear, the amount of gehlenite contained in the incineration ash is reduced by lowering the incineration temperature of the raw material to 700 to 800 ° C. It is presumed to have something to do with it. In addition, the gehlenite etc. which are contained in incineration ash can be confirmed by X-ray diffraction.

  In the present invention, the wire wearability can be remarkably improved by heat-treating various incineration raw materials at a temperature of 700 to 800 ° C., but various incineration raw materials can be reused as a filler for papermaking, so the application range thereof Is wide. The incineration raw material used as a raw material can be used singly from a single source, or can be used by mixing from a plurality of sources. When mixing a plurality of incineration ash burned at a temperature of 700 to 800 ° C to make a filler for papermaking, each incineration ash needs to be heat-treated at a temperature of 700 to 800 ° C. The generated combustion equipment method and ash raw material may be different.

  In the present invention, the combustion apparatus is not particularly limited. For example, a stoker furnace (fixed bed), a burner furnace, a fluidized bed furnace, a fuel injection furnace, a cyclone furnace, a kiln furnace, an internal heat combustion furnace such as a multistage combustion furnace, A combustion apparatus such as an indirect heating type external heat combustion furnace using heavy oil or the like as a heat source can be used, and a stalker furnace (fixed bed), a burner furnace, a fluidized bed furnace, or a kiln furnace is preferable. Moreover, although combustion time (residence time) can also be determined according to the quantity of raw materials, oxygen conditions, etc., 0.1 to 60 seconds are preferable and 0.2 to 30 seconds are more preferable. Although the oxygen concentration in a combustion apparatus can also be suitably determined according to conditions, from a viewpoint of combustion efficiency, 0.1 to 15% is preferable and 1 to 10% is more preferable.

  Examples of the raw material of the present invention include papermaking sludge, coal, paper-containing waste, biomass, composite fuel, and the like, and other materials may be included in addition to these. Among them, it is preferable in the present invention to use paper sludge and / or coal incineration ash.

  Incineration residue obtained by heat-treating sludge (PS: paper sludge, also called paper sludge) generated in the paper making process at 700 to 800 ° C. in various combustion facilities such as a kiln and a heat recovery boiler (Incineration ash) can be suitably used. The incineration ash obtained from sludge derived from the papermaking process consists of inorganic pigments such as calcium carbonate, titanium dioxide, talc and kaolin discharged from the waste paper recycling process and papermaking white water, aluminum sulfate as an inorganic flocculant, and ink components and fibers. It includes a part of. In the present invention, when a paper filler is manufactured using sludge from the paper manufacturing process as a raw material, it can be reused as a paper manufacturing raw material while reducing waste from a paper mill, and it is extremely advantageous because it does not involve transportation costs. It is. Also, the incineration ash of paper sludge is advantageous in that its composition is relatively stable. The papermaking sludge combustion facility is not particularly limited, and examples thereof include a rotary kiln and a sludge boiler.

  Examples of the papermaking sludge of the present invention include sludge from a used paper recycling process (DIP process), a pulp manufacturing process, a papermaking process, and the like. Papermaking sludge is mainly composed of solids in wastewater washed away from the wastepaper recycling process, pulp manufacturing process, papermaking process, etc. And sludge obtained by dehydrating the waste liquid after the treatment. Such papermaking sludge contains fibers, ink particles and the like in addition to inorganic fillers and inorganic pigments such as kaolin clay and calcium carbonate.

  In the present invention, coal incineration ash refers to coal burnout generated in a combustion facility. In general, it is said that coal ash has a particle size of almost 100 μm or less in fly ash and a size of 1 to 1 mm or more in bottom ash. In the present invention, coal ash having any size and shape is used for papermaking. It may be used as a filler. As the coal incineration ash, for example, the coal incineration ash discharged from pulverized coal boilers in the electric power industry and the like, and the coal incineration ash obtained from the coal combustion facility of the paper mill can be used as a raw material for the paper filler of the present invention. .

  In the present invention, paper-containing waste includes various types of waste other than paper, in addition to waste mainly composed of so-called waste paper and waste paper, which is no longer necessary in homes, offices, and papermaking processes. This includes waste that is generated. For example, even if paper coated with a resin film or the like is used as a raw material, according to the present invention, a papermaking filler having excellent wire wear can be obtained.

  In the present invention, the biomass is an organism-derived industrial resource. For example, waste biomass includes paper, livestock manure, food waste, construction waste such as wood chips and wood flour, black liquor, sewage sludge, and raw garbage. Examples of unused biomass include agricultural waste such as rice straw, wheat straw, and rice husk, forest land residues such as thinned and damaged wood, timber, resource crops, and feed crops.

  In the present invention, the composite fuel is a material obtained by converting a material such as waste, such as waste solid fuel (RDF), and is mainly used for obtaining thermal energy by combustion, and is disposed of. It is effectively used as fuel for power generation and boilers. For example, RDF is a solid fuel made of waste such as raw garbage and plastic garbage that is thrown away at home and can be suitably used in the present invention. In addition, RPF (Refuse Paper & Plastic Fuel) obtained from waste, mainly waste paper and waste plastics, has a clear content of waste, so its calorific value is easy to control and its water content is low. Since polyvinyl chloride (PVC), which is considered to be the cause of the occurrence of the above, can be excluded, it can be particularly preferably used in the present invention.

  The paper filler of the present invention is preferably used by subjecting the incinerated ash heat-treated at 700 to 800 ° C. to a pulverization treatment and an average particle size of 0.1 to 10 μm. In general, calcium carbonate, filler kaolin, talc, hydrous silicic acid (white carbon), titanium dioxide, etc., used as a papermaking filler, when used as a papermaking filler, preferably have an average particle size of 0.1 to 30 μm. Has been. However, since incineration ash has a relatively high hardness, if paper is manufactured by simply adding incineration ash in the above-mentioned particle size range, the wire life of the paper machine will be greatly worn, shortening the wire life. There was a problem that productivity was remarkably lowered. In the present invention, by pulverizing the incinerated ash to make the particle size in the range of 0.1 to 10 μm, the wire wearability is greatly improved. The details of this reason are not clear, and the present invention is not limited to the following, but the incineration ash having high hardness is appropriately pulverized by the pulverization process, and the weight of the filler particles is reduced so that the particles are in the paper machine. Since the kinetic energy at the time of moving is reduced, it is presumed that the wire wearability is improved.

  In consideration of the balance between filler yield and wire wear, the papermaking filler of the present invention preferably has an average particle size after pulverization of incinerated ash of 0.1 to 10 μm, preferably 0.5 to 5.0 μm. More preferably, 1.0-4.0 micrometers is further more preferable, and 1.0-3.0 micrometers is the most preferable. If the average particle size is smaller than 0.1 μm, it is difficult to stay in the paper in the paper making process and the yield of incinerated ash in the paper is lowered, which is not industrially preferable.

  The incineration ash in the present invention can be pulverized by various methods, and is preferably pulverized using a pulverizer. The pulverization method can be either dry or wet. Pulverizers used in the pulverization process include ball mills, rod mills, and other broad ball mills; bead mills, tower mills, attritors, sateley mills, sand grinders, annular mills, and other medium agitation mills, colloid mills, homomixers, homogenizers, and inline In addition to a high-speed rotary pulverizer such as a mill, a dry pulverizer such as a jet mill, a dry bead mill, or a dry ball mill may be used. In addition, a classification step using a sieve or the like can be combined for the purpose of increasing the efficiency of pulverization or removing non-standard products before, after or during the pulverization step. Examples of classification means using a sieve include a vibrating sieve, an ultrasonic sieve, a jet screen, an air separator, and a trommel screen. The pulverization step may be performed by combining a plurality of pulverizers. The pulverizer used at this time may be dry or wet as described above, and a dry pulverizer and a wet pulverizer may be used in combination.

  In the case where the incineration ash is pulverized in a wet manner in the present invention, the incineration ash is slurried prior to the wet pulverization. Although there will be no restriction | limiting in particular if the density | concentration of a slurry is a density | concentration which can perform wet grinding, 0.05 to 50% is preferable and 1 to 40% is more preferable. If it is less than 0.05%, the amount of particles produced is small and the efficiency is poor, and if it exceeds 50%, the fluidity of the slurry is deteriorated and the operability of the pulverization process may be lowered. Before applying the slurry to the pulverizer, it is desirable to uniformly disperse the incinerated ash particles in the slurry by stirring and dispersing treatment. This agitation / dispersion treatment poses no problem unless the incinerated ash is sufficiently dispersed and extremely agglomerated, and there is no particular limitation on time, agitation strength, and the like. As the stirrer or disperser, known stirrers or dispersers including, for example, an agitator, a homomixer, a homogenizer, and a mixer can be used without any problem. The solvent of the incineration ash slurry is preferably an aqueous solvent.

  In carrying out the pulverization step and / or slurry dispersion treatment in the present invention, a pulverization aid and / or a dispersant may be used for the purpose of adjusting the viscosity. The type of grinding aid used for dry grinding is not particularly limited, and known grinding aids such as alcohols such as ethanol and isopropyl alcohol, propylene glycol, triethanolamine, triethylamine, water or water-based aids. It can be used without any problems. Further, the type of the dispersant used for the wet pulverization and / or slurry dispersion treatment is not particularly limited, and an aqueous polymer containing acrylic acid, methacrylic acid, polyacrylic acid, and derivatives and salts thereof as constituents Any known dispersant can be used without any problem. The addition amount of the grinding aid / dispersant is appropriately adjusted according to the particle size, particle size distribution, slurry concentration, viscosity and the like.

  The pH of the papermaking filler of the present invention is preferably adjusted to a range of 7 to 10, and more preferably adjusted to a pH of 8 to 10. Incinerated ash generally shows a high alkalinity of pH 11 or higher, and if this alkali content is brought into the paper machine as it is, there is a possibility that the effects of various chemicals added to the paper stock may be hindered. When the incinerated ash of the invention exhibits high alkalinity, it is desirable to perform pH adjustment treatment on this. If the pH is more than 10, when added internally as a papermaking filler, the effects of various chemicals added to the paper may be hindered. In addition, a large amount of acidic substances are required to make the pH less than 7, and it is not industrially practical, and sulfuric acid and / or sulfates that are acidic substances react with calcium contained in ash. Calcium sulfate is produced by the process, which may increase the possibility of scale generation in the paper machine. In the present invention, the pH of the papermaking filler refers to the pH of the slurry when the papermaking filler is dispersed in water to prepare a slurry having a solid content of 12% by weight.

  When adjusting the pH of the paper filler of the present invention, sulfuric acid and / or sulfate is used as an acidic substance. It is industrially preferable to use sulfuric acid or aluminum sulfate from the viewpoint of easy availability in paper mills, cost and workability.

  When adjusting the pH in the present invention, the step of adjusting the pH may be performed at any stage before the pulverization process, during the pulverization process, or after the pulverization process, or may be performed in a plurality of stages. On the other hand, in order to uniformly adjust the pH of the incinerated ash, it is preferable to disperse the incinerated ash into a slurry and then add an acidic substance to the slurry. When the acidic substance is added, it is desirable to uniformly disperse the acidic substance in the slurry by stirring and dispersing treatment. This agitation / dispersion treatment is not a problem as long as the acidic substance is sufficiently dispersed, and there is no particular limitation on time and agitation strength. As the stirrer or disperser, any known stirrer or disperser including, for example, an agitator, a homomixer, a homogenizer, and a mixer can be used without any problem. In addition, when an acidic substance is added at the same time as the pulverization process, it is considered that the acidic substance is dispersed in the slurry by the pulverization process, so the pH should be sufficiently adjusted even if the step of performing only the stirring process is omitted. Can do.

  The incinerated ash material of the present invention can be filtered, washed with water, and redispersed for the purpose of removing by-products. In addition, when drying is necessary for transportation or the like, it can be dried by heating or reduced pressure. The paper filler of the present invention can be subjected to a drying treatment because the physical properties hardly change even if it is dispersed again after drying to form a slurry.

  The incineration ash material obtained by the present invention has the same whiteness as that of the incineration ash when the incineration ash is used as it is as a filler for papermaking. Also, when the incinerated ash is used after being pulverized, the whiteness of the papermaking filler is almost the same as that of the incinerated ash used as a starting material, and the average particle size is preferably 0.1 to 10 μm. By adjusting the temperature at which the incinerated ash used as a raw material is subjected to heat treatment to 700 to 800 ° C., it is possible to remarkably improve the wear properties that have been an inevitable problem in the conventional use of incinerated ash. The whiteness of the paper filler of the present invention is low compared to calcium carbonate, filler kaolin, talc, hydrous silicic acid (white carbon), titanium dioxide, etc., which are generally used as paper fillers, but low because of excellent wire wear. Whiteness grade paper can be used without any problem, and even high whiteness grade paper can be used by adjusting the addition rate or combining with other papermaking fillers. In general, it is difficult to increase the whiteness of the incinerated ash, and enormous costs and work time are essential.However, in the present invention, since the process of adjusting the whiteness is not essential, it is extremely economical to adjust the starting material. The incinerated ash material in which the whiteness is substantially maintained can be used as a filler for papermaking. Since the whiteness of the incinerated ash is generally 60% or less, the whiteness of the papermaking filler of the present invention is 60% or less unless the whiteness improvement treatment is performed. On the other hand, the whiteness of the papermaking filler of the present invention is preferably 10% or more, and more preferably 30% or more in order to maintain a practical level as a papermaking filler. If the whiteness is 30 to 60%, a desired quality can be achieved at the same time while effectively using waste without significantly reducing the whiteness of the paper. If the whiteness of the papermaking filler is less than 30%, there is a possibility that the whiteness of the paper cannot be fully maintained when internally added to the paper, but the effect of increasing the opacity of the paper is Depending on the required quality, it may be used appropriately. Moreover, the use of coal ash having a relatively low whiteness can be expected to lead to further reduction of waste.

  According to the present invention, since the incinerated ash disposed as waste can be reused, the burden on the environment can be reduced. Moreover, since the process with respect to incineration ash is comparatively simple and few, this invention is advantageous from an energy and cost viewpoint, and can be implemented industrially simply.

Manufacture of paper Paper can be manufactured using the filler for paper manufacture of this invention. The papermaking filler of the present invention can be used for papermaking using a general papermaking machine because it hardly wears the wire of the papermaking machine.

  The papermaking filler of the present invention can be used alone or in combination with other papermaking fillers. When used in combination with other papermaking fillers, known fillers can be used alone or in appropriate combination of two or more, for example, calcium carbonate, kaolin (filler kaolin, calcined kaolin, etc.), talc, hydrous silicic acid (White carbon), hydrous silicate, magnesium carbonate, barium carbonate, zinc oxide, silicon oxide, aluminum hydroxide, calcium hydroxide, magnesium hydroxide, zinc hydroxide, and other inorganic fillers; vinyl chloride resin, polystyrene resin, urea / Formalin resins, melamine resins, styrene / butadiene copolymer resins, phenol resins, organic fillers such as plastic hollow particles, or organic / inorganic composite fillers can be used.

  When producing paper using the papermaking filler of the present invention, various papermaking chemicals can be used. Specifically, if necessary, the paper strength of polyacrylamide polymer, polyvinyl alcohol polymer, starch polymer (cationized starch, modified starch, etc.), urea / formalin resin, melamine / formalin resin, etc. is increased. Agent: Acrylamide / aminomethylacrylamide copolymer salt, starch polymer (cationized starch, modified starch, etc.), polyethyleneimine, polyethylene oxide, acrylamide / sodium acrylate copolymer, etc. An auxiliary agent such as an agent; aluminum sulfate (sulfuric acid band); water resistance agent; ultraviolet light inhibitor; printability improver; These auxiliary agents may be added to the incineration ash filler slurry of the present invention in advance and then applied to the paper machine, or may be applied separately to the incineration ash filler slurry of the present invention to the paper machine. .

Physical property values Each characteristic value in the present invention is a value obtained by the following measuring method.
(1) Particle size distribution measurement (laser method): The particle size distribution is measured by a laser diffraction method. The sample slurry was dropped and mixed in pure water to which a dispersant (sodium hexametaphosphate) 0.2% by weight (based on the solid content of the sample) was added to form a uniform dispersion, and a laser particle size measuring instrument (equipment used: Malvern) The particle size is measured using a master sizer.
(2) Degree of wire wear: Wire wear is measured with an Einlehner AT1000 wear tester using a phosphor bronze wire disk (hereinafter referred to as wire). The wire used for measurement was washed in an ultrasonic bath for 5 minutes, then washed with ion-exchanged water, and further washed with acetone. This was dried at 105 ° C. for 1 hour or longer, allowed to cool in a desiccator, and then weighed with an accuracy of 0.1 mg. This wire was fixed to the bottom of the test cylinder, and the stirrer was lowered to contact the wire. A slurry having a concentration of 10% with ion-exchanged water was used as a measurement sample and injected into a test cylinder machine. In this state, the stirrer was rotated 174,000 to wear the wire. The wire after the abrasion test was washed again in an ultrasonic bath for 5 minutes, then washed with ion-exchanged water, and further washed with acetone. This was dried at 105 ° C. for 1 hour or longer, allowed to cool in a desiccator, and then weighed with an accuracy of 0.1 mg. The wire weight after the wear test was subtracted from the wire weight before the wear test to obtain the degree of wire wear (mg).
(3) Whiteness: The sample was placed in a ring-shaped measuring instrument so as to have a thickness that did not allow the measurement light to pass through the back side, and pelletized by applying a pressure of about 20 kg / cm ² . About this pellet, using Murakami Color Research Laboratory CMS-35SPX, the whiteness was measured under conditions including a D65 light source, a 10-degree field of view, and ultraviolet light.
(4) Crystal composition: The crystal composition of the sample was measured with an X-ray diffractometer (X'Pert PRO: manufactured by PANalytical).
(5) Elemental analysis: The elemental composition of the sample was measured with a fluorescent X-ray measurement apparatus (ED2000: manufactured by Oxford Instruments).

  Examples of the present invention will be specifically described below in comparison with comparative examples, but the present invention is not limited to these examples. In the description, “%” and “part” indicate “weight percent” and “part by weight” unless otherwise specified. In addition, the material addition rate indicates the solid content addition rate unless otherwise specified.

<Manufacture of paper fillers>
By the method shown below, paper filler was manufactured using incinerated ash as a raw material. As the raw material, sludge derived from the papermaking process (approximately 80% by weight sludge derived from the recycled paper recycling process, approximately 20% by weight sludge derived from papermaking white water) or coal was used. In addition, the physical property evaluation (particle size, wire wear degree, whiteness) of the incinerated ash material was carried out by the method described above.

[Example 1]
As a starting material, sludge derived from the papermaking process was used. This sludge was incinerated using a fluidized bed furnace at an oxygen concentration of 7%, a residence time of 2 seconds, and 770 ° C. to obtain 300 kg of incinerated ash. When this incinerated ash was measured, the average particle size was 230 μm and the whiteness was 51%.

  Add 2200 kg of water to 300 kg of the above incinerated ash, add 1% of solid sodium acrylate (Aron T-40: manufactured by Toa Gosei Co., Ltd.) as a dispersant to the incinerated ash, and thoroughly stir with an agitator Thus, an incineration ash slurry having a solid content concentration of 12% was obtained.

  Next, the slurry was pulverized using a sand grinder (grinding medium: 0.8 mm diameter glass beads). The pulverization treatment was performed for 3 hours 30 minutes by circulating the slurry between the holding tank and the pulverizer, and finally an incinerated ash material having an average particle size of 2.7 μm was obtained. While performing the pulverization step, sulfuric acid was gradually added for pH adjustment. Specifically, 97% sulfuric acid was added to the holding tank by a rotary pump, and the total amount of 97% sulfuric acid added was 24L. Sulfuric acid was added directly below the stirring blade of the agitator rotating at 1000 rpm so that the added sulfuric acid was sufficiently dispersed. The pH of the incinerated ash slurry after pH adjustment was 8.5.

  After removing coarse particles from the slurry using a 200-mesh sieve (aperture: 0.075 mm), no. Suction filtered using 2 filter papers. A part of the solid phase was dried under reduced pressure to obtain a sample for measuring whiteness. Further, a part of the filtered cake was redispersed in water at a concentration of 10% to obtain a sample for measuring the average particle diameter and wire wear. Furthermore, the remainder of the filtered cake was redispersed in water at a concentration of 1% and used as a papermaking sample. Further, the galenite content of the papermaking filler is X-ray diffraction relative to the gehlenite content of Comparative Example 1 described later (using the same starting materials as in Example 1 with the same incineration conditions other than temperature). As estimated from the peak area, it was 20%.

[Example 2]
Incinerated ash was obtained from sludge from the papermaking process in the same manner as in Example 1. 300 kg of this incinerated ash (average particle size 230 μm, whiteness 51%) is added to 2200 kg of water, and sodium polyacrylate (Aron T-40: manufactured by Toa Gosei Co., Ltd.) as a dispersant is 1 in solid content with respect to the incinerated ash. % And the mixture was sufficiently stirred with an agitator to obtain an incinerated ash slurry having a solid content of 12%.

  Next, using this slurry, a grinding process was performed for 3 hours and 20 minutes using a sand grinder (grinding medium: 0.8 mm diameter glass beads) as the first stage grinding. The pulverization treatment was performed by circulating the slurry between the holding tank and the pulverizer to obtain an incinerated ash material having an average particle size of 2.9 μm. Next, using this slurry, a grinding process was performed for 1 hour 30 minutes using a horizontal bead mill (grinding medium: 0.5 mm zircon beads) as the second stage grinding. The pulverization process was performed by circulating the slurry between the holding tank and the pulverizer, and finally an incinerated ash material having an average particle diameter of 1.6 μm was obtained. Sulfuric acid was gradually added for the purpose of pH adjustment while performing the first and second pulverization steps. Specifically, 97% sulfuric acid was added to the holding tank by a rotary pump, and the total amount of 97% sulfuric acid added was 24L. Sulfuric acid was added directly below the stirring blade of the agitator rotating at 1000 rpm so that the added sulfuric acid was sufficiently dispersed. The pH of the incinerated ash slurry after pH adjustment was 8.5.

  After removing the coarse particles from the slurry using a 200 mesh sieve, Suction filtered using 2 filter papers. A part of the solid phase was dried under reduced pressure to obtain a sample for measuring whiteness. Further, a part of the filtered cake was redispersed in water at a concentration of 10% to obtain a sample for measuring the average particle diameter and wire wear. Further, the remainder of the filtered cake was redispersed in water at a concentration of 1% and used as a paper sample as a filler. In addition, the galenite content of the papermaking filler is a peak of X-ray diffraction with respect to the gehlenite content of Comparative Example 1 (which uses the same starting materials as in Example 1 and has the same incineration conditions other than temperature), which will be described later. According to the estimation from the area, it was 20%.

[Example 3]
A papermaking filler was produced and evaluated in the same manner as in Example 1 except that the pulverization time was 1 hour and 45 minutes, and finally an incinerated ash material having an average particle diameter of 7.8 μm was obtained.

[Example 4]
In the same manner as in Example 1, sludge derived from the papermaking process was incinerated at 770 ° C. to obtain a papermaking filler. In this example, neither pulverization nor pH adjustment was performed on the incinerated ash. Therefore, the incinerated ash of this example had an average particle size of 230 μm and a whiteness of 51%. In addition, the galenite content of the papermaking filler is a peak of X-ray diffraction with respect to the gehlenite content of Comparative Example 1 (which uses the same starting materials as in Example 1 and has the same incineration conditions other than temperature), which will be described later. According to the estimation from the area, it was 20%.

[Example 5]
As the starting material, sludge from the same papermaking process as in Example 1 was used. This sludge was incinerated using a fluidized bed furnace at an oxygen concentration of 7%, a residence time of 2 seconds, and 730 ° C. to obtain 300 kg of incinerated ash. When the incinerated ash was measured, the average particle size was 205 μm and the whiteness was 53%.

  Add 2200 kg of water to 300 kg of the above incinerated ash, add 1% of solid sodium acrylate (Aron T-40: manufactured by Toa Gosei Co., Ltd.) as a dispersant to the incinerated ash, and thoroughly stir with an agitator Thus, an incineration ash slurry having a solid content concentration of 12% was obtained.

  Next, the slurry was pulverized using a sand grinder (grinding medium: 0.8 mm diameter glass beads). The pulverization treatment was performed for 3 hours and 30 minutes by circulating the slurry between the holding tank and the pulverizer, and finally an incinerated ash material having an average particle diameter of 2.5 μm was obtained. While performing the pulverization step, sulfuric acid was gradually added for pH adjustment. Specifically, 97% sulfuric acid was added to the holding tank by a rotary pump, and the total amount of 97% sulfuric acid added was 24L. Sulfuric acid was added directly below the stirring blade of the agitator rotating at 1000 rpm so that the added sulfuric acid was sufficiently dispersed. The pH of the incinerated ash slurry after pH adjustment was 8.5.

  After removing the coarse particles from the slurry using a 200 mesh sieve, Suction filtered using 2 filter papers. A part of the solid phase was dried under reduced pressure to obtain a sample for measuring whiteness. Further, a part of the filtered cake was redispersed in water at a concentration of 10% to obtain a sample for measuring the average particle diameter and wire wear. Further, the remainder of the filtered cake was redispersed in water at a concentration of 1% and used as a filler as a papermaking sample. In addition, the galenite content of the papermaking filler is a peak of X-ray diffraction with respect to the gehlenite content of Comparative Example 1 (the same starting material as in Example 1 and the same incineration conditions other than temperature) described later. As estimated from the area, it was 13%.

[Example 6]
Coal was used as a starting material. The coal was incinerated using a burner furnace at an oxygen concentration of 4%, a residence time of 2 seconds, and 750 ° C. to obtain 300 kg of incinerated ash. When this incinerated ash was measured, the average particle size was 145 μm and the whiteness was 21%.

  Add 2200 kg of water to 300 kg of the above incinerated ash, add 1% of solid sodium acrylate (Aron T-40: manufactured by Toa Gosei Co., Ltd.) as a dispersant to the incinerated ash, and thoroughly stir with an agitator Thus, an incineration ash slurry having a solid content concentration of 12% was obtained.

  Next, the slurry was pulverized using a sand grinder (grinding medium: 0.8 mm diameter glass beads). The pulverization treatment was performed by circulating the slurry between the holding tank and the pulverizer for 3 hours and 10 minutes, and finally an incinerated ash material having an average particle size of 2.6 μm was obtained. While performing the pulverization step, sulfuric acid was gradually added for pH adjustment. Specifically, 97% sulfuric acid was added to the holding tank by a rotary pump, and the total amount of 97% sulfuric acid added was 24L. Sulfuric acid was added directly below the stirring blade of the agitator rotating at 1000 rpm so that the added sulfuric acid was sufficiently dispersed. The pH of the incinerated ash slurry after pH adjustment was 8.5.

  After removing the coarse particles from the slurry using a 200 mesh sieve, Suction filtered using 2 filter papers. A part of the solid phase was dried under reduced pressure to obtain a sample for measuring whiteness. Further, a part of the filtered cake was redispersed in water at a concentration of 10% to obtain a sample for measuring the average particle diameter and wire wear. Further, the remainder of the filtered cake was redispersed in water at a concentration of 1% and used as a filler as a papermaking sample. Moreover, according to the place estimated from the peak area of an X-ray diffraction with respect to the gehlenite content of the comparative example 1 mentioned later, the gehlenite content of the said filler for paper manufacture was 8%.

[Comparative Example 1]
As the starting material, sludge derived from the same papermaking process as in Example 1 was used. The sludge was incinerated using a fluidized bed furnace at an oxygen concentration of 7%, a residence time of 2 seconds, and 860 ° C. to obtain 300 kg of incinerated ash. When this incinerated ash was measured, the average particle size was 220 μm and the whiteness was 48%.

  Add 2200 kg of water to 300 kg of the above incinerated ash, add 1% of solid sodium acrylate (Aron T-40: manufactured by Toa Gosei Co., Ltd.) as a dispersant to the incinerated ash, and thoroughly stir with an agitator Thus, an incineration ash slurry having a solid content concentration of 12% was obtained.

  Next, the slurry was pulverized using a sand grinder (grinding medium: 0.8 mm diameter glass beads). The pulverization was performed by circulating the slurry between the holding tank and the pulverizer for 3 hours and 30 minutes, and finally an incinerated ash material having an average particle diameter of 2.8 μm was obtained. While performing the pulverization step, sulfuric acid was gradually added for pH adjustment. Specifically, 97% sulfuric acid was added to the holding tank by a rotary pump, and the total amount of 97% sulfuric acid added was 24L. Sulfuric acid was added directly below the stirring blade of the agitator rotating at 1000 rpm so that the added sulfuric acid was sufficiently dispersed. The pH of the incinerated ash slurry after pH adjustment was 8.5.

  After removing the coarse particles from the slurry using a 200 mesh sieve, Suction filtered using 2 filter papers. A part of the solid phase was dried under reduced pressure to obtain a sample for measuring whiteness. Further, a part of the filtered cake was redispersed in water at a concentration of 10% to obtain a sample for measuring the average particle diameter and wire wear. Further, the remainder of the filtered cake was redispersed in water at a concentration of 1% and used as a filler as a papermaking sample.

[Comparative Example 2]
A paper filler was produced in the same manner as in Example 2 except that the grinding time by the sand grinder was shortened to 2 hours and 50 minutes, and finally an incinerated ash material having an average particle size of 7.3 μm was obtained.

  Table 1 shows various performances of the incinerated ash materials obtained by the above examples and comparative examples. Compared with the incinerated ash materials of Comparative Examples 1 and 2, the incinerated ash materials of Examples 1 to 6 obtained by incinerating the raw materials at 700 to 800 ° C. could greatly improve the degree of wire wear. In particular, when Example 1 and Comparative Example 1 are compared, both have the same combustion raw material, and the average particle size after pulverization is only about 4%, which is 2.7 μm in Example 1 and 2.8 μm in Comparative Example 1. Nevertheless, there was a marked difference in the degree of wire wear, and there was a difference of about 3.1 times between Example 1 treated at 770 ° C. and Comparative Example treated at 860 ° C. Such a significant difference in the degree of wire wear at the heat treatment temperature of about 800 ° C. is a knowledge that has not been known so far and is an effect found by the present invention.

  Regarding the whiteness, there was almost no change before and after the pulverization treatment. In the present invention, it is not essential to include a process for increasing the whiteness, and the processes according to such a process are not actually performed in Examples 1 to 6. However, in order to increase the added value as a papermaking filler, the papermaking filler of the present invention may be subjected to a treatment for increasing the whiteness by a known method.

  Table 2 shows the results of analyzing the elemental composition of the various incinerated ash materials obtained by fluorescent X-rays. Since Examples 1-4 and Comparative Examples 1-2 use the same papermaking process-derived sludge, the elemental composition is also the same. Example 5 also uses papermaking process-derived sludge, and has a composition similar to Examples 1-4 and Comparative Examples 1-2. On the other hand, since Example 6 is coal incineration ash, it has an element composition different from these.

  Furthermore, the result of having analyzed the crystal composition of the obtained incineration ash material by X-ray diffraction is shown in FIG. Compared with comparative example 1 heat-treated at 860 ° C., in example 1 heat-treated at 770 ° C., the peak derived from gehlenite was small, and the production of gehlenite having high hardness was suppressed.

  The incinerated ash material of the present invention is particularly suitable as a filler for papermaking because it is excellent in wire wear and hardly damages the papermaking wire when internally added in the papermaking process.

<Manufacture of paper using papermaking filler>
By the following method, paper was produced by internally adding the papermaking filler of the present invention. The sheet basis weight (ISO536), ash (ISO1762), whiteness (ISO2470), opacity (ISO2471), and tensile strength (ISO1924) when used as a papermaking filler were also measured.

[Example 7]
The incinerated ash material obtained in Example 1 was used as a papermaking filler, and paper was actually produced. The paper manufacturing procedure is as follows.

  To a pulp slurry prepared by mixing and disaggregating 80 parts of DIP (CSF: 180 ml), 15 parts of TMP (CSF: 100 ml), and 5 parts of softwood bleached kraft pulp (NBKP, CSF: 600 ml), 2. 0% liquid sulfuric acid band, 0.5% cation-modified starch for pulp solids, 2% of incinerated ash material obtained in Example 1 as filler, and light calcium carbonate as filler for pulp solids. After sequentially adding a 6% yield improver with 200 ppm of pulp solids, the slurry was diluted to 1%.

This stock was neutralized using a twin wire type paper machine so that the basis weight was 42 g / m ² at a paper making speed of 1200 m / min to obtain a newsprint base paper. The obtained base paper had a paper surface pH of 6.5 and an ash content of 13.0%. Using a gate roll coater on this base paper, a surface coating agent comprising a hydroxyethylated starch and a cationic surface sizing agent (styrene / acrylate copolymer) (solid content concentration of hydroxyethylated starch 6.0%, Coat the surface sizing agent with a solid content of 0.30% on both the felt surface and the wire surface evenly (coating amount: 0.5 g / m ^{2 in} total). Obtained.

[Example 8]
Cold offset printing newsprint was obtained in the same manner as in Example 7 except that the incinerated ash material obtained in Example 2 was used instead of the incinerated ash material obtained in Example 1.

[Example 9]
Cold offset printing newsprint was obtained in the same manner as in Example 7 except that the incinerated ash material obtained in Example 3 was used instead of the incinerated ash material obtained in Example 1.

[Example 10]
Cold offset printing newsprint was obtained in the same manner as in Example 7 except that the incinerated ash material obtained in Example 4 was used instead of the incinerated ash material obtained in Example 1.

[Example 11]
Cold offset printing newsprint was obtained in the same manner as in Example 7 except that the incinerated ash material obtained in Example 5 was used instead of the incinerated ash material obtained in Example 1.

[Example 12]
Cold offset printing newsprint was obtained in the same manner as in Example 7 except that the incinerated ash material obtained in Example 6 was used instead of the incinerated ash material obtained in Example 1.

[Comparative Example 3]
To a pulp slurry prepared by mixing and disaggregating 80 parts of DIP (CSF: 180 ml), 15 parts of TMP (CSF: 100 ml), and 5 parts of softwood bleached kraft pulp (NBKP, CSF: 600 ml), 2. After sequentially adding a 0% liquid sulfuric acid band, a cation-modified starch having a pulp solid content of 0.5%, a light calcium carbonate as a filler, a calcium carbonate content of 8%, and a yield improver having a pulp solid content of 200 ppm. The slurry was diluted to 1%.

This stock was neutralized using a twin wire type paper machine so that the basis weight was 42 g / m ² at a paper making speed of 1200 m / min to obtain a newsprint base paper. The obtained base paper had a paper surface pH of 6.5 and an ash content of 13.0%. Using a gate roll coater on this base paper, a surface coating agent comprising a hydroxyethylated starch and a cationic surface sizing agent (styrene / acrylate copolymer) (solid content concentration of hydroxyethylated starch 6.0%, Coat the surface sizing agent with a solid content of 0.30% on both the felt surface and the wire surface evenly (coating amount: 0.5 g / m ^{2 in} total). Obtained.

  Table 3 shows the quality of the sheets obtained by the above examples and comparative examples. From the results of the papermaking test shown in Table 3, when the incinerated ash material of the present invention was used as a papermaking filler (Examples 7 to 12), the incinerated ash material was not used as a papermaking filler (Comparative Example 3). In the same way as above, the newsprint for cold offset printing could be produced without any problems. Compared with Comparative Example 3 in which calcium carbonate is used for the total amount of filler, even in Examples 7 to 11 in which a part thereof is replaced with sludge incineration ash material, the whiteness and opacity are not greatly reduced, and the strength is also increased. The same level is maintained. Compared with Comparative Example 3 in which calcium carbonate is used for the total amount of filler, Example 12 in which a part of the filler is replaced with coal incineration ash material has a slightly lower whiteness, but the strength is maintained at the same level. Since the opacity is high in Example 12, it can be said that the quality of newsprint is improved in this aspect.

Claims (5)

A process of obtaining incinerated ash by incinerating a raw material comprising at least one selected from the group consisting of papermaking sludge, coal, paper-containing waste, biomass, and composite fuel at a temperature of 700 to 800 ° C;
A step of dispersing incineration ash into a slurry and adding sulfuric acid and / or sulfate to the incineration ash slurry to obtain a papermaking filler slurry;
A method for producing a filler for papermaking, comprising:   The manufacturing method of the filler for paper manufacture of Claim 1 which further includes the process of grind | pulverizing the said incineration ash and making an average particle diameter into 0.1-10 micrometers.   A papermaking filler obtained by the method according to claim 1 or 2.   The papermaking filler according to claim 3, wherein the whiteness is 10% to 60%.   A paper comprising a papermaking filler obtained by the method according to claim 1 or 2.

Images