JP2007501337A - Method for filling a fiber material suspension and apparatus for carrying out the method - Google Patents

Abstract

  In a method for loading a fiber material suspension containing cellulose fibers with calcium carbonate, the method comprises the following method steps: calcium hydroxide in liquid form or in dry form or calcium oxide fibers Feeding into the material suspension, feeding gaseous carbon dioxide into the fiber material suspension, precipitating calcium carbonate with carbon dioxide and beating the fiber material suspension during the filling process ing.

Description

  The present invention relates to a method for filling a fibrous material suspension with calcium carbonate.

  Several methods for filling the pulp fibers with calcium carbonate are already known. U.S. Pat. No. 6,413,365 describes a method of conveying fiber material through a supply line together with calcium oxide and / or calcium hydroxide present in a suspension. From this supply line, the fiber material suspension is subsequently guided into the rotating distributor. The reaction gas is introduced into the fiber material suspension in an annular fashion. Thereby, calcium carbonate crystals are formed in the fiber material suspension. The calcium carbonate crystals in the fiber material suspension are distributed over a rotating distributor. This process is called a fiber filling process.

  Another method and apparatus for filling a fiber contained in a fiber material suspension with a filler or auxiliary material is described in DE 10 107 448 and DE 10 13 998 A1. It is known based on the book.

By these known methods, cigarette paper, all kinds of carton paper and packaging paper, all kinds of bag kraft paper and filler-containing paper such as filter paper can be produced. The following applies to the manufacture of cigarette paper. Cigarette paper is paper with a basis weight of 16-26 g / m ² . Cigarette paper is often offset with press marks, and is desirably very thin, flammable, and tasteless. Furthermore, it is desirable that cigarette paper has a good optical value for whiteness. Flammability is often achieved by impregnation to leave behind a white ash that looks good. Cigarette paper is usually produced from flax or cannabis fiber, cotton, kraft pulp, paper machine waste paper and other fiber sources. The filler content of cigarette paper is between 5 and 40%. In this case, 30% is considered a standard value.

Wrapping paper and paperboard are divided into three main categories: containerboard for packaging use, containerboard and special paper for use within consumer packaging, such as wallpaper, book backs, etc. be able to. The wrapping paper is usually manufactured as a multilayer product with a basis weight of more than 150 g / m ² . The beating degree varies from 600 to 50 CSF (freeness value) or 20 to 80 ⁰ SR (shopper regler value) for the final product to be manufactured.

Bag paper requires high porosity and high mechanical strength in order to respond quickly to the high demands created by rough handling during the filling process and period of use, for example cement bags. The paper must be strong enough to absorb impacts and correspondingly have a high energy absorption rate. The bag paper must be porous and sufficiently air permeable to ensure easy filling. The bag paper is produced as a product made of long fiber kraft pulp, for example with a basis weight between 70-80 g / m ² and a beating degree between 600-425 CSF or 20-30 ⁰ SR. Further, as described above, the average beating degree is targeted. This degree of beating is usually achieved by high concentration beating, whereas in conventional paper varieties such as graphite paper, low concentration beating is used. The result of high concentration beating is a good bond between the fibers as well as a high porosity. Bag kraft paper is mainly made from bleached fibers and unbleached fibers. In this case, a filler content of 5-15% may be present in the produced bag paper.

  Filter paper requires a controlled high porosity and pore distribution. The filter paper must have a sufficiently high mechanical strength to resist the flow of the medium to be filtered.

Filter paper are produced with a basis weight of 12~1200g / ^{m 2.} For example, basis weight, when the air filter is between 100 to 200 g / ^{m 2,} in the case of oil filter and fuel filter is between 50 to 80 g / ^{m 2,} the maximum in the case of food filters was 1000 g / ^{m 2,} in the case of coffee filter is a maximum 100 g / ^{m 2,} in the case of tea bags is between 12~20g / ^{m 2,} in the case of the dust suction unit bag 100 to 150 g / ^{m 2} Between. All filters are made from a number of fibers, such as pulp fibers, bleached fibers, unbleached fibers, kraft pulp, DIP (deinked) paper, recycled fibers, TMP (thermomechanical) paper, and the like.

  The object of the present invention is to further improve the method described at the outset.

According to the present invention, this task comprises the following method steps:
Feeding calcium hydroxide in liquid or dry form or calcium oxide into the fiber material suspension;
-Supplying gaseous carbon dioxide into the fiber material suspension;
-Precipitating calcium carbonate with carbon dioxide;
-Solved by a method comprising beating a fiber material suspension during the filling process.

The present invention describes a method for producing a fiber-loaded precipitated calcium carbonate (FLPCC) and at the same time applying a beating process. In this beating process, the fiber material that can be filled is recycled paper, DIP (deinked paper), secondary fiber material, bleached or unbleached pulp, wood pulp, bleached kraft pulp or bleached It may consist of no kraft pulp, furnish losses, flax, cotton and / or cannabis fiber (mainly cigarette paper) and / or any paper material used in paper machines. This means that the final product contains a filler produced in a batch reactor by a precipitation process or a filler produced by a beating process, or talc, talc, TiO ₂ , silicon etc. Regardless of whether it is used. The beating process is also called GCC method (GCC = ground Kalzium carbonate = beaten calcium carbonate).

  When the fiber material suspension is treated with fiber filling technology, a completely new product is produced for the range of papermaking with new and improved properties compared to products according to the known prior art. Fiber filling technology precipitates the filler directly into the paper mill's stock preparation equipment, especially the calcium carbonate that is evenly distributed and deposited in and between the paper fibers. The fiber to be treated can be subjected to fiber treatment in the beater simultaneously during the precipitation process.

  The beating process by the fiber filling combined process at the same time as the process for producing the precipitated calcium carbonate is performed by the process data described in detail below. This is also shown in German Offenlegungsschrift 10107448, German Offenlegungsschrift 10113998 and U.S. Pat. No. 6,413,365.

  The FLPCC combination process described in the present invention replaces the filler material used according to the known prior art with a filler material manufactured with fiber-filled combination process technology. The field of use of fillers manufactured with fiber-filled combination process technology extends to the field of papermaking for all paper varieties, including cigarette paper varieties, filter paper varieties, bag kraft paper varieties and paperboard varieties and wrapping paper varieties. These paper varieties have a filler content between 1 and 60% and / or have a white coating layer with a filler content between 1 and 60%. Filled manufactured paper varieties include recycled paper, deinked paper (DIP), secondary fiber materials, bleached or unbleached pulp, wood pulp, bleached kraft pulp or unbleached kraft Manufactured on paper machine from pulp, furnish loss, flax, cotton and / or cannabis fiber (mainly for cigarette paper) and / or any paper material, regardless of whether the final product contains filler can do.

Fiber materials made with fiber-filled combination process technology generally have higher dewatering properties than fiber materials made by other methods. The improvement in dewaterability is 5-100 ml CSF or 0.2-15 ⁰ SR in relation to the required beating degree. Additionally, the stock or pulp produced by the fiber filling method has a lower water retention performance of 2-25% relative to the material used for production. This allows different paper varieties, such as all types of FL (fiber-filled) copy paper and printing paper, all types of FL coated paper, all types of FL newspaper printing paper and all types of FL cigarette paper, all types of FL・ Efficient production of B & P paper, all types of kraft paper for FL bags and FL filter paper is possible. This is because the existing water in the stock suspension can be removed more quickly. Correspondingly, the stock is also dried more quickly.

  In FL cigarette paper, FL / B & P paper, FL bag kraft paper and FL filter paper that do not require filler, unnecessary filler is added before the beating process, after the beating process or in the headbox tank by an intervening cleaning process. It can be removed after passing through or before feeding to the paper machine. This corresponds to a filler which is not deposited on or in the fiber and correspondingly does not have to be washed. The fibers themselves still have fillers inside and outside, so that the advantageous effects of fiber filling technology can be used.

  Fiber filling technology may be used before or after the beating process, depending on what requirements are placed on the final product.

With fiber-filled combination technology, a high beating degree can be achieved in an energy advantage compared to the known prior art. This is because up to 50% of beating energy can be saved. This has an advantageous effect especially on all paper varieties that carry out the beating process during their production or have a high to very high beating degree, for example FL cigarette paper, FL B & P paper, FL bag kraft paper and FL filter paper. give. They were equipped in particular FL cigarette paper having a 100~25CSF or 68~90 ⁰ SR, 600~50CSF or 20~80 ⁰ FL · B & P paper having a SR, a 600~425CSF or 20 to 30 ⁰ SR FL bags for kraft paper and a FL filter paper having a 600~350CSF or 20 to 35 ⁰ SR.

  The mechanical strength achieved by the high beating degree of the final product has a favorable impact on the production of FL cigarette paper, FL B & P paper, FL bag kraft paper and FL filter paper. This is because the intermediate product produced and the final product to be produced by the mechanical load due to the process in different sections of the paper machine, for example in the areas where the press part, dry part and paper web are rolled up, This is because the load is mechanically increased by the use of the rewinding machine and the processing machine. Particularly during the manufacture of cigarette paper, the low basis weight and the high mechanical loads that are partly created by the use of winders are created in the cigarette paper used.

  Better drying, i.e. drying to a residual moisture content of 1-20%, can improve the efficiency for all paper varieties. Higher water retention performance, i.e., 1-25% water retention performance, has a beneficial impact on moisture retention, which is less in the manufacturing process, and printability on the manufactured paper web. Another advantage over all paper varieties is higher whiteness or optical values that are only up to 15 brightness points together or higher. This value can stand out with or without a white coating layer in the production of all forms of paper and paperboard. Through the use of fiber filling technology, the optical values are also improved only up to 10 brightness points or more, for example with cigarette paper.

  Another advantage of fiber filling is that the above-mentioned paper varieties are provided with glazing for special use cases, in which case the so-called “roll burn (black glow)” is caused in the fiber by the use of fiber filling. It is to be suppressed or eliminated by layering FL particles around and on the fibers.

  Advantageous embodiments of the invention result from the dependent claims, the description and the drawings.

  According to one embodiment of the invention, a water-based fiber material, in particular water-based pulp, is used as the starting material with a concentration of 0.1 to 20%, preferably between 2 and 15%. The

  According to the invention, as filler, calcium hydroxide is advantageously mixed in the water-like fiber material, in particular in the paper fiber material, in which case the fiber material is between 0.01 and 60% solids. Has a physical proportion. According to the invention, it is also possible to use starting materials different from calcium hydroxide or calcium oxide to form the filler.

  Calcium hydroxide is added by a static mixer or a pre-vessel. Advantageously, carbon dioxide is incorporated in the fiber material suspension with moisture in a concentration of 0.1 to 15%, corresponding to the reaction parameters. In this case, calcium carbonate is precipitated in a carbon dioxide gas atmosphere.

  According to the present invention, the beating process is performed in a predetermined apparatus (crystallizer) simultaneously with the filling process (fiber filling). In this case, beating energy in the range between 0.1 and 300 kWh per ton of dry pulp is used. In this case, a short reaction time between calcium hydroxide and carbon dioxide is important. Energy supply, ie, the thermal energy or heating of the paper suspension to produce different forms of crystals, is important to the present invention.

  As a starting material, depending on the use case of each reactor, a watery pulp with a paper proportion of between 0.01 and 60% works.

  In an advantageous embodiment of the method, a refiner, a disperser and / or a fluffer / FLPCC / reactor are used as the reactor and / or static mixer, in which case the fiber material content, in particular the paper content. Is between 0.01 and 15% for static mixers, between 2 and 40% for refiners and dispersers, and 15 to 60% for fluffer, FLPCC and reactors It is proposed to be between.

  According to the invention, it is proposed to supply dilution water before, during or after the addition of carbon dioxide, calcium hydroxide or calcium oxide. In this case, calcium carbonate precipitates when carbon dioxide is mixed into the calcium hydroxide solution or calcium hydroxide suspension. On the contrary, the precipitation reaction is similarly performed even when calcium hydroxide is supplied into water under a carbon dioxide atmosphere. In this case, dilution water may be added before, during or after the addition of carbon dioxide or calcium hydroxide.

  For precipitation reactions, it is advantageous if an energy consumption of between 0.3 and 8 kWh / t, in particular between 0.5 and 4 kWh / t, is used.

  It may also be proposed that the process temperature is between −15 ° C. and 120 ° C., in particular between 20 and 90 ° C.

  According to the present invention, rhombohedral, declinated trihedral or spherical crystals can be generated.

  It is advantageous if the crystals have a size between 0.05 and 5 μm, in particular between 0.3 and 2.5 μm. Static and / or movable, especially rotating mixing elements may be used. It is advantageous to carry out the process in a pressure range between 0 and 15 bar, in particular between 0 and 6 bar. In this case, the pH value is preferably between 6 and 10, in particular between 6.5 and 9.5. It is advantageous if the reaction time is between 0.01 and 1 minute, in particular between 0.05 and 10 seconds.

  In the following, an embodiment of the present invention will be described in detail with reference to only one drawing. This figure shows a schematic view of an apparatus for filling a fiber material suspension.

  The fiber material suspension is conveyed in apparatus 1 (see FIG. 1) to a conduit system for filling with calcium carbonate, equipped with control valves 10,12. The control valve 10 is disposed in the pipeline 14. Via this line 14 the conduit system is connected to a static mixer 16. Dilution water can be supplied to the mixer 16 via a valve 18. In addition, the inflow of the calcium hydroxide suspension is controlled via another valve 22 installed in the pipe line 20. This calcium hydroxide is provided by the preparation device 24. In this preparation device 24, solid calcium oxide or calcium hydroxide is supplied into the water. For this purpose, water is supplied to the preparation device 24 via a conduit provided with a valve 26. The suspension formed in the preparation device is introduced into the line 20 via the pump 28.

  Therefore, the fiber material suspension mixed with calcium hydroxide and diluted from the mixer 16 flows into the pipe line 30 provided with the valve 32. From this pipeline 30, the suspension is fed directly to the disperser 42 (crystallizer). The disperser 42 is connected to a carbon dioxide storage container 52 through a conduit 50 for supplying carbon dioxide, which is equipped with valves 44 and 46 and a pump 48. From this carbon dioxide storage container 52, carbon dioxide is introduced into the disperser 42, whereupon a desired precipitation reaction between calcium hydroxide and carbon dioxide is generated, and calcium carbonate as a filler is used as the fiber material. Formed in the fiber. Instead of using the mixer 16, calcium hydroxide may be mixed from the pre-vessel.

  Line 50 is connected to static mixer 60 via another valve 58. This mixer 60 serves to add additional carbon dioxide to the fiber material suspension flowing out of the disperser 42 via a line 64 equipped with a valve 62.

  The mixing vessel 66 may additionally be fed with a fiber material suspension not loaded with calcium hydroxide via the valve 12 and the conduit 70.

  From the mixer 60, the fiber material suspension flows into the mixing container 66. The mixing container 66 is equipped with a rotor 68 for thoroughly mixing the fiber material suspension. From the mixing vessel 66, the fiber material suspension flows directly into the paper machine headbox or is subjected to another mechanical treatment, for example in a refiner supply vessel.

  Additionally, the conduit system may be provided with a refiner 80 for refining the fiber material suspension by an additional beating process. A fiber material suspension is supplied to the refiner 80 via a pipe 82 branched from the pipe 30. From the refiner 80, the beaten fiber material suspension reaches the pipe 64 via the pipe 84, and then reaches the container 66 as described above.

  In addition, carbon dioxide is stored in the refiner 80 through a pipe 86 branched from the pipe 50 and a static mixer 88 connecting the pipe 86 to the pipe 82. It may be proposed to be supplied by

  The structure according to the invention for filling a fiber material suspension with calcium carbonate is based on known prior art, compared to known devices, machines for homogenizing the fiber material suspension, for example screw presses and fiber materials It has the advantage that the use of an equalization machine (equalization reactor) for homogenizing the suspension is dispensed with. The container 82 additionally takes over the beating process, which allows a significantly simpler construction of the stock preparation apparatus compared to the known prior art. This beating process simultaneously acts as an agitation process, whereby calcium carbonate is layered in the fibers by a shearing process.

  In the process according to the invention for preparing a fiber material suspension by a filling process, calcium hydroxide having a solubility in water of 1.65 g / l at 20 ° C. to 0.7 g / l at 100 ° C. (slaked lime, Lime milk) is used. In this case, a pH value of up to 12.6 is produced, depending on how far the solution concentration reaches the maximum value. In the case of commercially available slaked lime concentrations, a solids content of 0-60% can be achieved. In this case, the suspension has a pH value of up to 12.6. Thus, the original amount of slaked lime in the suspension consists of the dissolved percentage and the solids concentration.

  Thus, for a 20 ° C. suspension with 20% calcium hydroxide per liter, 1.65 g of calcium hydroxide dissolved and 198.35 g of solids fraction are produced. For fiber filling processes (FL processes), the goal is to use slaked lime with the shortest possible transition time, since the transition rate or reaction rate affects the final product of the FL process.

  This is achieved by the fact that calcium oxide (CaO) is in the average particle size range of 0.01-100 mm, in particular in the size range of 0.05-50 mm, in order to produce slaked lime by a digestion process. . Furthermore, the calcium oxide used is preferably produced by a light baking process.

1 is a schematic view of an apparatus for filling a fiber material suspension. FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 apparatus, 10 control valve, 12 control valve, 14 pipe line, 16 mixer, 18 valve, 20 pipe line, 22 valve, 24 preparation apparatus, 26 valve, 28 pump, 30 pipe line, 32 valve, 42 distributor, 44 valves, 46 valves, 48 pumps, 50 pipes, 52 carbon dioxide storage containers, 58 valves, 60 mixers, 62 valves, 64 pipes, 66 mixing containers, 68 rotors, 70 pipe lines, 80 refiners, 82 pipe lines 84 lines, 86 lines, 88 mixers

Claims (18)

In a method for loading a fibrous material suspension containing cellulose fibers with calcium carbonate, the method comprises the following method steps:
Feeding calcium hydroxide in liquid or dry form or calcium oxide into the fiber material suspension;
-Supplying gaseous carbon dioxide into the fiber material suspension;
-Precipitating calcium carbonate with carbon dioxide;
A method for loading a fiber material suspension containing cellulose fibers with calcium carbonate, comprising: beating the fiber material suspension during a filling process.   The method according to claim 1, wherein a beating energy in the range of between 0.1 and 300 kWh per ton of dry pulp is provided, in which case the filling and beating is carried out in a disperser (42).   3. The process as claimed in claim 1, wherein a water-based fiber material, in particular water-based pulp, is used as the starting material at a concentration of 0.1 to 20%, preferably between 2 and 6%.   Calcium hydroxide is mixed in a water-like fiber material, in particular a paper fiber material, in which case the fiber material has a solids proportion of between 0.01 and 60%. 4. The method according to any one of up to 3.   The process according to claim 4, wherein calcium hydroxide is mixed in by means of a static mixer (16) or a pre-vessel.   6. A process as claimed in claim 1, wherein carbon dioxide is mixed into the fiber material suspension with moisture.   A refiner (80), a disperser (42) and / or a fluffer / FLPCC / reactor are used as reactors and / or static mixers, in which the fiber material content, in particular the paper content, is static. Between 0.01 and 15% for typical mixers, between 2 and 40% for refiners (80) and dispersers (42), and 15 for fluffers, FLPCCs and reactors. 7. A method according to any one of claims 1 to 6, which is between -60%.   The method according to any one of claims 1 to 7, wherein the dilution water is supplied before, during or after the addition of carbon dioxide, calcium hydroxide or calcium oxide.   9. The process as claimed in claim 1, wherein an energy consumption of between 0.3 and 8 kWh / t, in particular between 0.5 and 4 kWh / t, is used for the precipitation reaction.   10. A process according to any one of claims 1 to 9, wherein the process temperature is between -15 [deg.] C and 120 [deg.] C, in particular between 20 [deg.] C and 90 [deg.] C.   The method according to any one of claims 1 to 10, wherein rhombohedral, declinated trihedral or spherical crystals are generated.   12. The method according to claim 11, wherein the crystals have a dimension between 0.05 and 5 [mu] m, in particular between 0.3 and 2.5 [mu] m.   13. A method as claimed in any one of the preceding claims, wherein a static and / or movable, especially rotating mixing element (68) is used.   14. The method according to claim 1, wherein the method is carried out in a pressure range between 0 and 15 bar, in particular between 0 and 6 bar.   15. A process according to any one of the preceding claims, wherein the process is carried out at a pH value between 6 and 10, in particular between 6.5 and 9.5.   16. A process as claimed in claim 1, wherein the reaction time is between 0.01 and 1 minute, in particular between 0.05 and 10 seconds.   Apparatus for carrying out the method according to any one of the preceding claims. An apparatus for carrying out the method according to any one of claims 1 to 17,
The apparatus comprises a static mixer (16) for mixing calcium hydroxide into the fiber material suspension and beating and / or fluffing and hydroxylating the fiber material suspension in a carbon dioxide atmosphere. An apparatus comprising a disperser (42) and / or a refiner for precipitating calcium to form a fiber filled with calcium carbonate in a fiber material suspension.

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