METHOD AND APPARATUS FOR LOADING FIBERS OR CELLULOSE WHICH ARE CONTAINED IN A SUSPENSION WITH A FILLER

The present invention provides a method for the loading of fibers or cellulose included in a suspension with a filler by way of a chemical precipitation reaction, wherein the fibers or cellulose are provided in the form of a suspension having a predetermined solids concentration. Carbon dioxide is added to the fibers or to the cellulose in the form of a suspension. The fibers or the cellulose in form of a suspension to which carbon dioxide has been added are mixed with milk of lime or slaked lime, such as in at least one reactor, thereby triggering and extensively, such as completely, concluding the chemical precipitation reaction.

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Description
CROSS REFERENCE TO RELATED APPLICATIONS

This is a continuation of PCT application No. PCT/EP2005/011498, entitled “METHOD AND DEVICE FOR LOADING FIBERS OR CELLULOSE CONTAINED IN A SUSPENSION WITH A FILLER”, filed Oct. 27, 2005.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a method as well as to an apparatus for loading of fibers or cellulose contained in a suspension with a filler by way of a chemical precipitation reaction, wherein the fibers or cellulose are provided in the form of a suspension having a predetermined solids concentration.

2. Description of the Related Art

In the production of fibrous webs, especially paper or cardboard webs fillers, especially precipitated calcium carbonate (PCC) or disintegrated or ground calcium carbonate (GCC) represent conventional substances which are used to reduce the fibrous material content as well as to improve the optical characteristics of the web.

The commercially available PCC or GCC fillers are bulk materials which are produced in special manufacturing facilities which may be satellite plants of a paper or cardboard plant. An on-line production of PCC however has never been considered, or is never considered in the paper or cardboard industry because of the special process characteristics which are associated with the production of PCC. Instead, PCC or GCC are transported as bulk material or in the form of a suspension to the paper or cardboard plants.

Loading of fibers or cellulose contained in a suspension with an additive, for example a filler, may for example occur through a chemical precipitation reaction, in other words especially through a so-called “Fiber Loading™” process as described in the U.S. patent document U.S. Pat. No. 5,223,090 A. In said “Fiber Loading™” process at least one additive, especially a filler is deposited onto the moistened fiber surfaces of the fibrous material. In this context the fibers may for example be loaded with calcium carbonate. To accomplish this calcium oxide and/or calcium hydroxide is added to the moist, disintegrated fibrous material in such a way that at least a portion associates itself with the water which is contained in the fibrous material. The thus treated fibrous material is subsequently supplied, preferably in a shear field with carbon dioxide.

A method which is based on and at the same time improves upon the method described in the aforementioned U.S. patent specification for loading of fibers contained in a suspension is known, for example from the German disclosure document DE 102 04 254 A1. The fibers which are loaded with a precipitant are ground in order to produce precipitant product particles having maximum dimensions in the range of approximately 0.05 to approximately 5 μm, wherein the creation of the crystalline precipitant product particles occurs in an online process in the stock preparation line.

In addition a method and an apparatus for loading fibers which are contained in a suspension with a filler by way of a chemical precipitation method are known from the German disclosure document DE 101 07 448 A1. In this scenario the suspension containing the fibers is fed into a pump disperger and is treated in said disperger with shear forces in order to break larger fiber agglomerates into smaller ones or even into individual fibers. At the same time the pump disperger is used as a reactor for the chemical precipitation reaction.

In addition a method for the production of cellulose for subsequent use in the production of a fibrous web, especially a paper or cardboard web is known from the German disclosure document DE 101 20 526 A1. The cellulose obtained in a cellulose production process is initially loaded with an additive through a chemical precipitation reaction, preferably in accordance with the already mentioned U.S. patent document U.S. Pat. No. 5,223,090. The already loaded cellulose is then dried and made available for subsequent use or shipment.

The methods described in the current state of the art all distinguish themselves in that the milk of lime [CA(OH)2; slaked lime suspended in water; unslaked lime; lime hydrate, slaked lime], or the slaked lime is initially brought into contact, or in other words is mixed with the fibers or the cellulose contained in the suspension and characterized in that the carbon dioxide is then added when the chemical precipitation reaction is triggered.

The disadvantage of these cited methods consists especially in that they offer only a low degree of effectiveness since the milk of lime or the slaked lime, cover the surfaces of the fibers or the cellulose, thereby blocking access of the carbon dioxide. The chemical precipitation reaction on the surfaces becomes possible only after the supplied carbon dioxide has penetrated the layers of milk of lime or slaked lime. This impedes particularly a loading of the interior fiber surfaces (lumen). Consequently only a small portion of the precipitated calcium carbonate (PCC) is adhered on the surfaces. The remaining calcium carbonate (PCC) is free.

What is needed in the art is an improved method of the type described at the beginning which, on the one hand assures a chemical reaction that is as fast and as complete as possible and on the other hand assures an efficient loading of the fiber surfaces (inside and outside) or of the cellulose. In addition, an improved apparatus of the type described at the beginning is needed which permits the relevant chemical reaction to be carried out continuously, efficiently and economically.

SUMMARY OF THE INVENTION

The present invention provides a method wherein carbon dioxide is added to the fibers or the cellulose in the form of a suspension, and the fibers or the cellulose in form of a suspension to which carbon dioxide has been added are mixed with milk of lime or slaked lime, such as in at least one reactor, thereby triggering and extensively, such as completely, concluding the chemical precipitation reaction.

Through the addition of carbon dioxide and by depositing it on the fibers or on the cellulose material in form of a suspension prior to adding milk of lime or slaked lime a chemical reaction which is as complete and fast as possible can be achieved on the one hand and an efficient loading of the fiber surfaces (inside and outside) or of the cellulose on the other hand. When adding milk of lime or slaked lime the chemical reaction occurs immediately, thereby influencing the loading process very positively. Integration to the greatest possible extent and encasement of the fibers, inside as well as outside, or of the cellulose with calcium carbonate is achieved.

In particular, the loaded cellulose can—as supported by the already mentioned disclosure document DE 101 20 526 A1—subsequently be dried and be made available or prepared for shipment for subsequent use. The cellulose material can be made available for subsequent use or shipped in the form of bales, rolls or the like. The cellulose itself can for example be manufactured in accordance with the sulphate and/or sulphite method.

During the fiber loading process the milk of lime or the slaked lime reacts to the introduction of carbon dioxide such, that crystalline structures are formed.

The shape of the forming conglomerates can be influenced partially by the volume of carbon dioxide and the speed of introducing the carbon dioxide and by the system temperature and possibly also substantially by the prevailing flow conditions. Two basic types can be determined under the microscope: the rather rod shaped or the flat or round shaped structures. The shape of the structure is especially significant with certain specialty papers. Cigarette paper, for example, requires rod-shaped structures in order to guarantee the necessary opacity at a defined porosity.

There are at least two methods regarding process related aspects: the carbon dioxide is added to the suspension in a unit which is located upstream from the reactor in the process sequence and which can be heated, or the carbon dioxide is added to the suspension in the reactor where the blending of the suspension with the milk of lime or the slaked lime can be staggered. Both methods offer individual advantages.

In the first method the suspension receives a massive carbon dioxide treatment prior to the chemical reaction. The fibers enrich themselves with carbon dioxide on the inside and arrive practically “pre-loaded” in the actual reaction vessel. The same applies of course also to the cellulose. There, the calcium carbonate which is being formed deposits itself around the respective surface of the fibers or the cellulose. An additional improvement of the loading process is also made possible by the inventive method characterized in that the fibers or the cellulose themselves are “saturated” with carbon dioxide. Regarding the pending precipitation reaction the milk of lime or the slaked lime, therefore comes into contact already with the surfaces which are activated by the educt carbon dioxide. The precipitation reaction can therefore run its course in a shorter period of time and, above all, completely. The first method also permits continuous adding of the carbon dioxide and/or continuous mixing with milk of lime or slaked lime.

The second method basically offers the same advantages, however it is disadvantageous that the addition of the carbon dioxide and the mixing process with the milk of lime or the slaked lime can occur only in batch operation. The output volume in this second method is therefore accordingly reduced wherein however investment and even operational costs can be saved due to a simplified system design.

Also, the first method offers a plurality of variations:

    • the carbon dioxide can be added to the suspension under the influence of shear forces, such as in a pump disperger;
    • the carbon dioxide can be added to the suspension by utilizing mixing effects, such as in a stationary mixing system, especially a stationary mixer;
    • the carbon dioxide can be added to the suspension in at least one stationary mixer under the influence of flow turbulences, wherein the flow turbulences may be utilized during a possible injection of carbon dioxide into a supply line; and/or
    • the carbon dioxide can be added to the suspension by utilizing at least one at least partially driven mixing system such as in an agitator

All aforementioned design variations possess an exemplary character and in addition distinguish themselves through a high efficiency level regarding the chemical reaction.

With regard to the adjustment of an optimum consistency of the suspension at a predetermined solids concentration, it can be advantageous if water, for example fresh water and/or white water, is added to the suspension prior to the addition of the carbon dioxide. This allows the consistency of the suspension to be varied within certain limits.

In addition it can also be advantageous if water, for example fresh water or white water, is added into the reactor itself prior to and/or during and/or after the addition of milk of lime or slaked lime. This allows a subsequent adjustment of the suspension's consistency.

Additional designs provide that the suspension is degassed by way of at least one degassing unit prior to the addition of the carbon dioxide and/or that the carbon dioxide is added to the suspension under pressure. Both specified designs contribute positively to a successful loading of the fibers or the cellulose in the course of the chemical reaction.

The carbon dioxide can be added to the suspension as pure carbon dioxide and/or as flue gas. The flue gas can be taken for example from boilers or power plants. Both methods support the loading process, wherein the utilization of flue gas is generally probably more cost efficient.

Due to economic and ecological reasons the suspension is produced by dissolving cellulose or waste paper with additives in at least one pulper, or is supplied to the loading process as a non-dried pulp which is also known as so-called “never dried pulp” for example from another pulp mill.

In order to ensure that the loading process proceeds reliably according to the method, the reaction parameters are measured in at least one reactor and if necessary are utilized for the control of the chemical precipitation reaction. The reaction parameters which are relevant for a reliable and optimum process progression include at least the pH-value, the temperature, the dwell time, the throughput of suspension and/or milk of lime or slaked lime. At least the pH-value of the suspension as measured at the end of the reaction can be compared with a desired value and any deviation is ideally reduced or removed through at least one of the following correcting variables: addition of milk of lime or slaked lime, addition of carbon dioxide, throughput of suspension and/or the like.

The present invention also provides an apparatus for loading of fibers or cellulose which are contained in a suspension with a filler by way of a chemical precipitation reaction, wherein the fibers or cellulose are provided in the form of a suspension having a predetermined solids concentration. This apparatus is characterized in that at least one reactor is provided in which the fibers or the cellulose in form of a suspension to which carbon dioxide has been added are mixed with milk of lime or slaked lime, thereby triggering and extensively, such as completely, concluding the chemical precipitation reaction.

The inventive method and the inventive apparatus can also be applied in a suitable manner in the production of a fibrous web, especially a paper or cardboard web, wherein at least fibers or cellulose in the form of a suspension which were loaded according to the inventive method were utilized for the production of said web.

BRIEF DESCRIPTION OF THE DRAWINGS

The above-mentioned and other features and advantages of this invention, and the manner of attaining them, will become more apparent and the invention will be better understood by reference to the following description of embodiments of the invention taken in conjunction with the accompanying drawings, wherein:

FIG. 1 is a schematic depiction of an apparatus for loading fibers which are contained in a suspension with a filler by way of a chemical precipitation reaction; and

FIG. 2 is a schematic depiction of an additional apparatus for loading fibers which are contained in a suspension with a filler by way of a chemical precipitation reaction.

Corresponding reference characters indicate corresponding parts throughout the several views. The exemplifications set out herein illustrate embodiments of the invention, and such exemplifications are not to be construed as limiting the scope of the invention in any manner.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to the drawings, and more particularly to FIG. 1, there is shown a schematic depiction of a device 1 for loading fibers 2.1 or cellulose 2.2 which are contained in a suspension 3 with a filler 4 by way of a chemical precipitation reaction, wherein the fibers 2.1 or the cellulose 2.2 in form of a suspension 3 are made available with a pre-determined solids concentration c.

The apparatus 1 includes reactor 5 in which the fibers 2.1 or the cellulose 2.2 in form of a suspension 3 to which carbon dioxide 6 has been added are mixed with milk of lime or slaked lime 7, thereby triggering and extensively, such as completely, concluding the chemical precipitation reaction. The carbon dioxide 6 can be added to the suspension 3 as pure carbon dioxide and/or as flue gas.

In the example of apparatus 1 depicted in FIG. 1 the addition of the carbon dioxide 6 and mixing of the milk of lime or slaked lime 7 occurs in batch operation.

The reactor 5 includes at least one supply line 8 for carbon dioxide 6 so that the carbon dioxide 6 can be supplied to the fibers 2.1 or to the cellulose 2.2 in form of a suspension 3 prior to and/or at the same time as the milk of lime or the slaked lime 7 is supplied via a line 9. The filler 4 in this scenario is calcium carbonate.

In addition a supply line 11 is provided for water 10 which can be added prior to the addition of carbon dioxide and/or prior to and/or during and/or after the addition of milk of lime or slaked lime 7.

In addition, a degassing unit 12 for the purpose of degassing the suspension 3 prior to adding of the carbon dioxide 6, as well as a pressure generating unit 13 for the purpose of a pressurized addition of carbon dioxide 6 to the suspension 3, are provided. The known and purely schematically depicted degassing unit 12 is connected to the reactor 5 by way of a line 14 whereas the known and also purely schematically depicted pressure generating unit 13 is connected to the reactor 5 via the already present line 8.

A pulper 15 which is known in the state of the art is provided in order to produce the suspension 3 by way of dissolving cellulose or waste paper through the use of additives. The production of the suspension 3 can of course also occur through a supply of non-dried pulp.

In addition, the reactor 5 includes at least one system 16 to measure the reaction parameter and if necessary to adjust the chemical precipitation reaction. The relevant reaction parameters include at least the pH-value, the temperature, the dwell time, the throughput of suspension and/or milk of lime or slaked lime. A system of this type 16 including measuring devices and actuators or control elements are generally known and are therefore indicated merely exemplary.

In the implementation of the inventive method the reaction parameters can be in the following value ranges: pH-value of the suspension in the reactor between 6 and 11, preferably between 7 and 10; temperature of the suspension in the reactor between approximately −15 and approximately 120° C., preferably between approximately 20 and approximately 90° C.; dwell time of the suspension in the reactor between 0.5 minutes and approximately 4 hours, preferably between 3 minutes and approximately 1 hour.

The throughput of the suspension and/or the milk of lime or slaked lime depends substantially upon the size of the reactor and cannot therefore be easily quantified.

FIG. 2 illustrates a schematic depiction of an additional apparatus 1 for loading fibers 2.1 or cellulose 2.2 which are contained in a suspension 3 with a filler 4 by way of a chemical precipitation reaction.

This device 1 is essentially based on the apparatus described in FIG. 1, so that reference is made to said apparatus regarding basic components and their description.

The apparatus 1 also includes a reactor 5 in which the fibers 2.1 or the cellulose 2.2 in form of a suspension 3 are mixed with milk or lime or slaked lime 7 thereby triggering and largely, such as completely, concluding the chemical precipitation reaction. A supply line 9 is provided for the addition of milk of lime or slaked lime 7 into the reactor.

In contrast to the embodiment in FIG. 1, this example includes a unit 17 which is located upstream from the reactor 5 in the process sequence and which can be heated and in which carbon dioxide 6 is added to the fibers 2.1 or to the cellulose 2.2 in form of a suspension. For this purpose the unit 17 includes at least one supply line 8 for carbon dioxide 6. The possible heating of the unit 17 in a known manner allows for a direct influence upon the reaction temperature of the subsequent chemical reaction.

The carbon dioxide 6 can be added to the suspension 3 as pure carbon dioxide and/or as flue gas. The filler in this instance is then calcium carbonate.

In the example of the apparatus 1 in FIG. 2, the addition of the carbon dioxide 6 and mixing with the milk of lime or slaked lime 7 therefore occurs continuously.

The unit 17 which is located upstream from the reactor 5 in the process sequence includes at least one pump disperger 18 which produces shear forces during the addition of carbon dioxide 6 to the suspension 3 via the at least one supply line 8. A pump disperger 18 of this type is constructively and functionally already cited for example in the German disclosure document DE 101 07 448 A1. The content of said document is therefore included into the present description by way of reference.

In an additional arrangement the unit 17 which is located upstream from the reactor 5 in the process sequence can also include at least one stationary mixing system—for example a stationary mixer or a supply line through which the suspension flows—which causes mixing effects during the addition of the carbon dioxide to the suspension. In addition it can also include at least a partially driven mixing system, for example an agitator, which produces mixing effects while the carbon dioxide is added to the suspension. Such arrangements are well known to the expert so that there is no need for a detailed description.

The apparatus 1 also includes a degassing unit 12 for the purpose of degassing the suspension 3 prior to the addition of the carbon dioxide 6, as well as a pressure generating unit 13 for the purpose of a pressurized addition of carbon dioxide 6 to the suspension 3. The known and purely schematically depicted degassing unit 12 is connected to the reactor 5 by way of a line 14, whereas the known and also purely schematically depicted pressure generating unit 13 is connected to the reactor 5 via the already present line 8.

A pulper 15 which is known in the state of the art is provided in order to produce the suspension 3 by way of dissolving cellulose or waste paper through the use of additives. The production of the suspension 3 can of course also occur through a supply of non-dried pulp.

In addition, the reactor 5 again includes at least one system 16 to measure the reaction parameter and to possibly make adjustments to the chemical precipitation reaction. The relevant reaction parameters include at least the pH-value, the temperature, the dwell time, the throughput of suspension and/or milk of lime or slaked lime. A system of this type 16 including measuring devices and actuators or control elements are generally known and are therefore indicated merely as an example.

The apparatus 1 therefore is ideally suited for the production of a fibrous web in the production of which at least fibers 2.1 or cellulose 2.2 in the form of at least one suspension 3 were used which were loaded in accordance with the inventive method while utilizing the inventive apparatus 1.

In conclusion it can be said that an improved method as well as an improved apparatus of the type described at the beginning are provided by the current invention which, on the one hand assures a fast and an as complete as possible chemical reaction and on the other hand assures an efficient loading of the fiber surfaces (inside and outside) or of the cellulose.

While this invention has been described with respect to at least one embodiment, the present invention can be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims.

Claims

1. A method for loading one of a plurality of fibers and cellulose included in a suspension with a filler by using a chemical precipitation reaction, said method comprising the steps of:

providing one of the plurality of fibers and the cellulose in a form of the suspension having a predetermined solids concentration;
adding carbon dioxide to one of the plurality of fibers and the cellulose in said form of the suspension; and
mixing one of the plurality of fibers and the cellulose in said form of the suspension to which carbon dioxide has been added with one of a milk of lime and a slaked lime, thereby triggering and extensively concluding the chemical precipitation reaction.

2. The method in accordance with claim 1, wherein said mixing step occurs in at least one reactor.

3. The method in accordance with claim 2, wherein said carbon dioxide is added to the suspension in at least one unit which is located upstream from said reactor in a process sequence.

4. The method in accordance with claim 3, wherein said at least one unit is heated.

5. The method in accordance with claim 3, wherein said carbon dioxide is added to the suspension under an influence of a plurality of shear forces.

6. The method in accordance with claim 3, wherein said carbon dioxide is added to the suspension by utilizing a plurality of mixing effects.

7. The method in accordance with claim 6, wherein said carbon dioxide is added to the suspension by utilizing at least one stationary mixing system.

8. The method in accordance with claim 6, wherein said carbon dioxide is added to the suspension in at least one stationary mixer.

9. The method in accordance with claim 8, wherein said carbon dioxide is added to the suspension in said at least one stationary mixer under an influence of a plurality of flow turbulences.

10. The method in accordance with claim 6, wherein said carbon dioxide is added to the suspension by utilizing at least a partially driven mixing system.

11. The method in accordance with claim 10, wherein said carbon dioxide is added to the suspension in at least one agitator.

12. The method in accordance with claim 5, wherein said carbon dioxide is added to the suspension in a pump disperger.

13. The method in accordance with claim 1, wherein the chemical precipitation reaction is completely concluded.

14. The method in accordance with claim 1, wherein at least one of said step of adding said carbon dioxide and said step of mixing with one of said milk of lime and said slaked lime occurs continuously.

15. The method in accordance with claim 1, wherein said mixing step occurs in at least one reactor, said carbon dioxide being added to the suspension in said reactor where a blending of the suspension with one of said milk of lime and said slaked lime is staggered.

16. The method in accordance with claim 15, wherein said step of adding said carbon dioxide and said step of mixing with one of said milk of lime and said slaked lime occurs in a batch operation.

17. The method in accordance with claim 1, further comprising the step of adding water to the suspension prior to adding said carbon dioxide.

18. The method in accordance with claim 1, wherein said mixing step occurs in at least one reactor, further comprising the step of adding water into said reactor at least one of prior to, during, and after adding one of said milk of lime and said slaked lime.

19. The method in accordance with claim 1, further comprising the step of degassing the suspension using a degassing unit prior to said step of adding said carbon dioxide.

20. The method in accordance with claim 1, wherein said carbon dioxide is added to the suspension under pressure.

21. The method in accordance with claim 1, wherein said carbon dioxide is added to the suspension at least one of as pure carbon dioxide and as flue gas.

22. The method in accordance with claim 1, wherein the suspension one of is produced by dissolving one of a cellulose and a waste paper using additives in at least one pulper and is supplied to the loading process as a non-dried pulp.

23. The method in accordance with claim 22, wherein said non-dried pulp is from another pulp mill.

24. The method in accordance with claim 1, wherein said mixing step occurs in at least one reactor, further comprising the step of measuring a plurality of reaction parameters in said at least one reactor, said plurality of reaction parameters being utilized if necessary to adjust the chemical precipitation reaction.

25. The method in accordance with claim 24, wherein said plurality of reaction parameters includes at least one of a pH-value, a temperature, a dwell time, a throughput of the suspension, and one of said milk of lime and said slaked lime.

26. The method in accordance with claim 25, wherein said pH-value of the suspension as measured at an end of the chemical precipitation reaction is compared with a desired value and a deviation is one of reduced and removed through at least one of a plurality of correcting variables including an addition of one of said milk of lime and said slaked lime, an addition of said carbon dioxide, and a throughput of the suspension.

27. An apparatus for loading one of a plurality of fibers and cellulose included in a suspension with a filler by using a chemical precipitation reaction, said apparatus comprising:

at least one reactor configured for being that in which one of the plurality of fibers and the cellulose in a form of the suspension to which carbon dioxide has been added is mixed with one of a milk of lime and a slaked lime such that the chemical precipitation reaction is triggered and largely concluded, one of the plurality of fibers and the cellulose being in said form of the suspension having a predetermined solids concentration, the apparatus being configured for:
adding carbon dioxide to one of the plurality of fibers and the cellulose in said form of the suspension; and
mixing one of the plurality of fibers and the cellulose in said form of the suspension to which carbon dioxide has been added with one of said milk of lime and said slaked lime, thereby triggering and extensively concluding the chemical precipitation reaction.

28. The apparatus in accordance with claim 27, wherein said reactor is configured such that the chemical precipitation reaction is completely concluded.

29. The apparatus in accordance with claim 27, further comprising at least one unit located upstream from said reactor in a process sequence, said at least one unit configured for being that in which carbon dioxide is added to one of the plurality of fibers and the cellulose in said form of the suspension.

30. The apparatus in accordance with claim 27, wherein said at least one unit is heated.

31. The apparatus in accordance with claim 30, wherein said at least one unit which is located upstream from said reactor in said process sequence includes at least one pump disperger configured for producing shear forces during said addition of carbon dioxide to the suspension.

32. The apparatus in accordance with claim 30, wherein said at least one unit which is located upstream from said reactor in said process sequence includes at least one stationary mixing system configured for causing a plurality of mixing effects during said addition of said carbon dioxide to the suspension.

33. The apparatus in accordance with claim 32, wherein said stationary mixing system includes at least one stationary mixer.

34. The apparatus in accordance with claim 33, wherein said at least one stationary mixer includes a supply line through which the suspension flows and which produces a plurality of flow turbulences, at least over a plurality of segments, during said addition of said carbon dioxide to the suspension.

35. The apparatus in accordance with claim 30, wherein said at least one unit which is located upstream from said reactor in said process sequence includes at least one partially driven mixing system which produces a plurality of mixing effects during said addition of said carbon dioxide to the suspension.

36. The apparatus in accordance with claim 35, wherein said at least one partially driven mixing system includes at least one agitator.

37. The apparatus in accordance with claim 27, wherein said at least one reactor includes at least one supply line configured for supplying carbon dioxide to one of the plurality of fibers and the cellulose in said form of the suspension at least one of prior to and at the same time as one of said milk of lime and said slaked lime is supplied.

38. The apparatus in accordance with claim 27, further comprising at least one supply line configured for adding water at least one of prior to said addition of said carbon dioxide and at least one of prior to, during, and after adding one of said milk of lime and said slaked lime.

39. The apparatus in accordance with claim 27, further comprising at least one degassing unit configured for degassing the suspension prior to said addition of said carbon dioxide.

40. The apparatus in accordance with claim 27, further comprising a pressure generating unit configured for adding pressurized carbon dioxide to the suspension.

41. The apparatus in accordance with claim 27, further comprising at least one pulper configured for producing the suspension one of by dissolving one of a cellulose and a waste paper using additives and through a supply of a non-dried pulp.

42. The apparatus in accordance with claim 27, wherein said reactor includes at least one system configured for measuring a plurality of reaction parameters and for adjusting if necessary the chemical precipitation reaction.

43. The apparatus in accordance with claim 42, wherein said plurality of reaction parameters includes at least one of a pH-value, a temperature, a dwell time, a throughput of suspension, and one of said milk of lime and said slaked lime.

44. A fiber web comprising:

a filler; and
one of a plurality of fibers and a cellulose in a form of at least one suspension including said filler, one of said plurality of fibers and said cellulose configured for being loaded with said filler using a chemical precipitation reaction by: providing one of said plurality of fibers and said cellulose in said form of said at least one suspension having a predetermined solids concentration; adding carbon dioxide to one of said plurality of fibers and said cellulose in said form of said at least one suspension; and mixing one of said plurality of fibers and said cellulose in said form of said at least one suspension to which carbon dioxide has been added with one of a milk of lime and a slaked lime, thereby triggering and extensively concluding the chemical precipitation reaction.
Patent History
Publication number: 20080023161
Type: Application
Filed: May 15, 2007
Publication Date: Jan 31, 2008
Inventor: Reinhard Gather (Neustadt)
Application Number: 11/748,814
Classifications
Current U.S. Class: 162/63.000; 162/157.600; 162/243.000
International Classification: D21H 11/16 (20060101); D21H 17/70 (20060101);