CA2590079A1

CA2590079A1 - Method and apparatus for loading fibers or cellulose which are contained in a suspension with a filler

Info

Publication number: CA2590079A1
Application number: CA002590079A
Authority: CA
Inventors: Reinhard Gather
Original assignee: Individual
Current assignee: Voith Patent GmbH
Priority date: 2004-12-14
Filing date: 2005-10-27
Publication date: 2006-06-22
Also published as: CN101091021A; DE102004060405A1; US20080023161A1; WO2006063632A1; BRPI0518040A; EP1828478A1

Abstract

The invention relates to a method for loading fibers (2.1) or cellulose (2.2) contained in a suspension (3) with a filler (4) by means of a chemical precipitation reaction, the fibers (2.1) or the cellulose (2.2) being provided in the form of a suspension (3) with a predefined solid concentration (c). The inventive method is characterized in that carbon dioxide (6) is added to the fibers (2.1) or the cellulose (2.2) in the form of a suspension (3) while the fibers (2.1) or the cellulose (2.2) is/are mixed, preferably in at least one reactor (5), with lime milk or quenched lime (7) in the form of a suspension (3) to which carbon dioxide (6) has been added, thus triggering and largely, preferably entirely, completing the chemical precipitation reaction.

Description

Method and device for loading fibers or cellulose contained in a suspension with a filler 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 means of a chemical precipitation reaction, whereby the fibers or cellulose are provided in the form of a suspension having a predetermined solids concentration.

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 TM" process as described in the US patent document US 5 223 090 A. In said "Fiber Loading TM" 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 US patent specification for loading of fibers contained in a suspension is known, for example from the German disclosure document DE 102 04 254 Al. 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 m, whereby 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 means of a chemical precipitation method are known from the German disclosure document DE 101 07 448 Al. 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 Al. 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 US patent document US 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 characterized 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 characterized 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.

It is therefore the objective of the current invention to create 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 to be created which permits the relevant chemical reaction to be carried out continuously, efficiently and economically.

In accordance with the current invention this objective is met characterized in that - carbon dioxide is added to the fibers or 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, preferably in at least one reactor, thereby triggering and extensively, preferably completely concluding the chemical precipitation reaction.

The inventive objective is met in totality in this manner.

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 similar. 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 two preferred 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 preferably 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 is preferably 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 whereby however investment and even operational costs can be saved due to a simplified system design.

Also, the first method offers a plurality of preferred variations:
- the carbon dioxide can be added to the suspension under the influence of shear forces, preferably in a pump disperger;
- the carbon dioxide can be added to the suspension by utilizing mixing effects, preferably 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, whereby 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 preferably 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 preferred designs provide that the suspension is degassed by means 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 is added to the suspension preferably 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, whereby 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 the 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 comprise at least the pH-value, the temperature, the dwell time, the throughput of suspension and/or milk of lime or slaked lime.
Preferably, at least the pH-value of the suspension as measured at the end of the reaction is 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 suchlike.

The objective cited at the beginning is also met by an apparatus for loading of fibers or cellulose which are contained in a suspension with a filler by means of a chemical precipitation reaction, whereby 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, preferably completely concluding the chemical precipitation reaction.

Preferred design variations of the inventive apparatus are cited in the sub-claims.

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, whereby 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.

Additional characteristics and advantages of the invention result from the following description of preferred design examples with reference to the drawings:

Figure 1 a schematic depiction of an apparatus for loading fibers which are contained in a suspension with a filler by means of a chemical precipitation reaction;
and Figure 2 a schematic depiction of an additional apparatus for loading fibers which are contained in a suspension with a filler by means of a chemical precipitation reaction.

Figure 1 illustrates 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 means of a chemical precipitation reaction, whereby 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 comprises a 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, preferably 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 Figure 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 comprises 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 means 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 means 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 comprises 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 preferred reaction parameters are 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.

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

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

The apparatus 1 also comprises 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, preferably 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 Figure 1 this example comprises a unit 17 which is located upstream from the reactor 5 in the process sequence and which can preferably 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 comprises 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 Figure 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 comprises 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 Al. The content of said document is therefore included into the present description by means of reference.

In an additional arrangement the unit 17 which is located upstream from the reactor 5 in the process sequence can also comprise 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 comprise 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 comprises 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 pressureigenerating 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 means 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 means of dissolving cellulose or waste paper through the use of additives 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 comprises 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 have been created by the current invention which, on the one hand assures a fast and a 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.

Claims

1. Method for loading of fibers (2.1) or cellulose (2.2) contained in a suspension (3) with a filler (4) by means of a chemical precipitation reaction, whereby the fibers (2.1) or cellulose (2.2) are provided in the form of a suspension (3) having a predetermined solids concentration (c), characterized in that carbon dioxide (6) is added to the fibers (2.1) or to the cellulose (2.2) in the form of a suspension (3) and that 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), preferably in at least one reactor (5), thereby triggering and extensively, preferably completely concluding the chemical precipitation reaction.

2. Method in accordance with claim 1, characterized in that the carbon dioxide (6) is added to the suspension (3) in at least on unit (17) which is located upstream from the reactor (5) in the process sequence and which can preferably be heated.

3. Method in accordance with claim 2, characterized in that the carbon dioxide (6) is added to the suspension (3) under the influence of shear forces.

4. Method in accordance with claim 2 or 3, characterized in that the carbon dioxide (6) is added to the suspension (3) in a pump disperger (18).

5. Method in accordance with claim 2, characterized in that the carbon dioxide (6) is added to the suspension (3) by utilizing mixing effects.

6. Method in accordance with claim 2 or 5, characterized in that the carbon dioxide (6) is added to the suspension (3) by utilizing at least one stationary mixing system.

7. Method in accordance with claim 2, 5 or 6, characterized in that the carbon dioxide (6) is added to the suspension (3) in at least one stationary mixer.

8. Method in accordance with claim 2 or 7, characterized in that the carbon dioxide (6) is added to the suspension (3) in at least one stationary mixer under the influence of flow turbulences.

9. Method in accordance with claim 2 or 5, characterized in that the carbon dioxide (6) is added to the suspension (3) by utilizing a least a partially driven mixing system.

10. Method in accordance with claim 9, characterized in that the carbon dioxide (6) is added to the suspension (3) in at least one agitator.

11. Method in accordance with one of the aforementioned claims, characterized in that the addition of the carbon dioxide (6) and/or mixing with milk of lime or slaked lime (7), occurs continuously.

12. Method in accordance with claim 1, characterized in that the carbon dioxide (6) is added to the suspension (3) in the reactor (5) where the blending of the suspension (3) with the milk of lime or the slaked lime (7) is preferably staggered.

13. Method in accordance with claim 12, characterized in that the addition of the carbon dioxide (6) and the mixing process with the milk of lime or the slaked lime (7) occurs in batch operation.

14. Method in accordance with one of the aforementioned claims, characterized in that water (10) is added to the suspension (3) prior to adding the carbon dioxide.

15. Method in accordance with one of the aforementioned claims, characterized in that water (10) is added into the reactor (5) prior to and/or during and/or after the addition of the milk of lime or slaked lime (7).

16. Method in accordance with one of the aforementioned claims, characterized in that the suspension (3) is degassed by means of a degassing unit (12) prior to the addition of the carbon dioxide (6).

17. Method in accordance with one of the aforementioned claims, characterized in that the carbon dioxide (6) is added to the suspension (3) under pressure.

18. Method in accordance with one of the aforementioned claims, characterized in that the carbon dioxide (6) is added to the suspension (3) as pure carbon dioxide and/or as flue gas.

19. Method in accordance with one of the aforementioned claims, characterized in that the suspension (3) is produced by dissolving cellulose or waste paper through the use of additives in at least one pulper (15), or it is supplied to the loading process as a non-dried pulp, for example from another pulp mill.

20. Method in accordance with one of the aforementioned claims, characterized in that the reaction parameters are measured in the at least one reactor (5) and are utilized if necessary to adjust the chemical precipitation reaction.

21. Method in accordance with claim 20, characterized in that the reaction parameters include at least the pH-value, the temperature, the dwell time, the throughput of suspension (3) and/or milk of lime or slaked lime (7).

22. Method on accordance with claim 20 or 21, characterized in that the pH value of the suspension (3) as measured at the end of the reaction is compared with a desired value and that the deviation is reduced or removed through at least one of the following correcting variables: addition of milk of lime or slaked lime (7), addition of carbon dioxide (6), throughput of suspension (3) and/or similar.

23. Apparatus (1) for loading of fibers (2.1) or cellulose (2.2) contained in a suspension (3) with a filler (4) by means of a chemical precipitation reaction, whereby the fibers (2.1) or cellulose (2.2) are provided in the form of a suspension (3) having a predetermined solids concentration (c), especially for the implementation of the method in accordance with one of the aforementioned claims;

characterized in that at least one reactor (5) is provided 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 largely, preferably completely concluding the chemical precipitation reaction.

24. Apparatus (1) in accordance with claim 23, characterized in that at least one unit (17) is located upstream from the reactor (5) in the process sequence which can preferably be heated and in which carbon dioxide (6) is added to the fibers (2.1) or the cellulose (2.2) in form of a suspension (3).

25. Apparatus (1) in accordance with claim 24, characterized in that the unit (17) which is located upstream from the reactor (5) in the process sequence comprises at least one pump disperger (16) which produces shear forces during the addition of carbon dioxide (6) to the suspension (3).

26. Apparatus (1) in accordance with claim 24, characterized in that the unit (17) which is located upstream from the reactor (5) in the process sequence comprises at least one stationary mixing system which causes mixing effects during the addition of the carbon dioxide (6) to the suspension (3).

27. Apparatus (1) in accordance with claim 26, characterized in that the stationary mixing system comprises at least one stationary mixer.

28. Apparatus (1) in accordance with claim 26 or 27, characterized in that the stationary mixing system comprises a stationary mixer in the embodiment of a supply line (8) through which the suspension (3) flows and which produces flow turbulences, at least over segments, during the addition of the carbon dioxide (6) to the suspension (3).

29. Apparatus (1) in accordance with claim 24, characterized in that the unit (17) which is located upstream from the reactor (5) in the process sequence comprises at least one partially driven mixing system which produces mixing effects during the addition of the carbon dioxide (6) to the suspension (3).

30. Apparatus (1) in accordance with claim 29, characterized in that the mixing system comprises at least one agitator.

31. Apparatus (1) in accordance with claim 23, characterized in that the reactor (5) comprises 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.

32. Apparatus (1) in accordance with one of the claims 23 through 31, characterized in that at least one supply line (11) is provided for water (10) which can be added prior to the addition of the carbon dioxide (6) and/or prior to and/or during and/or after the addition of milk of lime or slaked lime (7).

33. Apparatus (1) in accordance with one of the claims 23 through 32, characterized in that at least one degassing unit (12) is provided for the purpose of degassing the suspension (3) prior to the addition of the carbon dioxide (6).

34. Apparatus in accordance with one of the claims 23 through 33, characterized in that a pressure generating unit (13) is provided for the purpose of a pressurized addition of carbon dioxide (6) to the suspension (3).

35. Apparatus (1) in accordance with one of the claims 23 through 34, characterized in that at least one pulper (15) is provided for the production of the suspension (3) by means of dissolving cellulose or waste paper through the use of additives or through the supply of non-dried pulp.

36. Apparatus (1) in accordance with one of the claims 23 through 35, characterized in that the reactor (5) comprises at least one system (16) to measure the reaction parameters and if necessary to adjust the chemical precipitation reaction.

37. Apparatus (1) in accordance with claim 36, characterized in that the reaction parameters include at least the pH-value, the temperature, the dwell time, the throughput of suspension (3) and/or of milk of lime or slaked lime (7).

38. Fiber web, especially paper or cardboard web, characterized in that at least fibers (2.1) or cellulose (2.2) in the form of at least one suspension (3) were used in its production which were loaded in accordance with one of the claims 1 through 22.