DE102006003647A1 - Loading of cellulose fiber suspension with calcium hydroxide filler, comprises controlling the concentration of filler in vat, dump chest, machine chest and/or in a pipeline by recirculation and/or bypass mechanism - Google Patents

Abstract

The loading of cellulose fiber suspension with calcium hydroxide filler, comprises the concentration of filler that is controlled in a vat (2), dump chest, machine chest and/or in a pipeline by recirculation and/or bypass mechanism. The recirculation and/or bypass mechanism and/or liquid calcium hydroxide and/or carbon dioxide gas are heated by a heating mechanism (6). The calcium hydroxide filler in liquid or dry form is mixed with aqueous paper fibers. The portion of the calcium hydroxide lies between 0.01-60 % of the solid content of the dry paper pulp. The loading of cellulose fiber suspension with calcium hydroxide filler, comprises the concentration of filler that is controlled in a vat (2), dump chest, machine chest and/or in a pipeline by recirculation and/or bypass mechanism. The recirculation and/or bypass mechanism and/or liquid calcium hydroxide and/or carbon dioxide gas are heated by a heating mechanism (6). The calcium hydroxide filler in liquid or dry form is mixed with aqueous paper fibers. The portion of the calcium hydroxide lies between 0.01-60 % of the solid content of the dry paper pulp. The portion of the calcium hydroxide lies between 0.01-60 % of the solid content of the dry paper pulp. A target filler content has a value of 0.01-15 % above the original filler content (0.05-3%) of the fibrous material. A pH value of 9-12 is maintained in an arrangement for dissolving the fibrous material in a static mixing device, sample vat or material dissolving system. The filler is prepared by a precipitation process in a batch reactor or by a grinding process. In the process talc, titanium dioxide, silicon, is used. In the loading of cellulose fiber, an aqueous paper fibers raw material is 0.1-20% consistency. The reactivity of the calcium hydroxide lies between 1 second-3 min. Dilution water is mixed into the fibrous material suspension before, during or after the addition of carbon dioxide and/or calcium hydroxide or calcium oxide. The carbon dioxide is mixed as pure or as flue gas into the damp fibrous material suspension and/or into the dilution water. The process temperature lies at 20-90[deg]C. Rhombohedric, scalenohedric, and spherical crystals are produced. The crystals have dimensions of 0.3-2.5 mu m. Static and/or mobile, rotary, mixing elements are used in the loading of cellulose fiber. The loading is carried out with a pH of 6.5-9.5 and at a pressure 0 -6 bar. The reaction time lies between 0.05-10 seconds. Ash content is determined over pH value and/or over a measurement of the ash content within the range of the recirculation and the vat for the fibrous material preparation or within the piping. An independent claim is included for an arrangement for the execution of above method.

Description

The The invention relates to a method for charging a pulp suspension of cellulose fibers with a filler, especially with calcium hydroxide, wherein the filler in liquid or dry form is introduced into the pulp suspension.

Several methods of fiber loading technology for loading pulp fibers with calcium carbonate are already known. In the US 5,223,090 For example, there is described a method employing fibrous material having elongated fibers with a cell wall surrounding a cavity, the fibers having a humidity sufficient to form a dewatered pulp slurry. The fibers have a moisture content corresponding to a proportion of 40 to 50% of the weight of the fibers. The water is essentially present inside the fibers and inside the fiber walls. Subsequently, alternatively calcium oxide or calcium hydroxide is added to the pulp so that at least part of the incorporated calcium oxide or calcium hydroxide is associated with the water present in the pulp. Subsequently, the fibrous cellulosic material is contacted with carbon dioxide while simultaneously subjected to a shear mixing process to produce a fibrous material having a substantial amount of calcium carbonate in the hollow interior and within the fibrous walls of the cellulosic fibers by precipitation.

From the DE 103 17 719 A1 For example, a method for adjusting the ash content of a pulp suspension and an arrangement for carrying out the method are known. The known method comprises the following steps: introduction of calcium hydroxide in liquid or dry form or of calcium oxide into the pulp suspension, introduction of gaseous carbon dioxide into the pulp suspension, precipitation of calcium carbonate by the carbon dioxide. In an arrangement for carrying out the method, the ash value of the pulp suspension is checked and adjusted to a desired value by means of a controller comprising a controller.

It The object of the invention is a process for loading a pulp suspension to create, in which the ash content can be adjusted.

According to the invention this Task solved by that the content of filler, especially in a chest, a dumping hut, a machine chest or the like, and / or in a pipeline through a mixing device, in particular a recirculation and / or a bypass device, is regulated.

By The invention describes a method to precipitated, with Fiber loaded calcium carbonate (FLPCC = fiber loaded precipitate calcium carbonate), in particular for pulp production or for pulp utilization in papermaking. The fiber raw material to be loaded is made, for example, from recycled paper, from DIP (= Deinked Paper), made of secondary pulp, bleached or unbleached pulp, wood pulp of any kind, any paper pulp, bleached or unbleached sulphate pulp, Finished pulp, linen, cotton and / or hemp fibers (predominantly for cigarette paper used) and / or any other paper stock, which is used in a paper machine. The procedure can be independently of the fiber raw material to be loaded.

The inventive method can be used regardless of whether the final product contains filler, which was prepared by a precipitation process in a batch reactor or by a grinding process (GCC = ground calcium carbonate), or in the talc, silicon, titanium dioxide (TiO ₂ ) used come. The filler content can be regulated, for example, in a range between 0.01% and 15% above the original filler content of the fiber material. The field of application of the invention extends to papermaking and process technology, including the filler produced, and includes applications of all types of paper including packaging paper grades having a filler content between 1% and 60% and / or a white topcoat having a filler content between 1% and 60% % own.

The Field of application of the invention is not to the use of these fillers limited in paper producing processes; the invention can be found in any paper producing process or auxiliary process including the Pulp production can be used. Will be a pulp suspension treated in paper making with the fiber-loading technology, results in a completely new product, the new and improved Properties over the has products known in the market. The one described below Process allows it, directly at stock preparation in a paper mill filler Precipitate (calcium carbonate), the exclusively on and in the pulp, especially the paper fiber, evenly distributed and is attached.

Through a combination or an individual In the embodiments of the invention described below, it is achieved that pulp loaded exclusively with precipitated calcium carbonate is produced, the calcium carbonate being attached to or embedded in the fibers; In this case, the formation of free precipitated calcium carbonate (PCC) is prevented: by the use of an additional washing before a grinding process and / or after the grinding process and / or before the crystallization process in a crystallizer and / or before the headbox or before being fed to the paper machine or By returning the press filtrate to a receiver chest or other input-side storage arrangement, it is achieved that a constant content of calcium hydroxide in the feed system of the fiber-loading device is set or adjusted. The calcium hydroxide can be fed directly into a pulp dissolver. The press filtrate can be recycled to the pulping system. Calcium hydroxide, which does not accumulate on or in the fibers, is recycled to the upstream processes.

Just the filler, not deposited on or in the fibers, d. H. free precipitated calcium carbonate, is washed out. The fibers themselves, the inside and outside with filler are lost by the washing process and the return of the Press filtrates do not, so the positive effects of fiber-loading technology remain.

Especially The invention includes a method according to which the pulp suspension introduced into a press assembly for squeezing a filtrate becomes. Subsequently the filtrate is at least partially in an arrangement for dissolving the Recycled pulp suspension, d. h., In an input-side storage vessel, for example, in a receiver chest. The Calcium hydroxide is at least partially in the arrangement for dissolving the Added pulp. In the complete material dissolving system, d. h., in the arrangement for dissolving of the pulp, will have a pH between 7 and 12, in particular between 9 and 12, maintained.

According to the invention let yourself aqueous starting material Fiber material, in particular aqueous paper pulp, of 0.1 up to 20% consistency, preferably between 2 and 8%.

calcium hydroxide in water or in dry form or calcium oxide is in a range between 0.01 and 60% of the existing solids content in the aqueous Paper pulp mixed. For The mixing process is a static mixer, a receiver or a material dissolution system used; Here, a pH in the range between 7 and 12, preferably between 9 and 12, used. The reactivity of the calcium hydroxide is between 0.01 and 10 minutes, preferably between 1 second and 3 minutes. According to predetermined Reaction parameters becomes dilution water mixed.

carbon dioxide is determined according to the reaction parameters in a wet paper pulp dimension mixed. It falls Calcium carbonate in the carbon dioxide atmosphere.

Compared to conventional Processes for producing a pulp suspension according to the invention, a higher freeness achieved energiegünstig become; according to the invention can Up to 50% of the grinding energy can be saved. This affects in particular on all paper grades that have a milling process in their manufacture go through, and especially with those who have a high or very high Have grind such as FL cigarette papers (FL = Fiber Loading), FL-B & P papers, FL sack kraft papers and FL filter paper. For these papers, no fillers need, can be free filler, which is not deposited on or in the fibers after the milling process or before introducing the pulp suspension in the headbox or before the feeder be removed to the paper machine. However, the fibers themselves are inside and outside with filler provided so that the positive effects of fiber-loading technology remain.

The The high freeness achieved high mechanical skills of the final product have a positive effect on the production of all types of paper because of process-related mechanical stresses in the various Sections of the paper machine, as in the press section, the dryer section or in the area in which the paper web is rolled up, the produced intermediate and the final product to be produced by the use of reeling, wrapping, rewinding and converting machines is loaded mechanically high.

By the pretreatment according to the invention The pulp suspension is also the prerequisite for a better Drying created by the production efficiency of all paper types increased becomes. Advantageous residual moisture in the range between 1 and 20%.

By The invention will also be higher degrees of whiteness and / or higher optical values with up to 15 brightness points better Brightness in the production of all types of paper, cardboard or in different uses of cardboard, including the white Cover layer on a cardboard layer, reached.

The Energy input during the milling process, d. H. the amount of heat and the resulting heating, is controlled. According to the control can be crystals produce a variety of forms.

The Invention relates in a further embodiment to a method in which as a reactor, a static mixer, a refiner, a disperser and / or a fluffer FLPCC reactor is used, the pulp content, in particular the paper content, for a static mixer between 0.01 and 15%; at a refiner and in the case of a disperser between 2 and 40%, in particular for LC grinding between 2 and 8% and at a HC-grinding between 20 and 35%, and at a fluffer-FLPCC reactor is between 15 and 60%.

Preferably the process temperature is between -15 ° C and 120 ° C, in particular between 20 ° and 90 ° C. Preferably rhombohedral, scaleohedral and spherical crystals are produced, wherein the crystals have dimensions between 0.05 and 5 microns, in particular between 0.3 and 2.5 μm, to have.

to Preparation of a loaded with calcium carbonate pulp suspension become static and / or moving, in particular rotating, mixing elements used.

The Method is preferably in a pressure range between 0 and 15 bar, in particular between 0 and 6 bar performed. As well the process is advantageous at a pH between 6 and 10, in particular between 6.5 and 9.5 performed. This is the reaction time between 0.03 seconds and 1 minute, in particular between 0.05 and 10 seconds.

One Another advantage of using the technology of the invention in the above listed Paper types is that they also processed in a calender can be. Due to the fact that fiber-loading-particles in, around and attached to the fibers, the blackening, i. H. Black satin, avoided.

The The invention also relates to an arrangement for carrying out a the above listed Method. The arrangement is characterized in that it has a Mixing device includes, as a bypass and / or recirculation for the pulp suspension is operated.

From Advantage is an arrangement in which the mixing device as static Mixer, as a presentation chest or as a material dissolving system is trained. In such a mixing device is calcium hydroxide in dry or liquid Form (milk of lime) in aqueous Paper pulp in the range of 0.01% to 60% of the existing Solid content of the dry pulp mixed.

below the invention is in an embodiment closer by the single figure described.

Paper stock intended for fiber loading 1 becomes a chest 2 fed from which it is transported in a machine for producing a paper web (paper production 3 ).

The Bünd 2 is via two lines with a mixing device 4 in connection. The mixing device 4 on the one hand lime milk 8th from a device for providing this substance (Kalkmilcherzeugung 5 ) and on the other hand from CO ₂ production 7 originating carbon dioxide 9 fed. To set a suitable reaction temperature is also a heater 6 present in either lime milk 8th' or carbon dioxide 9 ' or both substances are heated in such a way that sets the desired reaction rate.

In addition, there is also direct exchange of the liquid in the mixing device 4 with the heater 6 possible, so that medium from the mixing device 4 for heating in the heater 6 is pumped and then recirculated again.

Claims (22)

A method for charging a pulp suspension of cellulose fibers with a filler, in particular with calcium hydroxide, wherein the filler is introduced into the pulp suspension in liquid or dry form, characterized in that the content of filler, in particular in a Bütte ( 2 ), a Ableerbütte, a machine chest or the like., And / or in a pipeline through a mixing device ( 4 ), in particular a recirculation and / or a bypass device, is regulated. Method according to claim 1, characterized in that the mixing device ( 4 ) and / or liquid calcium hydroxide and / or carbon dioxide gas ( 9 . 9 ' ) by a heating device ( 6 ) are heated. A method according to claim 1 or 2, characterized in that calcium hydroxide in liquid or dry form in aqueous paper pulp is mixed in. Method according to claim 3, characterized the proportion of calcium hydroxide is between 0.01% and 60% of the existing solids content of the dry pulp. Method according to one of claims 1 to 4, characterized that a target filler content a value in the range between 0.01% and 15% over the original one filler of the fiber material, in particular between 0.05% and 3% becomes. Method according to one of claims 1 to 5, characterized that at least in the arrangement for dissolving the pulp, in particular a static mixing device, in a receiver or in a pulping system, a pH between 7 and 12, in particular between 9 and 12, maintained becomes. Method according to one of claims 1 to 6, characterized that the filler through a precipitation process produced in a batch reactor or by a grinding process or that talc, titanium dioxide, silicon, etc. is used. Method according to one of claims 1 to 7, characterized that as starting material aqueous Fiber material, in particular aqueous paper pulp, of 0.1 to 20% consistency, preferably between 2 and 8% used becomes. Method according to one of claims 1 to 8, characterized that reactivity of the calcium hydroxide in the range between 0.01 and 10 minutes, in particular between 1 sec and 3 min. Method according to one of claims 1 to 9, characterized that dilution water in the pulp suspension is mixed in, in particular before, during or after the addition of carbon dioxide and / or calcium hydroxide or calcium oxide. Method according to one of claims 1 to 10, characterized that dilution water mixed according to reaction parameters in the pulp suspension is, in particular before, during or after the addition of carbon dioxide and / or calcium hydroxide or Calcium oxide. Method according to one of claims 1 to 11, characterized that carbon dioxide as pure or as flue gas in the moist pulp suspension and / or into the dilution water is mixed in. Method according to one of claims 1 to 12, characterized that the process temperature between -15 ° C and 120 ° C, in particular between 20 ° and 90 ° C, is. Method according to one of claims 1 to 13, characterized that rhombohedral, scaleohedral and spherical crystals are generated. Method according to claim 14, characterized in that that the crystals dimensions between 0.05 and 5 microns, in particular between 0.3 and 2.5 μm, to have. Method according to one of claims 1 to 15, characterized that static and / or movable, in particular rotating, mixing elements be used. Method according to one of claims 1 to 16, characterized that it is in a pressure range between 0 and 15 bar, in particular between 0 and 6 bar, performed becomes. Method according to one of claims 1 to 17, characterized that it is at a pH between 6 and 10, in particular between 6.5 and 9.5, performed becomes. Method according to one of claims 1 to 18, characterized that the reaction time is between 0.03 seconds and 1 minute, in particular between 0.05 and 10 seconds. Method according to one of claims 1 to 19, characterized that the ash content is over the pH and / or over a measurement of the ash content in the area of recirculation, Bypasses, a chest for the Pulp processing or in a pipeline. Arrangement for carrying out a method according to one of the claims 1 to 20, characterized in that it comprises a mixing device includes, as a bypass and / or recirculation area for the pulp suspension is operated. Arrangement according to claim 21, characterized that the mixing device as a static mixer, as a receiver or as a material dissolving system is trained.