DD201996A5 - METHOD FOR THE PRODUCTION OF CERAMIC FIBERS CONTAINING, CORE, FIRE-RESISTANT OR FIRE-RESISTANT MATERIALS, MATERIALS MANUFACTURED BY THE METHOD AND THEIR USE - Google Patents

Abstract

A process for the preparation of nuclear fire-resistant or refractory materials, wherein 100 parts by weight of ceramic fibers, 2-15 parts by weight of clay and / or finely divided refractory oxides, optionally mixed to 10 parts by weight of other refractory additives, 1-10 parts by weight of organic binders and water, and Mixture compacted by the volume factor of at least 3, dried and comminuted to a Kernung. The use of the granular material with the addition of inorganic binder in a spray mass and as a mass for the production of refractory components leads to improved strength.

Description

23 7 3 7 7 7 ~ ^ ~ Berlin »the 23 · S ₀ 82

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Process for the preparation of ceramic fiber-containing, granular, refractory or refractory materials, materials produced by the process and their use

Field of application of the invention

The invention relates to a process for the production of ceramic fibers containing granular, fire-resistant or refractory materials containing ceramic fibers, clay binders and optionally other conventional additives, the material produced by the process and its use.

Characteristic of the known technical solutions

Heat-insulating ceramic fiber bodies of refractory fibers, organic or inorganic binder on the one hand low strength and high compressibility and on the other hand, increased values for strength, density and dimensional stability are known «Thus, DE-AS 1 274 490 describes a combustion chamber for furnaces, by shaping the "Binder, alkali metal silicates, aluminum phosphates colloidal silica with a weight fraction of 5 to 35, optimally 10 % g called as a suitable binder." The fibrous body is due to because its dense hard wall surface and the opposite soft flexible wall surface are not sufficiently suitable for high loads «

In the process according to DE-AS 2 732 387, the mineral fiber board prebound with an organic plastic binder is intended to be impregnated by impregnation with an aqueous slurry

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Furthermore, from OE-AS 2 618 813 fiber spraying compositions are known "which contain, in addition to a larger proportion of inorganic fibers, small proportions of binder or other inorganic additives as well as a chemical additive binder, these fiber spraying compounds being used for avoidance the dust formation even more 5 to 20 percent "-% of this contained" in the use of this fiber injection compositions is expressly stated that the inorganic fibers such as _# B ", the rock wool used in fanned condition"

Object of the invention

The aim of the invention is the provision of ceramic fibers containing, granular, * fire-resistant or refractory materials which in the processed state have a higher strength »in particular with respect to mechanical stress, and which can be used particularly advantageously in so-called fiber spraying masses»

Explanation of the essence of the invention

The invention has for its object to find suitable components and to provide a method by which refractory materials can be produced with the desired properties «

The inventive method for the production of ceramic fibers containing granular, refractory or refractory materials containing ceramic fibers, clay, binder and optionally other conventional additives, is

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characterized in that

a) 100 parts by weight of ceramic fibers, 2 to 15 parts by weight of clay and / or finely divided Al-O ₃ and / or finely divided SiO 2 and / or Alurainiumhydroxide and / or finely divided magnesia and / or finely divided titanium dioxide and / or finely divided chromium oxide, optionally up to 10 parts by weight of other refractory additives and 1 to 10 parts by weight of organic binder, calculated in solid form, are thoroughly mixed with about 5 to 25 parts by weight of water in a mixer, and

b) the mixture obtained in step a) is compacted by a volume factor of at least 3, dried and then comminuted to the desired grain size »

Bentonite is preferably used as the clay, fibers digested as ceramic fibers and molasses as binders *

In a particular embodiment of the invention, sulfite waste liquor in solid form or as a solution is used as the binder. Methylcellulose in solid form and / or as a solution in water can likewise be used advantageously as binder.

As a further refractory material is advantageously used porcelain flour or chamotte »

The compaction in stage b) is carried out by a volcanic factor of 5 to 8. The compaction in stage b) is preferably carried out by extrusion, but then in stage a) up to 100 parts by weight of water are used to prepare the mixture. The compaction in stage b) can also be carried out in a briquetting facility «

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The invention furthermore relates to the granular ¹ "fire-resistant or refractory material containing ceramic fibers produced according to the process and having particularly good properties.

The ceramic fibers or mineral fibers used in the process according to the invention can all be conventional fibers of this type, eg * rockwool or fibers based on aluminum silicate with, in particular, high AlpO.sub.x content in the range from 45 to 95% by weight also mixtures of different ceramic fibers are used *

The clay used in the process according to the invention can be a customary clay or a special binder clay, eg bentonite. This clay is usually used in an amount of 2 to 15 parts by weight per 100 parts by weight of the ceramic fibers. Furthermore, up to 10 parts by weight of other refractory additives can be used in the process according to the invention, examples of which are porcelain flour and chamotte. The other finely divided components optionally present in the composition of the granular materials according to the invention, such as finely divided Al ₂ O, and / or Finely divided SiO ₂ and / or aluminum hydroxides and / or very finely divided magnesia and / or finely divided titanium dioxide and / or finely divided chromium oxide are known components in the refractory art. "As used herein" finely divided "in connection with the aforementioned components is to be understood that these ingredients in the finely ground or in the colloidal state. Especially when using such in the colloidal state

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Materials such as colloidal SiO ₂ or "colloidal alumina, it is possible to use only small amounts of binder, namely close to the lower limit of 1 Gew" part of such a binder "

Advantageously, the total amount of clay and / or other finely divided components plus other refractory additions is 20 parts by weight per 100 parts by weight of the ceramic fibers. "

The organic binders used in the process according to the invention are customary binders of this type, preference is given to molasses, sulfite waste liquor and, in particular, methyl cellulose,

The organic binder is usually used in the form of a concentrated solution "part of the organic binder, advantageously up to 50% by weight, but can also be used in solid, finely divided form." "If methyl cellulose is used as a binder, it becomes common used in the form of a 5% strength by weight solution in water "Sulfite waste liquor can be used as sulfite waste liquor with a usual solids content of about 50% by weight, but it is also possible to use dried, finely pulverized liquor waste liquor."

The mixing of the constituents of stage a) of the process according to the invention can be carried out in a conventional mixer, for example in a Drais mixer.

In an advantageous embodiment of the method according to the invention, the ceramic fibers are used as

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closed fibers used in stage a) "For this purpose, commercial fibers are supplied in their delivery state in a turbomixer (make Drais-turbulent high-speed mixer), wherein the fibers usually supplied as fiber bundles are converted into open-ended fibers» Such a turbomixer consists of a mixing unit with rapidly rotating cutterheads * whereby any agglomerates present in commercially available fibers, some of which are in highly compressed form, are digested without the fibers being crushed or crushed to an inadmissible extent. "

Of course, it is also possible to mix the ingredients to be mixed in stage a), namely the clay and / or the other very finely divided components, optionally the other refractory additives and, if the organic binder is used in solid form, with the fibers in such Mixing turbomixer, at the same time a digestion of the fibers and a particularly good homogeneous mixing with the components added in step a) is carried out · Then then possibly dissolved binder and water are added and mixed.

The mixture obtained in stage a) of the process according to the invention must be compacted by a volume factor of at least 3. This may advantageously be done in an extruder. Further, such compaction may be carried out in a rotary press or a conventional pelletizer, but it may be any other In the method according to the invention, the compression must take place by a volume factor of at least 3, advantageously

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the compression is performed by a volume factor of 3 to 6 * The maximum volume factor of the compression is about 12 to 14 «Then the product compacted by the volume factor of at least 3 is dried, usually at temperatures between 110 and 180 ⁰ C, until it contains Water is largely or completely removed * The pieces then obtained are crushed to the desired grain size, the maximum grain size is usually 8 ram and advantageously 6 ram * However, the crushing can also be set to a certain range, for example, a product with a grain between 2 and 3 mm or a maximum grain size of up to 2 mm or 3 mm can easily be obtained by comminution in customary crushing devices and, if appropriate, screening out of the desired grits.

The granular material obtained by the method according to the invention has a density of 0.7 to 1.75 g / cm and has a pore volume in the order of 35 to 75 % on «

The granular material obtained by the process according to the invention can be used particularly suitably in fiber spraying compositions. For this purpose, the material is supplied either in dry form to a spray nozzle at the top of which it is mixed with water and an inorganic further binder or additives Slurry of the granular material prepared and sprayed with water and at least one inorganic binder. As such additives, either phosphate binders or hydraulically setting binders such as Portland cement or

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high-refractory cements such as high-alumina cement are also added, the addition of other conventional additives when used as a fiber spraying mass is also possible «splashing is also possible with the addition of water» binder and ceramic fibers «When using the granular material according to the invention in fiber spraying the advantage is given that the fiber savings may be up to 50 % . "Furthermore, the atomization of the fibers is largely reduced Used deliveries, wherein such fiber spraying masses can also be used for the subsequent fire-side insulation of existing deliveries, z «B« in repairs · In the case of Verw In the course of spraying the fiber spraying trains, a further high-temperature-resistant binder, for example a phosphate binder or high-alumina cement, must of course be present in these

A particularly advantageous application of the fiber spraying masses relates to the spraying of the Oecken Feuerungsräumen · Such Oeckenauskleidungen for Feuerungsräume are described for example in DE-AS 2,832,079, in which mats made of temperature-resistant Faserraaterial be inserted by means of brackets and the last Mattenläge then with a protective layer of high temperature resistant Lightweight construction material is completely covered "In the use of fiber spray paths according to the invention, it is possible to construct such ceiling constructions with the fiber spraying according to the invention.

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masses »which after drying produce a compact insulating layer» which do not require a cover plate «

A further advantage of the fiber granulation according to the invention is that the organic binder burns out partially or completely at higher temperatures in the application of such fiber granules, either as such or in the form of slugs to other refractory materials or refractory bodies of 500 ⁰ C, then the individual grains of this material no longer obtain binder, so that the elastic properties of the ceramic fibers come to light again "When using such a ceramic fiber grain, for example, as a supplement in a refractory Hasse, is therefore the advantage given that after the burning out of the organic binder, the individual grains of the fiber grains are elastic, so that the heat-resistant or refractory components made from such masses is given the advantageous property that voltages occurring here can be compensated s causes such fire-resistant or refractory components, which receive the Faserkörörnung invention, have less cracking, since the stresses are canceled by the elastic single grains of Faserkörörnung «

In the process according to the invention different amounts of water are used in the preparation of the mixture in step a). The amount of water used depends essentially on the device in which the mixture obtained in step a) is subsequently compressed in step b) Compression is done in a briquetting or rotary table press, are Wassermengsn of

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- ίο -

5 to 25 parts by weight is sufficient, but if the compression is carried out on an extruder, the amount of water to be added in this stage a) is higher, it can amount to up to 100 parts by weight * Based on simple preliminary tests, the amount of water to be used However, the amount of water used also depends on how large the amount of clay added in step a) is, finely divided Al ₂ O ₃ or the other finely divided constituents mentioned, in particular when using colloidal SiO ₂ and colloidal Al ₂ O ₃ larger amounts of water can be beneficial «

embodiment

The invention is explained in more detail with reference to the following examples. Ceramic fibers A with 47 % Al ₂ O ₃ and 53 % SiO ₂ or fibers B with 95 % Al ₂ O ₃ and 5% SiO _{2 were} used here.

Examples 1 to 5

The following approaches were used:

Example 1 2 3 4 5

ceramic fibers A 100 6 _ 100 4 - _ _ 2 50 ceramic fibers B - 100 Wed. 6 100 - · 50 Bindeton (with 35 % Al ₂ O ₃ ) 15 6 4 4 - Chromium oxide, <63, um - 4 _ colloid "SiO ₂ - - 4 colloid «Al ₂ O ₃ - - 6 Methylcellulose, solid 1

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- 11 -

sulfite waste liquor, firmly - Fireclay flour 2 water 25

10 15 12 25

On an Eirich mixer, the ceramic fibers were mixed with binding clay or the other constituents, but then the organic binder or binder mixture was added and finally the water was added. The mixture was mixed for a total of 20 minutes.

This mixture was compacted in a Brikettiereinrichtung (make KHO) to the specified volume factors, then dried for 12 hours at 120 ⁰ C and finally comminuted to a maximum particle size of about 6 mm · The following properties were determined on the fiber granules obtained;

Example 1 2 3 4 5

Volume weight ;, R, (g / cm) 1 25 1 • 09 " 1 »15 1 .20 1 , 23 compression factor 5 »4 7 2 6 "8th 6 , 0 6 , 5 Pore volume, Pg, (Vol .- *) 49 »5 69 .7 68 .0 53 .8th 62 .6 Examples 6 to 10

The formulations of Examples 1 to 5 were repeated, but here open-ended fibers were used. The fibers were pulped in a turbo-mixer (manufactured by Drais) for 5 minutes. Then the remaining additives were added and mixed in for 2 minutes.

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- 12 -

The compaction was carried out in a hydraulic press to stones of 250 χ 125 χ 30 mm, these were dried for 12 hours at 120 ⁰ C and then comminuted to a maximum grain size of 6 mm · The following properties were determined on the fiber granules obtained:

Example 6 7 8 9 10

R (g / cm ³ ) 1.10 0 .95 1 .01 1 , 04 l »09 compression factor 6.0 7 .9 7 »2 6 .9 7.3 Pg (Vol · - ^) 56.0 73 »5 71 .7 59 »9 66.6 Example 11

It has been the formulation of Example 6 with the exception that 80 parts by wt _# of water were mixed. The densification was carried out in an extruder, in which case the cross-section of the nozzle 250 χ 190 mm was · · press the strand emerging from the Rohbatzen were cut to suitable lengths and dried for 24 hours at 120 ⁰ C. Subsequently, the resulting dried batches were comminuted to a maximum grain size of 3 mm. The following properties were determined on the fiber granulation obtained:

R (g / cm ³ ) 0.95

Compression factor 3.2 Pg (Vol .-%) 62.7

Claims (13)

AP C 04 B / 237 377/7 237377 7 ", inventor claim 1 «Process for the preparation of ceramic fibers containing granular, refractory or refractory materials containing ceramic fibers, clay, binder and optionally other conventional additives, characterized in that a) 100 parts by weight of ceramic fibers, 2 to 15 parts by weight of clay and / or finely divided Al-O ₃ and / or very finely divided SiO ₂ and / or aluminum hydroxides and / or finely divided magnesia and / or finely divided titanium dioxide and / or finely divided chromium oxide, optionally up to 10 parts by weight of other refractory additives and 1 to 10 parts by weight of organic binder, calculated in solid form, are thoroughly mixed with about 5 to 25 parts by weight of water in a mixer, and b) the mixture obtained in step a) compacted by a volume factor of at least 3, dried and
then crushed to the desired grain size, 2 «method according to item 1, characterized in that bentonite is used as the clay. 3 * Process according to item 1, characterized in that fibers which have been treated with ceramic fibers are used « 4 · Method according to item 1, characterized in that molasses is used as binder « 5, method according to one of the items 1 to 3, characterized AP C 04 B / 237 377/7 60 420 18 237377 7 - 14 - the use of sulphite waste liquor in solid form or as a solution as binder 6. Process according to one of the items 1 to 3 »characterized in that methylcellulose in solid form and / or as a solution in water is used as binder« 7. The method according to item 1, characterized in that porcelain flour or chamotte is used as a further refractory material · 8. The method according to any one of the preceding points, characterized in that the compression in step b) by a volume factor of 5 to 8 is performed. 9 »method according to item 1, characterized in that in step b) the compaction is carried out by extrusion, but then in step a) up to 100 parts by weight of water are used to prepare the mixture. 10. The method according to item 1, characterized in that in step b) the compression is carried out in a Brikettiereinrichtung. 11. Ceramic fiber-containing, granular, fire-resistant or refractory material, characterized in that it was prepared by the method according to any one of items 1 to 10. 12. Use of the ceramic fiber-containing, granular, fire-resistant or refractory material, characterized AP C 04 B / 237 377/7 60 420 18 237 37 7 7. ". net in that it is used in fiber spraying masses · 13 »Use of the ceramic fiber-containing, granular, fire-resistant or refractory material, characterized in that it is used as a supplement in fire-stressed or refractory components subjected to stress during operation *