DE102008062810B3 - Manufacture of high-alumina mineral fibers, employs clay or clay minerals of given composition, to reduce melting point under oxidizing conditions - Google Patents

Abstract

The melting point range of mixed raw minerals containing silicon and aluminum, is reduced. They are melted in a ladle, with air introduction. A nozzle-blowing operation forms the mineral fibers. The composition is expressed in mass percentages by: SiO 235-75, Al 2O 317-38, TiO 20.01-1.5, Fe 2O 30.01-3, CaO 0.01-2, MgO 0.01-2, Na 2O 0.05-2, K 2O 0.01-3. Losses on heating are 4-14 wt%. The mixture is formed from silicate minerals and aluminum oxide. The clay or clay minerals are selected from kaolin, especially kaolin-bearing clays, kaolinitic fired ceramics, kaolinitic, illite-containing clays, stoneware clays, fired stoneware, foundry clays, blue, green and yellow clays, allophanes or hallosites, illites, especially glauconite, illicite, sericite, smectites, especially montmorillonites, nontronite, beidellite, chlorites and vermiculites. The non-clay portion of the raw mixture comprises 10-50%, especially 20-40% of the total raw material. In an earlier (REX) process, high-alumina mineral fibers were made using a reducing-atmosphere cupola furnace followed by centrifugal operations. Compared with the temperatures used in this (REX) process, the melting point temperature range is reduced by 100-500[deg] C, especially 250-400[deg] C. The reduction is preferably about 300[deg] C.

Description

The The present invention relates to the use of clays and / or Clay minerals for melting range lowering of a Si and Al-containing Mineralgemenges, which under oxidizing conditions for the production melted by mineral fibers in a melting tank with air access is melted and the melt by means of a Düsenblasverfahrens is according to claim 1.

In the prior art, mineral fibers are produced essentially by two basic processes:
On the one hand, mineral fibers are produced by melting mineral mixtures under reducing conditions in the cupola furnace with subsequent defibration of the melt in a cascade centrifugation process, which is referred to in the art as the so-called REX process.

The REX method and a device for its implementation is, for example DE 26 38 412 A1 known.

on the other hand it is known from the prior art and by the applicant of the present patent application for the manufacture of mineral fibers usual Mixed raw materials in a melting tank, which under oxidizing Conditions, namely working under atmospheric oxygen, to melt and melt to fiberize according to the so-called SILLAN process. It will the resulting mineral melt over Platinum-iridium nozzles by means of a jet blowing process frayed and the resulting mineral fibers in the chute with Binder provided and stored to a web.

The SILLAN process is first described in DE 35 09 426 A1 ,

Although the SILLAN process has proven its worth in the practice of the user since 1985, it was not suitable for the production of mineral fibers with a high content of aluminum, in particular Al ₂ O ₃ , so-called "high aluminum-containing" mineral fibers.

Such highly aluminum-containing mineral fibers have hitherto been economically produced only with the aid of the REX process in a cupola furnace. Corresponding glass compositions are described, for example, in EP 0767762 B2 . EP 0790962 B1 . EP 0792844 B1 . EP 0792 845 B1 . EP 0877 004 B1 . EP 0 791 087 B1 . EP 0 866 776 B2 . EP 0 883 581 B1 . EP 1 157 974 A1 . WO 00/73230 A1 and WO 01/60754 A1 ,

Furthermore, from the DE 14 96 662 A high melting and high aluminum content glass fibers known which can be prepared from a melt of clay mineral-containing raw materials and which have an iron oxide content of 4 to 12% by mass.

For the purposes of the present patent application, the term "high aluminum-containing mineral fibers" is understood to mean those which contain more than 16% by mass of Al ₂ O ₃ .

As mentioned above, the state-of-the-art high aluminum mineral fibers have hitherto only been able to be produced by the abovementioned REX process, but not by the SILLAN process with an upstream melting tank described at the outset. This essentially has the following reasons:
The REX process uses a so-called cupola furnace to melt the raw batch, which works under strongly reducing conditions, ie essentially under exclusion of air, which in turn means that especially iron is mainly present as FeO. Although such a melted material could in principle be defibered with a platinum or platinum iridium nozzle, the reducing melt would reduce the service life of the Pt / Ir nozzles in an unsustainable manner.

Furthermore, the cupola works with a significantly higher melting temperature at about 1700 ° C than a melting tank, can be achieved with the melting temperatures up to about 1500 ° C. For this reason, a high aluminum-containing composition of a raw batch, which is to be defibered, can not be melted at a sufficient rate due to the significantly lower temperature of a melting furnace. In addition, certain components of the raw batch can not be melted at these temperatures at all, so far the SILLAN process for the production of mineral fibers with a high aluminum content can hardly be used. This is also due to the fact that the temperature of the molten glass for the platinum nozzles of the SILLAN process is too high and a melting of the mixture in the cupola would be energetically uneconomical, since the melt would have to be cooled to the permissible processing temperature in the platinum nozzle, but without this already shows crystallization tendencies.

Therefore It was an object of the present invention, a possibility despite the problems described using the SILLAN process to produce mineral fibers with a high aluminum content.

The solution This object is achieved by the features of claim 1.

In particular, the present invention relates to the use of clays and / or clay minerals (clay materials) to melt range lowering of a Si and Al-containing mineral mixture, which is melted under oxidizing conditions for the production of mineral fibers in a melting furnace with access of air and the melt is fiberized by a jet blow , wherein the clays and / or clay minerals have the quantitative composition shown in Table 1 (based on calcined clay or clay mineral substance): TABLE 1 Quantitative composition of the clay materials used according to the invention (% by mass based on calcined clay or clay mineral substance) connection Dimensions-% SiO ₂ 35-75 Al ₂ O ₃ 17-38 TiO ₂ 0.01-1.5 Fe ₂ O ₃ 0.01-3 CaO 0.01-2 MgO 0.01-2 Na ₂ O 0.05-2 K ₂ O 0.01-3 loss on ignition 4-14

It has been surprising pointed out that with clay materials of the aforementioned quantitative Composition Melting range reductions of up to more than 300 ° C for raw material mixtures, which for the production of mineral fibers with a high aluminum content to be used. This is the first time possible, such high aluminum mineral fibers under oxidizing Conditions using SILLAN method with upstream melting tank at trough temperatures of about 1400 ° C-1500 ° C produce. From economic aspects, in particular the travel time of a tub, that of the tub temperature essentially depends a lower melting temperature is preferred.

In particular, some of the high-melting and high aluminum-containing raw materials, such as bauxite (55 to 65 mass% Al ₂ O ₃ , melting point Al ₂ O ₃ above 2000 ° C), by corresponding aluminosilicates such as the clays described and / or clay minerals replace.

"Side effects" of the used Clay materials, such as foaming the mineral melt let through appropriate countermeasures such as limiting the clay content to about 50 parts at 100 parts other raw mixture, slow addition and briquetting of the clay materials before adding to the melt, adjusting the water content of the clay materials dominate.

For the purpose In the present invention, the term "clay" is a fine-grained sedimentary rock with a major one Proportion of clay minerals and phyllosilicates with a primary grain size of <65 μm in accordance with ISO 14688 to understand.

In geology and soil science applies to clay a particle size <2 microns, in the Sedimentology <4 μm, in the Colloid chemistry <1 micron and after According to ISO 14688, particles smaller than 63 μm are considered to be clay particles.

The main mineral phases that build the tone are the "clay minerals" such as. Kaolinite and illite. It also contains fine-grained mineral debris such as mica (biotite, sericite), quartz, feldspar, as well as new mineral formations such as iron minerals (pyrite) and carbonates, biogenic efforts and amorphous constituents (SiO ₂ ).

Decisive for the use of a glass melt in the sense of the present patent application is the low primary particle size of the material, which causes the good melting behavior. Therefore, at first any sound can be used. The only prerequisite is that the chemical composition in the batch matches the resulting glass, therefore clays with low alkali contents and low iron contents are preferred. Particular preference is given to using kaolins or refractory clays with high Al ₂ O ₃ contents, ie high kaolinite contents, in order to avoid the use of other refractory raw materials, such as, for example, B. to avoid bauxite or reduce their share of the raw material mixture. This can be combined with a ceramic clay with a lower Al ₂ O ₃ content. This makes it possible to dispense with the use of sand, in this case the best meltability of the batch is achieved. Another requirement for the clay for the melting process is the lowest possible sulphide content.

A preferred clay for the purposes of the present invention typically has the following quantitative characteristics: > 33% Al ₂ O ₃ , <6% alkalis, alkaline earths and iron oxide

In Tables 2 and 3 are some of the present invention usable commercially available clays listed with their quantitative compositions.

The clays or clay minerals (clay materials) in question are available, for example, from Lasselsberger, Munich or from Kärlicher Ton- und Schamottewerke, Mühlheim-Kärlich. Table 2 Commercially available clay materials Lasselsberger Information Lasselsberger, data refer to unbleached substance Oxide kaolins Kaolinitic clays Kaolinitic hard stone key kaolinitic-illitic clays, stoneware clays Steingutton Foundry Sound SiO2 50-60 48-68 50-70 53-75 35-51 52-58 Al2O3 28-35 17-34 18-32 16-30 22-37 18-22 TiO2 <1 1.6-4 0.6-2 1-2 0.4-1 1-1,5 Fe2O3 <0.8 0.8-4 1-2 1.5 to 11 1-2 7-10 CaO <0.25 k. A. k. A. k. A. k. A. k. A. MgO <0.4 k. A. k. A. k. A. k. A. k. A. Na2O <0.25 k. A. k. A. k. A. k. A. k. A. K2O <3 k. A. k. A. k. A. k. A. k. A. GV 9-12 6-13 7-17 4-11 10-40 7-10 Table 3 Commercially available clay materials Kärlicher Ton- und Schamottewerke Mühlheim-Kärlich (KTS) Information KTS, data refer to annealed substance Oxide blue tone shade of green yellow color Agrarton KTS 7012 SiO2 53-60 60.70 51.00 54,50 59,00 Al2O3 29-38 20.00 20.00 17.80 32,60 TiO2 3.7-4.3 1.00 1.00 1.10 2.85 Fe2O3 2.9 to 3.9 12,00 24,80 19,70 2.90 CaO 0.6-0.75 1.25 0.90 0.80 0.60 MgO 0.6-0.7 1.72 2.00 2.30 0.60 Na2O 0.06 0.07 0.15 0.30 0.10 K2O 0.75 to 0.9 2.16 3.00 2.80 1.50 GV 12.5-14 12,00 10-12 10-12 10-12

embodiments

The following examples serve to check the melting point-lowering effect of clays on a raw material mixture for the production of mineral fibers with a high aluminum content depending on the added clay content. For this purpose, Table 4 uses a raw material base with slight deviations in the composition of natural raw materials for the production of mineral wool by the REX process, as described in the EP 0 880 480 B1 is disclosed. Table 4 Qualitative composition of the raw material base (based on EP 0 880 480 B1 [In% by mass] bauxite quartz sand slag apatite olivine SiO2 6 99.1 36 3.5 41 Al2O3 85 0.6 9 0.5 0.5 TiO2 4 1 MgO 10 0.8 50 CaO 38 51 R2O 0.5 0.1 1 Fe2O3 2 0.1 0.3 0.8 6.5 P2O5 0.3 31 other 0.1 1 8th 1.1 water 2.2 3.7 4.4 0.9

In contrast to the embodiments of the EP 0 880 480 B1 For example, in order to study the effect of clay addition on lowering the melting point, it is desirable to have an aluminum oxide content in the molten fiber of about 18.5 mass%, a silicon dioxide content greater than 40 mass%, and calcium and manganese oxide contents of about 16 mass%, respectively.

The production of mineral fibers is based on the following basic principle: The raw materials are fed into a batch plant where they are processed in defined compositions for the subsequent melting and defibration process. The pure mineral raw material mixture, which forms the later mineral wool product with a share between 93 and 99 percent, is melted in melting tanks at approx. 1400 ° C. The melt is melted using the SILLAN method according to DE 35 09 426 A1 by platinum nozzles ge conducts and parts there into individual molten primary threads. These are then accelerated by means of high-speed air streams, multiplied and warped to uniform, long fibers. During defibration, a binder dissolved in water, in the example a phenol-formaldehyde binder, is fed to the fiber stream in a chute. The water evaporates while the fibers cool down so quickly that they glassy solidify. The fibers are deposited on a conveyor belt, the thickness and bulk density being determined by its speed and by rolling. The products are then cut to size, optionally coated, laminated and packaged.

For the investigations, the clays listed in Table 5 were used, in Table 6 are given for 3 clays the batch compositions. TABLE 5 Quantitative compositions of the clay materials used in accordance with the invention [in% by mass, based on the calcined substance] sample SiO2 Al2O3 Fe2O3 TiO2 CaO MgO Na2O K2O GV Sound QCA1 35.5 38.67 2.41 1.28 0.43 0.32 0.25 2.89 18.8 Sound QCA2 40,25 39.34 2.18 1.33 0.14 0.29 0.27 1.88 14.6 Sound QW1 44.75 35.72 1.87 1.39 0.11 0.27 0.16 0.78 14.30. Sound QW2 47.24 33.54 2.40 0.90 0.25 0.39 0.23 1.92 12.43 Tone B1 46.44 32.15 2.29 0.80 0.28 0.47 0.21 2.14 14.59 Tone B10 47.65 33.26 2.28 0.80 0.28 0.45 0.20 2.13 12.32 Tone B14 47.26 31.81 2.56 0.82 0.36 0.45 0.15 1.37 14.91 Sound QCA3 51.23 28.97 2.52 0.92 0.21 0.44 0.12 1.25 13.59 Tone FT-P203 tone QCA4 60.9 70.72 24.9 17.48 2.4 1.88 1,2,15 0.3 0.24 0.5 0.27 0.1 0.11 2.6 2.1 7.2 6.08 Table 6 Mixture composition [in (mass) parts] Ex. bauxite quartz sand slag apatite olivine Parts sound key Reference without sound 17 16 36 5 25 - 1 15 14 33 10 28 10 QW 1 2 13 12 33 12 30 20 QW 1 3 10 10 33 14 33 30 QW 1 4 8th 9 30 18 36 40 QW 1 5 5 7 31 20 37 50 QW 1 6 15 14 33 10 28 10 B10 7 13 12 32 13 30 20 B10 8th 11 10 32 15 33 30 B10 9 9 8th 31 18 35 40 B10 10 7 6 30 20 37 50 B10 11 16 13 32 11 28 10 FT-P203 12 15 9 34 12 30 20 FT-P203 13 14 5 35 13 33 30 FT-P203 14 13 2 35 16 35 40 FT-P203 15 12 - 32 19 37 50 FT-P203

The mixture has a melting range of about 1650 ° C to 1700 ° C without the addition of clay (reference without clay) and would industrially melt in a cupola furnace and thus the melt thus only by the REX process, but not according to the SILLAN method according to DE 35 09 426 A1 zerfaserbar.

Already with an addition of 10 parts of clay per 100 parts of raw material base (examples 1, 6, 11) was a significant decrease in the melting range determined to a range of 1450-1500 ° C. With that you can already using this clay-containing mixture in a SILLAN process upstream melting tank can be used.

With Increasing levels of clay resulted in a further significant reduction the melting range, wherein this for the clays QW1 and B10 in one Range from about 1350 to 1400 ° C, for the Tone FT-P203 gave a slightly lower range of 1340-1390 ° C. surprisingly Way has an increasing sound content between 20 and 50 parts only a small influence on the melting range reduction, wherein the change over the Increase from 20 to 50 parts below 10 ° C (Examples 2-5, 7-10, 12-15), ie within the measuring accuracy falls within the specified range. Without being bound by it, this could be training of a eutectoid in the melt. All these compositions are in a melting tank for the SILLAN method can be used.

Out The examples show that a higher clay content than 50 parts on the mixture virtually no effect on the melting range reduction Has.

It It was found that with increasing proportions of sound an increasing Foaming during the Merging. The mixtures tested proved this foaming in the mixtures with 50 parts of clay (examples 5, 10, 15) as still tolerable.

Under consideration the melting range reduction and the procedural problems with Foaming is a clay addition of 20 to 40 parts per 100 Parts of raw material base or other raw materials preferred.

Claims (5)

Use of clays and / or clay minerals for lowering the melting range of an Si and Al-containing mineral mixture, which is melted under oxidizing conditions for the production of mineral fibers in a melting bath with air inlet and the melt is fiberized by means of a Düsenblasverfahrens, the clays and / or clay minerals following quantitative composition (based on annealed clay or clay mineral substance) have: connection Dimensions-% SiO ₂ 35-75 Al ₂ O ₃ 17-38 TiO ₂ 0.01-1.5 Fe ₂ O ₃ 0.01-3 CaO 0.01-2 MgO 0.01-2 Na ₂ O 0.05-2 K ₂ O 0.01-3 loss on ignition 4-14 Use according to claim 1, characterized that as minerals for the mineral mixture uses silicate minerals and aluminas become. Use according to claim 1 or 2, characterized that the clays or clay minerals are selected from the group consisting of: kaolins, in particular kaolinitic clays, kaolinitic hard stone clusters, kaolinitisch-illitischen clays, stoneware clays, stoneware clays, Giessereitonen, Blue, green, Yellow tints, agrarones; Allophanes or halloysites; Illites, in particular Glauconite, illicit, sericite; Smectites, especially montmorillonites, Nontronite, beidellite; Chlorites and vermiculites. Use according to one of Claims 1 to 3, characterized that the clays or clay minerals account for 10 to 50 parts, in particular 20 to 40 parts, based on 100 parts of non-clays of the raw material mixture for make up the fiber production. Use according to one of Claims 1 to 4, characterized that the melt range decrease compared to a raw melt melt for high-alumina mineral fiber production by means of a working under reducing conditions Kupolofens and downstream Cascade spinning method 100-500 ° C, in particular 250 to 400 ° C, preferably about 300 ° C, is.