WO2011104007A2

WO2011104007A2 - Plastic refractory high-temperature resistant material and refractory high-temperature resistant mortar

Info

Publication number: WO2011104007A2
Application number: PCT/EP2011/000871
Authority: WO
Inventors: Rainer Angenendt; Peer Genth
Original assignee: Vatramaxx Gmbh
Priority date: 2010-02-24
Filing date: 2011-02-23
Publication date: 2011-09-01
Also published as: WO2011104007A3; DE102010009142B4; DE102010009142A1

Abstract

The plastic refractory high-temperature resistant material or the refractory high-temperature resistant mortar have a classification temperature of 900 to 1600°C, harden when dried and contain at least two light-weight fillers, a binder, fibers and/or wollastonite as well as water. The light-weight fillers are fly ash cenospheres or blown closed-cell volcanic ash provided with a superficial water-protection layer. An inorganic-organic hybrid binder is used as the binder, said binder containing silicic acid (5) and an acrylate-based polymer (6). The material or the mortar contains white clay or kaolinite and silicon dioxide in the form of silica gel or silica.

Description

Plastic refractory high temperature resistant compound and refractory

high temperature resistant mortar

The invention relates to a plastic refractory high temperature resistant mass and a refractory high temperature resistant mortar, which harden on drying and a light filler, a binder, fibers and / or wollastonite and water, for applications up to 1600 ° C.

The term lightweight fillers are here to be understood as meaning low-density, high-melting mineral granules, for example fly ash, volcanic erosion bulges, inflated perlite, etc.

State of the art

Mortar blends are known for the production and repair of refractory moldings containing fibers and lightweight fillers. Known mortars and plastic masses for temperatures up to 1600 ° C and higher have significantly higher densities than 700 kg / m ³ and shrink when dried, which can cause fine cracks.

Object of the invention and its solution The invention has for its object to develop a plastic refractory material and a refractory mortar of the type mentioned for cost-effective full-surface backfilling of areas to be insulated, which only a very small shrinkage in a drying up to the classification temperature of to about 1600 ° C, a gross density of only 400 to 700 kg / m ³ and a

Classification temperature of about 900 - 1600 ° C have. The shrinkage when drying up to the maximum temperature of 1600 ° C should be less than 0.5%.

The classification temperature for unformed heat-insulating refractory

Products is the one specified by the standard EN 1402-6

Total length change

for firebets: a shrinkage of less than 1.5%; and for refractory shotcrete: a shrinkage of less than 1, 5% corresponds.

CONFIRMATION COPY This object is achieved according to the invention in the plastic refractory material and the refractory mortar of the type mentioned by the features of claim 1. In the present application "finely divided" is not in the sense of a certain small grain size, but in the sense of "powdery" or "granular" in

Thus, it does not depend on a specific particle size or particle size distribution The uncontaminated composition according to the invention or the corresponding mortar shows practically no shrinkage up to a temperature of about 1500 ° C., as tests have shown.

The water protection layer increases the resistance of the fly ash and volcanic ash particles in aqueous media and thus the shelf life of the mass or the mortar. Further advantages of the plastic refractory material according to the invention and the refractory mortar will be apparent from the comments below.

In the following, the meaning and function of the individual components of the plastic mass will be explained. The content of fibers and / or wollastonite serves to cohesion of the mass in the wet state. The hybrid binder provides for the cohesion after drying at temperatures up to about 200 ° C due to the organic component and at higher temperatures by the sintering of the silica particles. The kaolin used and the silica sol are also a binder, which develops its function at elevated temperature. The lightweight fillers provide the necessary volume and a relatively low density compared to the prior art. The volcanic ash softens at temperatures above about 1000 ° C and higher and then serves as a flux and binder between the high-temperature resistant fly ash.

It is also advantageous if high-melting additives such as silicon carbide, carbon, corundum, etc., are included in order to reduce the viscosity, printer softening point,

Temperature resistance, shrinkage behavior and other properties to set targeted.

Further advantageous embodiments of the invention are in the other

Subclaims cited. Furthermore, the invention relates to the use of the aforementioned composition for various advantageous applications. The microcellular expanded volcanic stones are surface treated to protect against water attack in the plastic masses and mortars, thereby rendering the masses shelf stable. On the one hand inflated cellular volcanic rock in the form of nonporous hollow granules is used as light filler. In the case of porous hollow granules, on the other hand, the bulk density would increase, more glue and more minerals would be required, the masses would become duller and thus would be worse to process and the porosity of the end product would increase significantly. According to the invention, the mass after hardening is extremely stable, shows virtually no shrinkage from the original plastic mass or mortar even when reaching the respective classification temperature, no external or internal cracks and no crumbling and can be produced for continuous temperatures of up to 1600 ° C.

fly ash

The main constituent of the composition according to the invention is fly ash, which in particular has a content of from 20 to 45% by weight.

Fly ash is the solid, disperse (particulate, particulate, dusty) residue of burns, which is due to its high dispersity (fineness) discharged with the flue gases. Fly ash is produced in large quantities in

Thermal power plants and waste incineration plants and must there by filter from the

Flue gases are separated. The particle size ranges from about 1 μηι to 1 mm. Particle shapes include both smooth, massive spheres and hollow spheres (so-called cenospheres), platelets, fibers and agglomerates. The density is 2.2 to 2.4 kg / dm ³ , the bulk density is between 0.9 to 1.1 kg / dm ³ .

The composition of the fly ash depends strongly on the fuel (lignite or hard coal) and extends from residual carbon and minerals (quartz) up to to toxic substances such as heavy metals (arsenic to zinc) and dioxins. The fly ash also acts as a carrier of adsorbed pollutants. While pure, uniform, consistent fuels such as hard coal provide a good usable fly ash, the brown coal fly ash (BFA) is composed of many different substances.

Due to their chemical and physical properties, such as the pozzolanic reactivity, the spherical grain shape and the grain distribution, hard coal fly ash (SFA) in particular is a high - quality secondary raw material and is found in the

Construction a variety of uses.

Pollutant-free fly ash is used in the building materials industry according to DIN EN 450 as an additive in cement and concrete. Furthermore, the fly ash can be used for the production of bricks made of sand-lime brick or aerated concrete. In road and earthworks the fly ash is used together with aggregate as a building material for unbound base courses.

(Source: Wikipedia)

Only the fraction of the cenospheres is used in the compositions according to the invention, since the density in the range of 0.5-0.9 g / ml and the bulk density of 0.3-0.6 g / ml are considerably lower.

Kaolin / silica / silica sol

Kaolin, also referred to as china clay or aluminum silicate, is a fine, iron-free, white rock containing kaolinite, a weathering product of feldspar, as the major constituent. The kaolin used as a film covers the high-melting light filler and forms a solid structure even at about 900 ° C. The strength of the structure and the shrinkage is influenced by the ratio kaolin / silica / silica sol and their distribution. Another advantage of the used mixture of kaolin / silica / silica sol is that the mass after hardening is hard and mechanically stable. The high mechanical stability without shrinkage at temperatures up to about 1600 ° C according to the invention by the interaction of the essential components

• high melting light filler cenospheres,

• (T up to 1650 ° C)

• microcellular puffed volcanic rock

• kaolin, silica, silica sol

• Mineral aggregates such as corundum, quartz, mullite,

Calcium magnesium silicates, chrome ore, zirconium silicate, etc.

Ceramic or other refractory fibers and / or wollastonite

reached.

It is also proposed that a binder mixture of several

Binders is used with a binding effect in different temperature ranges.

The innovation of the product according to the invention is, in particular, that suitable, complementary binder systems are used, for. B. the

Hybrid binder, which crosslinks the support structures made of fibers already during drying under room temperature with the light filler (expanded volcanic ash) sufficient to fix the structure above 900 ° C. By mineral binders, z. As kaolin, which are already included, as well as the silica contained in the hybrid binder, this structure is sufficiently strong reinforced from about 900 ° C, that at the respective desired application temperatures also no shrinkage.

Above 1050 ° C serve the softening microcellular distended

Volcanic rocks as a flux for the additional minerals and as a fixation for the cenospheres. Due to the cavities formed by the melting, stresses can be buffered by increasing the temperature and expanding within the mass.

If temperatures continue to rise, additional chemical changes take place, depending on the aggregate. The fixation of the cenospheres remains untouched up to their softening point and thus guarantees the dimensional stability.

Particularly innovative is that the different binders and the high-melting mineral granules in terms of temperature increase consolidate the resulting solidification of these materials so that a dimensionally stable and constant weight product with different adjustable structures, densities and strengths up to the maximum application temperature. A key customer benefit when using the products according to the invention is that, in addition to the desired goal of efficient high-temperature insulation, a significant cost savings in the area of opportunity costs can be realized for the customers. The reduction of these costs is achieved primarily by improving the energy balance and also the life cycle assessment by reducing emissions for the customer.

Further important advantages of the products according to the invention:

• Non-flammable

• Low weight

· High temperature resistance

• Low thermal conductivity

• Good strength properties

• Easy installation and processing

• Many combination options

· Low flue gas development

• low odor development

• Low alkalinity

• Non-hygroscopic

• Chemical resistant

· Good electrical insulation

• Recyclable

• Landfillable

Perlite (English: perlite) refers to an altered (chemically and physically converted) volcanic glass (obsidian) in the geosciences and is one of the

Rocks. The so-called pearlitic structure is formed here by approximately pea-sized glass beads. Perlite contains up to 2% water and has a density of about 900 to 1000 kg / m ³ (bulk density of crude perlite). By annealing to about 800 ° C to 1000 ° C, perlite inflates to the fifteen to twenty times its original volume and then has a bulk density of 50 to 100 kg / m ³ and a thermal conductivity of λ = 0.040 to 0.070 W / mK. According to the invention, these perlites can not be used because of the porosity.

In contrast, microcellularly-expanded volcanic rocks are suitable for the purposes of the invention, produced according to new environmentally friendly and energy-saving methods, and achieve properties and technical values that expand from older, porous ones

Volcanic rocks ("expanded perlites") differs. Microcellular expanded volcanic rock is a filler of the group of aluminum silicates and is composed of spherical ("honeycomb"), rod-shaped and flaked particles, resulting in high packing densities and higher bond strengths than conventional hollow microspheres due to mechanical and cohesive bonding forces. Targeted surface coatings enable an advantageous bond with the inorganic or organic matrix. This results in less shrinkage and better technical properties. Commercially available is blown impregnated perlite z. B. under the trade name NOBLITE® (product of the company NOBLITE, Route de Claye, F-77181 LE PIN, France) and Technoperl® (product of Europerl Germany, D-94032 Passau, Nibelungenplatz 4).

Fibers used according to the invention

In particular, ceramic and / or mineral high-melting fibers and / or organic high-melting fibers, for example carbon fibers, are used. Wollastonite is also possible. Ceramic fibers or ceramic fibers are fibers

inorganic, non-metallic material. Originally, only polycrystalline inorganic materials were called ceramic. Meanwhile, however, there are various polymers, so-called precursors, produced by pyrolysis amorphous fibers, which are referred to by their properties as ceramic fibers. The distinction to amorphous glass fibers, which are not counted among the ceramic fibers, is best made possible by the manufacturing process (glass fibers from glass melt, amorphous ceramic fibers from polymeric precursors by pyrolysis). The ceramic fibers are classified into oxidic and non-oxidic. On oxide ceramic fibers are fibers based on alumina and silica in different proportions and some with additional Boron oxide or zirconium oxide known. Mixed oxide fibers of 85% A1 ₂ 0 ₃ and 15% Si0 ₂ are also referred to as mullite fibers. All of these fibers are polycrystalline.

Non-oxide, industrially produced fibers (other than carbon fibers) have various types of silicon carbide fibers known. Starting polymers are almost exclusively so-called poly-carbosilanes. These are polymers of hydrocarbons in which individual carbon atoms have been replaced by silicon atoms or silanes in which individual silicon atoms have been replaced by carbon atoms. By additions, the polymers are crosslinked in a curing process, so they do not simply evaporate after the spinning process in the pyrolysis, but - as in the

Production of carbon fibers - to be converted into an amorphous, usually non-stoichiometric, still free carbon-containing SiC ceramic fiber. In special manufacturing processes, it is also possible to produce very finely crystalline and pure SiC fibers with significantly improved high-temperature properties.

Use according to the invention

The mortar mixture according to the invention is preferably used for fire protection and / or for thermal insulation, in particular as high-temperature insulation material, as

Mastic for sealing cavities or for filling of wall surfaces and / or for the isolation of hard to reach or unbalanced places and / or for thermal insulation and fire insulation at openings in fire walls such as pipe and cable ducts at elevated

Temperature stress.

Advantageously, the mortar composition according to the invention is also used for the production of refractory doors for the firebox of boilers, for the production of furnace doors and thermal insulation panels, for lining trolleys in ceramic kilns, and in many other applications.

The fields of application are industrial furnace construction, foundry technology, industrial power plant and plant construction, structural engineering and technical heat insulation.

From the different application and processing possibilities of the

Mortar mixture according to the invention results in an enormous number of Areas of application, which are summed up here, without claim to completeness, in a nutshell:

• cable / pipe bulkheads,

• joint seals,

· Closing holes and cracks in walls and ceilings,

• fire protection seals,

• fire dampers,

• fire doors,

• feeders for foundry technology,

· Insulation / repair of fireplaces,

• insulation of industrial furnaces and combustion plants,

• Wall and ceiling coatings

• transport crucible,

• spray plaster on reinforced concrete structures,

· Sprayed coatings

• Fire protection for tunnel construction

Hybrid binder used according to the invention

Preferably, an organic-inorganic hybrid binder is used, which is available under the trade name COL.9 BASF. It contains 50 to 100 nm composite particles containing amorphous silica particles 5 and a polymer 6 based on n-butyl acrylate and methyl methacrylate (see Figure 1). The particles are dispersed in water. Due to the stickiness of the particles due to the polymer content is obtained an excellent binder for low temperatures, up to about 200 ° C. At elevated temperatures, the polymer fraction decomposes and the silica particles remain and thus preserve the structure, wherein the silica particles also forms a solid framework at a correspondingly high temperature. Shrinkage therefore does not occur at low or elevated

Temperature up. The binder has a solids content of about 35 to 40% by weight. The silicate content, based on the solids content, is 30 to 50 wt .-%. Silica used according to the invention

Preferably, a surface-treated silica is used. Silica is an intimate mixture of finely divided silica and kaolinite. For example, the Neuburg Siliceous Earth is known, which is preferably used according to the invention. For better wettability with water, the silica is treated with a silane so that the individual particles have a functional hydrophilic surface. Such an activated silica is available under the trade name "AKTISIL EM" from Hoffmann Mineral GmbH, Neuburg (Danube) Here, the silica is treated with 3-epoxypropyloxipropyltrimethoxysilane.This so-called activated silica can be used in powder form the use of a mixture of silica sol and kaolin / kaolinite.

Production examples and example formulations

1. Preparation

First, mix all the liquid components of the recipe; then the components are weighed separately according to the recipe.

2nd stage 1

Mixer to be used: e.g. beba compulsory mixer

All liquid raw materials should be mixed with the water (avoid foaming); then the fibers are picked by hand and wetted with the water mixture until they are completely moistened. 3rd stage 2

Addition of the first half of the cenospheres. Now mix with the lid closed.

Mixing time: approx. 10 minutes 4th stage 3

Now, the addition of mineral aggregates such as kaolin, corundum, silica, etc. takes place. Mixing time: 20 minutes

The premix now has a creamy consistency and may no longer contain lumps. If there are any lumps left, rasp them by hand, mix again with the same setting until there are no more lumps.

5th stage 4

Now the second half of the cenosphere has to be kneaded under the mass. Mixing time: 15 minutes

6th stage 5

Addition of microcellular expanded volcanic rock. Then mix with the lid closed.

Mixing time: 25 minutes

The mass must have a loose, easy-to-fill consistency, otherwise mix again with the same setting for 10 - 15 minutes.

The now completed mixture can be filled into buckets and sacks.

example recipe

25 kg batch:

Water 8.50 kg

Ceramic fiber "Altra" B80 from the company Rath 0.75 kg

Binder "COL.9" from BASF. 0.60 kg

Silica sol "Levasil 200A / 30"

from Akzo Nobel Chemicals 1, 20 kg

"Cenosphere W300" from Fa. Omega Minerals 8,75 kg

Microcellular inflated volcanic rock

"Noblite 200 EC" from Fa. Noblite 2,60 1 kg

Silica "Aktisil EM" from Fa. Hoffmann Mineral 2.00 1 kg

Corundum "Sepasil EK-R 220 MST" from Fa. Quarzwerke 0,60 kg

Claims

claims

Plastic refractory high-temperature resistant compound or refractory high-temperature resistant mortar, which have a classification temperature of 900 to 1600 ° C, harden on drying and at least two

Lightweight fillers, a binder, fibers and / or wollastonite and water, wherein as light fillers cenospheres of fly ash and expanded closed cell volcanic ash are present, which are equipped with a superficial water protection layer, wherein the binder is an inorganic-organic hybrid binder, the silica (5) and an acrylate-based polymer (6), and wherein the mass or mortar contains kaolin or kaolinite and silica in the form of silica sol or silica.

Plastic refractory high temperature resistant composition or refractory high temperature resistant mortar according to claim 1,

characterized,

the polymer is an n-butyl acrylate or a methyl methacrylate.

characterized,

that a modified silica is used which contains silica-kaolinite particles whose surface is coated with a wetting agent, in particular a silane.

characterized,

that a uniform type of fibers or a mixture of different fibers, in particular ceramic fibers, having a softening point of at least 1200 ° C are used.

Plastic refractory high temperature resistant composition or refractory high temperature resistant mortar according to claim 3,

marked by the following composition

Cenospheres 20 to 45% by weight -%

microcellular expanded volcanic rock 5 to 20% by weight

Hybrid binder 1 to 6% by weight

Fibers Obis 6% by weight -%

Wollastonite Obis 15% by weight -%

modified silica 3 to 15% by weight,

wherein fibers and / or wollastonite are present.

characterized,

that high-melting additives such as silicon carbide, carbon, corundum are included.

Use of the plastic refractory mass or of the refractory mortar according to claim 1 as high-temperature insulation, for fire protection and / or for thermal insulation.

Use according to claim 7,

characterized,

that the mass or mortar as filling material for sealing cavities or for filling wall surfaces and / or for the isolation of hard to reach or unbalanced sites and / or thermal insulation and fire insulation at openings in fire walls such as pipe and cable ducts at elevated temperature stress up to 1600 ° C is used.