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WO1992000928A1 - Agregats poreux resistants aux hautes temperatures, leur procede de production et pieces moulees constituees de ces agregats - Google Patents

Agregats poreux resistants aux hautes temperatures, leur procede de production et pieces moulees constituees de ces agregats Download PDF

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Publication number
WO1992000928A1
WO1992000928A1 PCT/AT1991/000086 AT9100086W WO9200928A1 WO 1992000928 A1 WO1992000928 A1 WO 1992000928A1 AT 9100086 W AT9100086 W AT 9100086W WO 9200928 A1 WO9200928 A1 WO 9200928A1
Authority
WO
WIPO (PCT)
Prior art keywords
hours
temperatures
calcium
aluminates
magnesium
Prior art date
Application number
PCT/AT1991/000086
Other languages
German (de)
English (en)
Inventor
Harald Seifert
Ernst Schlegel
Original Assignee
Magindag Steirische Magnesit-Industrie Aktiengesellschaft
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Magindag Steirische Magnesit-Industrie Aktiengesellschaft filed Critical Magindag Steirische Magnesit-Industrie Aktiengesellschaft
Publication of WO1992000928A1 publication Critical patent/WO1992000928A1/fr

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B18/00—Use of agglomerated or waste materials or refuse as fillers for mortars, concrete or artificial stone; Treatment of agglomerated or waste materials or refuse, specially adapted to enhance their filling properties in mortars, concrete or artificial stone
    • C04B18/02—Agglomerated materials, e.g. artificial aggregates
    • C04B18/027—Lightweight materials
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/01—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics
    • C04B35/44—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on aluminates
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B38/00—Porous mortars, concrete, artificial stone or ceramic ware; Preparation thereof
    • C04B38/009—Porous or hollow ceramic granular materials, e.g. microballoons

Definitions

  • the invention relates to a porous aggregate that is resistant to high temperatures, a process for its production and molded parts produced therefrom.
  • the high-temperature-resistant porous additives are the basis for the production of highly effective thermal insulation materials in the form of batches or shaped products which are used in industrial furnace construction and for high-temperature systems.
  • Heat and high temperature resistant materials that are used for thermal insulation in industrial furnace construction and for all high temperature systems are diverse and 5 are manufactured using different technological processes. This applies to batches, lightweight fire concrete and burned lightweight fire bricks.
  • the high proportions of pores required for thermal insulation are achieved by using granular burnout materials, by blowing gas or by using foaming agents or similar measures.
  • the use of natural or technological ⁇ won highly porous Vormateria ⁇ 's lien, such as expanded clays, expanded shale that are processed in a granular form is known. These technological measures lead to macropores.
  • the Gassilicatbeton-Rohgemenges formed in the pore formation by addition of metallic aluminum by the reaction of aluminum with water with evolution of hydrogen pores with a Poren ⁇ size of 10 ⁇ 3 to 10 "4 m with a proportion 80-90% of the total porosity.
  • These large pores are disadvantageous for thermal insulation at high temperatures, because experience has shown that they lead to "radiation breakthrough" and there is no longer any thermal insulation effect, which is independent of the overall porosity.
  • Lightweight concrete that is characterized by the highest possible porosity and by micropores (below 10 ⁇ ⁇ m) can be used advantageously at medium to high temperatures.
  • the aim of the invention is to improve the thermal insulation effect of thermal insulation materials at high temperatures and thus to reduce the energy consumption of industrial furnaces and other high-temperature systems.
  • the invention is based on the technical problem of developing a high-temperature-resistant additive with a variable total porosity on a different material basis, this additive using known binders and using known processes to produce highly effective thermal insulation materials with a largely proportional behavior of heat transport and temperature even at high temperatures to give molded parts , such as Shaped stones should be processable.
  • the technical problem is solved by a porous additive based on calcium aluminates and / or magnesium aluminates and / or one-component or multi-component derived therefrom
  • the porous additive is produced according to the invention in that the corresponding oxidic or hydroxide finely divided raw materials are mixed with 0.1-4.0 parts by mass of water, based on a mass fraction of the dry raw materials, the homogeneous mixture at temperatures from> 125 ° C to an autoclave treatment with a holding time of 1 to 25 hours, preferably 8 to 12 hours, the solidified mass is dried, then at temperatures of> .1000 ° C and holding times of 1 - 25 hours, preferably 3 - 5 hours, sintered and the sintered product is worked up to the additive. 5
  • Aluminum oxide, calcium oxide, calcium hydroxide, magnesium oxide, magnesium hydroxide, calcium magnesium oxide and / or calcium magnesium hydroxide can be used as oxidic or hydroxide raw materials, depending on the desired composition of the porous additive.
  • the process conditions in hydrothermal synthesis depend on the mineral to be formed.
  • advantageous conditions are treatment temperatures of 125-350 ° C., preferably 175-225 ° C., with holding times 1-25
  • Hours preferably 8-12 hours.
  • the substances newly formed in the autoclave under hydrothermal conditions have a widespread network of hydrates with stored water. This water is expelled by the subsequent drying process and a solid framework with a high proportion of pores remains in the form of micropores.
  • the chemically bound water is driven out and the sintering with the parallel compression and solidification is terminated at the suitable temperature and holding time to be determined individually for each material combination.
  • firing temperatures of 1000-2000 ° C., preferably 1350-1650 ° C., with holding times of 1-25 hours, preferably 3-5 hours are for calcium aluminates and for calcium magnesium aluminates, firing temperatures of 1000 to 1700 ° C, preferably from 1200 to 1600 ° C with holding times from 1 to 25 hours, preferably from 2 to 6 hours, particularly suitable.
  • the firing temperatures are determined by the later application temperature.
  • the firing temperature should be at least 50 K above the application temperature.
  • the highly porous materials with a microporous structure are then subjected to various comminution processes and the material is classified into the desired additives.
  • These additives can be mixed with all suitable binders, such as, for example, a hydrothermal type, a hydraulic, a chemical, a ceramic, or an organic as well as various combinations, and different from those that can be processed at the construction site
  • the advantage of the production process according to the invention is that the material variability, including the water-solid ratio, means that the application temperatures and the overall porosity, and therefore also the structural strength, are varied, using the high-temperature-resistant porous additive Impact fabricated thermal insulation materials is given. Due to the large number of solid walls, this microporous structure offers greater resistance to the passage of heat from the steel, so that the thermal insulation capacity is considerably improved at high temperatures.
  • the invention is illustrated by the following examples:
  • the raw materials aluminum hydroxide and calcium oxide or calcium hydroxide are mixed with such high water proportions, which are 150%, based on the dry weight, that very easily pourable but stable suspensions with a very high water content are formed.
  • the ratio of aluminum oxide to calcium oxide the solid is selected and adjusted such that so-called calcium hexaaluminate or at least in the desired proportions is formed after the high-temperature treatment.
  • the highly water-containing suspension is finely ground in a grinder, poured into molds, in an autoclave
  • Sintered temperatures of> 1250 ° C. The sintered shaped body is then divided into predetermined grain classes by conventional comminution processes and classification processes. A certain variation of certain parameters is due to the amount of
  • Example 2 Analogously to Example 1, the water content is reduced so that it is 30%, based on the dry matter, and that a
  • Example 2 Analogously to Example 1, the water content, based on the dry matter, is reduced to 10%, so that a working mass which is suitable for dry pressing molding is formed.
  • This working mass which is only moistened in a conventional compulsory mixer, is processed into moldings by conventional pressing, which can then be cured freestanding in the autoclave and further treated in accordance with Example 1. After the fire at 1350 ° C., an aggregate with medium porosity arises, the quality values of which are set out in column 3 of the table.
  • the raw materials aluminum hydroxide and magnesium oxide or magnesium hydroxide are mixed with a water content, based on the dry content, of 150%, so that very easily pourable but stable suspensions with a very high water content are formed.
  • a water content based on the dry content, of 150%, so that very easily pourable but stable suspensions with a very high water content are formed.
  • the ratio of aluminum oxide to magnesium oxide the solid is selected and adjusted so that so-called spinel or at least in desired proportions is formed after the high-temperature treatment.
  • This product is processed in an autoclave at temperatures of 175 ° C and a holding time of 10 hours.
  • the additive is produced analogously to Example 1.
  • Column 4 of the table shows the quality parameters of the surcharge after pre-firing at 1400 ° C.
  • the porosity to be provided can be varied by differently designed water components and shaping processes for these products.
  • a microporous calcium aluminate aggregate (bulk density of the material about 0.5 g / cm, which corresponds to a total porosity of> 80%; pre-firing in an industrial tunnel kiln at 1500 ° C) is processed with high-tone cement according to the vibrating technology to a lightweight fire concrete.
  • This lightweight fire concrete has the following quality values:
  • Example 6 applies to a microporous calcium aluminate additive (bulk density of the material approximately 1.25 g / cm 3 , which corresponds to a total porosity of>60%; pre-firing in an industrial bell-type furnace at 1600 to 1700 ° C) and a similar type BinderSuspension thermal insulation material produced according to vibrating technology and subsequent hardening in an autoclave (10 hours at 191 ° C), which as a result of its increased strength has constructive properties and can be described as a special refractory concrete with hydrothermal bond.
  • a microporous calcium aluminate additive bulk density of the material approximately 1.25 g / cm 3 , which corresponds to a total porosity of>60%; pre-firing in an industrial bell-type furnace at 1600 to 1700 ° C
  • BinderSuspension thermal insulation material produced according to vibrating technology and subsequent hardening in an autoclave (10 hours at 191 ° C), which as a result of its increased strength has constructive properties
  • the thermal insulation material has the following quality properties:
  • Example 7 applies to a microporous calcium aluminate aggregate (bulk density of the material approx. 1.0 g / cm 3 , which corresponds to a total porosity of>70%; pre-firing in an industrial tunnel kiln at 1500 ° C) and a similar binder suspension the damp presses and subsequent hardening in an autoclave (10 hours at 191 ° C.) produced thermal insulation material which is not prebaked.
  • a microporous calcium aluminate aggregate bulk density of the material approx. 1.0 g / cm 3 , which corresponds to a total porosity of>70%; pre-firing in an industrial tunnel kiln at 1500 ° C
  • a similar binder suspension the damp presses and subsequent hardening in an autoclave (10 hours at 191 ° C.) produced thermal insulation material which is not prebaked.
  • Example 8 applies to one made of a microporous aggregate of the "Spinel" type (bulk density of the material approximately 1.45 g / cm 3 , which corresponds to a total porosity of>50%; pre-firing in the laboratory furnace at 1550 ° C.) and one A similar suspension type after casting-vibrating shaping and subsequent hardening in an autoclave (6 hours at 180 ° C.) produced thermal insulation material which is not prebaked. The following quality properties are determined:
  • the thermal conductivity of the primary material after pre-firing at 1100 ° C is:
  • At least minimum tensile strength at least mm ⁇ .

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Ceramic Engineering (AREA)
  • Materials Engineering (AREA)
  • Structural Engineering (AREA)
  • Organic Chemistry (AREA)
  • Civil Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Compositions Of Oxide Ceramics (AREA)
  • Porous Artificial Stone Or Porous Ceramic Products (AREA)

Abstract

L'invention concerne un aggrégat poreux résistant aux hautes températures, son procédé de production et des produits constituées de cet agrégat utiles pour fabriquer des matériaux calorifuges très efficaces dans la contruction de fours industriels ou d'installations à haute température. L'agrégat décrit est à base d'aluminates de calcium et/ou d'aluminates de magnésium et/ou de dérivés minéraux de ceux-ci à un ou plusieurs composants et il contient de 0,20 à 0,95 parts en volume de micropores, plus de 60 % des micropores ayant un diamètre inférieur à 40 νm. On produit cet agrégat poreux en mélangeant les matières premières oxydiques ou hydroxidiques correspondantes finement pulvérisées avec 0,1 à 4,0 parts en masse d'eau, par rapport à une part en masse de matières premières sèches. On soumet ensuite le mélange homogène à un traitement en autoclave à des températures supérieures à 125 °C, pendant 1 à 25 heures, on sèche la masse durcie, on la fritte à des températures égales ou supérieures à 1000 °C pendant 1 à 25 heures et on transforme le produit fritté en agrégats.
PCT/AT1991/000086 1990-07-13 1991-07-12 Agregats poreux resistants aux hautes temperatures, leur procede de production et pieces moulees constituees de ces agregats WO1992000928A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DDAPC04B/342763/7 1990-07-13
DD34276390A DD296477A5 (de) 1990-07-13 1990-07-13 Hochtemperaturbestaendige poroese zuschlagstoffkoernung und verfahren zu ihrer herstellung

Publications (1)

Publication Number Publication Date
WO1992000928A1 true WO1992000928A1 (fr) 1992-01-23

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DD (1) DD296477A5 (fr)
WO (1) WO1992000928A1 (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2001090030A1 (fr) * 2000-05-26 2001-11-29 Alcoa Chemie Gmbh Matiere premiere isolante pour applications haute temperature
US7987613B2 (en) * 2004-10-12 2011-08-02 Great River Energy Control system for particulate material drying apparatus and process
US10040693B2 (en) * 2016-01-29 2018-08-07 Coorstek Kk Particles for monolithic refractory

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102009055723B4 (de) * 2009-11-26 2012-10-31 Calsitherm Verwaltungs Gmbh Verfahren zur Herstellung eines alkaliresistenten Erdalkali-Aluminium-Wärmedämmstoffs, dieser selbst und seine Verwendung.

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3232772A (en) * 1962-05-04 1966-02-01 Morgan Refractories Ltd Refractory products and the production thereof
FR2075328A5 (en) * 1970-01-12 1971-10-08 Steirische Magnesit Ind Ag Light fire-brick production

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3232772A (en) * 1962-05-04 1966-02-01 Morgan Refractories Ltd Refractory products and the production thereof
FR2075328A5 (en) * 1970-01-12 1971-10-08 Steirische Magnesit Ind Ag Light fire-brick production

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
SILIKATTECHNIK. Bd. 38, Nr. 4, 1987, BERLIN DD Seiten 129 - 131; H. SIEFERT: 'Mikroporoese Feuerbeton-Leichtzuschlagstoffe ' siehe Zusammenfassung siehe Seite 130, linke Spalte, Zeile 59 - Zeile 62; Tabelle siehe Seite 130, rechte Spalte, Zeile 57 - Zeile SA 49771 03064 *

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2001090030A1 (fr) * 2000-05-26 2001-11-29 Alcoa Chemie Gmbh Matiere premiere isolante pour applications haute temperature
US7987613B2 (en) * 2004-10-12 2011-08-02 Great River Energy Control system for particulate material drying apparatus and process
US10040693B2 (en) * 2016-01-29 2018-08-07 Coorstek Kk Particles for monolithic refractory

Also Published As

Publication number Publication date
DD296477A5 (de) 1991-12-05

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