DE1915787C - Heat-shock resistant, refractory molded body based on aluminum titanate and process for its production - Google Patents

Description

i 915 787

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The invention relates to a refractory, tempera do not disturb; you can dense the esterification at

Shaped bodies which are resistant to changes in temperature and which are based on bodies even favor.

Aluminum titanate and a method of manufacturing In order to improve the high temperature strength,

of the same, in which from a starting mass it is advisable to use coarse-grained (0.2 to 3 mm) additives,

shaped body and then dried the shaped body 5 such as mullite chamotte, sillimanite, corundum and zirconium

and be burned. add silicate, which, however, reduces the heat

The invention is for ate production of dense expansion increases and thus the temperature

to hoci.porous moldings according to any change resistance according to the added

ceramic manufacturing process, ~ also ~ scH quantity gradually decreased somewhat,

probably of chemical-technical stoneware as well as to The invention principle can also be used to manufacture

of refractory bricks and tiles. of, refractory, temperature-change-resistant,

It is known that aluminum titanate has a low-porous shaped body based on aluminum genes. Use this litanat, the process then being carried out in such a way that the mixture of aluminum has a very high thermal expansion in the crystals »- 15 nium oxide, titanium dioxide and zirconium silicate burn-out graphical a- and Α-direction of the rhombic substances, such as wood / or coal dust, added crystal lattice and in a negative thermal expansion, in the r-kichtuiig. You can also use a slip made from a mixture

The * e high thermal expansion anisotropy brings it in from aluminum oxide, titanium dioxide and zirconium silicate

with himself. that the thermal expansion of the body in the known way foam and the foamed

Average is very low. This low heat slip to form moldings that after

However, due to the high internal stresses, elongation must be accompanied by drying in a manner known per se

are bought, which the strength of such moldings are fired 1400 to'1550'C,

affect so much that pure aluminum is preferably used, the grain size is in the order of magnitude

not yet able to produce titanium bodies. »5 tion of <60 μ, and with a particularly advantageous one

It is already known that an embodiment of the process according to the invention can be added to aluminum titanate

to be added, which, however, is only a gradual success, with the exception of the fine grain <10μ down,

provided and, in addition, the fire resistance of the burning can be intermittent or continuous

recovered material deteriorated significantly. respectively.

Ahiminium titanate masses containing silicon dioxide 30 The values given for the firing temperature

oerciis are also known (Swiss Patcut- show that at a relatively low temperature

font 309 125, USA.-fjatcnl-ch'Tt 2 776 896 and feucifistant bodies with low thermal expansion

Deutsche Auslcgesehriit I £ 38 376), the silicon aluminum titanate base according to the method according to

dioxidantcil are especially producible by the addition of clay or invention.

Kaolin gets into the mass. 35 Up to now the aluminum titanate had to be prepared first, although such additions of clay and silicic fire at temperatures above 165O ° C Masses have already achieved certain successes, manufactured and then after comminution and incidental goods they cannot be used for masses with a high amount of a binding agent in a second fire Aluminum minium content. In addition, the fire to be processed into molded body suffered while at strength of the finished molding. 40 surprisingly a method according to the invention

The object of the invention is therefore to provide a single fire at about 1400 to 1550 ° C, which

for the production of refractory, temoeraturwechselcl- fire that can be carried out in a furnace,

Resistant arm bodies based on aluminum, such as those used in the manufacture of common refractory products

nium titanate, which serves a low level.

Thermal expansion coefficient and such a high 45 subdivisions on the according to the invention Ability to possess. that you can show them up to temperatures ßen process produced bodies that this

of 165O ° C as refractory, temperature change resistant to about 500 ⁰ C have a thermal expansion that

digc moldings can use. lies between 0 and that of the quartz glass.

The object on which the invention is based is

solved in that a stoichiometric mixture of 30 elongation something, so that at about 100 ° C a

one mole of aluminum oxide and one mole of titanium dioxide coefficient of thermal expansion of 1.5 to 2.5-10 "

with 5 to 30 percent by weight, preferably with 10 to results.

20 percent by weight, zirconium silicate as finely as possible The results clearly show that even with very

Grain mixed and pressed to the moldings, low firing temperature em very large proportion of

is, which has arisen after the usual drying in per se 55 aluminum titanate, but that by the

as is known, fired at 1400 to 1550 ° C. Type of manufacture and, in particular, by the

will. Essence of the zirconium silicate the unfavorable effect

Of course, instead of the thermal expansion _{anisotropy, a substantially mild mixture of Al 1} O and TiO ₁ can be partially or completely changed beforehand, so that flexural strength values from 100 to aluminum titanate can be used, but a loss of η a 60 300 kp / cm ¹ can be achieved .

the advantage of cheap raw materials and the special composition of the invention

the overall simpler manufacturing method. It also evidently brings about a corresponding shaped body.

It is also not possible for the person to accept that the flexural strength is too high when the temperature increases

if either ΑΙ, Ο, or TiO ₁ in a somewhat larger size - not only does not decrease, but to at least 1500 ⁰ C

There is a lower amount than the stoichiometric 65 even increases. . .

ratio of aluminum tiianat is equivalent. —1 --_ 5.L ¹ APJLf-

Even small impurities and additives up to 2 ° / »A mixture of 15 ° /" zirconium silicate, 48 ° / _e * -Ton-

of oxides, such as alkaline earth ,. Alkali oxide, iron oxide etc., earth and 37 ° / ,, rutile (TiO ₁ ) with a grain size <60μ

i

is intimately mixed and mixed with a diluted organic plasticizer in such an amount that an iron pressure is possible. The pressure is about 400 kp / cm ¹ .

Plate-shaped bodies were produced which dried after pressing and fired in a tunnel kiln at SK 16. The preserved bodies had the following properties:

Open porosity 20 ^a / _o

Flexural strength at 20 ^° C. 105 kg / cm ¹

Flexural strength at 1400 ⁰ C 120 kp / un ^a

Thermal expansion coefficient (20 to

500 ⁰ C) 0.5-10-

Thermal expansion coefficient (20 to

1000 ⁰ C) _v . 2.4-10-

The resistance to temperature changes is excellent. Repeated deterrents sowol.l services in air and in water at 900 ⁰ C to the respective temperature neither visible nor detectable by dynamic "o measurements destruction.

The example given can also be used for the production of moldings with increased porosity, for example, on the production of refractory insulating bricks. as

You can either burn out components, for example heights or coal dust, which are to be pressed Add the mixture or produce a slip from the starting materials, the Foaming agent can be added and the foaming after Ai «ffoaming poured into molds by stirring or blowing air. The cast moldings are hardened, dried, and then fired under the same conditions as above for the pressed Shaped bodies are given.

Claims (4)

Patent claims: 1. Resistant to temperature changes, more refractory Moldings based on aluminum titanate, characterized in that it consists of 70 to 95 percent by weight of an at least approximately stoichiomelic mixture of one mole of aluminum oxide and one mole of T Cinoud, corresponding to a weight ratio of 56 to 44 · / »with 5 to 30 weight percent, preferably 10 to 20 weight percent, zirconium silicate as finer as possible Grit is pressed and fired. 2. A method for .Herstellung of refractory, temperature change-resistant moldings based on aluminum titanate according to claim 1, in which the moldings are formed, dried and fired from an initial wet, characterized in that a stoichiometric Gemi: <h of one mole of aluminum oxide and one Moles of titanium dioxide are mixed with 5 to 30 percent by weight, preferably 10 to 20 percent by weight of zirconium silicate in the finest possible grain size and pressed to form the shaped bodies which, after conventional drying, are fired at 1400 to 1550 ° C. in a manner known per se. 3. The method according to claim 2 for the production of refractory, temperature change-resistant, porous Shaped body based on aluminum titenate, characterized in that in the mixture substances that can be burned out from aluminum oxide, titanium dioxide and zirconium silicate, such as wood or Coal dust. 4. The method according to claim 2 for the production of feuerfcsen, temperature change resistant, porous Shaped bodies based on aluminum titanate, characterized in that in one Slurry made from the mixture of aluminum oxide, titanium dioxide and zirconium silicate is a foaming agent added or air blown in and the foamed slip is formed into moldings, which, after conventional drying, are fired at 1400 to 1550 ° C. in a manner known per se will.