DE3414153A1 - Process for the production of refractory bricks or other shaped articles - Google Patents

Abstract

The invention relates to a process for the production of substantially weathering-resistant, synthetic-resin-bound, refractory bricks or other shaped articles from a free-flowing, usually water-containing mixture of high-temperature-resistant, inorganic base materials by adding from 0.1 to 20% by weight, based on the mixture of the inorganic base materials, of synthetic resins at room temperature. The synthetic resins employed are a liquid phenolic resin of the resol type, a pulverulent phenolic resin of the novolak type, a liquid furan resin or mixtures of these resins, optionally in the presence of a catalytically or chemically active curing agent.

Description

The invention relates to a method for the production of largely weather-resistant, synthetic resin-bonded, refractory bricks or other shaped bodies.

The following methods are known for the production of refractory bricks or other shaped bodies (see Härders, Kienow: Feuerfestkunde, Springer-Verlag, 1960):

15 ·

Use of a ceramic bond in which the refractory hard materials are bonded with refractory clay and then fired.
20th

Use of a chemical bond in which the refractory hard materials, optionally in the presence of refractories

Tone, with e.g .:

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1 a) Phosphorus compounds, e.g. based on aluminum phosphate,

b) alkali silicates (water glasses), - ^ c) tar and pitch

be bound. According to DE-OS 28 22 653 is already a heat-hardening organic binder known for refractory masses and moldings based on phenolic resole resins and tall oil.

3.

Use of a hydraulic bond in which the refractory hard materials, optionally in the presence of refractory clay, to be bonded with refractory cements.

4th

Use of a unique bond, e.g. for fused stones.

It is known to use organic auxiliaries in the binding of refractory bricks or other shaped bodies, e.g. pressing aids, deformation aids (e.g. Polyvinyl acetates, dextrins, polyvinyl alcohols, cellulose compounds), to use.

The processes mentioned have the following disadvantages:

1 .

In the production of refractory bricks or other shaped bodies with a ceramic bond, a lot of energy is required Primary firing required.

2.

Phosphorus-containing binders are expensive and require annealing temperatures from 280 to 400 ⁰ C.

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y \ With the chemical bonds mentioned above (under 2a to 2c) - depending on the type of composition - additional tempering at 300 to 800 C can or must be carried out during the manufacture of the stones or shaped bodies

c take place or a fire may be necessary.

3.

The mixtures produced by known processes for the manufacture of refractory bricks or other shapes -, _ When using the chemical binders mentioned above, bodies must be processed within a short period of time will. They have a short so-called pot life

4th

- [- Binding systems with e.g. hydraulic binding only be heated slowly at the place of use due to the higher water content or have to be heated in a special process be pre-dried.

P_ The invention is based on the object in a method the type referred to in the preamble of claim 1 to avoid the disadvantages listed. This object is achieved by the characterizing features of claim 1. Advantageous configurations of the invention are set out in claims 2 to 10. Claims 11 and 12 are the preferred applications of the products according to the invention. Claim 13 comprises the new products according to the invention. In the process according to the invention, mixtures of high-temperature-resistant, inorganic raw materials such as bauxites, andalusites, zirconium silicates, zirconium dioxide, Magnesites, dolomites, graphites, kaolins, sillimanites, mullites, corundums, quartzites, spinels,

35 silicon carbides, silicon nitrides,

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Fireclay, clays and / or raw cyanites with phenolic resins of the resol or novolak type and / or furan resins, if appropriate in the presence of catalytically or chemically active hardeners.

The proportion of synthetic resins is 0.1 to 20% by weight, preferably 0.5 to 5% by weight, based on the weight of the inorganic raw materials. Regarding the resins, a Resole type phenolic resin may be mixed with a novolak type phenolic resin or with a furan resin. That Resole-type phenolic resin is optionally used together with a hardener, the other resins and resin mixtures a hardener is definitely added.

Phenol-resole resins are liquid, water-containing condensation products which are formed from phenol and formaldehyde in the range of a molar ratio of phenol to formaldehyde of 1: 1.2 to 1: 3.0 in the presence of alkaline catalysts and which are both warm or hot curing as well as exothermic curing under the catalytic influence of acids are accessible. Preferably a liquid phenolic resole resin is used in combination with acidic curing agents, the viscosity (Höppler) at 2O ⁰ C in the range from 100 to 2000 cp and the solid resin content in the range of 63 to 78 wt .-? O lies and which has the property of hardening in an exothermic reaction when acids are added.

Typical hardeners, both catalytically and chemically active, are organic sulfonic acids such as p-toluenesulfonic acid.

As novolak resins, those become solid at room temperature Condensation products from phenol and formaldehyde "~

stood in the range of a molar ratio of phenol to formaldehyde of 1: less than 1, preferably 1: 0.6 up to 1: 0.9, are formed in the presence of acidic catalysts. Dxese novolak resins are only available in the presence of one Hardener, e.g. hexamethylenetetramine, is accessible to irreversible hardening or bonding. The necessary addition of hexamethylenetetramine is 4-20 wt .-? i, calculated; net on the novolak resin. The novolak resins are at the manufacture of the products according to the invention, if appropriate in solution, e.g. dissolved in alcohols or ketones.

Liquid, furfuryl alcohol-containing resins are used as furan resins Condensation products understood that result from furfuryl alcohol and furfurol in the range of a molar ratio form from 1: 0.8 to 1: 1.5 under the catalytic influence of acids. These furan resins are under the catalytic influence of acids such as p-toluenesulfonic acid in curable in a strongly exothermic reaction. A liquid furan resin is preferably used in Combination with acidic hardeners used, the viscosity (according to Hoeppler) at 20 ° C in the range of 100 up to 1000 cp and the solid resin content of which is in the range from 50 to 65% by weight.

The mixtures according to the invention optionally contain additional organic auxiliaries, such as pressing auxiliaries, Deformation aid.

The mixtures of the above-mentioned refractory raw materials with additives of the above-mentioned synthetic resins and Other ingredients become stones by compression at room temperature and pressures of 10 to 200 N / mm or other molded bodies or given

35 if clogged and then by heat treatment up to

a maximum of 20O ⁰ C, preferably at 20 to 170 ° Γ, bound for a period of one hour to 4 days, so that the stones or other shaped bodies have such a strength that they are sufficiently storable and transportable. This also includes adequate weather resistance and, in particular, water resistance. It has surprisingly been found that such stones or other shaped bodies can be converted into the ceramic bond without any problems after they have been bricked up and heated for the first time. It was also found that the strength in the transition range (200-800 ° C.) up to the onset of the ceramic bond at temperatures above 800 ° C. is unexpectedly and advantageously increased by the addition of synthetic resin described above. The stones or other shaped bodies produced by the process according to the invention preferably have a cold compressive strength of after pressing or tamping and hardening

at least 10 N / mm. The synthetic resin content in the stones or other moldings is partly decomposed to products that are gaseous under the given conditions and partly graphitized ^{when the material is first heated to temperatures above 200 ° C.}

The invention includes a novel binding system which is essentially independent of the conventional refractory raw materials is. Such base materials can therefore have the compositions customary in the refractory industry and grain structures with one of the inventive Bonding systems are provided. Included it should be noted that the overall composition is so it is chosen that there is no firing shrinkage. This is usually the case, for example, in the case of a first fire Ceramic bond forming clay / kaolin additions is achieved in that the proportion of clay or kaolin, which is usually which cause high shrinkage, is kept low (approx. 10 wt .-? o). To promote the

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Regrowth in the fire can e.g. with chamotte, andalusite, Sillimanite, mullite, bauxite and corundum stones a small amount (e.g. 1-10 wt .-? O) of fine raw cyanite be admitted.

There is also the possibility of working completely without clay / kaolin and only binding the hard materials with synthetic resin. In a particular embodiment of the process, the mixture of the inorganic base materials contains 0 to 30 wt. Jo ', preferably 1 to 10 wt.? O', clays and / or Contain kaolins, the graphite content being a maximum of 50 wt .-? I.

The refractory bricks or other shaped bodies produced by the process according to the invention are preferred for lining vessels for pouring molten metal, in particular molten steel, as well as for Lining of thermally highly stressed process units, such as ladles, torpedo pans and converters, used. They are also used to line transport containers in the steel and non-ferrous metal industry .

The method according to the invention has the following advantages on:

a) No primary firing is necessary in the manufacture of the stones, which saves energy.

b) For the production of the stones according to the invention or other shaped bodies, a temperature treatment up to preferably 170 C is sufficient so that the conventional drying units for the production of these stones can be used and not new ones Tempering units necessary for higher temperatures are. Another advantage is that hardening

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c)

10

d)

20th

e)

30 f)

and drying temperature are in the same range.

From b) there is a further advantage that the stones directly on untreated after deformation Wooden pallets can be stored ready for dispatch.

This saves one work step. At temperatures above 200 C show untreated Wooden pallets can show signs of decomposition, i.e. stones produced using conventional methods not be placed on such pallets immediately after deformation.

It is known that there is a carbon content in refractory products positively (quality-increasing) on the slagging resistance and fire resistance and counteracts the infiltration of liquid metal melts. The invention Due to their decomposition characteristics, stones or other shaped bodies have the typical advantage of a Graphitization or an internal gas pressure.

The processing time (= pot life: time from preparation of the mixture to deformation) of the refractory Masses for the production of the stones or other mixtures as well as the hardening temperature can be used varies within wide limits via the addition of resin and, if necessary, hardener, and so the different ones be adapted to operational conditions.

Compared to the conventional chemically / ceramically and hydraulically / ceramically bonded unfired stones or other shaped bodies is the bond of the invention Stones generally cheaper.

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g) In addition, the following circumstances apply during production of the stones or shaped bodies according to the invention advantageously:

g1) Possibility of producing carbon, in particular graphite-containing stones by adding graphite and temperature treatment up to preferably 170 C, i.e. without a reducing

Primary fire at higher temperatures. 10

g2) Due to the low chemically bound water content the stones or other shaped bodies according to the invention can have a higher heating rate at the place of use can be achieved, i.e. ^ 5 faster availability of one with such

Aggregates equipped with stones.

g3) The stones produced according to the invention are

largely weatherproof. They stay in Central European after six months of weathering

Climate dimensionally stable and edge-proof.

The invention is explained in more detail below with the aid of the examples.

Table 1 gives the property values for the tests resins used.

The determination of the property values in the examples The phenolic and furan resins used were as follows

30 carried out:

Solid resin content

2-3 g of resin were weighed into a metal dish (diameter 50 mm, height 10 mm) to the nearest 0.0001 g and standing horizontally for 90 minutes in a circulatory dry

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left cabinet at 15O ⁰ C. After the sample had cooled in a desiccator, it was weighed back in order to determine the weight loss.

viscosity

The viscosity was measured with a ball drop Viscometer according to Hoeppler (see DIN 53015).

Melting range

The melting range was determined by the capillary method determined according to DLN 53181. The sample is heated with a temperature increase of 2 + 0.2 C / min. without interruption.

Gel time,

, 150 ° C

It is the time that the resin needs to get out of the flow sigen or molten state irreversibly change into a gelatinous, rubbery state.

In a dome (diameter 20 mm, depth 10 mm), which is thermostatically heated to 130 ° C or 150 ° C Iron plate incorporated, were about 150 mg of resin given, and then it was determined by stirring with a pointed glass rod when the resin sample gelled. This point is reached when no thread can be found by pulling the rod out of the resin allows more to pull, but tears off the resin from the tip of the rod because it has become gelatinous.

Flow path at 125 ^° C

It is the length in mm, a compressed into a tablet 1 g sample on a 125 ⁰ C hot glass plate, with a 60 ° inclination in an oven standing, to Eigenhär-

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3 Λ 1 £ 1 5 3

1 flow through. The tablet diameter of 12.25 mm is also measured when specifying the flow distance.

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Phenolic resole resin O
V " Table 1 Phenol-
Novolak C LA
OJ Phenol novolak
Hexa mixture D O
K \ LA
KN fluid A furan resin B fluid powdery shape 65-70 fluid 66 98 Solid resin content
(Weight S) water
205 53 Ethanol
2300 - solvent
viscosity
at 20 ° C
(m p s) - Furfuryl "
alcohol
310 - 81-84 Melting range
( ⁰ C) 2.2 - - 12th Gel times
B 13O ⁰ C (min)
B 15O ⁰ C (min) - - - 71 Flow path
(mm) at
125 ⁰ C - ν IA LTN O
ν OJ

Τ, ίΙ) Oi] i! 2 Attempt no. water Weight X Curing temp. ⁰ C 1 2 3 4th 5 Z 6th 7- 2. S. -ΛΟ 1 Andalusite 0-3 mm p-toluenesulfonic acid Il Curing time hrs. <P <P <P <P J? O 2 . bauxite 0-3 mm '. 6i> dew. - ° o)
Phenolic Resole Resin A. Il Measurements after curing /O sfO 5 ι
Raw cyanite 0- ^ mm Furan resin B Il Cold compressive strength N / mm ² Z Z Z 3, ί Z 2 Z Z ή graphite 0-0.2 mm Hexamethylenetetramine Il Pressure fire resistance ta ° C 0.2 5
ι Τοπ 0-0.1 mm alcoholic novolak solubles Il Water resistance _a ) %
b) Loss of wt JO sfO /O / to ΑΪ sfO Sf (P SfO ■ -ftp 6th Novolak-Hexa Mixture D. M. Bronzing temperature ⁰ C 3, Z 3, r 3, r St ₁ O 3.0 2, Γ I ₁ O 7th Measurements after the fire 0.2 0 / O, Z ^8th Il Cold compressive strength N / mm ¹ *, e 0, T- sr, o 9 Il Pressure fire resistance ta ° C 10 C » Regrowth in the fire %
(Change in length after the fire) / f <tO <fo 0.3 11th Il ' Explanations of the recipe variants
(see also page 15) 2V 42. 3.0 2 / Γ ■ 26 2.0 " 3 Where / UO / Ib O / fC / Q / 1-2 (P. fo / t ^ hOV / ΙΉ Z ^ 2h 27 2 V sf (PO
0.4 / L sfOO
0.2 IZ 2Z Z6 /? Γ0ο -Zf ⁵ / 17 ZO / IO A7ZO /? sfO Λ & 30 sf6 <fp ^L (Z si> ΟΊ> Sf w ί IP ₁ O / IT-ZfO 0.0 3/2 / ThZo / OO
0.0 SfOO
o, r sf6VO sfOO I.
St '& iyf) 7th
Q stroo sfflO / fj-0v +4 λ • sf3ft> sfroo 9 / ΓΟΟ 6Z raw material
variant Z.
default 6 / sr- Synthetic resin
binding
based
l'uriiiiharz
Ii if sfroo sl ^ OO 6o /? - oo 6o s / J-Zo Λίο % / ty ο ο SfJ "0 \ O
I. -tsf / J ' S6VO S. default Resol without
Harder I.
I. raw material
variant Z.
default higher
Resin A-
Harder- Kuns thfir ^ -
bindumj
on Hhüin
alkohn1.
Novo 1; ik-
I r; RUiHi V • «f. *, - - < Zero ver
search gcringe
Mi'nye Re-
s ('- l + Här
ter
Border ripr
Wtoacrfent Artificial heart
binr] un ij ·
; inf ü; isi.i
Νονοί iik-
llnxii-de-
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Trial description

The tests listed in Table 2 are described in more detail below:

The refractory raw materials (andalusite to clay = lines 1 to 5) are the usual qualities used in the refractory industry with a grain size range optimized for compaction.In a 1Ol laboratory mixer, the hard materials (lines 1 to 3) are first moistened with water. With constant mixing, graphite and clay and after 3 minutes first the hardeners (lines 7 and 10) and then the resins are added. Total mixing time approx. 10 minutes. This is followed by deformation to test specimens using a hydraulic laboratory press with a constant

Pressure of 80 N / mm each. The cylindrical test specimen have a diameter of 50 mm and a height of 50 mm, as required by the following DIN standards .

The hardening takes place in a drying cabinet. The cold compressive strength is determined according to DIN 51067. The pressure fire resistance is determined according to DIN 51064 .

The water resistance (lines 17 and 18) is than that Strength of the stone after 24 hours of immersion in easy-flowing, cold tap water and subsequent drying at 110 ° C. In line 17, 100? I means that a Stone has its original shape, no or only a few grains have fallen off and the edge strength has been preserved. 0? Ό means the stone already disintegrates within 1 hour under the conditions described above. 80? Ά means that the stone is within Crumbles around the edges for 24 hours, but retains its original shape overall.

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The water resistance according to line 17 is a separate, arbitrary specification, as a standardized method is not known.
The percentage weight loss (line

18) determined following the water storage and drying determined above.

As part of the water resistance tests, be determined that

10 ^a ) the test specimens according to the one described above

Water storage and drying are equally 'great or had a slightly higher cold compressive strength than before the water resistance test,

b) immersed in boiling water for one hour at comparable or slightly less favorable Results than the above-described water resistance test leads.

The fire of the test specimen is in a gas-fired one Tunnel furnace with a holding time at the firing temperature of a constant 24 hours.

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Comments on experiment no .:

1. Standard attempt

With 1.8% by weight of phenol resole resin A and 0.2% by weight of S5 p-Toluenesulfonic acid as hardener, processing time up limited to approx. 1 day.

2. Zero test without synthetic resin bond

As can be seen, a lack of synthetic resin addition leads to a completely lacking water resistance and a reduced cold compressive strength.

3. Phenol-Resole-Resin A, without added hardener, so pure temperature hardening

Compared to Experiment 1, this mixture shows a longer processing time (approx. 2 weeks) and a slight one increased cold compressive strength.

The reduced addition of phenolic resole resin A and hardener leads to stones with reduced water resistance.

5th to 6th

Variants with regard to the refractory raw materials.

Try with a higher hardener / resin A ratio to reduce the hardening temperature and the hardening time with a shortened processing time (approx. 1 hour) of the mixture can be exploited.

8-10

The test results show that the inventive Properties can also be achieved when using the above-mentioned furan and novolak resins.

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Claims (1)

1. A process for the preparation of substantially weather-resistant, resin-bonded, refractory bricks s- or other molded bodies, characterized in that
that a) ' a free-flowing, usually water-containing mixture ^ _n high temperature resistant, inorganic Base materials 0.1 to 20 wt. SS, based on dps mixture of inorganic base materials, the following synthetic resins to be mixed in at room temperature: 15 ^a1) Resole type liquid phenolic resin or a2) powdery phenolic resin of the novolak type or 20 ' a3) liquid furan resin or a4) a mixture of al and a2 or a5) a mixture of al and a3, ., _. where in case a1 if necessary, in cases a2 until a5 a catalytically or chemically active hardener is present in any case, and optionally it also contains organic auxiliaries, such as pressing auxiliaries, shaping auxiliaries, EPO COPY 3. 4th b) the earth-moist mixture obtained according to a) at room temperature 2 temperature and pressures of 10 to 200 N / mm pressed or given to stones or other shaped bodies if vasified and then made the synthetic resin bond by heating to 20 to 200 ° C will. c) the largely weather-resistant, transportable stones or other shaped bodies produced according to b) are ^{heated for the first time to over 200 °} C. and then to temperatures of over 800 ° C. after processing at the place of use. Process according to claim 1, characterized in that, as inorganic basic materials, e.g. bauxite, andalusite, Zirconium silicates, zirconium dioxide, magnesites, dolomites, graphites, kaolins, sillimanites, Mullites, corundums, quartzites, spinels, silicon carbides, silicon nitrides, fireclay, clays and / or raw cyanites can be used. Method according to claim 1 or 2, characterized in that the synthetic resin content is 0.5 to 5 wt of the mixture of inorganic raw materials, the curing temperature 20 to 170 C and the curing time is one hour to 4 days. Process according to one of Claims 1 to 3, characterized in that a liquid phenol-resole resin is used in combination with acidic hardeners whose viscosity (according to Hoeppler) at 20 C im Range from 100 to 2000 cp and its solid resin content in the range from 63 to 78 and which one has the property when acids are added COPY 34HT53 ¹ to cure in an exothermic reaction. 5. The method according to any one of claims 1 to 4, characterized characterized in that a powdery phenolic resin - ^ of the novolak type in the presence of 4 to 20 wt .-? i Hexamethylenetetramine, based on the phenolic resin, is used as a hardener. 6. The method according to any one of claims 1 to 4, characterized '^ characterized in that a liquid furan resin in combination is used with acidic hardeners whose viscosity (according to Hoeppler) at 20 C is in the range from 100 to 1000 cp and its solid resin content is in the range of 50 to 65. 7. The method according to any one of claims 1 to 4 or 6, characterized in that the hardener is p-toluenesulfonic acid contains. 8. The method according to any one of claims 1 to 7, characterized in that the stones or other shaped bodies after pressing or tamping and hardening 2nd a cold compressive strength of at least 10 N / mm according to DIN 51067. 9. The method according to any one of claims 1 to 8, characterized in that in the mixture of the inorganic Basic materials 0 to 30 wt .-? I, preferably 1 to 10 wt .-? I, clays and / or kaolins are included as well 50 the graphite content is a maximum of 50 wt .-? O. 10. The method according to any one of claims 1 to 9, characterized in that in the mixture of the inorganic Basic materials contain 1 to 10 wt .-? I of fine raw cyanite. 34H153 11. Use of the according to any one of claims 1 to 10 manufactured refractory bricks or other shaped bodies for lining vessels for potting of molten metal, preferably molten steel. 12. Use of the refractory bricks or other shaped bodies produced according to one of claims 1 to 10 for lining process units that are subject to high thermal loads. 13. Refractory bricks or other shaped bodies made from free-flowing, usually water-containing Mixture of high temperature resistant, inorganic base materials, which 0.1 to 20 wt .-? O, based on the mixture of inorganic base materials, the following synthetic resins at room temperature contains! al) Resole-type liquid phenolic resin, or a2) powdery phenolic resin of the novolak type or a3) liquid furan resin or a4) a mixture of al and a2 or a5) a mixture of al and a3, where in case a1 if necessary, in cases a2 until a5 a catalytically or chemically active hardener is present in any case, and optionally additional organic auxiliaries, such as pressing auxiliaries, shaping auxiliaries, are included EPO COPY