DE3620284A1 - ONE PIECE FIRE-RESISTANT DIMENSIONS - Google Patents

Description

"One-piece refractory masses"

claimed priority:

June 18, 1985, Japan, No. 130799/1985

The present application relates to one-piece refractory masses, which not only for the most diverse Types of furnaces for steel production but also for other industrial furnaces can be used, for example at in the technology of non-ferrous metals and in the ceramic industry.

Usually one-piece refractories are used Masses applied by using powdery substances in the required mixing ratios with one another and then with water or an aqueous solution of a binder mixed. However, there are various circumstances which require that they be made in one piece Refractory masses contain basic components, such as MgO or CaO, and if you consider the basic components in this case

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mixed with water, then the so-called quenching phenomenon occurs, which causes cracks to appear during curing or drying or even fractures occur.

In order to prevent such undesirable effects, improved Methods in Japanese Patent Application Laid-Open Nos. 52-32908, 53-113812, 57-129864 and 58-99177 describes according to which certain additives are also used. However, it can hardly be said that any of the in additives described in these publications Has properties which would enable the quenching phenomenon to be prevented as well as the good processability of the refractory materials in question is also retained.

Both Japanese Patent Application Nos. 52-32908 and 53-113812 disclose inhibitors in the form of organic materials used. In the first-mentioned reference is an additive that is also used in the Manufacture of refractory bricks acts as a binder. But then, although a certain effect of this additive can be seen when the refractory material is deformed under pressure after the aggregates with an aqueous solution have been mixed, it has proven difficult to use such an additive for pourable materials due to the high concentration in the aqueous solution.

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On the other hand, the additive mentioned in the second prior publication is mainly effective only for materials which are centrifugally processed, but it does not show sufficient improvements in processing materials by means of the technique of pouring, coating and spray gun application. Using one too Large amount of this additive can also cause undesirable Deterioration of the mechanical strength of the molded body produced from the refractory mass lead.

In the other two mentioned Japanese Publications No. 57-129864 and No. 58-99177, inorganic inhibitors are recommended. The additive used in the former publication is very effective when used in an aqueous solution and when drying in low temperature areas, but it does not show sufficient effect when drying under such conditions as in an autoclave at a temperature higher than 100 ⁰ C prevail. In the last-mentioned prior publication, silica aerosol is recommended, which is generally suitable for materials which are processed using the casting technique and coating technique. A small amount of this additive has a limited effect, but larger amounts can give rise to an undesirable deterioration in the corrosion resistance properties of the basic refractory aggregates.

The object of the present invention was therefore to find a solution to the problem outlined above.

In particular, it is the aim of the invention to be made in one piece to provide existing refractory compositions which have superior processability.

Another object of the invention is to be made in one piece To provide refractory masses available, which tend neither to crack nor to break, these Phenomena are based on a hydration effect, as it occurs as a quenching process in a molding of the refractory mass in Presence of water or steam during their application during curing or drying can occur.

The one-piece refractory masses according to the invention are characterized in that they contain one or more basic (s \ aggregates) and 0.02 to 20 parts by weight of a phosphate which is insoluble or only slightly soluble in water as an inhibitor for the occurrence of the extinguishing phenomenon Contain 100 parts by weight of the total amount of basic aggregate.

So far, phosphoric acid and water-soluble aluminum phosphate have been used as binders in such refractory masses, which do not contain any basic refractory aggregate. However, such binders are not in unshaped refractories Compounds containing such basic refractory aggregates as components have been used.

In terms of the reactivity of phosphoric acid and water-soluble Phosphates with basic refractory aggregates

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the inventors have investigated the most diverse methods by means of which it might be possible to prevent the quenching phenomenon prevent, so that the basic refractory aggregate is stabilized by having only a moderate reaction with the Phosphoric acid or the water-soluble phosphate enters, with only the surface of the basic refractory aggregate reacts with the phosphoric acid or only with the basic ions dissolved in the water. This way there should be a reaction of the entire basic refractory aggregate while the phosphoric acid or the water-soluble one becomes active Phosphate should be avoided.

In the context of the present invention, especially magnesia clinker, spinel clinker, Magnesia-chrome clinker, dolomite clinker and lime clinker.

It can be the most varied. on the market Clinker types are, for example, seawater magnesia clinker, natural magnesia clinker, and electric melted magnesia clinker, to sintered spinel clinker, to electrically melted spinel clinker, natural dolomite clinker, sintered lime clinker and electrically fused lime clinker.

In order to allow a free choice with regard to the particle size of those materials from which the refractory masses exist, clinker in the form of crushed

shrinkable lumpy lumps or in the form of classified particles of various particle sizes are used.

These types of clinker can be used alone or two or more can be used in combination. In addition, the refractory compositions according to the invention also contain a wide variety of other refractory components, provided they are stable to water and steam are such as aluminum oxide, bauxite, mullite, chamotte, silica, chrome ores and olivine. The proportions in which this Components present mixed in the compositions according to the invention are not subject to any particular restriction and are directed depending on the operating conditions of the various types of furnace for which the refractory compounds are intended.

Preferably, the water-insoluble or only sparingly water-soluble phosphates used in this invention as an inhibitor to 2.5 have a water solubility at a temperature of less than 4O ⁰ C of less than g / 100 ml water. In addition, it is expedient for the phosphates in question to have a pH of less than 7 in the form of an aqueous suspension. Namely, if the solubility of the phosphate in water of low temperature is too great, then a rapid reaction between the basic refractory aggregate takes place during the mixing process or the application of the mass and leads to flocculation or other defects, making the handling of the refractory mass difficult will. If the phosphate is in the form of an aqueous

rigen suspension has a pH value of more than 7, the inhibitor effect with regard to the quenching phenomenon is only relative limited.

Although the type of the water-soluble or only slightly water-soluble phosphates used as inhibitors according to the invention is not particularly limited, compounds are preferably used which have orthophosphate or polyphosphate groups and which are a salt of aluminum, chromium, iron, magnesium, calcium, potassium, sodium , Lithium, boron, zinc, lead, barium, bismuth or silver. For example, an aluminum phosphate of the formula Al (HpPO ₄ ) - is water-soluble and therefore not usable in the context of the invention. Aluminum phosphates of the formulas AlH ₃ (PO ₄ ), Al ₃ (HPO ₄ J ₃ and AlPO ₄ , however, are insoluble in water In the group of aluminum phosphates with the formula AlPO ₄ etc. there are those of the most varied crystal types and also amorphous compounds, and each of these modifications can be used in the context of the invention , such as aluminum metaphosphate, aluminum tripolyphosphate, etc. only slightly soluble in water and can therefore also be used within the scope of the invention. The same considerations apply to phosphates other than aluminum phosphate and to composite. which form a solid solution with each other.

The amount of the water insoluble or only sparingly soluble in water in the refractory masses according to the invention depends on the type the clinker brick used and the special recipe. If, for example, clinker is used, it is relatively water-stable are, like magnesia-chrome-clinker or spinel-clinker, which are rich in aluminum oxide, then one is enough a small amount of phosphate in order to achieve a corresponding effect. In refractory masses which contain magnesium oxide contain rich spinel clinker or magnesia clinker, however, the amount of phosphate must be increased more or less. In addition, when using dolomite clinker and lime clinker, which contain a large proportion of CaO and Therefore, if they are water-active, a larger amount of the phosphate must also be used. Of course, the amount varies Phosphate also according to the crystalline state and crystal size of MgO and CaO in each type of clinker. If mixtures of clinker types used, the amount of phosphate must depend on the specific type of used Aggregates are determined. In any case, however, the phosphate concentration should be in the range from 0.02 to 20 parts by weight per 100 parts by weight of the total amount of clinker component. If the amount of phosphate is below 0.0 2 parts by weight, can cracking may occur during drying under autoclave conditions. An addition of more than 20 parts by weight However, phosphate has no additional effect and is therefore economically inappropriate.

Of course, in the refractories according to the invention

Masses other common raw materials can also be used, for example inorganic binders such as cements, sodium silicate, water-soluble sodium phosphate or organic binders such as the various types of resin, as well as dispersants such as the various water-soluble sodium phosphates and carboxylates. In addition, a wide variety of means can also be used to control the hardening process, such as a wide variety of sulfates, carbonates, hydroxides, chlorides, borides and carboxylic acids. For the practical use of the one-piece refractory masses according to the invention, however, it is not always necessary to use a binder, especially if they are intended for casting processes. This results from the fact that the pH value increases to the extent _(such as divalent magnesium and calcium ions are eluted from the clinker material so that very little phosphoric acid is eluted with, which then compounds are formed with the magnesium and calcium ions, which reinforce the structure of the molding.

The particle size of the refractory aggregates in the inventive Refractory masses are chosen so that the size of the aggregate is suitable for a wide variety of purposes is how to use by pouring, applying with the spray gun, for touching up, for covering and for tamping. In addition, if desired, further components can be added, such as clay, finely divided silica, finely divided Aluminum oxide, in order to do certain properties related to this pourability, consistency and the like

to enhance.

Although the refractory compositions according to the invention are water-insoluble or contain only a little water-soluble phosphates, so that the compositions are stable to water and therefore hardly react after being mixed with water during their practical use, it can be said that In the course of time after the addition of water, the pH value rises to the same extent as divalent magnesium and calcium ions eluted from the clinker material, which then also releases a very small amount of phosphoric acid components which form compounds with the magnesium and calcium ions which ultimately lead to the formation of cracks or Breaks, which would otherwise be caused by the quenching phenomenon, do not occur.

Working examples example 1

There are various formulations according to the information in Table I below from the required ingredients and 6.5 parts by weight of water were added to each 100 parts by weight of these formulations. After mixing the one-piece refractory masses are poured into molds measuring 40 40 χ 160 mm and Cured for 24 hours at room temperature. Corresponding test samples are obtained in this way.

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After drying, each molding during 24 hours at 110 ⁰ C the modulus of rupture and the porosity are determined. Other test samples are subjected to an autoclave test immediately after curing (3 hours at 5 atm). The test samples that passed this autoclave test,
were then examined with regard to the Burch modulus and the porosity.

The results obtained are summarized in Table I below.

It is clear from Table I that the test samples made from refractory compositions according to the present invention did not crack or break even under the severe conditions of the autoclave test. In addition, the
Flexural strength of the Urlersuchungsbeispiele compared to that
after drying has been increased by the autoclave test,
while the porosity was reduced. On the other hand, the test samples of the comparative examples showed cracks or decreased strength. In addition, formulations containing soluble and acidic phosphates such as Al (H ₂ PO.) ₃
contained, cannot be used in practice because corresponding reactions occurred even during mixing.

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3320284

Tabel

Sea water> 3mm Λ I around cement 1 according to the invention 3 4th Examples 6th 7th B. 9 10 1) Comparative examples 12th 13th 14th 15th K) Mipnesla - 3 - 0.3mm Portland Znmenl 40 2 40 40 5 40 40 40 Clinker <0.3mm Na-silica 20th 40 20th 20th 40 20th 20th 20th 20th Natural-> 3mm soluble Na
phosphate 40 20th 40 40 20th 40 40 40 40 rather 3- 0.3mm Λί.1'0 /, (nerlJnlt -
Type ) 40 40 40 40 ^ - * Magnesia _<0 .3mm MVO ₁ , (CrJ s toba I It- 20th Q)
■ Η clinker ¹ B ¹ P) 40 in electro CaIIP (V _1. 2H ₂ O -μ oven -> 3 _mm Mf, (PO ₂ ) ₂ to melt - -
ner Magne-Ί ~ ^υ · -> ™ ^η
siaklinker <0.3mm Processability 40 40 40 40 40 40 wichi After drying: 20th
40 20th
40 20th
40 20th
40 20th
40 20th
. 40 Q) ISf ml er HO ⁰ C - 24 h -
Modulus of rupture (kgf / cnr 1.0 1.0 Z.ü I. P Porosity {· /.) 1.0 U Dis-,
persant Condition after car 1.0 eptu klaventest 0.1 0.1 ο ', ι 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 Rec U
O Modulus of rupture (kgf / cm ² 0.3 0.1 0.1 2.0 3.5 1.0 1.0 1.0 2.0 Silica
Aerosol Ho] leslie ' ■ rj 2 0.5 N / A- .O
• ri Porosity (%) 1.0 If) Oi) pll3 M. 0.1 (pii-8 / ^ 0.5 Well Well Well 1.5 Well Well ' Well Well Well Well Well" Well Well *) Well Well Well 75 61 70 65 02 78 89 05 83 45 77 92 - 51 13.6 57 15.1 14.0 71 14.2 14.5 13.1 13.2 13.3 13.5 13.7 13.5 12.8 - 13.3 unchanged 13.8 unchanged unchanged J3.9 unchanged ■ unchanged -unver -unver ■ unchanged -unver Rrnrh fracture Crack bil _ Brucl changes unchanged at the changes unchanged .at the .at the ; change ; change pikeperch stand manure 118 changes 99 112 at the 115 90 120 114 112 108 Measurement not 19th - Measurement 95 103 possible , ch light U.7 12.0 11.6 11.8 12.5 9.4 9.7 10.2 11.0 12.5 possible 12.1 11.7

*) hardens quickly, cannot be processed

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Example 2

Recipes were prepared according to the information in Table II below, to which water was added in the amounts required for the specified types of application. After mixing blocks were prepared mm with the dimensions 230 χ 230 χ 300 from these refractory masses, and these moldings were then cured for 24 hours at room temperature and then dried first for 3 hours at 11O ⁰ C and then again for 24 hours at 200 ⁰ C. Finally, the appearance of these molded blocks was visually assessed after drying. Since the internal vapor pressure of the shaped bodies is not identical due to different porosities, such a drying test on large blocks is a realistic method of assessing the extent to which defects can occur during drying in an oven in practical use.

As can be seen from Table II, all the blocks of the comparative examples were observed to be cracked or broken during the refractory compositions according to the invention have good processability showed and no change could be found in the mold blocks.

ORIGINAL INSPECTED

T a b e 1

ΙΪ

ο CD electrical > 3mm 21 according to the invention 22nd 23 2 Ix Examples 26th 27 28 29 Comparative examples 30th 31 32 3 3 1 0.1 3D r-t melted 40 40 25th 10 40 40 10 δ) ω
■ Ρ M.ignesla "3 - 0.3mm NAL co
+ J Clinker <0.3mm 20th 10 10 10 5 20th 10 10 ing "Z.
m υ sintered > 3 »> n» 40 40 40 10 40 30th 40 40 -ο
m -H Spinel ~ 3 - 0.3mm 40 40 20th IxQ Ä Q)
O Kl Inker <0.3mm 30th 20th σ scnnc ^r iiS ^{h er} ~ ^{> lmm} 30th 30th 10 40 to water U
3 Proprietary la-Cfironr 3 - 0.3mm 40 6.2
Q .μ
O) clinker 20th Well α) Synthetic 3 - 0.3mm Crack bil Dolomite -IQ Inker 20th manure Klectrisch -> 3mm melted 30th 30th / amount of water in Calkk left 3 - 0.3mm 30th Polysorbitol solution sintered> 3mm 10 10 Alumina 3 _ or 3mm 20th 40 20th 40 ■ ' ( 0.3mm 10 10 10 10 - Alumina "cement 40 IO 40: ■ Port land-Zsnient 1.0 1.0 2.0 2.0 2.0 1.0 2.0 Sodium silicate 2.0 2.0 2.0 soluble 2.0 2.0 Na-PhosphaC 0.1 0.1 0.1 4.0 0.1 0.1 0.1 0.1 0.1 0.1 (pll = 8) 0.1. AlVOi, (amorphous) I 4 y 0.5 0.05 6th 1.2 0.8 \) lysorbl I.
[OO / i-SOLUTION FeI ¹ O ^ Il ₂ O AJl ₁ Cr (PO ₄ ) ,, 0.02 6th type of application 6th 10 1.5 required amount of water to water Pound ι pour to water 8th to water to water to water 3ießen to water Pound to water Processability 6.5 ^4th 6.3 6.5 Spray
pistol 6.5 6.2 6.2 6.5 6.5 4th 10 * Appearance after drying Well Well Well Well 10 Well Well Well Well Well Well Pourable
speed unchanged unchanged unchanged unchanged Well unchanged unchanged unchanged unchanged Crack bil Crack bil fracture changes changes changes changes unchanged changes changes changes changes dung u.
partly manure changes fracture - Π - · - ■

Claims (9)

Claims 1. One-piece refractory masses, thereby characterized in that they contain one or more basic aggregate (s) and 0.02 to 20 parts by weight of one Contain little or no water-soluble phosphate as an inhibitor for the occurrence of the quenching phenomenon per 100 parts by weight of the total amount of basic aggregate. 2. Refractory masses according to claim 1, characterized in that the basic aggregate is a magnesia clinker, a spinel clinker, is a magnesia-chrome clinker, a dolomite clinker and / or a lime clinker. 3. Refractory masses according to claim 2, characterized in that that the basic aggregate is a magnesia clinker in the form of a seawater magnesia clinker, a natural magnesia clinker or an electrically fused magnesia clinker. 4. Refractory compositions according to claim 2, characterized in that the basic unit is a dolomite clinker in the form of a naturally occurring or synthetic clinker. 5. Refractory masses according to claim 2, characterized in that the basic unit is a lime clinker in the form of a ge ORIGINAL INSPECTED - 2 sintered or one electrically fused clinker. 6. Refractory masses according to claim 1 to 5, characterized in that that they also have sintered alumina bauxite, mullite, chamotte, silica / chrome ores and / or as further component (s) Contain olivine. 7. Refractory masses according to claim 1 to 6, characterized in that that they contain a compound with an orthophosphate or polyphosphate group in the molecule as a phosphate inhibitor, which is a salt of aluminum, chromium, iron, magnesium, calcium, potassium, sodium, lithium, boron, zinc, lead, barium, Is bismuth or silver. That the phosphate inhibitor than 2.5 8. Refractory materials according to claim 7, characterized in that a compound having a water solubility of less g / 100 ml water at temperatures below 4O ⁰ C. 9. Refractory masses according to claim 7, characterized in that that the phosphate inhibitor is a compound which has a pH value below 7 in the form of an aqueous suspension.