DE2730868B2 - Cold-curing ceramic binder system and its use - Google Patents

Description

In DE-OS 24 01 185 a base material that sets with water to form a solid mass is described, by a content of, in percent by weight,

a) about 30 to about 66% base material

b) about 25 to about 59% water-soluble, acidic orthophosphate, and

c) about 1 to about 27% water soluble polyphosphate

The base material consists of dead-burned magnesite, dead-burned dolomite, dead-burned aluminates of alkali or alkaline-earth metals, dead-burned magnesia and mixtures thereof.

This binder involves the known binder systems consisting of oxidic and / or Silicate raw materials consist and react with phosphoric acid or water-soluble acidic phosphates to be brought.

By adding the water-soluble polyphosphates, the compressive strength of the masses should be increased. No information is given about their adhesion ¹ on different substrates, hardness and fire-resistant wedge

In this known binder system, the weight percentages of the components Na ₂ O and Al ₂ O ₃ outweigh P ₂ Os if sodium aluminate is used as the base material and sodium dihydrogen phosphate is used as the water-soluble orthophosphate.

It has now been found that the disadvantages outlined are based on a cold-curing ceramic binder system with high temperature resistance of phosphates can be avoided, which is characterized in that it is i jS a phosphate solution with a Absät.tigung 0.2-2.0, the Cations sodium, potassium, ammonium, lithium, Represent aluminum, boron, calcium, magnesium, barium, titanium, iron or chromium or mixtures thereof and a tertiary orthophosphate of aluminum and / or boron and the molar ratio of Phosphate solution to the tertiary orthophosphate of aluminum and / or boron between 03: 1 and 1.25: 1 lies

Such pasty mixtures can be more or less depending on the binder components used Process less long-term in the usual way. After a certain period of time, e.g. B. Start 30 min to solidify these mixtures with gentle heating and then harden within a very short time to one solid, stone-like mass. Immediately after hardening, these masses achieve considerable strengths. The adhesion of such a mass on the The subsurface is excellent, even if this subsurface is unclean, damp or otherwise contaminated. The hardened mass can be heated to temperatures of, for example, 1250 ° C. without any significant change in its structure and strength is therefore particularly suitable for cementing refractory materials such as stones, molded parts, insulating materials with other materials, e.g. B. iron or steel.

The phosphate solution used is phosphoric acids that are between 0.2 and 2.0 basic saturated, preferably those whose saturation is between 0.5 and 1.8 cations that lead to partial saturation the phosphoric acid can be used, the alkali metals, the alkaline earth metals, also heavy metals such as iron, chromium, titanium, aluminum and the like., which are used either alone or as mixtures of the cations mentioned. Ie after which one Cations are used to saturate the phosphoric acid, the properties can be such as The strength, hardness, adhesion and fire resistance of the compositions according to the invention vary within wide limits.

Tertiary orthophosphates of aluminum and / or boron are used as reactants in the phosphate solution used.

The molar ratios of the phosphate to the tertiary orthophosphate, aluminum and / or boron can be between 03 mol and 1.25 mol, the proportion of acidic P ₂ Os predominating over that of the metal oxides, calculated in parts by weight. Per mole of tertiary orthophosphate is preferred of aluminum and boron 0.25-0.65 mol phosphate used as the phosphate solution

In the practical application of the binder system according to the invention, anhydrous substances are not used, but the phosphate is used as an aqueous solution, solutions with 30-40% P ₂ Os having proven to be particularly favorable for processing.

It has been shown that the hardening of the binder system according to the invention by the addition of other substances such as acids or salts, for example sulfates, Fluoride and the like can be influenced to a certain extent. For example, this is the setting a system according to the invention of sodium phosphate solution and tertiary aluminum orthophosphate significantly accelerated by the addition of sodium fluoride During the processing time of one without If the system made with the addition of fluoride is around 80-100 minutes, the processing time will be one with The system produced with the addition of fluoride is shortened to 20-30 minutes.

It has also been found that the grain size and structure of the reactant Tertiary orthophosphate used can influence the setting.

For most purposes, the binder systems according to the invention are not used on their own, but are tailored to the particular intended use by incorporating fillers. For example, up to 95% fillers such as sand, gravel, chamotte, corundum, bauxite, SiO ₂ , SiC and the like can be added to the composition according to the invention.

Systems according to the invention to which fillers have been added, as well as the pure unfilled systems, can be used for a wide variety of purposes, e.g. B. as fire-resistant and corrosion-preventing coatings in ovens, crucibles and the like. As Kittebzw. Adhesive to apply refractory or insulating materials to a base, e.g. B. metal surface to be puttied, also for the repair of furnace walls and the like, the systems according to the invention being pressed into cracks in the usual manner or used to fill cavities. Because of its exceptional strength and adhesion, the binder system according to the invention can also be used to repair or coat heavily used surfaces made of concrete and the like.

Example t

It was a binder system, as it is e.g. B. is used for cementing refractory components from the following Components manufactured:

250 g of a 0.6 basic sodium phosphate solution with a PjOv content of 36% by weight were

and 400 g of tertiary aluminum phosphate with a P ₂ Os content of 48% were added while stirring. The mass was stirred homogeneously to form a viscous paste

This slurry was used to produce test specimens in a triple mold according to DIN 1164, sheet 7, filled and shaken in according to the DIN standard mentioned. The mixture began to set after 80 minutes and had solidified for 150 minutes. The test specimens were molded and stored at room temperature The strength was determined after a total time of 50 hours, counted from the start of mixing

Flexural strength according to DIN 1164 = 51.5 kp / cm ² Compressive strength according to DIN 1164 = 345 kp / cm ²

Example 2

The binder system according to Example 1 was modified by adding a phosphate solution with several Cations was used.

250 g of a 03 basic sodium, calcium, iron and ammonium phosphate solution with a molar ratio Na: Ca: Fe: Al such as 2: 2: 1: 1 and a P ₂ Os gel of 35 wt. % was stirred to a paste with 400 g of tertiary aluminum phosphate.

The pulp was shaken into the form prescribed by DIN 1164. After 25 minutes, the Set mixture and was solidified after 90 minutes. The test specimens were molded, stored at room temperature and tested after 50 hours

Flexural strength according to DIN 1164 = 98 kp / cm ² Compressive strength according to DIN 1164 = 640 kp / cm ²

Example 3

This example illustrates the effect of adding an acid on the binder system. The acidic phosphate solution used in Example 2 was modified by adding sulfuric acid. The solution contained 35% by weight P ₂ O ₅ and 7.5% by weight H ₂ SO ₄ -

250 g of this mixture were mixed with 400 g of tertiary aluminum phosphate to form a paste. the Mixture was shaken into the mold according to DIN 1164. After 25 minutes, the mass began to set and was stared after 60 minutes. The molded test specimens were stored at room temperature and checked after 50 h.

Flexural tensile strength according to DIN 1164 = 105 kp / cm ² Compressive strength f ^ ach DIN 1164 = 673 kp / cm ²

Example 4

This example is the accelerating effect ve ¹ Natriumflüorid to the inventive binder systems document. The pure, unfilled system was also used here. The 0.6 basic phosphate solution used in Example 1 was added 0.5% by weight of sodium fluoride.

250 g of this solution were mixed with 400 g of tertiary aluminum phosphate and as in Example 1 further processed as described. The mixture began to set after 30 minutes and had solidified after 90 minutes. After a storage time of 50 hours at normal temperature, the strengths of the rods were tested.

Flexural strength according to DIN 1164 = 63.2 kp / cm 'Compressive strength according to DIN 1164 = 332 kp / cm ²

Example 5

The system according to the invention was used to bind an inert raw material. Such a way Bound masses can be used as refractory components or as ramming masses for monolithic lining processed by ovens and the like.

80% by weight of standard sand according to DIN 1164 was added 20% by weight of a Mi prepared according to Example 3 mixture from acidic phosphate solution and tertiary Aluminum phosphate was added and mixed well. The earth-moist mixture was converted into that according to DIN 1164 Filled in the prescribed shape and compacted by shaking and tamping. After a period of 90 minutes.

the test specimens were molded, stored at room temperature and their strength determined after 50 h.

Flexural strength according to DIN Ϊ164 = 23.4 kp / cm ² Compressive strength according to DIN 1164 =% kp / cm ²

B e i s ρ r. ·. · 1 6

To document the fire resistance of the pure, unfilled binder system according to the invention, test specimens were produced according to Example 1 Solidifying molded test specimens were placed in an electrically heated furnace and placed inside heated to a temperature of 1250 ° C. over a period of 6 h. The test specimens were for 25 hours at this Maintained temperature and then cooled the sample bodies had become through the previous tempera rate increase only marginally changed

The verification of the strengths showed the following results:

Flexural strength according to DIN 1164 = 47 kp / cm ² Compressive strength according to DIN 1164 = 216 kp / cm ²

In the following examples 7 - 12, changes in the mixing ratio of the acidic or acidic phosphate solutions to the tertiary orthophosphate as well as the degree of saturation of the Phosphoric acid showed the range of variation of the system according to the invention.

Example 7

250 g of a 1.1 basic sodium, iron and calcium phosphate solution in a _{molar ratio of 1: 1: 1 with a P 2} O ₅ content of 40% by weight were mixed with 500 g of tertiary aluminum phosphate to form a paste . The mass was in the form according to DIN I! 64 shaken in. The setting began after 5 minutes and was complete after 140 minutes. The test specimens were molded, stored at room temperature and tested after 50 h - from the start of mixing.

Flexural strength according to DIN 1164 = 12 kp / cm ² Compressive strength according to DIN 1164

580 kgf / cm ²

Example 8

250 g of a 0.6 basic sodium, calcium, iron and aluminum phosphate solution in molar ratio 2: 1; 1 ; 1 with a P2Os content of 36% by weight were added with 200 g of tertiary aluminum phosphate stirred into a pulp. The mixture was added to the after

Formed according to DIN 1164. To

180 minutes the mass begins to harden and was after Solidified for 12 h. The test bars were molded and stored at room temperature. The took place after 50 h

Strength test.

Bicyclic strength milk f 3IN 1 164 ~ 42 kp / cm · '
Compressive strength according to DIN 1164 - 700 kp / cm-

Ii eis ρ ic I ¹ I

250 g of the basic phosphate solution used in Example 8 were mixed with 500 g of tertiary aluminum phosphate to form a paste. The mixture was shaken into the form prescribed by DIN Ilb4. After 2 minutes, the compound began to set. After 15 minutes, it was eroded. The l'rulkoi formed and stored at room temperature per wiir ι Ir π d · ι im on their I csiigkcii übe ι ρ πι ft

Flexibility n.i'.h DIN I lht

ι kp C. Ill- '

Compressive strength nath DIN I Ih-I - = hhOkp'cm '

Me ι s ρ ι L- I 10

Is w lines 2 "> 0 g a ()."> B.isisc hen I ¹ Iu'sphat I solution with a Γ'ι> -, borrowed from -liin-ft "n um (_ '■> g Tertiary chlorophosphorus was stirred in. This mixture was converted into the prescribed DIN IhI. After 12 hours, the mass began to set and was solidified after 20 hours. The test rods were shaped and at room temperature for 50 hours stored The strength test was then carried out.

Hiege / ugfesligkeil according to DIN I IhI lokpcni · '

Thick strength according to DIN I Ih-I - I K) kp cm- '

Ii e i s ρ i e I Il

/ u 2) 0 g of a 0.2 basic sodium and calcium phosphate solution in a molar ratio of 2: 1 with 10% by weight of P ₂ O; 175 g of tertiary aluminum phosphate were added and both were mixed to a paste The mass was shaken into the form prescribed by DIN II bt. After 2 hours, the mass began to harden and only went wrong after 5 hours. The molded test specimens were stored at room temperature until their strength test after 50 hours.

Flexural tensile strength according to DIN I 164 - 58 kp / cm compressive strength according to DIN 1164 = 144 kp'cm- '

Example 12

r.a mixture of 250 g of a 1.2 basic sodium and potassium phosphate solution in a ratio of 2: 1 nut i) (iew. "Zn PjO-, and! 75g tertiary aluminum phosphate was mixed to a pulp. The mass became ii. the η.κ Ii DIN I IhI unseen I mm eiiigci ullelt N.u h IO Min started the '\ bbindii: ig and n.u h IH Mm the mass was frozen. The Pii'hcslahc were shaped and at Raiiinlemperanii up to i I estig Stored for 50 hours.

Flexibility according to DIN IhI> h kp .in

Compressive strength according to DIN I 164 MH kp ι in

Example 13

This example describes a Koiuiulstamp mass. bound with the crfimlungsgcmalt-n binding iron Such masses are used, for example, for I lei position large-format molded parts or monolithic ones / ustelliirg used by ovens and the like, / ii the after Example 8 pulpy mixture produced .ms 250 g excess phosphate solution with 36 (iew .- "'o I'll, and 200 g te. In the case of secondary aluminum phosphate, 200Dt! Smterkoriind I - 5 mm. KMM) g Sinterkonmd 0.2 I mm and K) (MIg Smtei corundum 0-0.5 mm given and the components are intimately connected to one another.

The earth-moist mixture obtained after a mixing time of 5 minutes was poured into the DIN Iht pulverized intended shape.

After 12 hours, the test specimens were molded and at Stored at room temperature. The strength was determined after 50 hours of storage.

Flexural strength according to DIN 1164 = ISkp / cm- ' Compressive strength according to DIN 1164 = 95 kp / cm-

Claims (5)

ι 2 umphosphat and the X-ray amorphous phases only patent claims: have weak binding properties. «Th, Chvatal describes in» lecture hall «108, year, 1. Cold-curing ceramic binder system with pages 576-589 that bind refractory raw materials with high temperature resistance based on 5 chromium aluminum phosphate This binder results in Phosphates and aluminum compounds, there- fore good bonds with Al ^ -containing raw materials, however characterized in that it only occurs when these mixtures are heated. In a) from a phosphate solution with a saturation J? ^r β ¹ «« *? " ^ΑΛ « * * ^ird ^ S ^ f that the acidity of 0.2-2Λ where the cations sodium, phosphate bond for magnesium oxide is bad. Like potassium, ammonium, lithium, aluminum, boron. ^{10 11} SS "" ^ * "* ^Γ If \ release calcium, magnesium, barium, titanium, iron or * ^{r from {uhn} ^ ^{ka" n ma "z} _h ^w mixtures represent refractories chromium or mixtures thereof, and T» ^acids phosphate binders by adding of basic b) a tertiary orthophosphate of aluminum ° ^{Xyden 2U} . ^a £ ^r ^ ^bb ' ^nd " ⁿ f - ^bel room temperature αϊ α ο u ^. ^ i ,; bring and also achieve good strengths, however and / or Bors exists _{) 5 after ΈΛ & αχΜ to 500} _ ₆ oo ° C this strength goes to and the molar ratio of the phosphate solution is lost for the most part. tertiary orthophosphate of aluminum and / or I _n of DE-PS 13 00 858 is a cold-setting Bors between 03: 1 and 1.25: 1 is the binder system described, which is based on that 2. Ceramic binder system according to claim 1 finely divided metal oxide with an acidic sub-thereby characterized in that the saturation of the 20 punch, which contains phosphate groups, is mixed. Phosphate solution is between 03 and 1.8 The metal oxide is dead-burned magnesia and / or 3. Use of the ceramic binder system FE ₃ O ₄ (hammer blow) ". The acidic according to claims 1 and 2 as a refractory cement and substance which contains phosphate groups is adhesive. Phosphoric acid. From the others 4. Use of the ceramic binder system 25 publications is known, however, that such bonds based on refractory raw materials produced by ceramic masses produced according to claims 1 and 2 ir. Combination with reaction of MgO with phosphoric acid do not have great strengths. Except like sand, gravel, chamotte, corundum, bauxite, SiO ₂ which it is for the bonding according to the mentioned or SiC. Invention required that the come to reaction 5. Use of the ceramic binder system 30 den, finely divided metal oxides very special Eigennach claims 1 and 2 as a binder that has shafts or textures. So z. B. Room temperature or at temperatures in the fire- only one magnesium oxide can be used, which most area of the ceramic masses used is absolutely burned to death, d. H. the magnesium oxide is allowed will. have no chemical reactivity whatsoever. as 35 According to the invention mentioned, iron oxide can only Hammerschlag (FejO «) can be used and it is it is necessary that he does not have water or water for a long time Exposed to air. The invention relates to a cold-curing binder system which sets at normal ambient temperature with high temperature resistance based on phosphate 40 compounds based on different types of cement for use as putty and adhesive, although they have the properties of rapid hardening possibly ceramic masses based on Tung, but such masses only reach after a longer period of time refractory raw materials such as chamotte, corundum, bauxite, storage time high strength. Your liability, in particular SiO ₂ or SiC can be added. The quick re on damp and dirty surfaces, as well Achieving strengths that can be achieved at 45 on metal surfaces is bad and ultimately are Room temperature are considerable values and are astonishingly - as is well known, such masses either not at all or only to a limited extent High temperature stable. fireproof. It is known, oxidic and / or silicate also the well-known magnesia cement, which by Raw materials with phosphoric acid or water-soluble reaction of magnesium oxide with magnesium chloride or To bring acidic phosphates to reaction, but 50 mg sulfate are obtained, harden rvar at normal Building materials bound in this way show a range of temperature more or less quickly, but this one of disadvantages. According to P. Bartha, H. Lehmann and H. Massen are special with regard to their fire resistance Koltermann in »Reports of the German ceramic not comparable with the masses according to the invention. Gesellschaft «48 (1971) No. 3, pages 111-115, react other, hydraulically setting compounds on the base acidic oxides with high ion potential at 20 ⁰ C not 55 MgO and ammonium phosphates or ammonium po- or slowly with phosphoric acid. Basic oxides, on the other hand, also harden quickly and lyphosphates react so quickly that there is no strength. That also achieve a good initial strength, however The optimum bond strength is weakly basic, their adhesion to the substrate is poor, and it is see or amphoteric cations with a small ion ra- as with the magnesia cements are not sufficient dins. But it is precisely these ions that do not count among the 60 fire resistance levels available. Substances with great fire resistance, which are due to cold In BE-PS 6 47 352 such binders are closer Binding of such materials with phosphoric acid is described. See Example 1 of this patent specification and / or acid metal phosphates contain evidence of the fire resistance of also do not have very high strengths, ammonium polyphosphate bound magnesite masses, which allowed their practical use. In the same 65 these indications show that such bound Work is on the binding of magnesia with masses after setting and weak heating Phosphoric acid said: »The results of the strength - good, but drop sharply at higher temperatures - Investigations show that the monobasic magneside has strengths.