DE2356524A1 - Aq. dispersion of silicates - for bonding rock material and for use as a glaze - Google Patents

Abstract

The aq. dispersion is composed of 30-50% soln. of phosphates or silicates and borates in water, the silicates being present pref. in the form of basic magma rocks or minerals of 0-0.09mm. grain size. The soln. contains in addn. alkaline salts such as R2O.B2O3 or R2O.P2O5 at a mole ratio of 3:2 in which R is the alkali aton. The dispersion contains mineral substances in sufficient quantity for the prodn. of mineral bodies which are hardened at 200-600 degrees C. The dispersion may contain mineral substances in sufficient amts. for use as a glaze, the coated mineral body being sintered at about 1000 degrees C.

Description

Applicant: Stuttgart, November 9, 1973

Claus Wüstefeld. . P 2790 S / kg 7035 Waidenbuch
Panoramaweg 17 ^c

Binding and glazing agent for granular rock material and its use

The invention relates to a binding and glazing agent for granular rock material in the form of a dispersion of silicates in an aqueous dispersant,

As is well known, glazes on ceramic products are usually made by very finely ground glass frits are floated in such an amount of water as is required to apply the material on the surface to be glazed is required, and

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then the body with the applied layer is heated to temperatures of over 1000 ^ C to daa To evaporate water and to melt the glass frit, so that a uniform glaze is formed. The glaze agent formed by the suspension of the glass frits in water forms, because glasses, essentially consist of silicates, a dispersion of silicates in water. The application of glazes in this method is relatively expensive because the glass frits are first made from suitable raw materials must be and the production of the actual glaze requires the use of very high temperatures.

It is also known to use silicates and phosphates as binders for the production of shaped bodies from rock material. From FR-PS 992 220 it is known to produce molded bodies from a sand mixture using an alkali silicate solution, namely soda water glass, as a binding agent is pressed to give shaped bodies and is cured either in the air or at temperatures up to 200 ⁰ C. The moldings produced in this way have an acceptable strength, but are not weather-resistant because of the water-glass solubility. To increase the compressive strength, these known shaped bodies can be treated with magnesium silicon fluoride. Glazing such a shaped body, as would be desirable for some applications, is not possible because the shaped body cannot withstand the temperatures required for glazing.

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-It is also from the magazine "Reports of the German Ceramic Society e" V. ", Volume 37 (1960), Issue 8, So 362 to 367, and Volume 4-0 (1963), Issue 7, S, 399" to 408, a binder for ceramic purposes is known which is formed by a mono-aluminum phosphate solution. This binder is used primarily to form refractory raw materials to bond to combustible shaped body "This binder gives a maximum compressive strength at a curing temperature of about 600 ⁰ C, However, the compressive strength drops rapidly when the temperature is increased above this value, as would be necessary, for example, to glaze such moldings above 600 ^° C. the chemical bond given by the binder is replaced by a ceramic bond.

In contrast, the invention is based on the object to create a binder for granular rock material that is waterproof and also burns with it manufactured moldings, so that the moldings can be provided with glazes »

This object is achieved according to the invention by a binder in which the dispersant consists of a concentrated, about 30 to [pO ^ igen solution of phosphates or silicates and borates in water and the silicates in the form of preferably basic, magnetic Rocks with a grain size of 0 to 0.09 mi are present.

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With the aid of the binder according to the invention can be by using relatively low temperatures in the range between 200 and 600 ⁰ C wajsserfeste moldings produced, for example, are suitable for use as cladding panels. In addition, the binder according to the invention is also suitable as a glaze agent and also produces coatings that are weatherproof and, when a suitable pigment is used, very decorative coatings even at temperatures of 200 to 600 C. Since the binding and glazing agent according to the invention consists of very cheap raw materials and no very high temperatures are required either for the production of the moldings or for the production of the glazes ₉ , the molded articles and glazes produced with the binding and glazing agents according to the invention are very cheap. It is of particular advantage that in the case of moldings which have been produced using the binder and glaze agent according to the invention, the binder and the glaze agent have the same properties so that the binder and glaze agent cannot interfere with one another. In addition, by using a suitable rock material for the shaped body, it can be achieved that there is an extensive correspondence between the thermal expansion coefficient of the shaped body and the glaze, which is important for the resistance and cracking; the glaze is of considerable importance. Furthermore, the elastic properties, viscosity and surface tension of the melt are decisive for the quality of a glaze. However, these properties also determine the quality of the

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Moldings produced according to the invention by binders. Therefore there is a practically complete correspondence of the properties between glaze and Foria bodies to be expected.

Suitable materials for the solution of the binder and the glazing agent according to the invention are other than acidic primary alkali metal phosphates u _e a. ITatriummetaphosphate polymerized, for example in the form of _o Kurrol's salt, Maddrell's salt (chain-like (NaPO ^)), or of Graham's salt (crosslinked (NaPO-,) (cross-linked (NaPO ₇₎ ^.), the soluble primary phosphates

D Z

of aluminum, magnesium and other metals, the sodium borates and boric acid together with Natriurametasilikato That there is the possibility of using boric acid and sodium metalicate together to achieve the highly concentrated solution required for the binding and glazing agent according to the invention, is in view of the. very surprisingly low solubility of boric acid alone. While the solubility of boric acid in water at room temperature is only about 4 g of boric acid per 100 g of water, it dissolves in 100 g of water with the addition of 100 g of sodium metasilicate (NagSiO ^. ^ H ^) 37 _? 5 S boric acid (Η-, ΒΟ,), so that one contains 237.5 g dispersant, in which, for example, 200 to 250 g basalt dust can be dispersed in order to obtain a finished binder »Basalt dust is particularly suitable for the silicate to be dispersed and at the same time it is available in large quantities for low costs, because it arises in the production of basalt gravel as a waste product in the cyclones of the basalt works and possibly also as a sieve fraction. Sin particularly high

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The literal starting material for the binder glaze agent according to the invention is that which occurs in magmatic rocks Wollastonite.

V / hen _v solution of the binder and the glazing agent according to the invention includes alkali metal salts, it has been found to be particularly advantageous if the molar ratio R ₂ OTB ₃ O ₅ or «R ₂ ORP ₃ O ₅ has the value '$: 2. In the above equations, R in each case represents the alkali atom. In order to adjust the molar ratio, the alkali content · Does may be the solution if necessary with NdpCO or NaIICO _3, or a similar alkali metal compound to be corrected, the dispersant ITaPO _3, and is therefore slightly acidic (p ™ = 6 at 1% solution), so develops when NaIIGO, is added. Carbon dioxide. The COp which forms can then be used as a blowing agent if a shaped body is to be produced using the binder according to the invention.

The binding and glazing agent according to the invention can also advantageously also contain an alumina mineral. When heating the binder and glaze When manufacturing or glazing moldings, their dispersed material is partially decomposed. Included arise alumina gels which promote the bond and therefore 'especially when using the invention Dispersion binders are useful.

When using the dispersion according to the invention as Glaze agent can apply this depending on the type of application the object to be glazed can be adjusted to a suitable consistency with water. Furthermore can

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the dispersion is also given a pigment to give the glaze the desired color. A preferred dispersion according to the invention that is particularly suitable as a glaze consists of about 50 parts by weight of monoaluminum phosphate solution and 50 parts by weight of volastonite. A glaze made from it is characterized by its particular hardness and strength. Also particularly good glaze gives a dispersion, the 78 wt% _o magnetic Gesteinsmateriäl, 14 wt.% ITatriumcalciumborat in the form of ulexite (UaCaBt-O. · _8Η ρ 0) and 8 wt% clay containing _e

Another dispersion, particularly suitable as a binder, contains 70 parts by weight of igneous rock material, 30 parts by weight of clay and 2 parts by weight of boron phosphate (BPCO ₀

The binding and glazing agent of the present invention is common by conventionally dissolving the specified substances in water and dispersing the rock or mineral dust When using certain starting materials or for certain applications, it can be produced in the solution the production of the binding and glazing agent according to the invention also take place according to other procedures. Bo the invention also has a method of making a * such binding and glazing agent to the subject, .which consists in that 55 "to 73 wt <,% of an igneous Rock material or minerals and 25 to 4-5% by weight Broken material from borate- and / or phosphate-containing glasses and possibly alumina-containing material in one The autoclave is reacted with water at a temperature of about 200 °

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borate- and / or phosphate-containing glasses in solution and form a 30 to 50% solution of phosphates or silicates and borate in water, in which the rock material or the ilinerals are then dispersed This process also allows waste products to be used to divide up the solution and int moreover favorable if the dispersed substances consist of an igneous rock or mineral with a low basicity or even with a high SiOp content. The obtained in this way Dispersion makes both a good binder and a good, in some cases slightly opalescent one .Glaze agent.

According to a further process for the production of the binding and glazing agent according to the invention, a mixture of alkali trisilicate, alkali bicarbonate and boric acid or alkali phosphate can be dissolved in water so that alkali metasilicate is formed in the solution of the alkali nitrilisate and the alkali bicarbonate, with CO ₂ and water being split off. This type of production is particularly advantageous if the dispersion according to the invention is to be used as a binder for moldings, because then the GOp that forms during the production of the solution can be used as a blowing agent for foaming the mass forming the moldings _o In this In this case it is particularly advantageous to add the dry mixture of alkali trisilicate, alkali bicarbonate and boric acid or alkali phosphate to granular magnetic rock material or mineral, which at least in part has a grain size of 0 to 0.09 mm, and by adding water

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to bring to the rock material in solution. In the produced within the rock material or mineral solution of Part disporgiert then the rock material or mineral whose grain size from 0 to 0.09 ^ i πηβ liöG ^to cL ^as binder according to the invention to be formed. The mixture used to produce the binder according to the invention can particularly advantageously consist of about 7 parts by weight of Na ₂ O.3SiO ₂ , about 9 parts by weight of NaHCO, and about 10 parts by weight of Na ₂ II ₂ P ₂ O ₇ .

The invention also relates to the use of the dispersion according to the invention for the production of fora bodies as well as for the production of glazed. Particle. In the production of molded bodies, the binder or whose starting material are mixed with a granular rock material in such an amount that a malleable mass is created. Moldings are then produced from the moldable mass and at temperatures cured between 200 and 600 C. The moldings produced in this way have a high compressive strength and are waterproof «, the rock material can in particular consist of basalt, diabase, melaphyr or similar rocks. The grain size should be appropriate than 5 rom.

The binder according to the invention is suitable not only for the production of moldings of high strength, but can also firing the shaped body at about 1OOO ⁰ C increases, thereby increasing the strength values of the shaped bodies can be achieved over those obtained by hardening the molded body at temperatures between 200 and 600 ⁰ G are achievable », In addition

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is it possible to start the burning process "immediately Applying a glaze to take advantage of. So it is when using the binder according to the invention it is not necessary to particularly fire the moldings before they are provided with a glaze. As already explained above, it is of special importance The advantage that the glaze agent and binder have the same composition.

If the glaze agent according to the invention is used for the production of glazed stones, the glaze agent is mixed with a coarse-grained rock material in such an amount that the individual parts of the stone material are coated with a film of the glaze agent, and the coated parts are then continuously moved exposed to a temperature of 200 to 600 ⁰ C. This creates a weatherproof coating on the individual parts of the rock material, the color of which depends on the pigment that was added to the glaze. These glazed stones can be used, for example, as aggregates for plaster, as material for the outer layers of exposed aggregate concrete and the like. Purposes. Here, too, the rock material can consist of basalt, diabase, andesite, melaphyr and similar natural stones. The grain size should expediently be more than 1 mm. Here, too, it is finally possible ^{to burn the coated parts at around 1000 °} C. if a particularly shiny and durable surface is to be achieved.

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Using the binder according to the invention, porous molded bodies can ultimately also be produced by mixing the binder or its starting materials, including water, in such an amount with a rock powder with a grain size of 0 to 0.09 mm that a mouldable mass arises that produced from the moldable composition, a molded article and dried slowly at temperatures between 140 and 200 ⁰ G, and is finally brought at temperatures between 700 and 900 ⁰ C to the softening glassy 'and foaming as a result of discharge of the residual water. This creates glass-like moldings that are suitable for a wide range of purposes »

In general, it can be stated that a high content of basic oxides and boric anhydride greatly improves the meltability of the material and increases the mass It is particularly suitable for the production of foam glass and for use as a glaze mass. Glazes from igneous rock material and such minerals easily crystallize. The crystallization of the Glazes are made with a significant amount of oxides of iron and bivalent metals. If the tol ratio SiOp / MOj if M is a metal atom, increased to 2.3 and the content of When alkalis and boric anhydride are increased, the crystallizability of the glaze is greatly reduced The crystallization can still be changed by different operating values during firing. at higher temperatures, higher burning rate and

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the conditions are higher difficult for crystals to separate and grow.

In contrast, when the dispersion according to the invention is used as a binder for the production of formal bodies, crystal formations are desirable. In moldings produced according to the invention, the crystals of the following minerals were identified: Pseudo-V / ollastonite CaSiO-,
Anorthite CaAl ₂ Si ₂ Og

Carnegite NaAlSiO ^

These crystals are the cause of considerable increases in strength, which can be achieved by firing the shaped bodies at about 1000 G. The formation of Pseudo-V / ollastonit is particularly favored when using a phosphate-containing binder and can through Adding wollastonite to the mixture of starting materials In addition, “this is the way to produce particularly hard moldings”.

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

example 1

A solution of 10 parts by weight of Na ₃ SiO ₅ .5H ₂ O and 3.6 parts by weight of H ₅ BO ₅ in 10 parts by weight of water was first prepared by first adding the sodium metasilicate

stirred into the water and then adding the boric acid

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entirely to the solution; brought; became. 20 parts by weight of this solution were added to 100 parts by weight of a basalt material composed of 4-0 / i from a portion with a grain size between 0.63 and 2.0 mm, and a further 40% from a portion with a grain size of 0.09 "to 0.63 mm and about ZCP / σ consisted of basalt powder with a grain size of less than 0.09 mm. When the basalt material and the solution were mixed, the solution and the dust content of the basalt material resulted in a dispersion that acts as a binding agent The amount of water brought in by the addition of the alkali silicate solution was also sufficient to turn the basalt material into a well-moistened, malleable mass

Made of approximately 100 χ 150 cm 'in size and 2 cm thick.

To compress the material, the! .Lasse was inserted into the. Shaking forms. Subsequently, the plates in the molds at a temperature of 200 ⁰ G were dried and cured. The molded plates obtained in this way were waterproof and therefore absolutely weatherproof. Its compressive strength was about 200 kg / cm

Example 2

The mold plates produced according to Example 1 were after removal from the molds coated with a glaze made from 50 parts by weight of the mixture according to Example 1 prepared alkali silicate solution and 50 parts by weight Basalt flour. The ones provided with the glaze layer

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"Mold plates were then fired at 1000 ° C. The fired mold plates had an increased pressure

strength of about 300 kg / cm and were provided with a shiny, extremely resistant glaze. The glaze can be colored with metal oxides as color pigments, including about -15 »metal oxide, based on the dry mass of the glaze.

Example 3

To 100 parts by weight of a basalt material as was used in Example 1, 15 parts by weight of a powdery mixture were added, consisting of about 7 parts by weight of Ua ₂ 0.3SiO ₂ , about 9 parts by weight of UaIICO, and about 10 parts by weight NapHpPp ^ consisted. To the dry mixture of these materials was added as much water as was necessary to obtain a moist, malleable mass. This cash register was then in turn filled into molds for the production of plates. The plates had an area of 100 × 150 cm and a thickness of 2 cm. The shaped bodies thus formed were then cured at 200 ⁰ C. Under the influence of heat, the sodium silicate and the sodium bicarbonate of the binder powder react to form sodium metasilicate, which then goes into solution together with the sodium phosphate in the water added to the mixture. The solution then in turn forms the binder dispersion with the basalt powder contained in the rock material. When converting the sodium silicate and dös sodium bicarbonate

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besides water, CC ^ is released, which causes the Molded body causes. The height of the plates formed in the iron molds was determined by the released GOp increased to 3 cm. The cured panels had a compressive strength of 150 kg / cm. The density was 1 g / cm. These foamed Pormplatten are also weatherproof and can be used in a variety of ways. In particular, they can be used in the in Example 2 provided with a glaze and used as light glazed cladding panels will.

Example 4-

To 150 parts by weight of a basalt material with a grain size of 1 to 5 mm, 2 parts by weight of a dispersion were added, the equal parts of the alkali metal catalyst solution prepared according to Example 1 and basalt powder with a grain size of less than 0.09 mm and a small Amount of pigment. These substances were mixed thoroughly so that the individual parts of the basalt material were coated with an egg of the dispersion as a glaze agent. To ensure an even coating, a small amount of water was added. The amount of water was less than 1 part by weight . Thereafter, the coated film with the stone material was heated in a rotary kiln to a maximum of 600 G ^0. the material was constantly circulated in the rotary kiln, so that · a free-flowing granulate formed,

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the particles of which are coated with a colored glaze was. The glaze obtained in this way is weatherproof, so that the color granulate obtained as Additive for plaster, for the production of the flat surfaces of exposed aggregate concrete, as Liosaikraaterial and the like. suitable is. If particularly hard and shiny glazes are required, the granulate can also be used afterwards can still be fired at temperatures of about 100 ° C.

Example 5

There were 100 parts by weight of basalt material, 4-0% consisted of basalt flour with a maximum grain size of 0.09 and 60% of a grain size of 0.09 to 0.7 mm, 13.7 parts by weight sodium hydrogen phosphate (NaHpPO ^) and 4.5 parts by weight of sodium bicarbonate (NaIICO,) mixed dry. 12 parts by weight of water were added to the dry mixture, so that a mouldable mass was formed.

ρ The mass was then made into plates of 100 χ 150 cm in molds and a thickness of 2 cm. Through the action of the reaction of acid phosphate with sodium bicarbonate The resulting propellant COp became the strength of the plates elevated. The effect was increased by gradually heating it to 200 ° C. In this way a total height of the 4 x cm plates achieved the compressive strength

the plates were about 150 kg / cm after curing. By firing at 1000 ^° C., the compressive strength could be increased to about 250 kg / cm.

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Example 6

A dry mixture of 100 g of basalt dust, 4-0 g of Ha ₂ SiO 5H ₂ O and 15 g of Η, ΒΟ-, was moistened with so much water that a malleable mass was formed. The mass was poured into a metal mold and slowly heated to 200 ° C. over the course of two hours. The mass retains a residual moisture level of about 5%. After that, the Hasse was heated to about 800 ° C. in order to bring it into a glassy, softened state. The mass was kept at 800 ^° C. for about 15 to 30 minutes. As a result, the remaining amount of the YTassera was driven out with foaming of the vitreous mass. In this way, space bodies with a weight of about 0.2 g / ciir are achieved. ·

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Claims (1)

- 18 - Claims Binding and glazing agent for granular rock material in the form of a dispersion of silicates and stones aqueous dispersion medium, characterized ■ that the dispersion medium consists of a concentrated solution of about 50% to 50% of phosphates or silicates and borates [in water ordered and the silicates in the form of preferably basic igneous rocks or minerals with a grain size of 0 to 0.09 ma. 2. Binding and glazing agent according to claim 1, characterized in that if the solution contains alkali salts and R denotes the alkali atom, the molar ratio R ₂ OiB ₂ O ₅ or R ₂ OtP ₂ O ₅ is 3: 2 . 3 · binding and glazing agent according to claim 1 or 2, characterized in that the dispersion additionally contains an alumina mineral. 4 ·. Binding and glazing agent according to one of the preceding claims, characterized in that the dispersion also contains a pigment. 5. binding and glazing agent according to claim 1 or 2, characterized in that the dispersion consists of about 50 parts by weight of tlonoaluminium phosphate solution and 50 parts by weight of wollastonite. 509822/0370 - 19 - 6. binding and glazing agent · according to claim 3 »characterized in that the dispersion is 78% by weight igneous rock material or mineral, 14% by weight, sodium calcium borate in the form of ulexite (NaCaB, -0, .. 8H ₀ O) P 9 2 and contains 8 wt.% clay. 7. Binding and glazing agent according to claim 3, characterized in that the dispersion contains 70 parts by weight of magnetic rock material or mineral, 30 parts by weight of clay and 2 parts by weight of boron phosphate (BPO ^). 8. A process for the production of a binding and glaze agent according to one of claims 1 to 3 »characterized in that 55 to 75 parts by weight of igneous rock material or mineral and 25 to 4-5 parts by weight of breeding material containing borate and / or phosphate glasses and optionally alumina-containing material is reacted in a Autoklaven.mit water at a temperature of et \ va 200 ⁰ C. 9. Process for the production of a binding and glazing agent according to one of claims 1 to 3 »characterized in that a mixture of alkali trisilicate, Alkali bicarbonate and boric acid or alkali phosphate is dissolved in water so that it is in the Solution of the alkali trisilicate and the alkali bicarbonate with elimination of COp and water alkali metasilicate educates « 10. The method according to claim 9i, characterized in that .that the dry mixture of alkali trisilicate, alkali bicarbonate and boric acid or alkali phosphate 50 98 22/03 70 granular igneous rock material or Mineral, which at least partially has a grain size of 0 to 0.09 ma size, is added and is brought into solution in the rock material by adding water. 11. The method according to claim 9 or 1O, characterized in that the mixture used of about 7 weight ropes Iia ₂ O.3SiO _? , about 9 parts by weight of ITaHCO-j and about 10 parts by weight of Ha ₀ H ₀ PO ₀ . 12. Use of the binding and glazing agent according to one of claims 1 to 7 for the production of molded articles, characterized in that the binding agent or its starting materials are mixed in such an amount with a granular rock material, for example. v / ground that a moldable mass is obtained, produced molding of the moldable material and, finally, these molded articles cured v / ground at TemperaiTuren between 200 and 600 ⁰ C. 13. · Use according to claim ^ 2, characterized in that the rock material consists of basalt, diabase, andesite, melaphyr and similar natural stones and has a grain size of less than 5 Β ⁰¹ · Use according to Claim 12 or 13, characterized in that the hardened shaped bodies are fired ^{at temperatures of approximately 1000 ° C.} 509822/0370 15 · Use after. Claim 14, characterized in that that the hardened molded bodies are provided with a layer of glaze before firing will. 16. Use according to claim 15 »characterized in that that the glaze layer consists of a glaze agent according to one of claims 1 to 7. Use of the binding and glazing agent according to one of claims 1 to 7 for the production of glazed stones, characterized in that the binding and glazing agent is mixed with a coarse-grained rock material in such an amount that the individual parts of the rock material are mixed with one Film of the binder and glaze agent are coated, and that the coated parts are then exposed to ^{a temperature of 200 to 600 0 G with constant movement.} 18. Use according to claim 17 »characterized in that that the rock material consists of basalt ^ diabase, andesite, melaphyr and similar natural stones exists and has a grain size of more than 1 mm. · 19. Use according to claim 1.7 or 18, characterized in that the coated parts are baked ^{at about 1000 ° C.} 509822/0370 20. Use of the binding and glazing agent according to one of claims 1'to 6 for the production of porous molded bodies, characterized in that the binding agent or its starting materials, including water, in such an odor with an igneous rock odor liineralmehl the grain size of 0 to 0.09 is now mixed so that a formable Eassa arises, that a molded body is produced from the mouldable mass and slowly dried at temperatures between 140 and 200 ° C. and finally at temperatures between 700 and 900 ^° C. for glassy softening and for Foaming is brought about as a result of the release of the residual water. > ■ OMQINAL INSPECTED 509822/0370