LU83082A1 - INORGANIC FOAM - Google Patents

Description

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The present invention relates to inorganic foams and, in particular, rigid foams made of a clay mineral material. In particular, the invention relates to inorganic foams made up of several movisse beads derived from one or more laminated mineral materials, as well as a process for the manufacture of these products. The invention also relates to inorganic foams made up of certain materials mineral laminates or a mixture of two or more laminated mineral materials, a process for the manufacture of these foams, the uses of inorganic foam products, and an intermediate product for use in the manufacture of foam products inorganic.

Layered mineral materials are natural forms of silica and they are phyllosilicate materials, that is, they have a layered structure. The term "layered mineral materials" includes, for example, vermiculite, kaolinite and other clay mineral materials, montmorillonite, sepiolite, attapulgite, illite and saponite.

Clay minerals are found in varieties of clays in the form of particles with a diameter of a few microns, which are aggregates or agglomerates of small crystalline units of mineral matter with a granularity below one micron. Kaolin-type clay * is essentially an agglomeration of laminated units of clay mineral kaolinite; it is understood that, as used in this specification, the expression "kaolinite" includes the mineral matter of kaolin is in its natural state, although these clays may not consist of pure kaolinite . The refractory clays are made up of a mixture of kaolinite and illite.

Layered mineral materials are well known £ and at least some of them are widely used in industry. Clays containing kaolinite and kaolin are widely used in many industries, for example, in the ceramic materials industry (main use) for the manufacture of white earthenware, porcelain and refractory materials, as well as as filler for paper, paints, adhesives, plastics and rubbers. Vermiculite is used, usually in a thermally exfoliated form (exfoliated vermiculite) as insulation by stuffing, in bonded form in slabs or plates for insulation and fire protection applications, as well as in applications agricultural where ions are involved. It has been proposed to use delaminated vermiculite (by this is meant vermiculite which has been delaminated by a chemical treatment followed by swelling in water and grinding or crushing) for the manufacture of papers or sheet materials, ^ as coating materials for substrates and also for

See the manufacture of rigid inorganic foam products for insulation and fire protection purposes.

The foam consisting of delaminated vermiculite and its uses are described, for example, in United States patent No. 4 * 130,687 by the Applicant. Montmorillonite ___L. J I___ * ___ "I _ _î -1 __ ^ f J ___-" * · _ J ____ I ___- ___ 1 - 4 - is widely used in the ceramic materials industry ·

Rigid materials formed from kaolinite, - for example, white fal'ence, porcelain and refractory materials, are dense and fragile materials manufactured by processes in which an operation of cooking or sintering is involved. Although kaolinite itself is a poor conductor of heat, rigid and high density materials made so far from this material do not have good insulating properties, due to their high density (and, therefore, their significant weight), their fragility and their non-exceptional insulation properties, products made from clays containing kaolin are not used to a large extent for thermal insulation or protective applications. against fire. Rigid materials made from thermally exfoliated vermiculite are dense (heavy) and quite brittle, however, although they are used in industry to protect steel constructions from fire, they are not '' widespread use as insulation material. Rigid foam materials made from delaminated vermiculite (as opposed to thermally exfoliated vermiculite) are lightweight and have good insulation and fire protection properties, but are difficult to obtain in large dimensions. Since these products tend to crack and deform strongly during drying, it is difficult to produce them in the form of slabs or plates having dimensions greater than __TT ____X _ T, on ~ -Λ-L '—ij _ OJ 1 · ______ - 5 -

In a first embodiment, the present invention lies in the discovery of a type of low density product consisting of laminated mineral materials, this product being both light and having good properties thermal desolation and protection against l 'incend :: die, while it can be easily manufactured in the form of slabs or plates of large dimensions, for example, of dimensions up to 3 ni x 1 mx 10 cm thick.

According to a first embodiment of the invention, there is provided a rigid inorganic foam product having, preferably, a density less than 0.4 g / ml, better still, less than 0.2 g / ml, this product consisting of pearls of one or more laminated mineral materials each having a cellular structure.

The expression "pearls", used throughout this specification, means particles, grains, pieces or small balls of foam having an essentially continuous cellular structure in which the walls of the cells are formed by the particles laminated mineral material (s), although this expression does not imply any particular size, shape or configuration of the pieces of foam. Specifically and for information only, the beads are cylindrical or essentially spherical pieces of foam of a maximum dimension less than about 5 nun, for example, from 0.5 to 5 mm.

As will be described below in more detail, the inorganic foam products are formed by assembling the cellular structure beads into products having the forms - 6 - so that the products thus obtained have an essentially cellular structure, although the actual cell structure may not be continuous throughout the product.

It is understood that the term "rigid inorganic foam product", used throughout this specification, includes products in which the cellular structure is not actually continuous. Thus, for example, this expression includes products in which the beads are bonded together by means of an adhesive or by mutual attraction, while voids exist between the beads within the structure of the product.

The density of the foam products of the present invention is normally less than 0.25 g / ml and may be as low as 0.06 g / ml for particularly light products. More specifically, these products have a density in the range of 0.08 g / ml h 0.15 g / ml.

By the expression "rigid foam", applied to pearls, is meant a material having a structural integrity which is a two-phase dispersion of a gas in a solid matrix which is an essentially continuous cellular structure while, by the expression "rigid inorganic foam" applied to pearls means a rigid foam which consists essentially of an inorganic material, although the presence of small amounts of organic material constituting impurities of the mineral material (s) laminated or deliberately added (by for example, an organic surfactant used in the manufacture of the foam as will be described below) is not excluded.

From dIus. nar exoression "inor foam product <ranimie ri σΐΗρ1 - 7 - applied to products made up of an assembly of pearls, we do not exclude the presence of a small quantity, for example, up to 20%, d an organic material present in the pearls or deliberately added, for example, as a binding agent to join the pearls into a self-supporting structure.

According to the above embodiment of the invention, a product of an essentially cellular structure is obtained comprising beads with a cellular structure made up of one or more laminated mineral materials. According to another * embodiment of the invention, a product with a real cellular structure is obtained which derives directly from a suspension of certain laminated mineral materials or from mixtures of laminated mineral materials.

According to a second embodiment of the invention, a rigid inorganic foam with a cellular structure is provided, made up of a mixture of laminated mineral materials and preferably having a density of less than 0.4 g / ml, better still less. at 0.2 g / ml.

Also provided is a rigid inorganic foam with a cellular structure consisting of montmorillonite and preferably having a density of less than 0.4 g / ml, better still less than 0.2 g / ml.

According to another embodiment of the invention, there is provided a rigid inorganic foam with a cellular structure consisting of sepiolite and preferably having a density of less than 0.4 g / ml, better still less than 0.2 g. / ml.

A rigid inorganic foam with cell structure is also provided, consisting of a figulin clay and / or a refractory clay and preferably having a density • î “· Ρ û * vî Cil * λ Γ4 OA rr / rn Ί m A ”. * Λ μ λ λ M ^ A i Γ4 O _ / _ 1 - 8 ~

Whether in the form of pearls or of products directly extruded, the foam products of the present invention are obtained by a process consisting in incorporating a gas in a suspension (or dispersion) of a mineral material laminated in a liquid medium and another characteristic of the invention resides in a method of manufacturing a rigid inorganic foam with a cellular structure made up of one or more laminated mineral materials, this method consisting in gasifying a suspension of one or more mineral materials laminated in a liquid medium containing a surfactant to form a foam or a stable wet foam, while removing at least part of the liquid medium from this foam.

The expression "stable moist foam or foam" means a carbonated suspension which does not collapse when it is left to stand or when the liquid is removed therefrom and which, in particular, when it is left to stand, does not not sag (no significant reduction in foam height) within 10 minutes. As will be described below in more detail, the stability of the carbonated suspension depends mainly on the particular surfactant used for its formation and the Applicant has found that, although certain surfactants · , for example, saponin and fatty amines, make it possible to obtain a foam, this however is not stable and collapses in a few minutes; the manufacture of such an unstable carbonated suspension does not fall within the scope of the present invention.

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As indicated, rigid foams are produced by a process consisting in gasifying a suspension of one or more laminated mineral materials, the liquid medium then being removed from the foam obtained. When the foam is produced in the form of pearls, the carbonated suspension or foam can be divided into droplets or wet particles before the liquid medium is removed. The division of the carbonated suspension or foam into particles or into wet droplets can be accomplished in various ways - for example, by spraying this foam through a nozzle or other orifice, by extruding this foam through orifices practiced in a strip or by any other known technique for dividing suspensions into droplets or particles. Wet particles or droplets must be dried at least partially before they can be recombined. Dry or partially dry beads can be obtained using a spray dryer. The partially dry beads can be further dried by heating them under conditions in which they cannot combine, for example, in individual layers or agitated beds such as a fluid bed. These beads can also be formed by shaping the foam into lengths similar to fibers, then drying and cutting the dry or partially dry material.

The density of the rigid foams (beads or directly extruded products) obtained by the process of the present invention can be varied in various ways, for example by incorporating different amounts of a gas into the suspension. . . , j, Λ i · »ry. . The solids content of the suspension. This solids content of the suspension influences the viscosity of the latter, in the same way as the particular surfactants used; and the temperature at which gasification is carried out, but, as a rule, an increase in the solids content of the suspension has the effect of increasing the density of the foam formed therefrom. More specifically, the solids content of the suspension will be between 10 and 60% by weight, preferably between 20 and 40% by weight thereof. A deflocculating agent, for example, sodium tripolyphosphate, can be added so as to be able to manufacture suspensions having a high solids content,

The suspension of the laminated mineral material will usually be aqueous and, in particular, it will be a suspension or dispersion of the particles of the laminated mineral material in water, preferably in distilled or demineralized water. The laminated mineral materials are generally suspended or dispersed easily in water in order to form suspensions having colloidal properties. The liquid medium of the suspension can optionally be a mixture of water and a water-miscible solvent such as than alcohol. However, the liquid can optionally be an organic liquid. When the suspension is transformed into a foam, then into a rigid foam, it is necessary to incorporate a surfactant in the suspension and this agent will normally be added to water before or during the formation of this suspension. It is understood that, in the case of the laminated mineral material "vermiculite", the delamination thereof may give rise to the incorporation J3 f - _ - _ J- w-v e—> 4 Λ _. Λ "î · Ρ Ί n · - · 1" "m -i ~ 4 λ μ η ^ Ώ1 Λ m 4 ^ 4 Q / -" λ4 * i 1 τ '"rv rf - 11 - active, before, during or after the suspension has been formed, other agents such as fillers, agents which improve compressive strength, agents which improve stability against water and agents may be incorporated into the latter. deflocculants.

Any surfactant can be used which, upon gasification of the suspension, gives a moist foam or foam which is stable. By this is meant that this foam or foam does not collapse when it is let stand for at least 10 minutes or when the liquid medium is removed. Anionic, nonionic or cationic surfactants can be used as long as they give a stable foam. Therefore, it will be easy to determine whether a surfactant can be used in the process by means of a simple experiment consisting purely in determining whether this agent makes it possible to form a foam or a wet foam from a suspension having, for example, a solids content of 30% and if, if so, the foam is stable. For your information, a moist foam or scum which, when left to stand, does not sag (for example, if a strong reduction in the height of the foam is not observed) within a period 10 minutes, preferably, within a period of one hour, will generally be suitable for undergoing drying in order to form a rigid foam in accordance with the invention. When it comes to - performing a test, the surfactant undergoing the latter can be used in any desired amount or in different concentrations as long as it does not cause flocculation of the foam ; as a rule, a large quantity of this agent (for example: 2% by weight of the solution) will indicate, during an initial test, whether the agent deserves a further test "

It is preferable, but not critical, to use surfactants which can be used in low concentrations. It has been observed that a surfactant forming a stable foam from a suspension of a laminated mineral material, was not able to give a foam of comparable stability from a suspension of another * layered mineral material or mixed mineral materials such as a mixture of kaolinite and delaminated vermiculite. Likewise, a surfactant which does not give a stable foam from a suspension of a laminated mineral material, can nevertheless form a stable foam from a suspension of another laminated mineral material or materials mixed minerals. For example, n-butyl ammonium chloride which is a surfactant, does not give a particularly stable foam from a suspension of kaolinite alone, but it does form a stable foam from a suspension of vermiculite delamified or a 50:50 mixture (by weight) of kaolinite and delamified vermiculite.

This characteristic should be taken into account when carrying out a test to determine whether a surfactant is suitable 3 in other words, the test should preferably be carried out using the actual suspension which the '' we want to gasify, then dry, to obtain a rigid foam.

With regard to the surface-active agents, it has also been observed that those which most readily form a foam η.τ η Λ "wm A Vk i — k / 4 Λ v * k Π η ^ T-. 4 "Λ nt ~> m ri Λ λ η ί— · η - η λ __- _ _Ι_ 1 t λ .. ._ ... 1 Λ W-» Ί * ι r * -13- surfactants giving no foam with certain difficulties (for example, after prolonged vigorous stirring of the suspension), tended to yield the most stable foam, however the ease with which a surfactant achieves a foam does not constitute conclusive proof concerning the compatibility of this agent for the process of the present invention and it is understood that this is by no means limited to agents having poor characteristics concerning the foaming.

The amount in which the surfactant is used can vary within wide limits, for example, depending on the solids content of the suspension, the particular laminate and surfactant, the particular gasification technique adopted and the temperature of this gasification. For information, the amount of surfactant will be specifically between 0.1 and 5% by weight, calculated on the weight of the layered mineral matter contained in the suspension to be gasified. Since the surfactant remains in the rigid foam when the liquid is removed from the foam and its presence in the rigid foam is undesirable, it is preferable to use it in as small an amount as possible. compatibility with the formation of a stable foam which does not collapse when the liquid is removed.

Gasification of the suspension can be carried out in various ways, for example, by releasing the vapor or gas contained in the suspension or by mechanically entraining a gas contained in the suspension by rapid agitation of the latter. The gas will normally be inert vis-à-vis cirο mo cirve 4 f o nu ai "" - "" ax ·· "" ît vT a 1 I on η 1 î Q "? Λ + a - 14 - bone. The mechanical entrainment of the gas contained in the suspension can be carried out, for example, by rapidly stirring, beating or vigorously agitating the suspension.

The vapor or the gas contained in the suspension can be released by heating the latter, preferably quickly, in order to release bubbles from the gaseous liquid medium (water vapor when this liquid medium is aqueous) or in order to release bubbles vapor of a substance (blowing agent) deliberately incorporated into the suspension as a source of vapor for the gasification of the foam. The blowing agent can be, for example, a hydrocarbon, a chlorocarbon, a fluorocarbon, a chlorofluorocarbon or a source of carbon dioxide. The suspension can be gasified by subjecting it to electromagnetic radiation having a frequency in the range of 10 ^ Hz to 1012 Hz.

The formation of the suspension and the gasification of the latter (when this gasification does not involve a heating step) can advantageously be carried out at room temperature, although it is possible to adopt higher or lower temperatures.

The elimination of the liquid medium from the gasified suspension will normally and mainly be carried out by means of evaporation usually caused by heating the gasified suspension. You can adjust the rate of liquid removal from the foam, for example, by adjusting the temperature or using a drying container with elements to control humidity to prevent drying too fast foam, which. · »I \ ·. AT . . m _t ___ _1 ___ _________ ____ ___ - 15 - the moist foam at room temperature for a prolonged period, for example, for several days, so that the foam can dry completely and acquire a rigid structure. However, the foam is normally heated, after shaping, to temperatures up to about 90 ° C in order to remove the liquid medium. The control of the drying conditions can be important during the manufacture of products such as slabs or plates directly by extrusion of the carbonated suspension and by drying, but this control is less important during the manufacture of pearls during which can dry quickly, for example, at temperatures up to 200 ° C or even higher.

Rigid inorganic foams made of layered mineral materials tend to be soft and of low compressive strength. Depending on the particular layered mineral material, the resistance of the foams can be improved by incorporating an agent improving the compressive strength therein and / or by heating the dry foam in order to sinter it. Generally, when incorporating strips of vermiculite (delaminated vermiculite) in the foam consisting of mixed mineral materials, for example, by incorporation in the suspension before gasification, there is an increase in the compressive strength of the foam . Except in the case of foams made entirely of vermiculite, robust foams are obtained by sintering the rigid and dry foam obtained by drying the carbonated suspension, for example, by heating the dry foam to a temperature of up to 1,000 ° C. or even , _, _ ry. ,, _ n ί,, A _, - 16 - cellular and remains a light matter. The sintering of foam made of a mixture of vermiculite and another mineral material can lead to an increase or a reduction or even a very small change in their density according to the proportion of vermiculite contained therein, and according to the weight loss undergone by the material when the foam is heated to sintering temperatures.

Sintered foams made of laminated mineral materials, as well as their manufacturing process fall within the scope of the present invention.

Rigid unsintered foams made of laminated mineral materials have a low resistance to degradation by liquid water and, according to the invention, it is preferable to subject these foams to a treatment in order to improve their water stability. . For example, the foams can be made waterproof by incorporating a precursor of a silicone polymer therein, then by creating, inside the foam, acid conditions under which the polymerization of the precursor takes place with formation. of a silicone polymer in the foam. For example, sodium methyl siliconate can be incorporated into an aqueous suspension of kaolinite before or during the gasification of the suspension and, while it is still wet, the foam obtained can be subjected to a treatment with an acid gas such as than carbon dioxide gas in order to create the acid conditions essential for the polymerization of siliconate in order to obtain a silicone polymer. Instead of treating the foam with an acid gas during the drying; rigid foam during the manufacturing process thereof: T ο λ "λ,, 4- ο λ4- om or \ + · ύ ~ \ ι ιτ c -î mr *> · η O rm OA <4 IO mi - 17 - • treatment with an acid gas, the moist foam can be allowed to sit in air for an extended period of time, after which carbon dioxide from the air is absorbed to create the necessary acid conditions in the foam. When a silicone polymer incorporated before sintering is to be destroyed, sintered foams can be made waterproof with a silicone polymer after sintering.

The relative proportions of the laminated mineral materials contained in the suspension of mixed mineral materials and, consequently, in the rigid foam obtained, can vary within wide limits, for example, depending on the compressive strength and thermal insulation properties which must be have rigid foam. The foams may consist, for example, of kaolinite or of a clay containing kaolin, and of vermiculite in the relative weight proportions ranging from 90:10 to 10:90. As a general rule, when you increase the relative proportion of vermiculite lamellae in rigid foam, you not only increase the compressive strength of this foam, but also its thermal insulation coefficient (K value).

Rigid foam with a cellular structure made up of vermiculite lamellae, as well as their manufacture by gasification of a suspension of vermiculite lamellae with a view to forming a foam, by extrusion thereof and elimination of the liquid medium out of this foam. described in British patent application No. 14764/76 and the corresponding patent of the United States of America No. 4 · 130 · 687 in the name of the Applicant, in which also describes the formation of suspensions of vermiculite lamellae. NPC m n + n nnc ri c »ri o Vino-irnt o4- ri a r ·» ci Kr »o- \ ro + · c? Nn + - 18 -

Rigid foams consisting of mixed mineral materials and containing delaminated vermiculite according to the present invention advantageously derive from a suspension of vermiculite lamellae by incorporating another mineral material laminated in this suspension before gasification thereof. As described in US Patent No. 4,130,687j the Vermiculite lamella suspension will usually contain a surfactant such as n-butylammonium chloride used in formulating the suspension so that the incorporation of another laminated mineral material in the latter has the effect of providing both this suspension and the surfactant which are necessary for the manufacture of rigid foams as described in this specification.

Preferably, the foams made up of mixed mineral materials and containing vermiculite comprise an agent improving the compressive strength and the water stability of rigid foams made up only of vermiculite strips. Improvement of the compressive strength and the water stability of vermiculite foams by incorporating an agent improving this compressive strength and which is a solid particulate matter having a basic reaction in water, is described in British patent application No. 33723/78 and the corresponding European patent application No. 79301577 ·? of the Applicant, the descriptions of which are given here for reference. As described in these patent applications, the preferred agent for improving compressive strength and water stability is magnesium oxide

An t% "-" "" + * î Ί oe <# -ii t I "î 1 e.e4- r \ i ^ APP» r »aK 1 a rî î i τι r * n τ * γ \ α · ρ p · τ '* <1 a tic: 1 P <3 - 19 - of Vermiculite) according to the present invention. As described above, as a variant, the compressive strength can be improved foams made of mixed mineral materials by sintering.

The suspensions containing a surfactant used to form the rigid foams of mixed laminated mineral materials of the present invention are obtained according to yet another characteristic of the latter, including the following suspensions of mixed laminated mineral materials: (i) a suspension of vermiculite lamellae and one or more other mineral materials laminated in a liquid medium containing a surfactant.

(ii) A suspension of vermiculite lamellae, one or more other laminated mineral materials, as well as an agent improving compressive strength and water stability, for example, magnesium oxide, in a liquid medium containing a surfactant; (iii) a suspension of the type indicated sub (i) or (ii) above and containing, in addition, a deflating agent, for example, a tripolyphosphate, and (iv) a suspension of two or more laminated mineral materials in a liquid medium containing a surfactant *

Preferably, the liquid medium of each of the suspensions is an aqueous medium and, in particular, water. Also preferably, in each of the material suspensions

mi nPPal ac * t · Ρ4 Pôc tnî v + oe itnû rlo nol 1 oc <- »- 5 aef 1 o Vonl i ni 4 P

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Each of the suspensions (i) to (iv) above can be dried in the same way as analogous suspensions free of surfactants, for example, by spray drying, in order to obtain a corresponding dry powder material and fluid $ materials of this type are also obtained - according to the invention. These dry powder materials are easily redispersed in a liquid medium, in particular water, in order to form a suspension which can be transformed into a rigid foam by the process described in this specification. In the case of dry powder materials containing magnesium oxide, it is preferable to dry a suspension free of magnesium oxide and to add the latter to the dried suspension. It will be understood that the dry powders according to the invention can also be obtained by mixing dry powder comprising strips of vermiculite, with another mineral material layered in powder (optionally in mixture with sodium tripolyphosphate) and optionally with dry magnesium oxide powder.

Whether they consist entirely of a single layered mineral material or mixed mineral materials, for example, kaolinite and vermiculite, the rigid foam products obtained according to the present invention are heat-resistant and thermally insulating materials useful in a wide variety of applications involving fire protection and thermal insulation. These products can be produced in the form of slabs or plates which will be used in subsequent manufacturing processes, for example, for the formation of laminates with sheets of a wide variety of materials such as r \ Ci * t ff IAT> rt ii "J" —— 1 Μ o * T {"M -i η τΛ 4" ATA "n - * Ci ri Ί A ri ni <5 4- -î XV" Ci fi - 21 - of canvas glass fibers impregnated with vermiculite and polymers. These laminates form decorative building panels useful for the building industry. The tiles can be used directly without being laminated with another material, for example, for coating building elements of wood, cement or steel to form a layer of fire protection and a layer of thermal insulation around these elements; these tiles can also be used as roofing panels, interior cladding panels and ceiling tiles.

Rigid foams can be subjected to elevated temperatures, for example, up to 1,000 ° C, for extended periods of time without undergoing any disintegration, although prolonged exposure to elevated temperatures will result in product embrittlement. The pressure molding of the surface of rigid foams after or during their drying gives a smooth surface which can optionally be sculpted to create decorative effects.

Rigid foams, possibly in the form of a laminate with another material, can be used in fire doors or in fire protection partitions. When in the form of beads, they can be used as stuffing for cavities, voids and the like. The foam beads can be glued together to form the desired products. A variety of inorganic and organic (but preferably inorganic) adhesives can be used to bond the beads together to form tiles for ^ - -, _ „, ^ _ * - -22- substrates such as wooden, cement and steel building components. Slabs up to 10 cm or more can be made by gluing together the dry foam beads. Among the inorganic binders. which may be used there are, for example, phosphoric acid, aqueous solutions of phosphates and silicates, cements and plasters. Among the organic binders that can be used, there are aqueous emulsions of polymers and copolymers of vinyl and vinylidene.

Foam beads, in particular, those made entirely or partially of delaminated vermiculite (vermiculite strips) can be dry molded into products with structural integrity without having to use an adhesive or binder. Preferably, the products obtained by molding beads dry are in the form of laminates in which the product consisting of beads is coated with layers or interposed between layers, for example, paper or sheets. Although it is possible to form products by dry molding, it is preferable to moisten or impregnate the pearls before transforming them into products by molding.

Wet foam (ie the carbonated suspension and the suspension before gasification can be used as a bonding agent to bond rigid beads of foam together. When used as an adhesive, it is preferable that the foam wet or the suspension contains or consists of strips of vermiculite and, preferably, a large proportion of these strips, for example, at least 50 / e by weight, calculated on the total solid content of the wet foam or suspension.

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According to one embodiment of the invention, for the production of products consisting of pearls, a method of manufacturing shaped articles is provided: from pearls of a rigid inorganic foam comprising one or more laminated mineral materials, this method consisting in applying to the beads a solution containing phosphate or silicate ions, the wet beads thus obtained are then dried while they are maintained in the desired shape.

The solution containing phosphate ions can be a phosphoric acid or a solution of a phosphate salt.

Organic and inorganic phosphates can be used, including complex phosphates, although it is preferable to use inorganic phosphates or phosphoric acid since both the shaped article obtained by this process is advantageously of a nature wholly or at least essentially inorganic. The preferred solution containing phosphate ions is orthophosphoric acid. A sodium silicate solution is the preferred solution containing silicate ions.

During the implementation of the process of the invention, foam beads are assembled to bring them to the shape of the desired product, for example, a slab or a plate and, while they are in this form, they are dries in the presence of a solution containing phosphate or silicate ions such that, after drying, the beads are bonded together and the shaped article obtained from these beads has structural integrity. The solution can be applied to the individual beads before assembling 0 - 24 - can be applied to the assembled beads while they are held in the desired configuration to obtain a shaped article. Alternatively, the solution can be applied to the beads before or after their assembly to the desired shape by forming, on these beads, a dry coating of a phosphoric acid, a phosphate salt or a silicate, then by impregnating the coated beads to form the solution containing phosphate or silicate ions.

It is best to apply the solution to the individual beads before assembling the beads to the desired shape 4. It is particularly preferable to form beads comprising a dry coating of a phosphoric acid, a phosphate salt or a silicate, these beads being easily stored and transported; on the other hand, a fabricated article maker simply has to impregnate these beads before or after assembling them into desired shaped articles. In practice, it is usually more convenient to impregnate the individual beads before assembling them to the desired shapes rather than to impregnate them after assembly and, in this way, it is also easier to adjust the amount of solution applied to the individual beads. and to ensure a uniform concentration of the solution throughout an assembly of pearls.

V

Pearls of a laminated mineral material foam comprising a dry coating of a phosphoric acid, a phosphate salt or a silicate are obtained according to a preferred characteristic of the invention. These coated pearls are easily prepared by applying to them a phosphoric acid or a solution of a phosphate salt or else a - "the pearls are prevented from sticking to each other; reiir.pré-gnant coated and dry beads, we reform, on the latter, the solution containing phosphate or silicate ions, The beads can be dried, for example, by means of a fluid bed,

The amount of the solution containing phosphate or silicate ions, as well as the concentration of the ions contained in the solution applied to the pearls, can vary within wide limits, however they influence the physical properties of the shaped articles formed from, these pearls. In particular, the quantity of solution applied and the concentration thereof influence the density of the shaped products. As a general rule, when the quantity of a particular solution applied to the beads is increased, this results in an increase in the density of the products. shaped products formed from these beads and, in the same way, an increase in the concentration of the ions of the solution has the effect of increasing the density of the shaped products formed from these beads,

The resistance of the products constitutes another physical property of these, this property being able to be influenced by the quantity and the concentration of the solution applied to the pearls, at least in the case of phosphate solutions. It has been observed that as the quantity of phosphate ions increases (at least the quantity situated in the surface area of the pearls), there is a maximum in the resistance of the product formed from these pearls and that by increasing this quantity beyond the value giving this maximum, by increasing either the quantity of the solution "^. "". . - "- 26 -

The amount of solution applied to the beads may depend, to some extent on the process by which this solution is applied but, for a particular application technique, the optimal combination of the amount of solution applied and the concentration thereof be easily determined by simple tests and experiments, The application of the solution to the beads can be carried out by any suitable technique, for example, by means of an immersion coating, by brush or roller, while the technique far preferred application is spraying. Spraying offers the advantage of being able to control the quantity of solution applied to the pearls most easily and, in particular, it allows the surface coating of pearls with minimal impregnation of the structure of the latter with the solution.

Foam beads of laminated mineral materials are generally highly porous structures which readily absorb liquids and any solution applied to these pearls will quickly penetrate into these structures into the interior of the pearls unless action is taken to avoid this penetration. According to the present invention, this penetration is inappropriate with regard to the density of the products made from the beads, as well as the thermal conductivity properties of these products.

Consequently, it is preferable to adopt a spraying technique implemented in a controlled manner in order to apply the minimum quantity of solution necessary for the surface coating of the beads.

- 27 -

In addition to applying the minimum quantity of solution which is required for the surface coating of the beads, according to the invention, it is preferable to use fairly dilute solutions of phosphoric acid or of phosphate or silicate salt in order to reduce again the amount of phosphoric acid, phosphate or silicate that is applied to the beads. For information, it is preferable to use solutions having concentrations of between 5 and 20% by weight, in particular, between 7 and 15% by weight. In the embodiment of the invention in which dry and coated pearls are impregnated with water and then transformed into products, the amount of water added will normally be approximately 60 to 10% by weight, calculated on the pearls .

Whether taken individually or assembled into shaped products, the impregnated beads can be allowed to dry at room temperature but usually will be subjected to heating to increase the speed of drying. The temperature adopted is not critical and can possibly reach a few hundred ° C. Typically, the impregnated beads will be heated to about the boiling point of the liquid to be removed when drying shaped products made from the impregnated beads, for example, at a temperature of about 90-110 ° C when the liquid is water but, to dry them. "individual pearls, it may be advantageous to adopt higher temperatures, for example temperatures up to 600 ° C. The physical properties of the coated dry pearls and of the shaped dry products obtained from these pearls do not appear depend on temperature J f> /. η _ - / -,, - 28 - *

The process can be carried out by gasifying a suspension of vermiculite strips to form a foam, the liquid of which is then eliminated under conditions in which the rigid foam obtained is in the form of pearls or of a product which can be transformed into pearls. An example of a suitable form of a product which can be made into beads by cutting, for example using a gas jet, is a foam extruded scum which can be cut into beads before drying or which can be dried, then cut into pearls. A wide variety of direct bead forming techniques can be adopted, for example, spray drying or extrusion in which the scum is caused to pass through holes in a strip to form beads.

It is known to subject vermiculite to chemical delamination to obtain suspensions, usually aqueous suspensions, of vermiculite lamellae which can be transformed into beads of rigid vermiculite foam .; delamination processes are described, for example, in the specifications of British patents Nos. 1,016,385a 1,076,786 and 1,119 * 305a as well as by Baumeister and Hahn in "Micron" 247 (1976). According to the present invention, it is possible to use foam beads obtained from the suspensions prepared by either of the known methods.

When used in the preparation of foam pearls, it is preferable to use suspensions of vermiculite lamellae which have been classified wet to remove all particles of granularity * * τ'r \ * T A. JC? A ΛΛ η λ ·. - - 29 ~ contain a high proportion (for example: 40 to 60% by weight) of lamellae of a dimension less than 5 microns.

The resistance of the shaped products of the invention and, in particular, their resistance to bending can be improved by laminating the layer of beads linked with a surface layer of a flexible sheet material such as paper (for example, paper kraft or vermiculite paper or a glass fiber canvas impregnated with vermiculite) or a metal strip or sheet. This or these covering layers can be applied by conventional lamination techniques to preformed foam articles but, for greater ease, this or these covering layers is or are applied ^) during the manufacture of the article in foam. Thus, for example, tiles or plates can be made by depositing beads coated with phosphate or silicate between layers of a coating material, slightly compressing the assembly and drying the beads to form a laminate comprising a central layer of foam secured to the covering layers.

Another characteristic of the present invention is slabs or plates made of rigid foam beads bonded in a cell matrix: v (i) Foam beads made of a mineral material laminated in a cell matrix comprising the same or another layered mineral material; (ii) mixtures of foam beads comprising various laminated mineral materials (iii) beads of kaolinite foam in a cellular matrix consisting of vermiculite; (iv) beads of vermiculite foam in a cellular matrix consisting of vermiculite and / or kaolinite (v) beads of kaolinite foam in a cellular matrix consisting of kaolinite, and (vi) beads of kaolinite / vermiculite foam in 'a cell matrix consisting of vermiculite and / or kaolinite.

The manufacture of products comprising foam pearls embedded in a cellular matrix consists in incorporating preformed pearls in a carbonated suspension or a foam of a laminated mineral material, then drying the foam thus obtained charged with pearls. The pearls can be incorporated into the foam by shaking them moderately in the latter and the foam thus loaded can be shaped, for example, by extrusion, to the shape of the desired product which is then subjected to drying. Alternatively, the beads can be assembled into the desired shape, for example, in a mold, while the scum can be removed from the assembled beads by applying pressure or it can be made into beads by applying a suction, for example, using a vacuum forming technique. The beads can also be compressed into a preformed layer of scum to form slabs or slabs although, as a general rule, this technique tends to cause the beads and / or scum to sag, thus giving a product 1 11 (- <<4 r »n *» A η Ί *. 4 «% a λ" f * Â4- λ λ! - * 4- r ~% "* i" "vn vt JT> ·. J— vt λ μ λ tfc -n -4 -31- limits, but it is usually just sufficient to completely fill the voids between the compressed pearls, for example, an approximately equal weight of foam after drying, based on the pearl weight ·

Another form of slab according to the present invention comprises thermally exfoliated granules of Vermiculite in a matrix of pearls or in a cellular matrix comprising kaolinite or a mixture of kaolinite and vermiculite,

The present invention will be illustrated by the following examples:

EXAMPLE X

For 40 minutes, in a food mixer "Kenwood Chef111, a mixture of 60 g of kaolin clay, 24Ο ml of demineralized water and a" Forafac 1157 "foaming agent (0.2 / o in weight, calculated on the kaolin), The foaming agent "Forafac" is a fluorochemical surfactant containing a C ^ F ^ group and an amphoteric group, this agent being sold by "Ugine Kuhlmann Company", A foam is obtained or an impregnated foam having, in the wet state, a density of 240 kg / m3 ·

This impregnated foam is placed in a mold and allowed to stand there for 24 hours, after which it is heated to a temperature of about 60 ° C. in an air oven J in order to dry it, The density of the rigid foam dry thus obtained is 75 kg / m3 "observes that the linear shrinkage of the foam during the oven-drying step is 9 ^.

- 32 - EXAMPLE 2

A dry rigid foam obtained as described in Example 1 is deposited in an oven at 600 ° C. and the temperature is brought to 1,150 ° C. After 30 minutes at 1,150 ° C., the foam is removed and it is found that obtained a sintered foam with a density of 90 kg / m3 and having a compression resistance of 200 KN / m2 under a compression of 20%.

EXAMPLE 3

During. 30 minutes, in a "Kenwood" food mixer, beat a mixture of 60 g of kaolin, 24Ο ml of demineralized water and a "Empigen BB" foaming agent ($ 0.45 by weight, calculated on kaolin). This foaming agent is sold by "Albright and Wilson" and is an amphoteric hydrocarbon surfactant having carboxy groups. A foam or a foam impregnated before a density of 195 kg / m3 is obtained. After having allowed it to stand for 24 hours and after having dried it at 60 ° C. as described in Example 1, the foam gives a dry rigid foam with a density of 63 kg / m 3. EXAMPLE 4

For 10 minutes, in a "Kenwood" food mixer, a mixture of 100 g of kaolin, 200 ml of demineralized water, 0.1 g of sodium tripolyphosphate as deflocculating agent and a foaming agent are beaten “Forafac 1157” (0.1% by weight, calculated on the kaolin) 5 at the end of this period, a stable impregnated foam or foam is obtained. This scum is dried as described in Example 1 to obtain a dry rigid foam with a density of 33.

In a "Kenwood" food mixer in which the wire accessory is used, 152 g of a suspension of delaminated vermiculite (vermiculite strips) are mixed with water with 125 g of demineralized water. demineralized (solids content: 21.9 ^). 0.5 g of sodium tripolyphosphate is added as deflocculating agent and 33.3 g of kaolin (light kaolin sold by "BDH Chemicals1 ') and they are mixed in the suspension * The mixture is vigorously stirred at maximum speed for approximately 10 minutes until the foam formed has reached a maximum height, after which the mixing speed is reduced, 37 g of magnesium oxide (light quality sold by UBDH Chemicals ") are added and mixed in The mixture speed is again increased to the maximum for about 1 minute.

The stable impregnated foam or foam thus obtained is spread out in an aluminum tray comprising an internal coating consisting of a polyethylene film and having the following dimensions: 15 cm x 15 cm x 2.5 cm. The foam is left to stand at room temperature for about 12 hours, then dried at 80 ° C in an air oven. The rigid dry foam has a density of 150 kg / m3 and its compressive strength is 445 KN / m2 under a compression of 20/3.

i EXAMPLE 6

A dry rigid foam is formed as described in Example S> with the exception that instead of 100 g of demineralized water, 70 g is used. The dry rigid foam thus obtained has a density of 202 kg / m 3 and its resistance to - 34 - EXAMPLE 7

A dry rigid foam is formed as described in 1 * example 5 * with the exception that instead of 33.3 g of kaolin, 67 g is used. The dry rigid foam has a density of 215 kg / m3 and its resistance at compression is 64Ο KN / m2 under compression of $ 20.

EXAMPLE 8

A dry rigid foam is formed as described in 1 * example 5, with the exception that instead of 33 * 3 g of kaolin, 100 g is used. The density of dry rigid foam is 302 kg / m3 and its compressive strength is 587 KN / m2 under compression of $ 20.

EXAMPLE 9

A dry rigid foam is formed as described in Example 5 * with the exception that instead of 33.3 g of kaolin, 133.3 g is used. The foam obtained has a density of 375 kg / m3 and its compressive strength is 943 KN / m2 under compression of $ 20.

EXAMPLES 10 TO 12

In these examples, the vermieulite beads used by the following general process are formed:

Pearl formation:

An aqueous suspension of worm-miculite strips obtained by swelling of vermieulite is kneaded by adopting -> successive treatments consisting of heating the saline solution at reflux, then heating, also at reflux, a solution of n-butylammonium chloride and of water, then this suspension is subjected to a wet classification by eliminating all the particles of greater granularity * r λ · Λ ^ · λ * · fr * r "* - 35 - taries" Kenwood "to form a scum and incorporated magnesium oxide powder ($ 10 by weight, calculated on vermiculite) during the gasification process.

The wet foam is immediately poured onto an i * strip.

r perforated "Melinex", the scum passing through the holes made in this strip, forming "grains" on the underside of the latter * These grains are allowed to harden and partially dry for a few minutes before dislodging them from the strip by scraping * These grains are then subjected to oven drying by placing them on trays to obtain beads of a rigid and dry foam which will be transformed into products. By varying the concentration of vermiculite in the suspension used, foam beads of different densities are obtained. The pearls have an approximately cylindrical shape having the following average dimensions: diameter = 2-3 mm $ length = 3-5 mm · These pearls have a uniform cellular structure.

EXAMPLE 10

20 g of vermiculite foam beads with a density of 112 kg / m3 are carefully stirred with 66.5 g of an aqueous solution consisting of 5 g of concentrated phosphoric acid in demineralized water. The beads thus moistened are spread out on a drying plate and they are dried in an oven at 60 ° C. for 16 hours. Any agglomerates of the beads are disintegrated manually, while any fine dust is removed by sieving.

8 g of dry beads coated with phosphate are suitably mixed with 16 g of demineralized water and, using a spatula with a knife blade, the mixture is slightly compressed. jy, /. _ _ 1 * 1 * * - 36 - tubes with a diameter of 4 * 35 cm and a height of 2 cm.

With the spatula, the flat upper and lower surfaces of the bead assembly are shaved to obtain a smooth finish, then the tubes are heated in an oven at 150 ° C for 4 hours v '· 7 The tubes are removed from the oven, then remove the foam cylinders from these tubes and immediately determine their compressive strength (under compression of $ 10) using a "Houdsfield" tensometer · The article obtained contains $ 20 by weight of a phosphate-based binding agent, its density (average of the two samples) is 206 kg / m 3 and its compressive strength is 274 * 8 KN / m 2.

Articles are formed as described in Example 1, with the exception that instead of $ 20 by weight of the phosphate-based binding agent, they contain $ 10 by weight; this charge of $ 10 by weight is obtained by mixing 20 g of the foam beads with 62.5 g of a solution consisting of 2.22 g of concentrated orthophosphoric acid in demineralized water.

The article obtained has a density (average of the two samples) of 154 kg / m3 and a compressive strength of 126.4 KN / m2.

EXAMPLE 12

Using a laboratory fluid bed dryer (model hFBD / L72 ”from” PR Engineering Ltd. ”), 50 g of beads of vermiculite foam with a density of 104 kg / m3 are coated with orthophosphoric acid. For coating the pearls, they are placed in a cylindrical fluidized bed 30 cm high and 13 cm in diameter, maintained "" 1. A., *. A -W ·, ry T · j · η * rj ^ - 37 - 2.5M orthophosphoric acid using a pneumatic siphon atomizer "Delàvan" (model "30610-1") at a flow rate of 0.22 cm3 / second. This gives beads containing 2 , $ 5 by weight of orthophosphoric acid, ~ 8 g of the dry beads thus coated are transformed into cylindrical articles which are subjected to tests as described in example 1, The finished articles have a density (average of the two samples ) of 127 kg / m3 and a compressive strength of 386 KN / m2.

EXAMPLES 13-15. Rigid and dry figulin clay foams are formed by the process described generally in Example 1 from the following figulin clay suspensions.

Example Figulin clay Water "Forafac" Beat time (g) (cm3) I (g) tage (minutes' 13 ”Hymod" / AT (l00) 200 2 20 14 ”BSK" / L (371) 200 2.4 20 15 ”Hycast” / VC (l00) 200 2 20 ”HYM0D” / AT is a figulin clay from Dorset and sold by "English China Clay", "HYCAST" / VC is a figulin clay from Devon and sold by " English China Clay ", ,, BSKn / L is a figulin clay from North Devon and sold by” Watson Blake ”“

We use demineralized water and "Forafac 115 We transform the impregnated foam into rigid foam N", /,, V 1, 14,1 · 1-1 - 38 - "

The properties of the impregnated and dry foams are determined, these properties being indicated below.

v —1 1 rini_ "1 ~" "- 13 Μ 15

PROPERTIES

Density in the wet state (kg / m3) 245 198 196

Density in dry state (kg / m3) 124 99 98

Sintering time (minutes) 55 5

Density in the sintered state (kg / m3) 128 101 99 ^ R.C. sintered foam (KN / m2) 700 114 172 * R.C. at 100 kg / m3 420 114 150 * R.C. at 200 kg / m3 1,340 - 630 * R.C. unsintered foam 40 - 10.8 _______________ 1 _! _ ___ * R.C. = compressive strength in KN / m2.

The compressive strengths at 100 kg / m3 and 200 kg / m3 are respectively the compressive strengths of foam having densities of 100 kg / m3 and 200 kg / m3 *

In another series of experiments, the: impregnated foams obtained in examples 13, 14 and 15 are transformed into rigid and dry foam beads by the technique of extrusion through a strip described for the formation of vermiculite foam beads in examples 10-12. In each case, handy beads with a cellular structure are obtained.

In yet another series of experiments, the impregnated foams are transformed into cell-structure beads in a spray dryer.

The beads from the six experiments are sintered at 1,050 ° C and, in each case, the cell structure of the samples. EXAMPLE 16

A refractory clay slip (kaolinite / illite) is passed through a 20 micron mesh screen in order to remove any large particles of quartz.

H

7 and 201 g of the screened slip (solids content: $ 47 by weight) are mixed with 128 g of demineralized water and 2.4 g of "Forafac 1157” ($ 0.03 by weight, calculated on the basis of The resulting slurry is vigorously stirred (solids content; $ 30) in a "Kenwood Chef" food mixer for about 20 minutes to form a stable impregnated foam.

Samples of the impregnated foam are transformed into a rigid, dry and extruded foam by the method of Example 1, after which the foam is subjected to sintering at 1150 ° C. as described in Example 2. The impregnated foam has a density of I90 kg / m3 and the sintered foam has a density of 116 kg / m3 and a compressive strength of 70 KN / m2 (under compression of $ 10).

EXAMPLE 17

7> 04 kg of “EWVA” figulin clay, 12.9 kg of demineralized water and 169 ml of “Forafac 1157” ($ 0.6, calculated on clay) are mixed to form a slurry having a content of $ 35 solids · Stir vigorously for 20 minutes in a "Kenwood Chef" food mixer and transform the stable impregnated foam thus obtained into pearls in a conventional spray-drying apparatus. obtained at 1.150 ° C. for 5 minutes The impregnated foam has a density of 256 kg / m3 and the sintered pearls have a density of 150 kg / - 40 - EXAMPLE 18

For 15 minutes, in a "Kenwood Chef" food mixer, 38 g of sepiolite are mixed with 162 g of demineralized water and 0.06 g of "Forafac 1157" ^ (0.4 / Sj calculated on clay ) to form a stable impregnated foam. This impregnated foam with a density of I95 kg / m3 is transformed into beads with a cellular structure by means of the technique of extrusion through a strip described in Examples 10-12. The beads are subjected to sintering at 1.050 ° C for 5 minutes and the beads thus sintered have a density of 58 kg / m3.

EXAMPLE 19

A 18.9 / 5 slurry of delaminated vermiculite in demineralized water (116 g) is mixed with 78 g of demineralized water and 0.5 g of sodium tripolyphosphate. 67 g of light grade "BDH" kaolin clay is added to the mixture, which is then vigorously stirred in a "Kenwood Chef" mixer for about 15 minutes. Then add 3.7 g of light quality magnesium oxide powder of "BDH11 and stir the mixture vigorously to disperse the powder. The impregnated foam is transformed into pearls by the extrusion process using a strip 7 described in Examples 10-12, then the beads obtained are sintered at 1.500 ° C. for 10 minutes The density of the sintered beads is Λ 238 kg / m3.

EXAMPLE 20

50 g of montmorillonite are dispersed in 338 g of demineralized water and, to the dispersion thus obtained, 137 g of a slurry with lSf3% of delamified vermiculite are added, then O _ IIP r 1 1 r / T! F Λ_ n · J -______________ J_ 1 _ 'Ί - 41 - a stable impregnated foam ”This impregnated foam is transformed into dry beads with cellular structure by the extrusion process by means of a strip, described in Examples 10-12. The pearls dried at 90 ° C have a density of 108 kg / m3 "EXAMPLE 21

In a “Kenwood Chef” mixer, 50 g of sodium montmorillonite (Wyoming bentonite) and 50 g of kaolin clay are mixed with 450 g of demineralized water until the montmorillonite has been intimately dispersed ”. 6 g of "Forafac 1157” and the mixture is vigorously stirred for one hour at maximum speed to obtain a stable impregnated foam. From the latter, beads of dry foam are formed by the extrusion process by means of a strip as described in Examples 10-12, then they are sintered at 1050 ° C for 10 minutes and they then have a density of 118 kg / m3.

EXAMPLE 22

In a "Kenwood Chef" mixer, 50 g of sodium montmorillonite (Wyoming bentonite) and 450 g of demineralized water are stirred until the montmorillonite is intimately dispersed. 6 g of "Forafac 1157" are added and the mixture is beaten with the accessory provided for this purpose, at maximum speed and for approximately one hour to obtain ": a stable impregnated foam. From it, beads are formed by the extrusion process using a strip of the type described in Examples 10-12 and sintered at 1,000 ° C for 10 minutes. The sintered pearls have a density of 110 kg / m3.

EXAMPLE 23 - 42 -

While stirring for 4 hours, 200 g of sodium montmorillonite and a 60% aqueous solution of 36Ο g of butyl ammonium chloride and 750 g of demineralized water are heated to 80 ° C. The butyl ammonium montmorillonite obtained (in the solid state) is separated by filtration and washed until it is free of chloride ion. In a "Kenwood Chefn" mixer, vigorously stir a quarter of the solid with 120 g of demineralized water and 12 g of "Forafac 1157" for 1 hour to obtain a stable impregnated foam.

This impregnated foam is transferred to a mold and dried as described in Example 1 to obtain a rigid foam with cellular structure, EXAMPLE 24

Magnesium montmorillonite is prepared by heating, at 80 ° C for 4 hours, 200 g of sodium montmorillonite (Wyoming bentonite) with 203 g of magnesium chloride (MgCl2.6H20) in 1 liter of demineralized water.

The magnesium montmorillonite (in the solid state) is separated by filtration and washed until it is free of chloride ion. In a “Kenwood Chef” mixer, vigorously stir a quarter of the solid with 100 g of demineralized water and 0.8 g of? Forafac 1157 "to obtain a stable impregnated foam. This impregnated foam is transformed into one, dry slab as described in Example 1. The dry foam has a cellular structure, EXAMPLE 25

Aluminum montmorillonite is prepared by heating, at 80 ° C. for 4 hours, 200 g of montmorillonite of _ -.j · - / 1 (J d. _ TT: Ί o rr rj T j____, _ "T _ ~ 43 - aluminum montmorillonite (in solid state) by filtration and washed until it is free of the nitrate ion, In a "Kenwood Chef" mixer, vigorously stir a quarter of the solid with 100 g of demineralized water and 0.8 g of "Forafac 1157" to obtain a stable impregnated foam. This impregnated foam is poured and dried as described in Example 1 to obtain a dry rigid foam with cellular structure, EXAMPLE 26

A plate measuring 15 cm × 15 cm × 2.5 cm is formed from approximately spherical dry pearls with a diameter of 3 nun, consisting of delaminated vermiculite foam and obtained as described in Examples 10-12, The pearls have an actual density of 65 kg / m3 and a packing density of 45 kg / m3. 22 g of the dry pearls are placed in a steel mold measuring 15 cm x 15 cm x 2.5 cm and a force of 15 kg / m3 is applied using a steel plate to compress the assembly of pearls. Pressure is applied until the volume of the bead assembly is reduced to approximately half. The product obtained is a plate with essentially cellular structure and it has a density of 90 kg / m3, a flexural strength of 30 KN / m2 and a compressive strength of 100 KN / m2, We push this plate out of the mold and, on its two main faces, a coating of a 35% aqueous sodium silicate solution is applied. On the coated surfaces, a glass fiber canvas weighing 50 g / m3 is pressed and the laminate thus obtained is dried in an oven for 2 hours. The laminate thus obtained has a density of 95 kg / m3, a flexural strength of 300 - 44 - thermal conductivity of this laminate (measured according to British standard 874) is 0.056.

EXAMPLE 27

A plate measuring 15 cm x 15 cm x 2.5 cm 'is formed as described in Example 26, with the exception that the beads are moistened with 44 g of demineralized water before depositing them in the mold. The plate thus obtained has an essentially cellular structure and its density is 90 kg / m3 · The flexural strength of this plate is 60 KN / m2, while its resistance to compression is 110 KN / m2. This plate is laminated with a glass fiber scrim as described in Example 26 and the dry laminate thus obtained has a density of 95 kg / m 3d a flexural strength of 400 KN / m 2 and a compressive strength of 130 KN / m2. EXAMPLE 28

A rigid and dry foam is formed by the process described in 1 * example 1 from 50 g * kaolin clay (light quality), 200 ml of demineralized water and 0.3 g of uVantoc CL11 (surfactant quaternary ammonium bromide active agent sold by Imperial Chemical Industries Limited ”) The density of the dry foam is 88 kg / m3 · EXAMPLE 29

As described below, a composite plate is formed containing dry beads obtained from vermiculite foam and a matrix of vermiculite foam.

Vermiculite foam is formed by beating a suspension at 20 $ ® by weight of delaminated vermiculite. 250 g of this suspension are beaten for 5 minutes using a "Kenwood" mixer rotating at a speed of 60 revolutions / ~ 45 - stirred with a large mechanical stirrer rotating at a rate of 5 revolutions / minute · Vermiculite pearls have a density 70 kg / m3, a compressive strength of 100 KN / m2 and a diameter of 3 mm ·

The mixture obtained is smoothed in a metal tray measuring 2.5 cm x 2.5 cm x 2.5 cm, dried at room temperature for 24 hours, then at 50 ° C for two days.

The block thus obtained has a compressive strength of 200 KN / m2, a flexural strength of 350 KN / m2 and a density of 95 kg / m3 # The thermal conductivity of this plate is 0.059 W / mk at 20 ° C.

EXAMPLE 30

As described below, a composite plate is formed containing dry grains of expanded perlite and a matrix of vermiculite foam.

The foam impregnated with vermiculite is formed as described in Example 29. Then, the foam obtained is mixed with 100 g of grains formed from expanded perlite.

These grains have a density of 130 kg / m3d a compressive strength of 250 KN / m2 and a diameter of 2-5 mm.

The block thus obtained has a compressive strength of 25Ο KN / m2, a flexural strength of 300 KN / m2 and a density of 110 kg / m3 * The thermal conductivity of this plate is 0.046 W / mk at 20 ° vs.

X EXAMPLE 31

As described below, a composite plate is formed containing dry beads obtained from kaolin foam and a matrix of vermiculite foam.

The vermiculite foam is obtained as described in Example 29 T · »·! / 1 _ „- 46 - 65 kg / m3, a compressive strength of 90 KN / m2 and a diameter of 3 mm #

The block obtained has a compressive strength of 110 KN / m2, a flexural strength of 2 $ 0 KN / m2 and a density of 85 kg / m3 # The thermal conductivity of this block is 0.045 W / mk at 20 ° C # tl W '

Claims (44)

1. Product in rigid inorganic foam, characterized in that it consists of beads of a foam of one or more laminated mineral materials, each bead having r .. a cellular structure. - 2, rigid inorganic foam product according to claim 1, characterized in that it has a density less than 0.4 g / ml. 3. Rigid foam product according to claim 2, characterized in that it has a density of less than 0.2 g / ml. , 4 · foam product according to any one of claims 1 to 3 * characterized in that the foam beads consist of delaminated vermiculite. 5. Foam product according to any one of claims 1 to 3} characterized in that the foam beads consist of kaolinite or a clay containing kaolin. 6, foam product according to any one of claims 1 to 3j characterized in that the foam beads consist of montmorillonite. 7 * foam product according to any one of claims 1 to 3> characterized in that the foam beads consist of sepiolite. 8, foam product according to any one of claims 1 to 7j characterized in that it consists of a mixture of foam beads of different laminated mineral materials · 9. Foam product according to any one of claims 1 to 8, characterized in that the beads of - 48 - » 10, foam product according to claim 9, characterized in that the adhesive is phosphoric acid or a phosphate, 11, foam product according to claim 9 * characterized in that 1 * adhesive is sodium silicate, v 12, foam product according to claim 9, characterized in that 1 * adhesive is an organic binder, 13, foam product according to any one of claims 1 to 9j characterized in that the foam beads are coated in a cellular matrix consisting of one or more laminated mineral materials, 14, foam product according to claim 13 * characterized in that the cell matrix consists of delaminated vermiculite, 15 · Rigid inorganic foam with cellular structure characterized in that it consists of a mixture of laminated mineral materials, 16, rigid inorganic foam with cellular structure "characterized in that it consists of montmorillonite, 17 · Rigid inorganic foam with cellular structure characterized in that it consists of sepiolite, 18, rigid inorganic foam with cellular structure <characterized in that it consists of a figulii clay and / or a refractory clay, • „19 · rigid inorganic foam according to any one of claims 15 to 18, characterized in that it has a density of less than 0.4 g / ml, 20, rigid inorganic foam according to claim 15 * characterized in that it consists of varnish— - 49 - 22. Rigid inorganic foam according to any one of claims 1 to 21, characterized in that it is in the form of a laminate formed with one or more layers of a material not transformed into foam, 23 · Method for manufacturing a rigid inorganic foam product, characterized in that it consists in gasifying: a suspension of one or more mineral materials laminated in a liquid medium containing a surfactant in order to form a foam or a stable impregnated foam, divide this impregnated foam or foam into droplets, remove * at least part of the liquid medium from these droplets to form beads of foam, then shape the beads into a foam product · 24 · Process for manufacturing a rigid inorganic foam in the form of pearls, characterized in that it consists in gasifying a suspension of one or more mineral materials laminated in a liquid medium to form a foam or a stable impregnated foam, shaping this scum or foam impregnated in droplets or in fiber-like extruded products and removing at least part of the liquid medium from the droplets or extruded products, 25. A method of manufacturing a rigid inorganic foam, characterized in that it consists in gasifying a suspension of two or more stratified mineral materials -r in a liquid medium to form a foam or a stable impregnated foam * and eliminate at least part of the liquid medium of this foam or of this impregnated foam, 26. A method of manufacturing a rigid inorganic foam, characterized in that it consists in gasifying a - 50 - to form a foam or a stable impregnated foam and to remove at least part of the liquid medium from this foam or foam impregnated. 27. Process according to any one of the resells! Cations 23 to 26, characterized in that the suspension includes delaminated vermiculite, while an agent improving the compressive strength and the stability to it is incorporated therein. water from the foam obtained. 28. The method of claim 27, characterized in that 1 * compressive strength improver 1 "water stability is 1 * magnesium oxide particulate. 29. A method according to any one of claims · i tions 23 to 26, characterized in that the suspension comprises a laminated mineral material other than delaminated vermiculite, while the rigid inorganic foam obtained is subjected to sintering in order to improve its resistance to compression and its water stability. 30. The method of claim 2Ç, characterized in that the foam is heated to a temperature up to I 1,200 ° C in order to sinter it. ! I 31 · Pearls of rigid inorganic foam having a cellular structure and comprising one or more laminated mineral materials. ^ 32. Pearls of rigid inorganic foam according to:, claim 31 * characterized in that they comprise delaminated vermiculite · 33 * Pearls of rigid inorganic foam according to; claim 31 * characterized in that they comprise kaolinite or kaolin-containing clay. - 51 - 34 · Pearls of rigid inorganic foam according to claim 31, characterized in that they comprise montmorillonite. 35 · Pearls of rigid inorganic foam according to ^ claim 3I5 characterized in that it comprises v sepiolite. 36 · Pearls of rigid inorganic foam according to claim 31, characterized in that they comprise vermiculite and kaolinite. 37 · Pearls of rigid inorganic foam according to »claim 31 * characterized in that they include delaminated vermiculite and kaolinite. 38. Pearls of rigid inorganic foam according to any one of claims 31 to 373 characterized in that they are coated with a binding agent or an adhesive " 39 · Pearls of rigid inorganic foam according to any one of claims 31 to 38, characterized in that they have a density of less than 0.4 g / ml. 40. Pearls of rigid inorganic foam according to claim 33, characterized in that they have a density of less than 0.2 g / ml · 41 · Use of a rigid inorganic foam product according to any one of claims 1 to 20 and: 30 to 34 as insulation material, a 42. Use of an inorganic foam product: rigid according to any one of claims 1 to 20 and 30 to 34 as a fire protection material * 43 * Method of manufacturing a rigid inorganic foam product, characterized in that it consists in assem- ~ 52 - forming the foam product. 44 · A method according to claim 43 * characterized in that the assembly of beads is consolidated by applying pressure thereto. 45 · A method according to claim 44 * characterized in that the beads are moistened before applying pressure to the assembly. 46. A method according to any one of claims 44 and 45j characterized in that the beads are moistened before being assembled into a product of the desired shape 1. 47 · A method according to claim 43 * characterized in that the consolidation of the assembly of pearls is carried out by means of a binding agent. 48. The method of claim 47 * caractéx * is in that the binding agent is an inorganic binder. 49 · A method according to claim 47 * characterized in that the binding agent is an organic binder. 50. A method of manufacturing a rigid inorganic foam product characterized in that it consists in incorporating beads of one or more laminated mineral materials and having a cellular structure, in a gasified suspension of one or more laminated mineral materials in a liquid medium and removing at least part of the liquid medium from the gasified suspension. ; 51 · Suspension of two or more laminated mineral materials in an aqueous solution of a surfactant. 52. Suspension according to claim 51 * character. that one of the layered mineral materials is • -. i # - 53 - 53. Suspension according to claim 52, characterized in that it consists of delaminated vermiculite and kaolinite or a clay containing kaolin, 54 · Suspension of one or more stratified mineral materials chosen from kaolinite or a clay containing ji * #} of kaolin, montmorillonite and sepiolite, in an aqueous solution of a surfactant, characterized in that that the surfactant is able to form a stable foam from the laminated mineral material (s), 55 "Dry powder comprising two or more laminated mineral materials and a surfactant, 56. Dry powder comprising kaolinite or a clay containing kaolin, montmorillonite or sepiolite and a surfactant. '^' v 'i i i i • ί