Classifications

• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
  • C04B35/622—Forming processes; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
  • C04B35/626—Preparing or treating the powders individually or as batches ; preparing or treating macroscopic reinforcing agents for ceramic products, e.g. fibres; mechanical aspects section B
  • C04B35/63—Preparing or treating the powders individually or as batches ; preparing or treating macroscopic reinforcing agents for ceramic products, e.g. fibres; mechanical aspects section B using additives specially adapted for forming the products, e.g.. binder binders
  • C04B35/6303—Inorganic additives
  • C04B35/6316—Binders based on silicon compounds
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
  • C01B33/00—Silicon; Compounds thereof
  • C01B33/20—Silicates
  • C01B33/26—Aluminium-containing silicates, i.e. silico-aluminates
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B12/00—Cements not provided for in groups C04B7/00 - C04B11/00
  • C04B12/005—Geopolymer cements, e.g. reaction products of aluminosilicates with alkali metal hydroxides or silicates
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
  • Y02P40/00—Technologies relating to the processing of minerals
  • Y02P40/10—Production of cement, e.g. improving or optimising the production methods; Cement grinding

Definitions

• Synthetic mineral polymeric compound from the family of silicoalu minates and process for its preparation; molded articles containing this polymeric compound and process for obtaining them.
• the subject of the invention is the use of a mineral polycondensation reaction of reaction mixtures based on alkali silico-aluminates, for manufacturing, at low temperature, in principle below 120 ° C., molded mineral objects containing a mineral polymer. from the family of silico-aluminates and various mineral charges.
• the mineral polycondensation reaction is close to that which is at the origin of the synthesis of very particular mineral products: synthetic zeolites or molecular sieves.
• these particular structures are used for their ion exchange properties. They have a certain catalytic action on many organic polymerizations.
• a large number of patents for the synthesis of these zeolites or molecular sieves describe the manufacturing processes of these particular minerals.
• M being a valence cation n.
• Many crystalline products have been obtained by various processes using this hydrothermal synthesis. The objective of all these processes is to obtain very porous products, generally in powder form, this crystalline powder possibly being then agglomerated by a binder. These products generally have poor mechanical characteristics.
• An object of this invention is to describe the use of this hydrothermal synthesis, more precisely of this mineral polycondensation, in order to obtain mineral products with very superior technical and mechanical characteristics, allowing the manufacture of relatively hard mineral objects (5 to 7 in the Mohs scale), thermally stable, with a very fine surface definition, which can be used as an object, art object, building material, industrial mold, tool, or other technological applications such as ceramic mineral binder or coating.
• relatively hard mineral objects 5 to 7 in the Mohs scale
• thermally stable with a very fine surface definition, which can be used as an object, art object, building material, industrial mold, tool, or other technological applications such as ceramic mineral binder or coating.
• the polymer (K) -PS described in this invention has a dif diagram X-ray fraction as shown in Table A.
• the diagram is very similar to that of an extremely rare natural mineral, Kalioplilite KAlSiO 4 , responding well to the general formula of Polysialates.
• This mineral is not a zeolite, but an anhydrous feldspar, that is to say that in the formula
• the polymer product obtained does not correspond to the (Na, K) PSS obtained according to French patent application No. 79.22041, in particular the X-ray diagram, and thermogravimetry.
• the product obtained is practically amorphous to X-rays, while the (Na, K) -PSS have an X-ray diagram close to that of the minerals Analcime, Gismondine, Gmelinite, Phillipsite.
• Thermogravimetry indicates a weight loss of 5% in water up to 325 ° C then the weight remains constant, while the (Na, K) -PSS have a weight loss of between 21% and 29% between 100 ° C and 500 ° C.
• the zeolitic character of the product is absent, while the macroscopic properties show a certain brittleness, although the product is hard: hardness 5 in the Mohs scale.
• a synthetic Kaliophilite KAlSiO 4 , o, 1H 2 O was prepared by
• a reaction mixture is used.
• aqueous potassium potassium aluminate such that the composition of the reaction mixture expressed by the ratio of the oxides, corresponds to the values indicated in Table C.
• the experimental value H 2 O is equal to the water present as solvent in the mixture, added water of chemical constitution of the compounds.
• K-Polysialate, (K) -PS The ordinary method of preparing K-Polysialate, (K) -PS is to mix an aluminum silicate oxide in an aqueous solution of potassium polysilicate, with KOH potash.
• This aluminosilicate oxide (Si 2 O 5 , Al 2 O 2 ) n is prepared from a polyhydroxy-aluminosilicate (Si 2 O 5 , Al 2 (OH) 4 ) n in which the aluminum cation is in the octahedral position and is hexacoordinated.
• the polyhydroxy-aluminosilicate is transformed into an extremely reactive aluminosilicate oxide (Si 2 O 5 , Al 2 O 2 ) n in which the aluminum cation is tetracoordinated.
• the polyhydroxy-aluminosilicates which can serve as raw material are the minerals corresponding to the class of clay minerals at 7 Angstroms, and having at least one aluminum cation in the octahedral layer subjacent to the tetrahedral layer of the silicon cation, such as for example natural minerals: alushite, carnat, china clay, lithomarge, specialtyokaolin, parakaolinite, pholénite, endellite glossecollite, halloysite, milanite, berthiérine, fraigonite, grovenite amesite, chamoisite.
• the inorganic polymeric compound of the family of silico-aluminates obtained by polycondensation of a reaction mixture according to Table C, has a chemical composition expressed in terms of oxide of
• the inorganic polymeric compound is in fact a solid solution comprising 35 to 90 parts by weight of a potassium polysilicate of formula (y-1) K 2 O: (x-2) SiO 2 : (w-1) H 2 O and from 10 to 65 parts by weight mineral polymer (K) PS of formula (K) n (-Si-O-Al-O-) n , nH 2 O of which
• the reaction mixture corresponding to Table C, is not a gel; it is fluid and behaves like a mineral resin having interesting rheological properties when it is left to mature for approximately at least 1 hour at room temperature, for example 25 ° C.
• this mineral resin is used either as it is, or with mineral and / or organic fillers, or as a binder or cement for mineral and / or organic products.
• the resulting mass is then introduced into a mold, either by simple casting if the mixture is sufficiently fluid; either by compaction, or by pressure or vibration or other mechanical or physical means, then the assembly is brought to a temperature at most equal to 120 ° C, preferably between 60 ° C and 95 ° C.
• the mineral object is removed from the mold or the impression and then dried at a temperature below 100 ° C.
• the curing or polycondensation times are obviously a function of the temperature and the heating technique. At room temperature of 25 ° C, the curing time is 15 hours; at 50 ° C for 4 hours; at 85 ° C for 1 hour 30 minutes; at 90 ° C of Oh3Omin.
• Other heating modes can also be used, such as high frequency, microwaves, Joule effect, embedded electrical resistance.
• the reaction mixtures being polyelectrolytes, under these conditions the polycondensation times will be faster.
• the order of introduction of the different reagents into the reaction mixture is important, especially if one wants to give the mineral resin a very long pot life, for example 2 to 4 hours in a workshop.
• the industrial applications of the invention are thereby greatly facilitated. It is therefore necessary to avoid direct contact of the concentrated potassium hydroxide KOH with the aluminosilicate oxide (Si 2 O 5 , Al 2 O 2 ) n .
• the aluminosilicate oxide or KOH To obtain the object of the invention, it is necessary to mask either the aluminosilicate oxide or KOH.
• the masking of KOH takes place by the preparation of a strongly alkaline solution of potassium polysilicate. Then added to this solution the aluminosilicate oxide which is thus dissolved therein.
• Another method of the invention consists, on the contrary, in masking the aluminosilicate oxide with an alkaline polysilicate solution, then in mixing this mixture with the concentrated KOH solution.
• the latter method has the advantage of being able to achieve the object of the invention from two mixtures stable over time, allowing storage and easy handling.
• the mineral resin obtained by allowing the reaction mixture to mature for approximately at least 1 hour at room temperature (25oC), or the mineral resin mixture (binder), are placed in a preferably closed mold.
• the polycondensation reaction is carried out under hydrothermal conditions, and it is necessary to conserve all the water present in the reaction medium.
• any surface evaporation will therefore be avoided either by using a closed mold or by covering it with any means of protection preventing the evaporation of water, such as a plastic film or a thin layer of a hydrophobic substance.
• the solid thus obtained is separated from its mold, and dried.
• the mold object thus obtained has very interesting physical and mechanical properties for the technological applications of the invention.
• the ultra fine definition of the surface of the object obtained allows the extremely precise faithful reproduction of all the details, even the finest, of the impression and the mold. This reproduction precision is comparable in quality to that obtained with organic resins commonly used in reproduction and molding, such as epoxy resins. xy and polyurethanes, but in the case of the invention, the surface hardness of the object is equal to 5 to 7 in the Mohs scale, against at most 2 to 3 for organic resins.
• Al 2 O 3 comes from the aluminosilicate oxide obtained by dehydr ⁇ xylation of a natural polyhydroxy-aluminosilicate
• the fluid mixture is left mature for at least 1 hour at room temperature (25 ° C), then is poured into a mold.
• the upper layer of the mass is covered with a polyethylene film and the whole is placed in an oven at 85oC for 1 hour 30 minutes. ; demoulded and after drying at 85 ° C, the density of the product is 1.7 grams per milliliter; the hardness is 4.5 on the Mohs scale; it is white, very little porous; physico-chemical analysis gives a molar composition of 1.5K 2 O: Al 2 O 3 : 4.1 SiO 2 : 3H 2 O corresponding to a polymeric compound containing in solid solution a phase of a potassium polysilicate of crude formula
• the solid obtained has very clear cracks. These cracks disappear when, at the reaction mixture, after, during maturation, or even before, at least one mineral filler is added.
• the molded articles thus obtained then have excellent physical and mechanical characteristics, such as for example a flexural strength of approximately 180 kg / cm 2 , a hardness which can reach 7 in the Mohs scale, a coefficient of linear expansion as a function of the temperature close to 2 to 5 .10 -6 m / m / ° C.
• Example 2
• Example 1 According to the technique described in Example 1), 960 grams of a reaction mixture containing H 2 O: 22.88 moles are prepared, the other constituents being unchanged.
• the molar ratio of the reaction oxides is that of Table D, except for H 2 O / A 1 2 O 3 equal to 21.
• the very fluid mixture is left mature for approximately 1 hour at room temperature, then 640 grams of synthetic cordierite, also containing Mullite, with a particle size of less than 120 microns, are added thereto.
• the viscous mixture obtained is poured into a mold and hardened at 85 ° C for 1 h 30 min. as in Example 1). After drying at 85 ° C, the density of the product is 2.3 grams per milliliter, the hardness is equal to 5 Mohs; its dimensions indicate that the polycondensation has been carried out practically without shrinkage.
• the X - ray examination is done using a different technique, recording the teta / 2 tetas curve, emission of the Cobalt line at 1.79 Angstroms.
• Example 1 According to the technique described in Example 1), 792 grams of a reaction mixture containing H 2 O: 13.5 moles are prepared, the other constituents being unchanged.
• the molar ratio of the reaction oxides is that of Table D, except for H 2 O / A1 2 O 3 equal to 12.5.
• the fluid mixture is left to mature for approximately 1 hour at room temperature, then 540 grams of synthetic cordierite, also containing Mullite, with a particle size of less than 120 are added. microns. Then we proceed as in example 2).
• the H 2 O / A1 2 O 3 ratio can vary between 10 and 25. However, it is preferable to approach values between 14 and 20. Larger values increase the porosity of the product obtained, while lower values seem to disturb the potassium silicate phase of the solid solution of the polymeric compound, accompanied by migration and free alkalinity. Also, in practice, we prefer to use reaction mixtures whose molar ratios of reactive oxides correspond to Table E;
• Example 2 860 grams of the reaction mixture of Example 1) are prepared and 220 grams of Muscovite with a particle size of less than 120 microns and 90 grams of Calcium Fluoride F 2 Ca in fine powder are added thereto.
• the viscous resin thus obtained is used to agglomerate 1 kg 150 grams of Zircon sand. This mixture is poured by vibration into a mold which is then placed at 85 ° C for 1 h 30 min. After drying, the product obtained has a density of 3.0 grams per milliliter. Its appearance is brilliant, its hardness is 6 in the Mohs scale.
• the analysis of the X-ray diagram is very delicate, because in addition to the intense lines of Zircon and Calcium Fluoride, those very numerous of Muscovite cover practically all the lines characteristic of (K) -PS.
• a reaction mixture is prepared according to Example 1). After maturation, the resin thus formed is applied with a brush, in a very thin layer on an imprint constituting the negative of a sculpture. At the same time, 5 kilograms of flint with a particle size between 0.5 and 5 mm are introduced into a mixer, and 0.5 kilograms, or 10% by weight of the flint, of this same mineral resin, are added thereto. To me the cloth is vibrated in the already coated impression and covered with a polyethylene film and allowed to harden at room temperature (25 °). The next day we unmold a sculpture with extremely thin, hard and shiny skin.
• the potassium silicoaluminate reaction mixtures described in this invention make it possible to manufacture molded articles resulting from the agglomeration of 5 to 95 parts by weight of mineral and / or organic products and fillers, with 5 to 95 parts by weight of a binder consisting of a mineral polymeric compound whose composition expressed in terms of oxide is yK 2 O: Al 2 O 3 : xSiO 2 : wH 2 O in the hydrated form of which "w” is at most equal to 4, "x” is a value between approximately 3, 3 and 4.5, "y” is a value between approximately 0.9 and 1.6.
• the inorganic polymeric compound is a solid solution comprising 35 to 90 parts by weight of a potassium polysilicate of formula
• the molded objects have very high resistance to thermal shock.
• the flame of a blowtorch can be applied directly to objects intended to undergo high temperatures, between 300oC and 1200 ° C, it is preferable to subject it to a heat treatment at a temperature at least equal to 325 ° C, in order to remove the constitution water.
• the inorganic polymeric compound is dehydrated and dehydroxylated and is transformed into a product of equivalent or higher quality than that of ceramic materials, and has excellent thermal stability. Its composition expressed in the form of oxides is then: yK 2 O: Al 2 O 3 : xSiO 2 in which "x" is a value between 3.3 and 4.5 approximately,
• y is a value between 0.9 and 1.6, approximately. It consists of a solid solution comprising a potassium polysilicate phase of composition
• the potassium silicoaluminate reaction mixtures described in this invention constitute a mineral resin which can be used with at least one mineral and / or organic filler, or as a binder or cement. Polycondensation or hardening takes place either at room temperature or up to a temperature below 120oC. All fillers, as well as compatible auxiliary products can be added, we will cite without limitation of any kind: dyes and pigments, debubbling agents, reinforcing fibers, water-repellent agents.
• the molded objects produced using the invention have multiple uses depending on the physical, mechanical or chemical characteristic involved: in industry, construction, decoration, in the form of an object, a mold, tool, block, panel, coating. They can undergo multiple subsequent physico-chemical, physical or mechanical treatments, as well as priming or finishing operations, plugging the porosity. If necessary, they will undergo a heat treatment at a temperature at least equal to approximately 325 ° C., transforming them into products having ceramic qualities, in particular excellent thermal and dimensional stability.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Organic Chemistry (AREA)
• Ceramic Engineering (AREA)
• Inorganic Chemistry (AREA)
• Structural Engineering (AREA)
• Materials Engineering (AREA)
• Manufacturing & Machinery (AREA)
• General Life Sciences & Earth Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Life Sciences & Earth Sciences (AREA)
• Silicates, Zeolites, And Molecular Sieves (AREA)
• Compositions Of Macromolecular Compounds (AREA)

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• 1980
  • 1980-09-03 FR FR8018971A patent/FR2489291A1/fr active Granted
• 1981
  • 1981-09-02 WO PCT/FR1981/000112 patent/WO1982000816A1/fr not_active Ceased
  • 1981-09-02 EP EP81902468A patent/EP0066571B1/fr not_active Expired
  • 1981-09-02 US US06/377,204 patent/US4472199A/en not_active Expired - Lifetime
• 1982
  • 1982-10-01 SU SU823500775A patent/SU1347864A3/ru active

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