FR3033556A1 - NON-FORMED PRODUCT FOR REPAIR OF GLASS FUSION OVENS - Google Patents

Abstract

Unshaped product comprising in percentages by weight, and for a total of 100%, A) particles (a) of at least one refractory material different from a glass and a glass-ceramic, the main constituent (s) of which are alumina (Al2O3) and / or zirconia (ZrO2) and / or silica (SiO2) and / or chromium oxide (Cr2O3), the particles (a) constituting the 100% complement, B) 2% at 15% of particles (b) of glass, C) less than 2% of particles (c) of hydraulic cement, D) less than 7% of other constituents, all of said particles (a) and (b), preferably, the fraction of all the particles of the unshaped product having a size of less than 40 μm being distributed, in percentages by weight relative to the mass of the unshaped product, in the following manner - fraction <0.5 μm: ≥ 1%, - fraction <2 μm: ≥ 4%, - fraction <10 μm: ≥ 13%, - fraction <40 μm: 25% - 52%.

Description

TECHNICAL FIELD The present invention relates to an unshaped product, particularly for the repair of a sole of a glass melting furnace. The invention also relates to a glass melting furnace repair method comprising a step of processing said unshaped product, and a glass melting furnace comprising at least a portion obtained from said unshaped product.

STATE OF THE ART The glass industry generally uses melted and sintered refractory products, obtained by sintering, which are highly resistant to glass corrosion, and which are in the form of blocks or slabs, for the construction of its furnaces. The molten glass is highly corrosive and the refractory products, in particular those constituting the melting tank, in particular the bottom of said tank, undergo significant wear, which can lead to the creation of molten glass leaks. These leaks are dangerous and may cause the oven to shut down. In order to increase the life of the oven, the glassmaker may need to carry out repairs. EP 0 739 861 B1 discloses a product for repairing glass melting furnaces. This product has poor hot flowability. For any repair, the oven must be cooled, which significantly increases the time required for repair. In addition, this product requires consolidation sintering at a high temperature for a long time. For this reason also, this product does not allow a quick repair.

EP 2 358 650 discloses a self-pourable concrete (ie, with cement) which can be used for the manufacture of a glass furnace hearth. Particles smaller than 40 μm may be distributed, in percentages by weight relative to the mass of unshaped concrete, in the following manner: fraction <0.5: - fraction <2 μm:> 5%, fraction <10:> 19%, - fraction <40 iam: 34% - 52%, 3033556 2 - fraction between 2 iam and 40 iam: 26.5% - 34%. Like the product of EP 0 739 861, this unshaped concrete is however not suitable for hot application. In addition, unshaped products are used in the repair of metal making furnaces. The mechanical constraints in this application are however very different from those encountered in the application to glass furnaces. The conditions of corrosion of the furnaces by a glass or a molten metal are also different. Finally, some impurities, tolerated in metal-making furnaces, are unacceptable for the manufacture of glass. In particular, the refractory materials used in glassmaking furnaces 10 must not generate the release of stones by splitting or producing bubbles. An unshaped product intended for a metal-making furnace is therefore not, a priori, usable for a glass-making furnace, in particular in a zone in contact with the glass. There is a need for an unshaped product capable of forming, after addition of water, a wet blend suitable for rapid repair of a region of a glass melting furnace. The present invention aims to satisfy, at least partially, this need. SUMMARY OF THE INVENTION The invention proposes an unshaped product, intended in particular for producing a sole 20 of a glassware furnace, comprising, in percentages by weight, and for a total of 100%, A) particles (a) at least one refractory material different from a glass and a glass-ceramic, and whose main constituent (s) are alumina (Al 2 O 3) and / or zirconia (ZrO 2) and / or silica (SiO 2 ) and / or chromium oxide (Cr 2 O 3), the particles (a) constituting the 100% complement, B) 2% to 15% of particles (b) of glass, C) less than 2% of particles ( c) hydraulic cement, D) less than 7% of other constituents (d), all of said particles (a) and (b), preferably all the particles of the unshaped product being distributed, in percentages of mass relative to the mass of the unformed product, as follows: fraction <0.5:> 1%, - fraction <2 iam:> 4%, 3033556 3 - fraction <10:> 13%, - fraction <40 iam: 25% - 52%. As will be seen in more detail in the following description, a wet mixture, obtained after adding water in the unshaped product according to the invention 5 - is pumpable with suction pressures less than or equal to 180 bar, - is "hot self-cast", - does not lead to harmful segregation, and thus, after sintering at low temperature, leads to a shaped product that has good crush resistance. An unshaped product according to the invention is therefore perfectly suitable for use in repairing a glass melting furnace, in particular for repairing a hearth of such an oven. An unshaped product according to the invention may further comprise one or more of the following optional features: The particles (a) and (b), preferably all the particles of the unshaped product, are distributed as follows, in percentages by weight: 20 - fraction <0.5: - fraction <2 iam: - fraction <10: - fraction <40 iam: <7%, preferably <6%, preferably <5%, and / or> 2%, and / or> 5%, preferably> 6%, preferably> 7% and / or preferably <18%, preferably <16%, preferably <14%, preferably <12%, and / or or> 16%, preferably> 19%, preferably> 20% and / or, preferably <40%, preferably <35%, preferably <33%, preferably <30%, preferably <28%, and / or> 27%, preferably> 29%, preferably> 30%, preferably> 33%, preferably> 35%, preferably> 37% and / or preferably <50%, preferably <47%. %, preferably <45%, preferably <42%, and / or fraction between 2 μm and 40 μm:> 16% and / or <40%. The maximum size of all the particles (a) and (b), preferably the maximum size of all the particles of the unshaped product, is less than or equal to 2.5 mm, preferably less than or equal to at 2 mm, or even less than or equal to 1.5 mm. The set of particles (a) and (b) less than 500 μm in size, preferably all of the particles of the unshaped product of size less than 500 μm, represents more than 50%, preferably more than 500 μm. 55%, preferably more than 60%, preferably more than 65% or even more than 70% of the mass of said unshaped product. All the particles (a) and (b) greater than 1 mm in size, preferably all of the particles of the unshaped product greater than 1 mm in size, represent between 0 and 22%, preferably between 0 and 22%; and 17%, preferably between 0 and 14%, or even between 7% and 14% of the mass of said unshaped product. The set of particles (a) and (b) greater than 1.25 mm in size, preferably all the particles of the unshaped product larger than 1.25 mm, represents between 0 and 19%, preferably between 0 and 15%, or even between 0 and 12%, or even between 0 and 10%, or even between 5% and 10% of the mass of said unshaped product. The amount of particles (a) in the unshaped product is greater than 82%, preferably greater than 85%, preferably greater than 91% and / or less than 98%, preferably less than 97%. Preferably, all the particles (a) comprise, in mass percentages on the basis of the mass of the unshaped product: an AZS content of particles greater than 10%, greater than 20% and / or less than 95% ; and / or a reactive alumina content greater than 2%, greater than 3%, greater than 4%, and / or less than 13%, less than 10%, less than 8%; and / or - a calcined alumina content greater than 5%, greater than 10%, and / or less than 38%, less than 35%; and / or - an electro-cast alumina content greater than 10%, greater than 20%, greater than 25%, and / or less than 70%, less than 65%; and / or particles having the following chemical analysis, in percentage by weight based on the oxides: Cr 2 O 3 + Al 2 O 3 + ZrO 2 + MgO + Fe 2 O 3 + SiO 2 + TiO 2> 90%, preferably> 95%, and Cr 2 O 3 + Al 2 O 3 > 40%, even> 50%, even> 60%, even> 70%, even> 80%, even> 90%, or even> 95%, and Cr203> 30 9%, even> 15%, even> 20 %, even> 29%, even> 39%, even> 49%, even> 59%, even> 70%, even> 80%, even> 90%, and 20%> Si02> 0.5%, and others oxides: <10%, preferably <5%, the content of said particles being greater than 10%, greater than 20%, greater than 30% and / or less than 95%, and / or - an oxide content pigment chromium greater than 5%, greater than 10%, and / or less than 25%, less than 20%. 5 - The particles (b) represent more than 3% and less than 13%, preferably less than 12%, preferably less than 10%, preferably less than 9%, preferably less than 8% of the mass of said product unshaped. - The particles (b) of the product are preferably distributed in the following manner, in percentages by mass, on the basis of the mass of the particles (b): fraction <1 mm:> 80%, preferably> 90%, or > 95%, even substantially 100%, and / or fraction <0.5 mm:> 80%, preferably> 90%, and / or - fraction <0.1 mm:> 25% and / or <48% preferably <45%, and / or fraction <0.04 mm: <30%, preferably <25%, or even <20%. The particles (b) consist of a glass preferably having a melting temperature above 750 ° C., preferably above 800 ° C., preferably above 900 ° C., and / or below 1650 ° C. preferably below 1600 ° C, preferably below 1550 ° C, or even below 1500 ° C. Preferably, the particles (b) consist of a glass whose chemical composition comprises more than 90%, preferably more than 94%, preferably more than 97% of oxides. In one embodiment, said glass is substantially entirely composed of oxides. The particles (b) consist of a glass whose chemical composition comprises more than 45%, preferably more than 50%, preferably more than 55% and / or less than 80%, preferably less than 75% of silica, in percent by mass. The amount of particles (c) of hydraulic cement is preferably less than 1%, preferably less than 0.5%. Preferably, the amount of particles (c) of hydraulic cement is substantially zero. - The content of "other constituents" (d) is preferably less than 5%, preferably less than 3%, preferably less than 2%, preferably less than 1%. The "other constituents" (d) preferably consist of oxides. Preferably, the "other constituents" (d) consist of surfactants, anti-segregation adjuvants and, optionally, fibers. The unshaped product comprises a surfactant, preferably between 0.075% to 1% of a surfactant. The surfactant is a modified polycarboxylate ether. The unshaped product preferably comprises an anti-segregation adjuvant, preferably in an amount between 0.05% and 0.5% of the mass of the unshaped product. In one embodiment, the unshaped product comprises fibers, preferably organic fibers, preferably between 0.01% and 0.06%, preferably between 0.01% and 0.03%. In one embodiment, the unshaped product has no fibers. The invention also relates to a wet unshaped mixture consisting of an unshaped mixture according to the invention and water in an amount of less than 13%, less than 12%, as a percentage by weight based on the wet mixture. Despite a limited amount of water, a wet mix according to the invention is self-flowable and does not lead to segregation. After sintering, it leads to a product perfectly suited for repairing a region of a glassmaking furnace intended to be in contact with molten glass. The invention also relates to a glass melting furnace comprising at least one region, in particular in contact with molten glass, in particular the sole, obtained from an unshaped product according to the invention. The invention further relates to a method of repairing a glass melting furnace, and in particular to a hearth of such a furnace, the method comprising the following steps: 1) independently of steps 2) to 4), preparation of an unshaped product according to the invention, 2) emptying the molten glass contained in the oven; 3) optionally, rinsing the hearth, particularly worn out areas, with a product adapted to melt the glass residues, 4) reducing the temperature in the furnace to a temperature at which the glass particles (b) of the unshaped product according to the invention are no longer in the solid state, preferably between 900 ° C and 1350 ° C; 5) moistening said unshaped product so as to obtain a wet mixture; 6) placing said wet mixture; 7) maintaining the temperature of the oven between 1250 ° C. and 1400 ° C. in order to allow sintering of said wet mixture, preferably for a time greater than 8 hours, preferably greater than 10 hours, and preferably less than 15 hours; hours; 8) introducing a glass composition to melt and increasing the temperature of the oven to its operating temperature. Definitions - A "non-shaped product" is a dry or wet particulate mixture capable of forming a mass so as to constitute a shaped product. By "wet mix" is meant an unshaped product containing a liquid, preferably water. - A hydraulic cement, or "hydraulic binder", is a binder that, upon activation, generates a setting and a hydraulic hardening. - "Refractory material" means a material having a melting temperature greater than 1500 ° C. This definition is commonly used by those skilled in the art and cited in "Refractory materials and technical ceramics (ceramics and technology elements)", G. Aliprandi, Editions Septima Paris, 1979. This book also gives on pages 297 to 301 examples of refractory materials, in particular oxides, carbides and nitrides. The "glass" of the particles (b) is a non-crystalline material having a glass transition temperature of less than 1100 ° C. The term "glass transition temperature" of a glass means the temperature at which the material passes from the solid state to the viscous state. The glass transition temperature can be determined by differential thermal analysis (DTA). The glass transition temperature is the temperature at which the glass has a viscosity substantially equal to 1012 steps. "Glass-ceramic" or "vitroceramic material" conventionally means a microcrystalline compound obtained by controlled crystallization of a "glass-ceramic precursor glass".

The controlled crystallization of a glass-ceramic precursor glass is conventionally carried out in a next step, immediately or not, the step of obtaining said glass-ceramic precursor glass. The microstructure of a glass-ceramic thus consists of microcrystallites bathed in a residual vitreous phase. A microcrystallite is a crystal whose half length and width are less than 101.tm. The length and width of a microcrystallite are conventionally evaluated from sectional views of the glass-ceramic. Fusion-cooling products which during their manufacture do not pass through a step in which they are in the glass state are therefore not glass-ceramic materials. Molten corundum, fused alumina, molten spinels, molten magnesia, molten mullite, molten mullite-zirconia, molten aluminum titanate, possibly doped, and molten nitrides are not, in particular, materials ceramic. The calcined, reactive and tabular aluminas are well known to those skilled in the art and commercially available. The calcined alumina is obtained from bauxite treated according to the Bayer process followed by calcination at a temperature typically between 1000 and 1250 ° C. in order to eliminate the hydrates and to obtain a powder mainly crystallized in the A1203 alpha form.

Tabular alumina is a calcined alumina sintered under air at a temperature above 1600 ° C and long enough for its shrinkage to no longer increase. The morphology of the crystals of this alumina in elongated hexagonal tablets is at the origin of its denomination. Reactive alumina is conventionally obtained by grinding calcined alumina. The powders of reactive alumina particles typically have a median diameter of less than 2 microns, preferably less than 1 micron. The percentiles or "percentiles" (Dio), 50 (D50), and 90 (D90) are the particle sizes of a powder corresponding to the percentages by weight, 10%, 50% and 90% respectively, on the cumulative size distribution curve of the particle sizes of the powder, the particle sizes being ranked in ascending order. For example, 90% by weight of the particles of the powder have a size less than D90 and 10% of the particles by mass have a size greater than or equal to D10. The percentiles can be determined using a particle size distribution made with a laser granulometer. The laser granulometer used can be a Partica LA-950 from the company HORIB A. D50 corresponds to the "median size" of a set of particles, that is to say, the size 5 dividing the particles of this set into first and second populations equal in mass, these first and second populations comprising only particles having a size greater than or equal to, or smaller than, the median size. The "maximum size" is the 99.5 percentile (D99.5) of a set of particles. It is clear that particles having a size less than 10 μm (which constitute the "fraction <10") are accounted for in the 29% to 52% of the particles having a size less than 40 μm, whereas particles having a size of less than at 2 iam are counted in particles having a size less than 40 iam and those having a size less than 10 pm, etc. "Impurities" means the inevitable constituents introduced involuntarily and necessarily with the raw materials or resulting from reactions with these constituents. Impurities are not necessary constituents, but only tolerated. Preferably, the amount of impurities is less than 2%, less than 1%, less than 0.5%, or even substantially zero. AZS products are products, preferably electrofused, the main constituents of which are alumina (Al 2 O 3), zirconia (ZrO 2) and silica (SiO 2). In other words, alumina, zirconia and silica are the constituents whose mass contents are the highest. These products are well suited for the manufacture of glass furnaces. More particularly, the current AZS products are mainly used for the areas in contact with molten glass as well as for the superstructure of glass furnaces. The AZS products include products marketed by Saint-Gobain SEFPRO, such as ER-1681, TER-1685 or ER-1711. When reference is made to ZrO 2 or zirconia, it is necessary to include ZrO 2 and the traces of HfO 2. Indeed, some HfO2, chemically indissociable from ZrO 2 in a melting process and having similar properties, is still naturally present in zirconia sources at levels generally below 2%. The hafnium oxide is then not considered an impurity. The content of HfO 2 in the AZS particles is preferably less than 5%, less than 3%, less than 2%. Elongated structures are called "fibers", typically having a diameter of 1 μm to 1 mm and a length of up to about 60 mm. 5 - All percentages of the present description are percentages by weight unless otherwise indicated. Detailed Description of the Unshaped Product General An unshaped product according to the invention can be packaged in bags or drums. Preferably, the unshaped product is ready for use, i.e., incorporates all components except water. Preferably, all the particles (a) and (b) represent more than 95%, preferably more than 97%, preferably more than 98%, or even more than 99% of the mass of the unshaped product. Preferably, the unshaped product has a chemical composition such that the sum Al 2 O 3 + ZrO 2 + SiO 2 + Cr 2 O 3> 85%, preferably> 90%, preferably> 92%, or even greater than 94%, or even greater than 95%. . In one embodiment, the unshaped product has a chemical composition such that the sum Al 2 O 3 + ZrO 2 + SiO 2> 85%, preferably> 90%, preferably> 92%, or even greater than 94%, or even greater than 95%.

In one embodiment, the unshaped product has the following mass composition, for a total of greater than 95%, preferably for a total of greater than 97%: A1203: 85% -97%, preferably> 90% %, and / or <94% - SiO2:> 1%, preferably> 2% and / or <10%, preferably <9%, preferably <7%.

In one embodiment, the unshaped product has the following mass composition, for a total of greater than 95%, preferably for a total of greater than 97%: Al 2 O 3: 43% - 60% - ZrO 2 20% 43% - SiO2: 10% - 26%.

Preferably, 3033556 11 - Al 2 O 3:> 45%, preferably> 50% and / or <58%, preferably <55%, and / or - ZrO 2> 25% and / or <35%, and / or - SiO2:> 12%, preferably> 14%, preferably> 15% and / or <23%, preferably <19%. In one embodiment, the unshaped product has the following mass composition, for a total of greater than 95%, preferably for a total of more than 97%: - Al 2 O 3: 5% - 60%, - ZrO 2 <35% , 10 - SiO2: 5% - 25%, - Cr2O3: 10% - 90%. Preferably, Al 2 O 3:> 40%, preferably> 50% and / or <60%, and / or - ZrO 2> 5%, preferably> 10% and / or <30%, or even <20%, and / or or 15 - SiO2:> 10% and / or <20%, and / or - Cr2O3:> 15%, preferably> 20% and / or <65%, or even <60%. In a preferred embodiment, all of the particles (a) and (b) have a composition whose complement to 100% of the oxides Al 2 O 3, SiO 2, ZrO 2 and Cr 2 O 3 consists of CaO and / or B 2 O 3 and / or Na 2 O and and / or P205 and / or MgO and / or K20 and / or BaO and / or Sr0 and / or ZnO (which conventionally result from the presence of a glass) and impurities. The impurities may be, for example, metal particles. Preferably, the maximum size of all the particles (a) and (b), preferably the maximum particle size of an unshaped product according to the invention is less than or equal to 2 mm, or even less than or equal to 1.5 mm. Advantageously, the flowability of the wet mixture at high temperature is improved. Preferably, all the particles (a) and (b), preferably all of the particles of the unshaped product are distributed as follows, in percentages by weight: fraction <0.5: <7%, preferably <6%, preferably <5%, and / or> 2%, and / or fraction <2 iam:> 5%, preferably> 6%, preferably> 7% and / or preferably <18 %, preferably <16%, preferably <14%, preferably <12%, and / or <10:> 16% fraction, preferably> 19%, preferably> 20% and / or preferably <40%, preferably <35%, preferably <33%, preferably <30%, preferably <28%, and / or fraction <40μm:> 27%, preferably> 29%, preferably > 30%, preferably> 33%, preferably> 35%, preferably> 37% and / or preferably <50%, preferably <47%, preferably <45%, preferably <42%, and or fraction between 2 μm and 40 μm:> 16% and / or <40%. Preferably, the particles of the unshaped unshaped product are distributed in the following manner: fraction <0.5: 1% - 6%, and - fraction <2 μm: 6% - 16%, and - fraction <10 : 16% - 35%, and - fraction <40 μm: 27% - 47%, and 15 - maximum particle size: <2.5 mm, preferably <2 mm. More preferably, the particles of the unshaped product are distributed as follows: fraction <0.5: 1% - 5%, and - fraction <2 μm: 7% - 12%, and 20 - fraction <10: 19% - 28%, and - fraction <40 μm: 29% - 45%, and - maximum particle size: <2.5 mm, preferably <2 mm. Conventional compaction models such as the Fuller-Bolomey model or the Andreasasen model can be used to determine the most suitable particle size distribution. Particles (a) The particles (a) may have different compositions from each other. In one embodiment, all the particles (a) preferably have the same composition. Preferably, they are homogeneous.

The particles (a) can be made from one or more sources of raw materials, having different chemical analyzes. Particle size distributions may also differ according to said sources.

The following sources can be used in particular: an electro-cast refractory product such as JARGAL M, produced and marketed by the European Company of Refractory Products, having the following typical chemical analysis: A1203: 95%, 5iO2: 0.5 %, Na 2 O 4%, other: 0.5%, the particle size of JARGAL M being preferably greater than 50 μm and less than 10 mm; refractory electro-fused products such as ER-1681 or ER-1711 produced and marketed by the European Company of Refractory Products. These two products, referred to in Table 1 as "AZS particles" (because of their contents of Al 2 O 3, ZrO 2 and TiO 2), contain, as a percentage by weight, on the basis of the oxides: 32 to 54% of ZrO 2, 36 to 51 % Al 2 O 3, 10 to 16% Li 2 O and 0.2 to 1.5% Na 2 O; mullite, melted or sintered, for example a powder which contains 76.5% of Al 2 O 3 and 22.5% of TiO 2 and whose particle size varies from 0.7 to 1.5 mm; products containing chromium oxide and having the following chemical analysis, in weight percent on the basis of the oxides: Cr 2 O 3 + Al 2 O 3 + ZrO 2 + MgO + Fe 2 O 3 + TiO 2 + TiO 2> 90%, preferably> 95 %, and Cr203 + A1203> 40%, even> 50%, even> 60%, even> 70%, even> 80%, even> 90%, or even> 95%, and Cr203> 9%, even> 15 %, even> 20%, even> 29%, even> 39%, even> 49%, even> 59%, even> 70%, even> 80%, even> 90%, and 20%> 5i02> 0, 5%, and other oxides: <10%, preferably <5%; 20 - products with a high zirconia content, such as zirconia CC10 marketed by the European Company of Refractory Products. This product contains more than 99% ZrO2 and the median size (D50) of the zirconia particles is 3.5; fused alumina, in the form of a powder whose particles have a size preferably of between 10 μm and 10 mm; Tabular alumina, in the form of a powder whose particles have a size preferably of between 10 μm and 10 mm; calcined alumina, in the form of a powder whose particles have a size preferably of between 1 μm and 50 μm; pigmentary chromium oxide, containing more than 98.5% of Cr 2 O 3, in the form of a powder having a median size of <10 μm, or even <5 μm, or even <1; Reactive alumina, or a reactive alumina mixture, containing more than 99% Al 2 O 3, the median size of the reactive alumina particles preferably ranging from 0.5 microns to 3 microns. tm. Particles (b) Particles (b) may have different compositions from each other. In one embodiment, all the particles (b) of a glass are made of the same material. Preferably, the particles (b) of a glass have a glass transition temperature of less than 1000 ° C., preferably less than 900 ° C., or even less than 800 ° C.

A quantity of particles (b) greater than 15% of the unshaped product mass decreases the corrosion resistance too much. A quantity of particles (b) of less than 2% of the mass of the unshaped product does not allow the particles (a) to be bonded together satisfactorily after placing said unshaped product and does not make it possible to obtain a mixture wet self-flowable hot.

In a particular embodiment, all the particles (b) comprise glass particles, preferably consisting of glass particles having the following specific chemical composition: SiO 2: 70% -75%, -Al 2 O 3: 2%, 20 - CaO: 8% - 12%, - Na2O: 11% - 14%, - 1 (20: - MgO: - Other: <3%.

The unshaped product is then particularly well suited for use in a soda-lime glass melting furnace. In a particular embodiment, all of the particles (b) comprise glass particles, preferably consisting of glass particles having the following specific chemical composition: SiO 2: 57% - 65%, - Al 2 O 3: 3%, - CaO: 6% - 8%, 3033556 15 - Na2O: 14% - 18%, - 1 (20: - MgO: 3% - 5%, - B203: 5% - 12%, 5 - Other < The unshaped product is then particularly well suited for use in a glass melting furnace for insulation, or even a soda-lime glass melting furnace, In a particular embodiment, all the particles (b) ) comprises glass particles, preferably consists of glass particles having the chemical composition. The unshaped product is then particularly well suited for use in a reinforcing glass melting furnace, and in a glass furnace for insulation, or even a melting furnace of soda-lime glass. Remarkably, an unshaped product according to the invention has less than 2% particles (c) of hydraulic cement. As shown by the examples described hereinafter, the inventors have discovered that, surprisingly, hydraulic cement has a deleterious effect when associated with the other components of an unshaped product according to the invention. Although the addition of cement is a standard measure in products for the repair of glass furnaces, the content of hydraulic cement must be, according to the invention as low as possible. The hydraulic cement may in particular be an aluminous cement, in particular having an alumina content of greater than 69%. Other constituents (d) The content of "other constituents" is acceptable when it is less than 7%. following mass: - 63%, - SiO2: 54% - 20%, - A1203: 14% - CaO: 4% - 17%, - Na2O: - MgO: - B203: 6% - 12%, - Sr0 + Ba0 + ZnO: 3% - 12%.

The content of "other components" is preferably 5%, 3%, 2%, 1%. Preferably, the unshaped product according to the invention comprises a surfactant, preferably in a mass content of 0.1% to 1%, preferably greater than or equal to 0.2% and / or less than 0, 5%, more preferably less than 0.4%. The role of this surfactant is in particular to modify the rheological properties of the unshaped product to facilitate pumping. Surfactants preferably selected from long chain sodium polyphosphates, sodium polyacrylates, ammonium polyacrylates, modified polycarboxylates, and mixtures thereof are preferably used. Preferably, the surfactants are chosen from modified polycarboxylates, preferably of modified polycarboxylate ether type, more preferably based on polyethylene glycol. Preferably, the unshaped product according to the invention also comprises at least one anti-segregation adjuvant, preferably in a proportion of 0.05% to 0.3%. The anti-segregation adjuvant may in particular be chosen from starch ethers. The choice of a surfactant and an anti-segregation adjuvant among the surfactants and anti-segregation adjuvants generally used by those skilled in the art is guided by the results of simple tests, such as those described in US Pat. this application, depending on the desired performance. In one embodiment, the fibers, preferably organic, are, for example, polypropylene, polyacrylonitrile or polyvinyl alcohol fibers.

In one embodiment, the unshaped product has more than 0.01% fiber. Preferably the average length (arithmetic mean) of these fibers is greater than 6 mm, preferably between 18 and 24 mm. These fibers are however not essential. Preferably, the unshaped product has no fibers.

Particular Embodiments In one embodiment, the unshaped product has a chemical composition such that the sum Al 2 O 3 + ZrO 2 + SiO 2> 85%, preferably> 90%, preferably> 92%, or even greater than 94%, even greater than 95%. In one embodiment, the unshaped product has the following mass composition, for a total of greater than 95%, preferably for a total of greater than 97%: A1203: 85% -97%, preferably> 90% %, and / or <94% SiO2:> 1%, preferably> 2% and / or <10%, preferably <9%, preferably <7%. In one embodiment, the unshaped product has the following mass composition, for a total of greater than 95%, preferably for a total of greater than 97%: 5 - Al 2 O 3: 43% - 60% - ZrO 2 20% - 43% - SiO2: 10% - 26%. Preferably, Al 2 O 3:> 45%, preferably> 50% and / or <58%, preferably <55%, and / or - ZrO 2> 25% and / or <35%, and / or - SiO 2: > 12%, preferably> 14%, preferably> 15% and / or <23%, preferably <19%. In one embodiment, the unshaped product has the following mass composition, for a total of greater than 95%, preferably for a total of greater than 97%: Al 2 O 3: 5% - 60%, - ZrO 2 %, - SiO2: 5% - 25%, - Cr203 10% - 90%.

Preferably, Al 2 O 3:> 40%, preferably> 50% and / or <60%, and / or - ZrO 2> 5%, preferably> 10% and / or <30%, or even <20%, and / or - SiO 2:> 10% and / or <20%, and / or - Cr 2 O 3:> 15%, preferably> 20% and / or <65%, or even <60%.

In one embodiment, the unshaped product has the following mass composition, for a total of greater than 95%, preferably for a total of greater than 97%, more preferably more than 99%: A1203: 85% - 97%, preferably> 90%, and / or <94% - SiO2:> 1%, preferably> 2% and / or <10%, preferably <9%, preferably <7%, and Preferably, all of the particles (a): - comprises reactive alumina in a mass quantity greater than 2%, greater than 4%, greater than 5%, and / or less than 13%, less than 10%. %, based on the mass of the unshaped product, and / or - comprises calcined alumina in a mass quantity greater than 20%, greater than 25%, and / or less than 38%, less than 35% on the basis of the mass of the unshaped product, and / or - comprises fused alumina in a mass quantity greater than 50%, greater than 55%, and / or less than 70%, less than 65%, based on the mass of the unshaped product, and preferably all the particles (b) of the unshaped product has the following chemical composition: SiO 2: 70% -75%, Al 2 O 3: <2%, - CaO: 8% - 12%, 15 - Na2O: 11% - 14%, - 1 (20: - MgO: - Other: <3%. In one embodiment, the unshaped product has the following mass composition, for a total of greater than 95%, preferably for a total of greater than 97%, preferably more than 99%: Al 2 O 3: ZrO 2 SiO 2: Preferably Al 2 O 3: ZrO 2 SiO 2: 43% - 60% 20% - 43% 10% - 26%. > 45%, preferably> 50% and / or <58%, preferably <55%, and / or> 25% and / or <35%, and / or> 12%, preferably> 14%, preferably > 15% and / or <23%, preferably <19%. and preferably, all of the particles (a): comprise particles of AZS in a mass quantity greater than 80%, preferably greater than 85% and / or less than 95%, on the basis of mass of the unshaped product, and / or - comprises reactive alumina in a mass quantity greater than 3%, greater than 5%, and / or less than 10%, less than 8%, based on the mass unshaped product, and preferably all of the particles (b) has the following chemical composition: SiO 2: 70% -75%, Al 2 O 3: <2%, CaO: 8% -12%, Na2O: 11% - 14%, - 1 (20: - MgO: - Other: <3%.

In one embodiment, the unshaped product has the following mass composition, for a total of greater than 95%, preferably for a total of greater than 97%, preferably more than 99%: Al 2 O 3: ZrO 2 SiO 2: Cr 2 O 3: Preferably Al 2 O 3: ZrO 2 - SiO 2: Cr 2 O 3: 5% - 60%, 5% - 25%, 10% - 90%,> 40%, preferably> 50% and / or <60%, and / or> 5%, preferably> 10% and / or <30%, or even <20%, and / or> 10% and / or <20%, and / or> 15%, preferably> 20% and / or <65%, even <60%, and preferably all of the particles (a) of the unshaped product: - comprises particles having the following chemical analysis, in percentage by mass on the base of the oxides: Cr 2 O 3 + Al 2 O 3 + ZrO 2 + MgO + Fe 2 O 3 + SiO 2 TiO 2> 90%, preferably> 95%, and Cr 2 O 3 + Al 2 O 3> 40%, or even> 50%, even> 60%, or even> 70% , even> 80%, even> 90%, or even> 95%, and Cr203> 9%, even> 15%, even> 20%, even> 29%, even> 39%, even> 49%, or even> 59%, 30 33556 20%> 70%, even> 80%, or even> 90%, and 20%> SiO2> 0.5%, and other oxides: <10%, preferably <5%, in a mass quantity greater than 10% , greater than 20%, greater than 30% and / or less than 95%, based on the mass of the unshaped product, and / or 5 - comprises reactive alumina in a mass quantity greater than 2%, greater than at 3%, greater than 4%, and / or less than 13%, less than 10%, less than 8%, based on the mass of the unshaped product, and / or - comprises calcined alumina in one mass quantity greater than 5%, greater than 10%, and / or less than 38%, less than 35%, less than 30%, less than 25%, less than 20%, based on the mass of the product not shaped, and / or - comprises fused alumina in a mass quantity greater than 10%, greater than 20%, greater than 25%, and / or less than 50%, less than 40%, based on the mass non f product and / or 15 - comprises AZS particles in a mass amount greater than 10%, greater than 20% and / or less than 50%, less than 40%, based on the mass of the unshaped product, and or - comprises pigmentary chromium oxide particles in a mass quantity greater than 5%, greater than 10%, and / or less than 25%, less than 20%, based on the mass of the unshaped product, and preferably all of the particles (b) has the following chemical composition: SiO 2: 57% - 65%, Al 2 O 3: <3%, CaO: 6% - 8%, Na 2 O: 14% 18%, - 1 (20: - MgO: 3% - 5%, - B203: 5% - 12%, - Other: <3%.

Detailed Description of the Repair Method A repair method according to the invention comprises the steps 1) to 8) described above.

Preferably, in step 1), the various raw materials are mixed in a kneader. The optional surfactant may be mixed at this stage or introduced at step 5). Preferably, in step 1), the chemical composition of the particles (b) is chosen so that their melting temperature is lower than the temperature of the region to be repaired. In one embodiment, the particles (b) have substantially the same composition as the molten glass in the furnace to be repaired. Preferably, in step 2), the melted glass is emptied at a temperature close to the melting temperature of the glass. Said emptying can take place, for example, through holes drilled in the hearth, or through holes created by the disassembly of one or more electrodes present. In step 3), optional flushing of the hearth, especially the waste areas is preferably carried out by spraying a product suitable for melting the glass residues. Preferably said product is selected from sodium sulfate, sodium carbonate, sodium hydroxide and mixtures thereof. The products make it possible to increase the fluidity of the glass, which facilitates its evacuation outside the oven. Preferably, the repair method according to the invention comprises a step 3). In step 4), the temperature in the oven is reduced to a temperature at which the glass of the particles (b) of the unshaped product according to the invention is no longer in the solid state, preferably between 900 ° C. C. and 1350 ° C., preferably between 1000 ° C. and 1300 ° C., preferably between 1150 ° C. and 1250 ° C. In step 5), the unshaped product is moistened so as to obtain a wet mixture, adding thereto an amount of water preferably greater than 8%, preferably greater than 9% and / or less than 13%, less than 12%, by weight relative to the mass of said unformed product. In step 6), the wet mixture is preferably pumped by means of a pump producing a suction pressure of less than or equal to 180 bar and conveyed into the oven, preferably by means of a water-cooled cane. The wet mixture is poured into the furnace, on the existing hearth, the holes made for the emptying of the glass in step 2) being pre-capped. Said casting can be carried out so as to carry out repairs in different areas of said sole. The wet mixture is preferably cast over the entire surface of the oven hearth.

In step 7), the oven is maintained at a temperature between 1250 ° C and 1400 ° C, preferably between 1300 ° C and 1400 ° C, to allow sintering of said wet mixture, preferably during a time greater than 8 hours, preferably greater than 10 hours and preferably less than 15 hours. The unshaped product according to the invention advantageously allows a low sintering temperature and / or a holding time at said reduced temperature. During this step, it is possible to pierce the sole in order to install electrodes. In step 8), the glass melt composition is introduced into the oven and the temperature thereof is increased to its operating temperature.

Examples The following nonlimiting examples are given to illustrate the invention. The hot "self-flowable" character, the segregation and the temperature after-drop appearance are evaluated by the following test: A flat-bottomed refractory crucible having an inner diameter of 170 mm and an internal height equal to 45 mm is mounted in a metal tank having a diameter equal to 400 mm. The space between the wall of the tank and the wall of the crucible is filled by insulating materials. A removable refractory concrete cover with a thickness of 100 mm is suspended above the crucible at a height of between 20 mm and 30 mm. This cover has a hole 100 mm in diameter at its center which allows to pass the flame of a gas burner positioned above said lid and to introduce the wet mixture. The gas burner is ignited and the interior of the refractory crucible is heated to 1300 ° C, at a temperature rise rate of 500 ° C / h.

The vat + crucible assembly is then rotated at a speed of 6 rpm. 5 kg of wet mix are prepared in a rotary blade mixer and fixed bowl, with a mixing time of 5 minutes. The wet mixture is then poured into a metal bracket having a length of 600 mm and edges of a height of 40 mm. Said angle has an inclination of 45 ° and one of its ends is supported on the edge of the central hole of the cover, to allow the hot introduction of the wet mixture in the crucible. The maximum height of 3033556 23 falls, at the beginning of the spill, is about 175 mm. The supply of wet mixture is stopped when it reaches the top of the refractory crucible. The temperature is then raised to 1450 ° C with a temperature rise rate of 100 ° C / h, and is maintained for 10 hours to allow sintering of the wet blend. The temperature decrease is carried out gradually at a speed equal to 100 ° C / h and the sintered product slab is then demolded. The appearance of the cake is then observed. The hot self-flow character is acquired if the sintered product wafer has a diameter substantially equal to the internal diameter of the refractory crucible, and if the wafer does not have, with the naked eye, a hole or a recess in its center. . The slab is then sawn so as to seek segregation. It is considered that segregation occurs when the sawn faces reveal a surface layer of laitance extending from the top face of the slab to a depth of 3 mm or more.

The resistance to cold compression is measured by means of a press LR150K marketed by AMETEK-LLOYD, on rolls of diameter equal to 30 mm and height equal to 30 mm taken from the slab. Table 1 provides the composition of the particulate mixtures (a) + (b) + (c). It also indicates the particle size distribution of the fused alumina particles and the AZS particles used. The calcined alumina used is alumina HVA FG marketed by Almatis. Silica fume is a silica fume comprising more than 90% of silica by mass, in the form of a powder whose particles have a size of between 0.1 and 5 μm and a median size of less than 0, 6 iam, marketed by the European Company of 25 Refractory Products. The cement used is CA25R cement marketed by Almatis. The glass of the particles (b) is a soda-lime glass having the following chemical analysis: 30 - 5iO 2: 72.3%, - Al 2 O 3: 0.5%, - CaO: 9.5%, - Na 2 O: 13.4% , - MgO: 4%, 3033556 24 - Other: 0.3%. The glass transition temperature of this glass is 580 ° C. The glass transition temperature is determined by differential thermal analysis (DTA) on an STA409C device marketed by Netsch. The sample holders are each equipped with a thermocouple allowing a direct measurement of the temperature of the glass placed in a dense sintered alumina crucible of capacity equal to 300 μm and an identical empty crucible considered as reference. The glass to be analyzed is ground so as to pass through a sieve of opening equal to 160 i.tm. The thermal cycle applied during the measurement consists of a rise at a speed equal to 10 ° C / min, under air, up to 1650 ° C.

On the thermogram obtained, the glass transition appears as the first endothermic event. The glass transition temperature is equal to the temperature of the point of inflection of the curve in said first endothermic event (ie "Tinfl" in the program used). After grinding, the glass particles have the following particle size distribution: fraction <0.5: 0%, and - fraction <2 iam: 0%, and - fraction <10: 5%, and - fraction <40 iam: 16%, and fraction <100 iam: 35%, and 20 - fraction <200 iam: 58%, and - maximum particle size: 1 mm. Comparative example 1, "Comp 1", is rammed earth described in EP 0 739 861 Bi, in particular used in the repair of glass melting furnaces. Comparative Example 2, "comp 2", is a self-leveling concrete according to WO2013132442 to which particles (b) of glass have been added, the particles (b) representing 5% of the total mass of the self-leveling concrete and glass. Table 2 provides the chemical compositions of the wet unshaped products tested, as well as the results of the tests performed. Examples "Comp 2" and 1 to 4 incorporate as the particles (d) 0.2% of a surfactant of the family of modified polycarboxylate ethers and 0.2% of an anti-dopant adjuvant. segregation of the family of starch ethers. In Table 2: for the example "comp 1", the 100% complement of Al 2 O 3 + SiO 2 + ZrO 2 consists of P 2 O 5 and impurities, for the example "comp 2", the complement to 100% Al 2 O 3 + SiO 2 + ZrO 2 + surfactant + anti-segregation adjuvant consists of CaO provided by the hydraulic cement and the glass, as well as Na 2 O, K 2 O and MgO provided by the glass, and impurities. and for examples 1 to 4, the 100% complement of Al 2 O 3 + SiO 2 + ZrO 2 + surfactant + anti-segregation adjuvant consists of CaO, Na 2 O, K 2 O and MgO provided by the glass, and only impurities.

The addition of water (g) is provided as a percentage by weight based on the unshaped product. Table 2 also provides the particle size distribution, measured using a HORIBA laser granulometer.

26 Particulate mixture (a) + (b) + (c), in percentages by weight Alumina Alumina Alumina Alumina Cement smoke Particles AZS 0.5 mm -2 mm Particles AZS Particles Powder Example electro-cast fuse calcined reactive silica hydraulic 40 lim - 500 pm AZS <40 μm of glass no. 0,5 mm - 3,5 mm 1011m - 200 Fim Comp 1 - - - - - - - - - - Comp 2 44,7 14,2 16,1 12,35 2, 85 4.8 0 0 0 5 1 0 0 0 5 0 0 27 31 34 3 2 0 0 0 6 0 0 27 31 31 5 3 0 0 0 3 0 0 27 31 31 8 4 0 0 0 6 0 0 34 38 17 5 Table 1 Unspecified dry product Add Distribution of particles (a) + (b) + (c) (mass percentages) (mass percentages) IV ° A1203 Si02 Zr02 Water <0.5 <2 <10 <40 <500 Fim > 1 size Auto-seg- ment Aspect after Resistance to (%) prn 1.tm gm 1.tm maximum mm castable? back down to (mm) at hot temperature cold compression (Mpa) Comp 57.2 12.5 25.1 5 10.1 11.7 37.1 53.9 80.3 8 2 non-porous 45 1 CoenP 91 6.3 0.1 11 7 11.7 30.2 38.2 55.5 32.8 3.5 yes not very cracked and very low mechanical strength nd 2 1 52.4 15.8 29.7 11 2, 5 9.5 24.6 41.5 76.2 11.9 2 yes no good 70 2 51.8 16.8 28.7 11 2.4 8.9 22.9 39 76.1 11.9 2 yes not good 65 3 48.9 18.9 28.7 11 1.8 7.7 21.3 37.8 75.8 11.9 2 yes no good 60 4 51.8 16.8 28.7 11 2, 3 6.9 16.4 28.6 69.8 15.1 2 yes no good ndnd: not determined Table 2 3033556 27 The results make it possible to make the following observations: - The example "Comp 1", which does not include of particles (b) does not have a hot self-flow character. - The example "Comp 2" has a self-flow character, but after descending in 5 temperature, the slab is very cracked and has a very low mechanical strength: some areas can be broken manually. Without being bound by any theory, the inventors attribute this phenomenon to the presence of 4.8% hydraulic cement in the product of the example "Comp 2". The "Comp 1" example has a lower cold compressive strength than the unshaped products of the examples according to the invention. The example "Comp 1" requires a sintering temperature greater than 1350 ° C. to develop a cold compressive strength similar to that of the products according to the invention: the reintroduction of the glass melting composition of step 8 ) can therefore be carried out more quickly with the products according to the invention. The return to production is thus faster than for the product of the example "Comp 1". The unshaped products of Examples 1 and 2 are the preferred examples. As now clearly apparent, the invention provides an unshaped product for making a self-flowable, non-segregated, wet blend which, after sintering, exhibits good cold compressive strength even after sintering at 1350 ° C. In addition, this unshaped product, after wetting, can be pumped with suction pressures less than or equal to 180 bar. Finally, other tests have shown that an unshaped product according to the invention, after sintering, generates little or no defects when in contact with molten glass.

An unshaped product according to the invention is therefore perfectly suitable for use in repairing a glass melting furnace, in particular for repairing a hearth of such an oven. Of course, the present invention is not limited to the embodiments described, provided by way of illustrative and non-limiting examples. 30

Claims (30)

REVENDICATIONS1. Unshaped product comprising in percentages by weight, and for a total of 100%, A) particles (a) of at least one refractory material different from a glass and a glass-ceramic, the main constituent (s) of which is alumina (Al 2 O 3) and / or zirconia (ZrO 2) and / or silica (SiO 2) and / or chromium oxide (Cr 2 O 3): 100% complement, B) 2% to 15% of particles (b) glass, a glass being a non-crystalline material having a glass transition temperature of less than 1100 ° C, C) less than 2% of particles (c) of hydraulic cement, D) less than 7% of other constituents, the whole said particles (a) and (b) being distributed, in percentages by weight relative to the mass of the unshaped product, in the following manner - fraction <0.5:> 1%, - fraction <2 pm: - fraction <10:> 13%, - fraction <40 μm: 25% - 52%. 2. Unformed product according to the preceding claim, wherein the amount of hydraulic cement is less than or equal to 1%. 3. Unformed product according to the preceding claim, wherein the amount of hydraulic cement is substantially zero. 4. Unformulated product according to any one of the preceding claims, in which the particles of the unshaped product are distributed in the following manner, in percentages by weight: fraction <0.5: <7% and / or - fraction <2 pm:> 5% and / or fraction <10:> 16% and / or 3033556 fraction <40 pm:> 27% and / or fraction between 2 iam and 40 iam:> 16% and / or < 40%. Unformulated product according to any one of the preceding claims, wherein the particles of the unshaped product are distributed in the following manner, in mass percentages: fraction <0.5: <6% and / or fraction < 2 μm: <18% and / or fraction <10: <40% and / or fraction <40 μm:> 29%. 10 An unshaped product according to any one of the preceding claims, wherein the particles of the unshaped product are distributed as follows in percentages by weight: fraction <2 μm: <14% and / or fraction <10: <35% and / or fraction <40 μm: <50%. Unformulated product according to any one of the preceding claims, wherein the particles of the unshaped product are distributed as follows, in percentages by weight: fraction <2 μm: <12% and / or <fraction <10% : <30% and / or - fraction <40 μm: <42%. Unformulated product according to any one of the preceding claims, wherein the maximum size of all the particles of the unshaped product is less than or equal to 2.5 mm. 25 9. Unformed product according to the preceding claim, wherein the maximum size of all the particles of the unshaped product is less than or equal to 2 mm. 3033556 Unformulated product according to any one of the preceding claims, wherein the amount of particles (a) is greater than 82% and / or less than 98% of the mass of the unshaped product. 11. The unshaped product according to any one of the preceding claims, wherein the amount of particles (b) is greater than 2% and less than 13% of the unshaped product mass. 12. Unformed product according to the preceding claim, wherein the amount of particles (b) is greater than 3% and less than 12%, preferably less than 10%, preferably less than 8% of the mass of the unshaped product. . 10 13. Unformulated product according to any one of the preceding claims, wherein the particles (b) consist of a glass having a melting point greater than 750 ° C, preferably greater than 800 ° C and less than 1650 ° C, preferably below 1550 ° C. 14. An unshaped product according to any one of the preceding claims, in which the particles (b) consist of a glass whose chemical composition comprises, as a percentage by weight, more than 90%, preferably more than 94% by weight. oxides. 15. Unformulated product according to any one of the preceding claims, in which the particles (b) consist of a glass whose chemical composition comprises, as a percentage by weight, more than 45%, preferably more than 50% and less 80%, preferably less than 75% silica. 16. Unformulated product according to any one of the preceding claims, in which the particles (b) are distributed in the following manner, as a mass percentage on the basis of particles (b): fraction <1 mm:> 80%, preferably> 90% and / or fraction <0.5 mm:> 80%, preferably> 90% and / or - fraction <0.1 mm:> 25% and / or <48%, and / or fraction <0.04 mm: <30%, preferably <25%. 3033556 31 17. An unshaped product according to any one of the preceding claims which has a chemical composition such that the sum Al 2 O 3 + ZrO 2 + SiO 2 + Cr 2 O 3> 85%, preferably> 90%. 18. Unformulated product according to the preceding claim, which has a chemical composition such that the sum Al 2 O 3 + ZrO 2 + SiO 2> 85%, preferably> 90%. 19. Unformulated product according to any one of the preceding claims, which has a following mass composition, for a total of more than 95%: Al 2 O 3: 85% - 97% - SiO 2:> 1% and <10%. 10 20. Unformed product according to any one of claims 1 to 18, which has a mass composition such that - Al 2 O 3: 43% - 60% ZrO 2 20% - 43% - SiO 2: 10% - 26%. 15 21. Unformulated product according to any one of claims 1 to 18, which has a mass composition such that - Al 2 O 3: 5% - 60%, - ZrO 2 - SiO 2: 5% - 25%, 20 - Cr 2 O 3: 10% - 90%. 22. The unshaped product according to any one of the preceding claims, which comprises a surfactant in an amount of between 0.075% and 1% of the mass of said unshaped product. 23. The unshaped product according to any one of the preceding claims, wherein the fraction of particles smaller than 500 μm represents more than 50% of the mass of said unshaped product. 3033556 32 24. An unshaped product according to any one of the preceding claims, wherein the fraction of particles larger than 1 mm is between 0 and 22% of the mass of said unshaped product. 25. A method of repairing a region of a glass melting furnace comprising the following steps: 1) independently of steps 2) to 4), preparing any unshaped product of any of the preceding claims; 2) emptying the molten glass contained in the furnace; 3) optionally, rinsing the hearth, in particular worn out areas, 10 product adapted to melt the glass residues, 4) reducing the temperature in the oven to a temperature at which the glass of the particles (b) of the product unshaped according to the invention is no longer in the solid state, preferably between 900 ° C and 1350 ° C; 5) moistening said unshaped product so as to obtain a wet mixture; 6) placing said wet mixture; 7) maintaining the oven temperature between 1250 ° C and 1400 ° C to allow sintering said wet mixture, preferably for a time greater than 8 hours, preferably greater than 10 hours, and preferably less than 15 hours; 8) introducing a glass composition to melt and increasing the temperature of the oven to its operating temperature. 26. The method according to the preceding claim, wherein, in step 7), the temperature is maintained for a time greater than 8 hours and less than 15 hours. 27. A process according to any one of the two immediately preceding claims wherein in step 1) the chemical composition of the particles (b) is selected so that the melting temperature of said particles is less than block temperature of the area to be repaired. 28. A method according to any one of the three immediately preceding claims wherein in step 5) said unformed product is moistened by adding thereto a quantity according to one with the aid of a 3033556 33 between 8% and 13%, in weight percentage relative to the mass of said unshaped product. 29. A method according to any one of the four immediately preceding claims wherein in step 6) said unshaped product is poured over the entire surface of the hearth 5 of the furnace. 30. A glass melting furnace comprising at least a part, in particular in contact with molten glass, in particular the sole, obtained from an unshaped product according to any one of claims 1 to 24 or obtained by a method according to any one of the five preceding claims. 10