FR2990940A1 - REFRACTORY MIXTURE NOT MADE. - Google Patents

Abstract

Unshaped refractory mixture consisting of: - a coarse fraction consisting of particles having a size greater than 100 μm, and - a fraction complementary to the coarse fraction consisting of - a fine fraction consisting of particles having a size less than or equal to 100 μm and representing more than 1% of the mass of the unshaped refractory mixture after calcination, and - optionally a liquid phase, the coarse fraction comprising more than 90% by mass of refractory particles, the fraction complementary to the coarse fraction comprising, as a percentage by mass on the base of the complementary fraction after calcination and for a total of 100%, - more than 50% silicon carbide and / or silicon nitride and / or silicon oxynitride, and less than 15% of other compounds silicon, or "SiO", - between 0.5% to 15% BO, - between 0.6% and 10% NaO, - less than 48.9% ZrO, - less than 10% PO , - less than 4.8% - less than 5% CaO, - less than 5% other species.

Description

TECHNICAL FIELD The invention relates to an unshaped refractory mixture, in particular for forming a mortar for grouting refractory blocks or a coating, in particular a coating for protecting a wall or a repair paste, in particular in a non-shaped refractory mixture. metallurgical furnace. The invention also relates to a hardened or even sintered mortar obtained from such an unshaped refractory mixture, as well as to an oven, in particular a copper remelting furnace, having a refractory coating that is grouted or protected or repaired by means of of such a hardened mortar.

BACKGROUND ART Copper reflow furnaces are furnaces in which copper (or "cathode"), generally in the form of plates, is remelted so that it can be converted, for example, into ingots, bars or wires. especially for making electric cables. Such furnaces are described for example in US 3 199 977, US 4 309 170, FR 2 483 957, or US 4,536,152. The refractory wall of such an oven can be produced by an assembly of refractory blocks, for example under brick shape. The blocks consisting of an SiC-based aggregate bonded with a silica (SiO 2) or nitride (Si 3 N 4) oxide matrix or oxynitride (mainly of the Si 2 ON 2 type) are particularly well suited. They are traditionally assembled through a joint consisting of grouting mortar. A protective coating can be applied to the inner surface of the refractory wall, up to an average thickness of 2 mm. Such a coating is particularly useful for providing protection when starting the oven. Finally, the refractory wall or the protective coating may degrade locally, leading to the appearance of cracks or holes, for example. Repairs can then be made by filling said cracks or holes with a repair paste. In an application relating to a copper remelting furnace, the activated mortar used to form the joints or the protective coating or the repair paste must have the following properties: ease of use, adapted rheology, good adhesion to blocks, in particular based on SiC, fast curing, mechanical strength allowing stable and solid stacking, before sintering in situ by starting the oven. After sintering, the cured mortar must have the following properties: abrasion resistance in order to withstand the stresses of copper loading, resistance to corrosion by molten copper, dimensional stability and oxidation resistance, especially during Beginning phase. In addition, these properties must be adapted to the area of the oven concerned: In the loading zone, typically the upper part of the oven, special attention is paid to the resistance to abrasion and impact due to the fact that stacking and moving copper plates. In the combustion zone, in the vicinity of the burners, special attention is given to resistance to infiltration, corrosion by molten copper, oxidation by the gases of the burners, such as CO2, O 2, CO and water vapor, and resistance to erosion by the hot gases leaving the burners at high speed. In the intermediate zone, conventionally the lower part of the furnace, particular interest is attached to the resistance to oxidation and corrosion by copper, this zone comprising the triple interface foamed by the refractory wall, the molten copper bath and the oxidizing atmosphere.

The unshaped refractory mixture is therefore conventionally adapted according to the zone for which it is intended. The degradation of the joints leads to premature wear of the refractory wall, in particular because it increases the contact area between the blocks and the copper and / or the oxidizing gases inside the furnace. This degradation may in particular make it possible to attack, by the molten copper or hot gases, the insulating back layer, or even the corrosion of the outer metal coating of the furnace.

There is therefore a permanent need for an unshaped refractory mixture to increase the life of the refractory walls of reflow furnaces. An object of the invention is to satisfy, at least partially, this need. SUMMARY OF THE INVENTION According to the invention, this object is achieved by means of an unshaped refractory mixture consisting of: a coarse fraction consisting of particles having a size greater than 100 gm, and a fraction complementary to the coarse fraction consisting of a fine fraction consisting of particles having a size of less than or equal to 100 μm and representing more than 1% and preferably less than 70% of the mass of the unshaped refractory mixture after calcination, and optionally a liquid phase, the fraction coarse having more than 90% by mass of refractory particles, the fraction complementary to the coarse fraction having, in percentage by weight on the basis of the complementary fraction after calcination, and for a total of 100%, more than 50% of silicon carbide and / or silicon nitride and / or silicon oxynitride, the silicon oxynitride being preferably in Si2ON2 form, e less than 15% and preferably more than 0.5% of other silicon compounds (which excludes metallic silicon), or "SiO 2", between 0.5% to 15% of B 2 O 3, between 0.6% and 10% Na 2 O, less than 48.9% ZrO 2, less than 10% P 2 O 5, less than 4.8% Al 2 O 3, less than 5% CaO, less than 5% other species. As will be seen in more detail in the following description, a refractory material obtained by activation, hardening and then sintering an unshaped refractory mixture according to the invention is well suited to application to a metal melting furnace, in particular particular copper. In addition, its qualities allow it to be used interchangeably in the loading zone, the combustion zone or the intermediate zone of a shaft furnace, more particularly for the reflow of copper cathodes. An unshaped refractory mixture according to the invention may further comprise one or more of the following optional features: The unshaped refractory mixture comprises more than 70% SiC, in weight percentage based on the unshaped refractory mixture after calcination. The fraction complementary to the coarse fraction represents less than 35% of the mass of the unshaped refractory mixture. - The fraction complementary to the coarse fraction comprises, in mass percentage on the basis of the complementary fraction after calcination, more than 55.0% and less than 90.0% of silicon carbide and / or of silicon nitride and / or of silicon oxynitride, the silicon oxynitride being preferably in Si2ON2 form, preferably SiC, and / or more than 1.0% and less than 10.0% SiO2, and / or more than 1.5 % and less than 8.0% of B2O3, and / or more than 1.0% and less than 4.5%, of A1203, and / or more than 1.0%, and less than 7.5% of Na 2 O, and / or more than 0.1% and less than 9.0% P 2 O 5, and / or more than 5.0% and less than 20.0% ZrO 2, and / or more than 0.05% and less than 5.0% CaO. - The fraction complementary to the coarse fraction comprises, as a mass percentage on the basis of the complementary fraction after calcination, more than 65.0% and less than 80.0% of silicon carbide and / or of silicon nitride and / or silicon oxynitride, the silicon oxynitride being preferably in Si2ON2 form, preferably SiC, and / or more than 2.0% and less than 7.0% SiO2, and / or less than 5.0% of SiO2; B2O3, and / or - more than 2.0% and less than 4.0% Al2O3, and / or more than 1.5% and less than 5.0% Na2O, and / or more than 2.0 % and less than 8.0% of P2O5, and / or - more than 7.0% and less than 15.0% of ZrO2 and / or - more than 0.05%, preferably more than 0.5%, and less than 2.0% CaO. - The fraction complementary to the coarse fraction has, in mass percentage on the basis of the complementary fraction after calcination, more than 70.0% and less than 80.0% of silicon carbide and / or silicon nitride and / or silicon oxynitride, the silicon oxynitride being preferably in Si2ON2 form, preferably Sie, and / or - more than 3.0% and less than 5.0% SiO2, and / or - less than 4.5% B203, and / or - more than 3.0% A1203, and / or - less than 3.0% Na2O, and / or - more than 1.5% and less than 5.5 % of P 2 O 5, and / or less than 12.0% ZrO 2 and / or more than 0.05%, preferably more than 0.5% and less than 2.0% CaO. - The fraction complementary to the coarse fraction comprises, in percentage by mass on the basis of the complementary fraction after calcination, - more than 60% of SiC, and / or - more than 4.0% of SiO 2, and / or - less than 3.8% of B203. The fraction complementary to the coarse fraction has a composition such that, for a total of more than 98%, as a percentage on the basis of the complementary fraction after calcination: SiC and / or Si3N4 and / or Si2ON2 61.1-85 , 0% SiO2: 3.0 - 5.0% B203: 1.0 - 5.0% A1203: 0 - 4.8% Na2O: 1.0 - 3.0% - p205 2.0 - 3.0 % ZrO0 5.0 - 15.0% Ca0: 0.05 - 3.1%.

The invention also relates to a mortar obtained by activating an unshaped refractory mixture according to the invention, or "activated mortar", a hardened refractory material obtained by curing an activated mortar according to the invention, or "hardened mortar". and a sintered refractory material obtained by sintering a hardened mortar according to the invention, or "sintered mortar". The inventors have observed that the joints formed with the mortars currently used could have, after the start-up phase under strongly oxidizing conditions, a cracking and a migration of certain chemical elements, in particular the alkalis, producing a contamination, by diffusion, of the blocks. adjacent. Advantageously, a sintered mortar according to the invention does not substantially lead to such contamination. The invention also relates to an oven, in particular a copper remelting furnace, comprising a refractory wall comprising an assembly of blocks joined by means of a seal and / or covered with a protective coating and / or comprising a repaired region. , said seal and / or said protective coating and / or said repaired region being in a hardened mortar, or sintered according to the invention. The furnace may be selected from a copper remelting furnace and a cast iron furnace.

The furnace may be in particular a vertical furnace with tank for continuous melting of copper cathodes, in particular obtained by electrolytic refining. Definitions An "unshaped refractory mixture" is an activatable, dry or moist particulate mixture.

Activation is a process of fattening. The activated state conventionally results from moistening an unshaped refractory mixture with water or other liquid. During this process, a wet unformed refractory mixture is called an "activated mortar". Caking or "curing" of an activated mortar may result from drying or, for example, curing of a resin.

It can be accelerated by means of a catalyst. The "hardened mortar" obtained can then undergo temperature rises which lead to a substantially total evaporation of the water. It can be sintered.

The terms "activated mortar" and "hardened mortar" are used in the present description and claims independently of their application, and in particular can be used to designate an "activated" or "hardened" grouting mortar, coating or repair paste. ", respectively.

By "block" is meant a solid object that is not a particle. By "particle" is meant a solid object whose size is less than 10 min. In particular, particles having a size of greater than 100 μm, referred to as "grains", and those having a size of less than or equal to 100 μm, referred to as "fine particles" or "matrix particles", are distinguished. All grains constitute the "coarse fraction". The set of matrix particles constitutes the "matrix fraction" or "fine fraction". In a "sintered mortar", the grains from the coarse fraction, or "granulate" are bound by a matrix that provides a binding structure between the grains. - A set of particles forms a "powder". The size of the particles of a powder is evaluated classically by a particle size distribution characterization performed with a laser granulometer. The laser granulometer can be, for example, a Partita LA-950 from the company HORIBA. The percentiles or "percentiles" (D10), 50 (D50), 90 (D90) and 99.5 (D99.5) of a powder are the particle sizes corresponding to the percentages, by mass, of 10%, 50 %, 90% and 99.5%, respectively, on the cumulative particle size distribution curve of the powder particles, the particle sizes being ranked in ascending order. For example, 10% by weight of the particles of the powder have a size less than or equal to D10 and 90% of the particles by mass have a size greater than D10. Percentiles can be determined using a particle size distribution using a laser granulometer. - We call "minimum size of a powder", the percentile 10 (D10) of said powder. The "maximum size" is the 99.5 percentile (D99.5) of said powder.

The so-called "median size" is the percentile D50, ie the size dividing a set of particles into first and second populations equal in mass, these first and second populations comprising only particles having a larger size, or less or equal respectively to the median size. The term "glass frit" is conventionally called a mixture based on silica sand and on various constituents that may be alkaline and / or alkaline earth carbonates (ie CaCO3, Na2CO3, etc.), or even mineral acids such as acid. boric or orthophosphoric acid, or even minerals added in small amounts (ie borax, alumina ...). This mixture undergoes a beginning of fusion in order to eliminate the carbonates and other hydrates, which makes it possible to facilitate its final use. The molten material is rapidly cooled to make a glass, and then milled to the desired particle size. - "Silica in micron form" means a silica powder whose particles, partially amorphous, have a median diameter between 0.01 and 4 pin. The colloidal colloidal silica has a median particle diameter which may be smaller, generally of the order of a few nanometers. - "refractory" means "having a melting point or dissociation greater than 1000 ° C". By extension, an unshaped mixture having a coarse fraction having greater than 90% by weight of refractory particles may be termed "unshaped refractory mixture". By "impurities" is meant 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. Unless otherwise indicated, all percentages for grades are percentages by mass measured after calcination (which excludes water and organic matter in particular). To measure the chemical composition of the material after calcination, it is conventionally carried out a heat treatment in air at 750 ° C. for 30 minutes, at atmospheric pressure. - The mass content of a constituent is conventionally expressed under the most stable oxide fauna. The devices conventionally used to determine the compositions (microprobe, X-ray fluorescence) automatically convert the contents of the non-oxide constituents into equivalent oxide contents. For silicon, the most stable oxide is SiO2. However, the contents of silicon in the form of silicon carbide, silicon nitride, silicon oxynitride and metallic silicon have been isolated, "SiO 2" thus corresponding to the mass content of silicon in all other forms other than carbide. silicon, silicon nitride, silicon oxynitride and metallic silicon, expressed as SiO 2. The contents of silicon carbide, silicon nitride, silicon oxynitride and metallic silicon can be measured by X-ray diffraction. The SiC content can also be measured according to a protocol defined according to the standard ANSI B74.15-1992- ( R2007) by difference between total carbon and free carbon, this difference corresponding to the carbon fixed in the form of silicon carbide. Conventionally, Si3N4 silicon nitride refers to all forms of Si3N4 (ie Si3N4-OE and Si3N4-P). - "Temporary" means "removed from the product during the sintering heat treatment".

"Containing a", "comprising a" or "containing a" means "having at least one", unless otherwise indicated. DETAILED DESCRIPTION 1) Unshaped refractory mixture The following tables provide preferred compositions, for a total of 100% of an unshaped refractory mixture according to the invention (whole of the coarse fraction, and of the complementary fraction): mini maxi SiC and / or Si3N4 and / or Si2ON2 70.0 98.0 B203 0.2 10.0 Na2 0 7.0 SiO2 0 10.0 Zr02 0 29.5 P205 0 7.0 Al203 0 2.0 CaO 0 3.5 Other species 0 5.0 Preferably: mirai maxi SiC and / or Si3N4 and / or Si2ON2 75.0 98.0 B203 0.2 7.0 Na20 0.3 3.5 Si02 0 7.0 Zr02 0 18.0 P205 0 3.5 A1203 0 2.0 CaO 0 3.5 Other species 0 2.0 The ranges in these two tables may be combined. Preferably, the "other species" (that is to say other than SiC, Si3N4, Si2ON2, SiO2, B203, Na2O, ZrO2, P205, Al2O3, and CaO, the other species including any metallic silicon), less than 1.5%, less than 1.0%, less than 0.5%, or even less than 0.1%. Preferably, the unshaped refractory mixture comprises greater than 70%, and even more than 80% or even more than 90% SiC, as a weight percentage based on the unshaped refractory mixture after calcination. Preferably, the unshaped refractory mixture comprises less than 15% ZrO 2, in weight percent based on the unshaped refractory mixture after calcination. Preferably, the unshaped refractory mixture comprises less than 1.8% and, more preferably, less than 1.5% Al 2 O 3, as a weight percentage based on the unshaped refractory mixture after calcination. The liquid phase (including water) preferably represents less than 30%, less than 20%, preferably more than 5%, more than 10% of the mass of the unshaped refractory mixture. In one embodiment, the unshaped refractory mixture is substantially dry. Preferably, it has a humidity of less than 2%, preferably less than or equal to 1%, the humidity of the mixture being measured by weight loss at 110 ° C for 4 hours. After activation, the unshaped refractory mixture preferably comprises less than 30%, less than 20%, preferably more than 5%, more than 10% water, as a weight percentage of the base of the unshaped refractory mixture.

Preferably, the SiAlON other than Si3N4 and Si2ON2 represent less than 3%, less than 2%, less than 1%, or even substantially 0% of the mass of the unshaped refractory mixture. 2) Coarse fraction The coarse fraction can represent more than 30%; more than 40%, more than 50% and / or less than 99%, less than 80%, less than 70% of the mass of the unshaped refractory mixture. In one embodiment, particularly for making a coating, the coarse fraction is less than 45%, preferably less than 40%, preferably less than 35% of the mass of the unshaped refractory mixture. In one embodiment, particularly for making a grouting mortar, the coarse fraction represents more than 55%, more than 60%, more than 65%, and / or less than 85%, less than 80%, less than 75%. % of the mass of the unshaped refractory mixture. Composition The nature of the coarse fraction is not limiting. However, the coarse fraction is preferably more than 95%, more than 98%, preferably substantially 100% refractory, in weight percent, preferably particles of a non-oxide material, preferably carbide. silicon. Advantageously, the silicon carbide improves the chemical resistance, in particular with respect to the molten copper, reduces the risk of infiltration and increases the hot stiffness of the hardened and sintered mortar. The coarse fraction may also consist of more than 95% by mass percentage, more than 98%, preferably substantially 100% SiC particles, black corundum, white corundum, tabular alumina, sintered mullite. , molten mullite, chromium oxide, magnesia, zirconia, zircon or a mixture of these materials. Preferably, the mass quantity of the impurities in the coarse fraction is less than 2%, less than 1%, less than 0.5%, or even substantially zero. Preferably, the percentile D90 of the coarse fraction is less than 5 mm, preferably less than 3 mm, preferably less than 2 mm, preferably less than 1 mm and / or greater than 0.2 mm, preferably greater than 0.3 mm, preferably greater than 0.4 mm. The median size of the coarse fraction is preferably less than 2 mm, preferably less than 1 mm and / or greater than 0.2 mm, preferably greater than 0.3 mm. 3) Complementary fraction (or "100% complement") of the coarse fraction 10 Composition The liquid phase of the fraction complementary to the coarse fraction is preferably less than 3 times (especially for a protective coating), preferably less than 2.5 times, preferably less than 2 times (especially for a grouting mortar or a repair paste) the mass of the fine fraction. In one embodiment, the fraction complementary to the coarse fraction has substantially no liquid phase. The liquid phase is preferably more than 90% more. 95% or substantially 100% by weight of water and / or boric acid and / or phosphoric acid, or even sodium silicate. The refractory fine particles preferably represent more than 70%, more than 80%, more than 90%, or even substantially 100% of the complementary fraction, in weight percent, based on the unshaped refractory mixture after calcination. The fine fraction preferably represents more than 10%, more than 20%, more than 25%, even more than 30% and / or less than 60%, less than 50%, less than 45%, less than 40%, and even less. 35% of the mass of the unshaped refractory mixture after calcination. The fraction complementary to the coarse fraction preferably comprises, in weight percentage on the basis of the complementary fraction after calcination, more than 52%, more than 55%, more than 57%, preferably more than 60%, more than 62% preferably more than 65%, more than 67%, preferably more than 70% and / or less than 90%, less than 80% of silicon compound in a form other than SiO 2, and in particular silicon carbide and / or silicon nitride and / or silicon oxynitride, the silicon oxynitride preferably being in the form of Si2ON2, preferably SiC. Preferably, more than 90%, more than 95%, or even substantially 100% by weight of silicon carbide, silicon nitride, and silicon oxynitride, is provided by particles comprising more than 60%, more than 70%, more than 75%, more than 90%, more than 95%, more than 98%, even substantially 100% by weight of silicon carbide, silicon nitride, and silicon oxynitride, respectively. In particular it is possible to use used SiC. The fraction complementary to the coarse fraction preferably comprises more than 1.0%, more than 2.0%, more than 3.0%, more than 4.0% and / or less than 10.0%, less than 7%. , 0%, preferably less than 5.0% SiO 2. SiO 2 can in particular be provided by micron silica, and in particular silica fume, a natural aluminosilicate, for example a clay, a bentonite, a cyanite or even a kerphalite, or even a calcined mullite powder or a synthetic aluminosilicate .

The fraction complementary to the coarse fraction preferably comprises more than 1.0%, more than 1.5% and / or less than 10% less than 5.0%, preferably less than 4.5%, preferably less than 3.8% of B203. Preferably, more than 90%, more than 95%, or even substantially 100% by weight of the B203 is provided by a liquid phase or particles comprising more than 90%, more than 95%, or even substantially 100% by weight of boric acid, and / or - particles comprising more than 90%, more than 95%, or even substantially 100% by weight of Borax (Na2B407), and / or particles comprising more than 90%, more than 95%, or substantially 100% by weight of CaB6 and / or particles comprising more than 90%, more than 95%, or even substantially 100% by mass of colemanite (Ca2B6011, 5H20) and / or particles comprising more than 90%, more than 95% , or substantially 100% by weight of B4C, and / or particles comprising more than 90%, more than 95%, or even substantially 100% by weight of a mixture of B4C and / or boric acid and / or Borax and / or CaB6 and / or colemanite.

Preferably, the boron supply is carried out essentially in oxide form, in particular acid, borax or colemanite. B203, for example under boric acid or borax, may be added in liquid form to the unshaped refractory mixture to activate it.

The fraction complementary to the coarse fraction preferably comprises more than 0.5%, more than 1.0%, more than 2.0%, more than 3.0% and / or less than 4.5%, preferably less 4.0% of A1203. Preferably, more than 90%, more than 95%, or even substantially 100% by weight of the A1203 of the fraction complementary to the coarse fraction is provided by particles comprising more than 90%, more than 95%, or even substantially 100%. % by weight of crystallized alumina, preferably of alpha alumina. A1203, for example in the form of alumina phosphate, may be added in liquid form to the unshaped refractory mixture to activate it. The fraction complementary to the coarse fraction preferably comprises more than 1.0%, preferably more than 1.5% and / or less than 7.5%, preferably less than 5.0%, or even less than 3.0%. Preferably, more than 90%, more than 95% or even substantially 100% by weight of the Na2O of the fraction complementary to the coarse fraction is provided by particles comprising more than 90%, more than 95%, even substantially 100% by weight of sodium silicate, or sodium hexametaphosphate (HMPNa) or sodium polymethacrylate or borax or a mixture of these species. Na 2 O, for example in the form of sodium silicate or sodium phosphate, can be added in liquid form to the unshaped refractory mixture in order to activate it. Preferably, the fraction complementary to the coarse fraction comprises more than 0.1%, more than 2.0%, and / or less than 9.0%, less than 8.0%, preferably less than 5.5% , less than 3.5% P2O5, or even less than 3.0% P2O5. Preferably, more than 90%, more than 95%, or even substantially 100% by weight of P2O5 is provided by phosphoric acid and / or aluminum monophosphate and / or alkali metal phosphates, for example hexametaphosphate. soda ash (HMPNa).

P2O5 can be added in liquid form to activate the unshaped refractory mixture.

Preferably, the fraction complementary to the coarse fraction comprises more than 5.0%, preferably more than 7.0% and / or less than 45.0%, less than 43.0%, less than 40.0%, less than 37.0%, less than 35.0%, less than 33.0%, less than 30.0%, less than 27.0%, less than 25.0%, less than 23.0%, less 20.0%, less than 17.0%, less than 15.0%, or even less than 12.0% Zr02. Preferably, more than 90%, more than 95%, even substantially 100% by weight of the ZrO 2 is provided in the form of zirconia or zircon, preferably in the form of particles having a size of less than 50 μm. Zirconia can be provided in stabilized form or not.

Preferably, the fraction complementary to the coarse fraction comprises more than 0.05% of CaO. In an advantageous embodiment, Ca0> 0.1%, preferably Ca0> 1.0%, or even CaO> 1.5%. Preferably, CaO <4.0%, preferably CaO <3.5%, preferably CaO <3.0%, even CaO <2.5% or CaO <2.0%.

Preferably, the mass quantity of "other species" of the fraction complementary to the coarse fraction (that is to say other than silicon carbide, silicon nitride, silicon oxynitride, SiO 2, B 2 O 3, Na 2 O , ZrO 2, P 2 O 5, Al 2 O 3, and CaO, the other species including the possible metallic silicon) in the fraction complementary to the coarse fraction is less than 2%, less than 1%, less than 0.5%, or even substantially zero. Part of the constituents of the fraction complementary to the coarse fraction may be introduced into the feedstock in the form of a frit or a mixture of glass frits. Preferably, the 90 percentile 90 percent of the frit or glass frit mixture is less than 200 μm, preferably less than 150 μm, preferably less than 100 μm. A preferred composition range of the fraction complementary to the coarse fraction is as follows, for a total of greater than 98%, or even substantially 100%, as a percentage on the basis of the complementary fraction after calcination: 30 min maxi SiC and / or Si3N4 and / or Si2ON2 50.0 95.0 B203 0.5 15.0 Na20 0.6 10.0 Si02 0 15.0 Zr02 0 48.9 P205 0 10.0 A1203 0 4.8 CaO 0 5 Other Species 0 5.0 The preferred composition of the fraction complementary to the coarse fraction is as follows, for a total of more than 98%, or even substantially 100%, in percentage on the basis of the complementary fraction after calcination: mini maxi SiC and / or Si3N4 and / or Si2ON2 50.0 95.0 B203 0.5 10.0 Na2 O 5.0 SiO2 0 10.0 Zr02 0 25.0 P205 0 5.0 A1203 0 4.8 CaO 0 5.0 Other species 0 2.0 Sintered refractory material The manufacture of an activated mortar according to the invention is conventionally carried out by adding water to an unshaped refractory mixture according to the invention, and then melting. nge.

In addition to the constituents mentioned above, the unshaped refractory mixture may also comprise a form-forming additive, preferably temporary, of the type conventionally used. As examples of usable additives, mention may be made, in a nonlimiting manner: organic temporary binders, such as resins, derivatives of cellulose or lignin, such as carboxymethylcellulose, dextrin, polyvinyl alcohols, polyethylene glycols ; inorganic binders, such as silica gels or colloidal silica; sintering promoters such as titanium dioxide or magnesium hydroxide; shaping agents such as magnesium or calcium stearates; and their mixtures. The appropriate additive contents are well known to those skilled in the art. The unshaped refractory mixture may typically comprise between 0.1% and 5% additive, in percent by weight based on the mass of the unshaped refractory mixture after calcination.

To form a grouting mortar, the amount of water added to the unshaped refractory mixture is preferably from 10% to 20%, based on the mass of the unshaped refractory mixture after calcination. Conventionally, the jointing joint has a thickness of between 0.5 and 10 mm, preferably between 1 and 5 mm.

To form a plaster, the amount of water is preferably between 10 and 30%, based on the mass of the unshaped refractory mixture after calcination. To form a repair paste, the amount of water is preferably between 10% and 25%, preferably between 10% and 20%, based on the mass of the unshaped refractory mixture after calcination.

The maximum size of the particles employed is preferably at least 3 times, preferably at least 5 times, less than the average thickness of the desired seal or coating or repair paste after curing. Finally, the shaping additive is chosen according to the desired rheology. Preferably, cellulosic derivatives (rheofluidifier), for example a Tylose H200 of Shin-Etsu, are used.

The coating can be applied in particular to the interior surface of an oven. All conventional techniques can be implemented. Preferably, the coating formed from the coating has a thickness of between 0.2 and 2 mm, preferably between 0.5 and 1 mm. The sintering is preferably carried out at a temperature between 600 and 1600 ° C and leads to the generation of the matrix. The matrix may be a crystallized phase or not. The contribution of zirconia peimet advantageously to obtain a sintered matrix stable at high temperature.

Preferably, the composition of the matrix is substantially the same as that of the fraction complementary to the coarse fraction. Oven The side wall of an oven conventionally comprises a plurality of assembled blocks. Preferably, the blocks are assembled by means of an activated mortar according to the invention and / or coated with a coating consisting of an activated mortar according to the invention and / or repaired by means of an activated mortar. according to the invention. After hardening, the sintering of the cured mortar can be carried out in situ, during the first temperature rise of the oven. In operation, the furnace vessel contains a bath of molten metal, particularly a copper bath. Preferably, the sintered mortar according to the invention is disposed in a zone in which it is likely to come into contact with the molten metal bath, in particular in a zone at the interface between the molten metal and the molten metal. gaseous environment. Examples of furnaces are described in particular in the documents cited in the preamble of the present description. Examples The following examples are provided for illustrative and not limiting. For each sample, a feedstock is prepared from the following raw materials: Black SiC provided by Saint-Gobain Ceramic Materials S1KA grades 36/70, 100F and 220F ("SiC source" in the Table below ), zirconia CC10 supplied by SEPR ("Zr source" in the table below), RR40 clay provided by DAMREC ("Al / Si / Na source" in the table below), - mixture white corundum grade 0-0,5mm supplied by Alkali and 100 mesh tabular alumina supplied by Almatis (source of "Al"), - zircon sand supplied by SEPR (source of "Zr / Si"), 30 - sodium hexametaphosphate provided by the company Budenheim ("source of P" in the table below), powder of colemanite (calcium borate) supplied by Solargil ("source of B" for example 1 of the table below). borate powder (borate of soda) called "Neobor powder" supplied by Mule team ("source of B" for example 2 of the table below), boric acid supplied by the company VWR ("source of B" in the examples in the table below, except for Examples 1 and 2). Formation of the feedstock (as a weight percentage based on unshaped refractory mixture after calcination) Example 1 2 3 4 5 6 7 Cl C2 C3 C4 C5 Source of SiC 90.8 91.3 91.8 91.8 90 , 1 95 86.9 84.8 84.4 0 0 0 Source of Zr 3.2 3.2 3.2 3.2 3.1 0 8.3 0 6.1 95 3.2 3.2 Source of Zr / Si 0 0 0 0 0 0 0 0 0 0 91.8 0 SourcedeA10000000000091.8 Source Al / Si / Na 2.7 2.7 2.7 2.7 2.7 2.7 2.6 7.6 5.1 2.7 2.7 2.7 Source of P 1.4 1.4 1.4 1.4 1.4 1.4 1.3 0 2.7 1.4 1.4 1.4 Source of B 1.9 1.4 0.9 0.9 2.7 0.9 0.9 7.6 1.7 0.9 0.9 0.9 Total 100 100 100 100 100 100 100 100 100 100 100 100 Composition of the fraction complementary to the coarse fraction (in weight percentage on the basis of the unshaped refractory mixture after calcination) Example 1 2 3 4 5 6 7 C1 C3 C3 C4 C5 SiC 23,17 23,17 23,17 23, 17 23.17 24.04 23.17 22.59 27.12 0 0 0 Si02 1.48 1.48 1.48 1.88 1.48 1.48 1.48 3.94 2.79 1.48 31.59 1.48 A1203 1.08 1.08 1.08 0.56 1.08 1.08 1.08 2.88 2.04 1.08 1.08 92.88 Zr02 3, 2 3.2 3.2 3.2 3.2 0 8.8 0 6.1 91.33 64.89 3.2 P205 0.72 0.72 0.72 0.72 0.72 0.72 0 , 72 0 1.39 0.72 0.72 0.72 Na2 O 0.57 0.8 0.57 0.64 0.57 0.57 0.57 0 1.11 0.57 0.57 0.57 CaO 0.53 0.02 0.02 0.04 0.02 0.02 0.02 0.04 0.03 3.69 0.02 0.02 MgO 0.01 0.01 0.01 0.07 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 B203 0.97 0.51 0.51 0.51 1.52 0.51 0.51 4.05 0 , 96 0.51 0.51 0.51 Total (*) 31.73 30.99 30.76 30.79 31.77 28.43 36.36 33.51 41.55 99.39 99.39 99, 3910 Composition of the fraction complementary to the coarse fraction (in weight percentage after calcination) Example 1111 2 3 4 Ill 6 iiiiiiii C3 C4 C5 1111311111173,01 74,78 75,34 75,24 72,93 84,58 63,73 67 , 39 65.27 0 0 0 Si02 4.66 4.77 4.8 6.11 4.65 Kg 4.06 11.75 6.72 1.49 31.78 1.49 A1203 3.4 3.49 Egi 1,82 3,4 3,8 2,97 8,59 4,91, 09 1,09 93,44 Zr02 10,09 10,33 10,41 10,4 10,08 0 24,21 0 14, 68 91.88 65.281311 P205 2.28 Egloging 2.27 2.54 1.99 0 EN 0.73 0.73 0.73 Na2 1.81 2.58 1.87 2.08 1., 81 2 , 02 1.58 0 2.66 0.58 0.58 0.58 CaO 1.69 0.05 0.05 0.11 0.05 0.06 0.04 0.13 0.07 mg 0.02 0.02 Mg0 0.02 0.02 0.02 0.24 0.02 0.02 0.01 0.04 0.02 0.01 0.01 0.01 B2O3 3.04 1.65 1.65 4.79 1.78 1.39 12.091311 0.51 0.51 0.51 Total 100 100 100 100 100 100 99.98 99.99 99.98 100 100 100 (*): The 100% complement consists of the coarse fraction. The activated mortar is prepared according to a conventional procedure comprising: dry mixing of the feedstock in a non-intensive planetary type mixer, for 2 minutes, then a water addition of 15% with respect to the mass of the feedstock starting, then - kneading for 10 minutes until a sufficient consistency for application as a grouting mortar. Cryston Cu® (SiC3N4 matrix SiC) refractory bricks, each with a groove, are prepared and immersed in water to limit roasting. The groove is then filled with activated mortar. The clavels thus prepared are left at room temperature for 24 hours and then baked at 110 ° C. The clavels are then assembled, without joint between the bells, so as to form a crucible, the grooves being oriented towards the interior of the crucible so as to expose the mortar samples. The crucible is sealed by pouring an aluminous refractory concrete outside the claveaux. The crucible is heat-treated at 400 ° C. The temperature of the oven is raised to 1450 ° C. The crucible is gradually filled halfway up with molten copper. The crucible is then maintained at 1450 ° C for at least 4814 in an oxidizing atmosphere. The oven rotates on itself to eliminate the "gas abrasion" factor, at a speed of 6 revolutions per minute.

At the end of the test, the aluminous concrete is removed in order to extract the corroded logs. On each sample, we observe the different zones involved: zone in contact with molten copper, zone in contact with the burner gases and interface between these two zones.

The "flame rank" measures the corrosion resistance of the zone in contact with the burner gases, taking into account the presence of grinding on the surface of the sample and the keel, corresponding to a diffusion of the mortar. The "flame + interface" rank adds the corrosion criterion at the triple interface between the sample, the claveau and the molten metal, taking into account the resistance of the mortar to infiltration by molten copper. The lower the index ("flame rank + interface" or "flame rank"), the better the performance. The following table gives the results obtained: Example 1 2 3 4 5 6 7 Cl C2 C3 C4 C5 Flame rank 1 2 4 5 6 7 14 16 17 18 19 20 Rank flame 5 7 6 13 14 8 11 15 16 18 19 20 + Interface Total 6 9 10 18 20 15 25 31 33 36 38 40 Examples 1 to 7 are according to the invention. Examples C1 to C5 are given for comparison. Example C4 consists of a matrix essentially based on zircon (ZrSiO4), thus with a high content of ZrO 2 and SiO 2. Examples 1 to 3, preferred, have a composition of about 73 to 76% of SiC, 1.6 to 1.7% of B 2 O 3, 1.8 to 2.6% of Na 2 O, less than 3.5% of Al 2 O 3 and less than 5% SiO 2.

As is clear from now on, the invention provides a mortar which is well suited for application to a copper remelting furnace. The invention is however not limited to this application. In particular, the mortar is also suitable for other metallurgical applications, especially for grouting cast iron blast furnace blocks. Preferably, the granulate is a corundum granulate, particularly with a brown or black corundum granulate.

Claims (14)

REVENDICATIONS1. Unshaped refractory mixture consisting of: a coarse fraction consisting of particles having a size greater than 100 μm, and a fraction complementary to the coarse fraction consisting of - a fine fraction consisting of particles having a size less than or equal to 100 μm and representing more of 1%, and preferably less than 70%, of the mass of the unshaped refractory mixture after calcination, and optionally a liquid phase, the coarse fraction comprising more than 90% by mass of refractory particles, the fraction complementary to the coarse fraction comprising, as a weight percentage on the basis of the complementary fraction after calcination and for a total of 100%, more than 50% silicon carbide and / or silicon nitride and / or silicon oxynitride, and less than % other silicon compounds, or "SiO 2", between 0.5 ° to 15% B 2 O 3, between 0.6% and 10% Na 2 O, less than 48.9% ZrO 2, ns of 10% P205, less than 4.8% A1203, less than 5% CaO, less than 5% other species. 2. Non-shaped refractory mixture according to the preceding claim, comprising more than 70% SiC, in weight percentage based on the unshaped refractory mixture after calcination. An unshaped refractory mixture according to any one of the preceding claims, wherein the fraction complementary to the coarse fraction is less than 35% of the mass of the unshaped refractory mixture after calcination. An unshaped refractory mixture according to any one of the preceding claims, wherein the fraction complementary to the coarse fraction comprises, in weight percentage based on the complementary fraction after calcination, greater than 55.0% and less than 90%, 0% silicon carbide and / or silicon nitride and / or silicon oxynitride, preferably SiC, and / or more than 1.0% and less than 10.0% SiO 2, and / or more 1.5% and less than 8.0% of B203, and / or more than 1.0% and less than 4.5%, A1203, and / or more than 1.0%, and less than , 5% Na2O, and / or - more than 0.1% and less than 9.0% P205, and / or more than 5.0% and less than 20.0% ZrO2, and / or more than 0.05% and less than 5.0% CaO. 5. Shaped refractory mixture according to the preceding claim, in which the fraction complementary to the coarse fraction comprises, in percentage by weight on the basis of the complementary fraction after calcination, greater than 65.0% and less than 80.0% of silicon carbide and / or silicon nitride and / or silicon oxynitride, preferably SiC, and / or more than 2.0% and less than 7.0% SiO 2, and / or less than 5, 0% B203, and / or more than 2.0% and less than 4.0% A1203, and / or more than 1.5% and less than 5.0% Na20, and / or more than 2% , 0% and less than 8.0% of P205, and / or - more than 7.0% and less than 15.0% of Zr02, and / or more than 0.05% and less than 5.0% of CaO. 6. Unshaped refractory mixture according to the preceding claim, wherein the fraction complementary to the coarse fraction comprises, in weight percentage on the basis of the complementary fraction after calcination, more than 70.0% and less than 80.0% of carbide silicon and / or silicon nitride and / or silicon oxynitride, preferably SiC, and / or - more than 3.0% and less than 5.0% SiO 2, and / or less than 4, 5% of B2O3, and / or more than 3.0% of A1203, and / or less than 3.0% of Na2O, and / or more than 1.5% and less than 5.5% of P2O5, and / or less than 12.0% ZrO2 ,. and / or more than 0.05% and less than 5.0% CaO. 7. The unshaped refractory mixture according to the preceding claim, in which the fraction complementary to the coarse fraction comprises, as a weight percentage on the basis of the complementary fraction after calcination, greater than 60% of SiC, and / or more than 4%. , 0% SiO2, and / or less than 3.8% B2O3. 8. Shaped refractory mixture according to any one of the preceding claims, wherein the fraction complementary to the coarse fraction has a composition such that, for a total of more than 98%, as a percentage on the basis of the complementary fraction after calcination : - SiC and / or Si3N4 and / or Si2ON2 61.1 - 85.0% SiO2 3.0 - 5.0% B2O3: 1.0 - 5.0% Al2O3: 0 - 4.8% Na2O: - 1 , 0 - 3.0% P2O5 ZrO2 2.0 - 3.0 5.0 - 15.0% - CaO: 0.05 - 3.1%. Unprefined refractory mixture according to any one of the preceding claims having the following chemical composition, in weight percentage after calcination: mini maxi SiC and / or Si3N4 and / or Si2ON2 70.0 98.0 B4O3 0.2 10.0 Na20 0.3 7.0 Si02 0 10.0 Zr02 0 29.5 P205 0 7.0 A1203 0 2.0 CaO 0 3.5 Other species 0 5.0 An unshaped refractory mixture according to any of the preceding claims having the following chemical composition, in weight percent after calcination: mini max SiC and / or Si3N4 and / or Si2ON2 75.0 98.0 B203 0.2 7.0 Na20 0.3 3.5 Si02 0 7.0 Zr02 0 18.0 P205 0 3.5 A1203 0 2.0 CaO 0 3.5 Other species 0 2.0 11. Refractory mixture according to any one of the preceding claims, wherein the coarse fraction represents more than 60% and less than 75%, in weight percentage after calcination. 12. Refractory mixture according to any one of the preceding claims, wherein the coarse fraction consists, in weight percent, of more than 95%, of particles of SiC, black corundum, white corundum, tabular alumina, sintered mullite, molten mullite, chromium oxide, magnesia, zirconia, zircon or a mixture of these materials. 13.For comprising a refractory wall comprising an assembly of blocks joined by means of a seal and / or covered with a protective coating and / or comprising a repaired region, said seal and / or said protective coating and / or said repaired region being a sintered mortar obtained by activating, hardening and sintering an unshaped refractory mixture according to any one of the preceding claims. 14.Four according to the preceding claim selected from a copper remelting furnace and a cast iron furnace.