Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F27—FURNACES; KILNS; OVENS; RETORTS
  • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
  • F27D1/00—Casings; Linings; Walls; Roofs
  • F27D1/16—Making or repairing linings ; Increasing the durability of linings; Breaking away linings
  • F27D1/1636—Repairing linings by projecting or spraying refractory materials on the lining
  • F27D1/1642—Repairing linings by projecting or spraying refractory materials on the lining using a gunning apparatus
  • F27D1/1647—Repairing linings by projecting or spraying refractory materials on the lining using a gunning apparatus the projected materials being partly melted, e.g. by exothermic reactions of metals (Al, Si) with oxygen
• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
  • C03C8/00—Enamels; Glazes; Fusion seal compositions being frit compositions having non-frit additions
  • C03C8/14—Glass frit mixtures having non-frit additions, e.g. opacifiers, colorants, mill-additions
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B41/00—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone
  • C04B41/009—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone characterised by the material treated
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B41/00—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone
  • C04B41/45—Coating or impregnating, e.g. injection in masonry, partial coating of green or fired ceramics, organic coating compositions for adhering together two concrete elements
  • C04B41/50—Coating or impregnating, e.g. injection in masonry, partial coating of green or fired ceramics, organic coating compositions for adhering together two concrete elements with inorganic materials
  • C04B41/5022—Coating or impregnating, e.g. injection in masonry, partial coating of green or fired ceramics, organic coating compositions for adhering together two concrete elements with inorganic materials with vitreous materials
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B41/00—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone
  • C04B41/80—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone of only ceramics
  • C04B41/81—Coating or impregnation
  • C04B41/85—Coating or impregnation with inorganic materials
  • C04B41/86—Glazes; Cold glazes

Definitions

• the present invention relates to a dry mixture of treatment of refractory substrates, comprising: - combustible particles of at least one oxidizable substance which, in the presence of oxygen, gives rise to an exothermic reaction, and
• the refractory walls which cover some production facilities, are damaged by erosion, corrosion, thermal shock, etc., making their surface rough, porous or strewn with defects (flaking, cracking, cavities, etc.).
• This can have various consequences on the operation of the production facilities: a brake on the circulation of solid products, crusting, leakage of liquids or gases, penetration of corroding agents; in particular, in coke ovens, the silica refractory walls of the carbonization chambers are lined with carbon, which over time transforms into graphite with swelling; regularly, it must be removed to avoid a power overload at the unloading of coke.
• the coal charging zone is also subject to such deposits of carbon, which requires their manual removal at regular intervals.
• the cracks passing between the carbonization chamber and the Heating flues offer a passage to organic matter towards the chimney, with the ecological consequences that one can guess.
• patent application FR-A-2202053 describes a method of projecting onto a damaged wall, at high temperature, an aqueous suspension containing, for the most part, a refractory granular material of the same nature as the wall (silica). a binder (carbonate type or alkali metal borate), a colloidal thickener (bentonite) and a melting point lowering component (sodium silicate).
• a binder carbonate type or alkali metal borate
• colloidal thickener bentonite
• melting point lowering component sodium silicate
• Patent application WO 2004/085341 also discloses an application on a substrate, by gunning (dry gunning), of a mixture mainly containing vitreous silica grains, an aluminous granulate, a clay and a chemical binder. .
• ceramic welding which consists of the projection, on a wall at high temperature and in an oxygen stream, of a mixture comprising mainly refractory grains (silica , alumina, zirconia, ...) and oxidizable particles (Si + Al), which by exothermic reaction (combustion) form a coherent refractory mass on the wall to be repaired (see, inter alia, FR-A-2066355, FR-A- 2516915 and BE-1005914).
• the quality of the coating obtained on the generally refractory wall depends on several parameters including the substrate temperature, the projection speed and the mass flow rate of the mixture.
• the carrier gas is a reactive gas with at least one of the elements of the pulverulent material.
• the mixture reacts spontaneously and a series of chemical reactions leads to the formation of an adherent refractory material, the characteristics of which are compatible with those of the treated support.
• the projection speed is therefore a preponderant element. Indeed, if it is too important, the amount of material may not react
• the object of the present invention is to develop a dry mixture for the treatment of refractory substrates and a process for its implementation which make it possible to obtain a slowed and controlled projection speed, while avoiding the possibility of backfire. in order to achieve a suitable surface treatment, and this with the aid of a simple and effective composition.
• a dry mixture as indicated at the beginning which comprises, as particles of at least one other substance, particles of at least one expansion substance, the dry mixture without particles of this at least one expansion substance having a first bulk density and the mixture comprising said at least one expansion substance having a second apparent density less than said first apparent density.
• the expansion substance gives the mixture to be sprayed with a lower apparent density, which contributes to slowing the mass flow rate. projected, and thus to reduce the thickness of the deposited layer (of the order of one millimeter) to the surface of the refractory at each passage of the jet spray.
• the application can be done in a single pass (surface treatment) or in several passes (filling a crack or a cavity).
• Said at least one expansion substance may be selected from expanded perlite, expanded vermiculite, wood powder or coke, and mixtures thereof.
• Expanded perlite is preferably used.
• Perlite is a granular silica glass of volcanic origin that can be thermally expanded to obtain expanded perlite particles.
• the size of the expanded perlite particles is less than or equal to 1 mm.
• oxidizable substances it is possible to envisage fine particles of one or more metals or metalloids capable of burning in the presence of oxygen, in particular at the normal operating temperature of the furnace to be repaired.
• particles of silicon, aluminum, zirconium, magnesium, calcium or iron, chromium, titanium, or their mixtures or alloys Preferably, the size of the combustible particles is less than or equal to 100 ⁇ m.
• said particles of at least one other substance are selected from the group consisting of siliceous glass, silica, vitreous or fused, and crystalline silica, such as quartz, tridymite and cristobalite, alumina, zirconia, magnesia, lime, alkaline compounds, and mixtures or mixtures thereof.
• the size of the silica particles is less than or equal to 0.5 mm, preferably between 0.1 and 0.3 mm.
• Silica glass is any glass containing silicon. There may be mentioned, preferably, silico-soda-lime glasses, borosilicates, cullet or cullet, advantageously obtained from untinted glass, as well as mixtures of these materials.
• the size of the siliceous glass particles is less than or equal to 1 mm so as to ensure complete melting of the particles.
• their size will be between 0.3 and 0.6 mm.
• a preferred mixture according to the invention contains one or more siliceous glasses as a majority by weight of the dry mixture. By this expression is meant that the weight fraction of the siliceous glass or glasses is greater than that of any other constituent of the mixture.
• Such a mixture is perfectly suitable for a well-known and well-controlled ceramic welding type treatment process, where the heat input results mainly from an exothermic oxidation of the combustible particles of the mixture.
• the combustion is spontaneous and the siliceous glass particles melt completely by forming an amorphous mass capable of being spread in a thin layer on the refractory wall. repair as well as infiltrate the cracks formed in this wall.
• the deposited layer is thin and has a smooth appearance that is not very conducive to the attachment of carbon deposits.
• Its roughness Ra is of the order of 50 - 100 microns. The calculation of this roughness meets the standards ISO 11652 and ISO 4287-1997.
• This Ra value is the arithmetic average deviation of the surface profile, ie the arithmetic mean of the absolute values of the profile deviations (either in peak or in hollow) within the limits of a base length L .
• the coherent mass applied to the refractory wall to be treated is either a surface treatment for smoothing a rough refractory wall, for example in the mouth of charging coal in a coking plant, or a means for filling fine cracks without extra thickness for the refractory wall damaged.
• the refracting agent or the slump start temperature of the amorphous mass obtained may advantageously be adapted to the operating temperature by the proportion of silica added relative to that of the milled siliceous glass.
• this weight ratio can be between 3/1 and 6/1.
• the mixture contains a) 0 to 88%, in particular 45 to 60%, by weight of siliceous glass particles, b) 10 to 40%, in particular 20 to 30%, by weight of combustible particles, c) 2 to 40%, in particular 5 to 10%, by weight of expanded perlite particles, d) 0 to 88%, in particular 10 to 25%, by weight of silica particles, the sum of the percentages by weight of the components a) to d) giving 100% by weight.
• the invention also relates to a refractory substrate treatment method of ceramic welding process type. It comprises a projection on this substrate of a dry mix jet according to the invention in the presence of oxygen and at a temperature at which said fuel particles give rise with said oxygen to an exothermic reaction, and an at least partial melting of the particles. of the mixture in the form of a coherent amorphous mass which adheres and / or interacts with the substrate.
• the method comprises moving the jet of dry mixture during the projection with the formation of a uniform thin layer deposit on the substrate.
• the method comprises, after projection, an annealing of said mass adhering to the substrate at a temperature at least greater than its glass transition temperature. This allows the deposited amorphous mass to perfect its densification and the smooth state of its surface.
• Example 1 The mixture to be sprayed consists of:
• the refractory wall to be treated is at a temperature of about
• Example 2 Compared with Example 2, part of the milled silica glass was replaced by fine silica sand in order to increase the refractant of the mass obtained.
• the mixture therefore consists of:
• the deposit thus obtained was subjected to annealing at 1250 ° C. for 5 hours, which made it possible to perfect its densification; it has kept its glassy appearance and does not show a creep tendency up to this temperature; it always adheres perfectly to the refractory support even after cooling.
• the perforation mixture according to the invention does not contain refractory particles, conventionally used in ceramic welding type processes.

Landscapes

• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Ceramic Engineering (AREA)
• Materials Engineering (AREA)
• Organic Chemistry (AREA)
• Structural Engineering (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Inorganic Chemistry (AREA)
• General Chemical & Material Sciences (AREA)
• General Engineering & Computer Science (AREA)
• Geochemistry & Mineralogy (AREA)
• Mechanical Engineering (AREA)
• Life Sciences & Earth Sciences (AREA)
• Furnace Housings, Linings, Walls, And Ceilings (AREA)
• Ceramic Products (AREA)
• Compositions Of Oxide Ceramics (AREA)
• Glass Compositions (AREA)
• Coating By Spraying Or Casting (AREA)
• Processing Of Solid Wastes (AREA)
• Preparation Of Clay, And Manufacture Of Mixtures Containing Clay Or Cement (AREA)
• Building Environments (AREA)
• Solid Fuels And Fuel-Associated Substances (AREA)

Priority Applications (21)

Applications Claiming Priority (2)

Publications (2)

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Family Applications (1)

Country Status (26)

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• 2007
  • 2007-07-05 BE BE2007/0336A patent/BE1017675A3/fr active
• 2008
  • 2008-07-03 US US12/667,837 patent/US8501650B2/en active Active
  • 2008-07-03 AT AT08774689T patent/ATE528270T1/de active
  • 2008-07-03 BR BRPI0814652-7A2 patent/BRPI0814652B1/pt active IP Right Grant
  • 2008-07-03 ES ES08774689T patent/ES2373765T3/es active Active
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  • 2008-07-03 EP EP08774689A patent/EP2176192B1/fr active Active
  • 2008-07-03 KR KR1020107002730A patent/KR101513534B1/ko active Active
  • 2008-07-03 CN CN2008800234242A patent/CN101801884B/zh active Active
  • 2008-07-03 DK DK08774689.7T patent/DK2176192T3/da active
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  • 2008-07-03 EA EA201070101A patent/EA019678B1/ru not_active IP Right Cessation
  • 2008-07-03 AU AU2008270261A patent/AU2008270261B2/en active Active
  • 2008-07-03 CA CA2692518A patent/CA2692518C/fr active Active
  • 2008-07-03 UA UAA201001204A patent/UA98152C2/ru unknown
  • 2008-07-03 MX MX2010000190A patent/MX2010000190A/es active IP Right Grant
  • 2008-07-03 JP JP2010513984A patent/JP5357869B2/ja active Active
  • 2008-07-03 SI SI200830458T patent/SI2176192T1/sl unknown
• 2009
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• 2010
  • 2010-01-03 EG EG2010010002A patent/EG26412A/en active
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  • 2010-02-05 CO CO10012779A patent/CO6251374A2/es active IP Right Grant

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