Classifications

• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B28/00—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements
  • C04B28/14—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements containing calcium sulfate cements
• • 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
  • C04B28/00—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements
  • C04B28/02—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements containing hydraulic cements other than calcium sulfates
  • C04B28/06—Aluminous cements
  • C04B28/065—Calcium aluminosulfate cements, e.g. cements hydrating into ettringite
• • 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
  • C04B14/00—Use of inorganic materials as fillers, e.g. pigments, for mortars, concrete or artificial stone; Treatment of inorganic materials specially adapted to enhance their filling properties in mortars, concrete or artificial stone
  • C04B14/02—Granular materials, e.g. microballoons
  • C04B14/04—Silica-rich materials; Silicates
  • C04B14/06—Quartz; Sand
• • 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
  • C04B14/00—Use of inorganic materials as fillers, e.g. pigments, for mortars, concrete or artificial stone; Treatment of inorganic materials specially adapted to enhance their filling properties in mortars, concrete or artificial stone
  • C04B14/02—Granular materials, e.g. microballoons
  • C04B14/30—Oxides other than silica
  • C04B14/303—Alumina
• • 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
  • C04B14/00—Use of inorganic materials as fillers, e.g. pigments, for mortars, concrete or artificial stone; Treatment of inorganic materials specially adapted to enhance their filling properties in mortars, concrete or artificial stone
  • C04B14/02—Granular materials, e.g. microballoons
  • C04B14/30—Oxides other than silica
  • C04B14/308—Iron oxide
• • 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
  • C04B20/00—Use of materials as fillers for mortars, concrete or artificial stone according to more than one of groups C04B14/00 - C04B18/00 and characterised by shape or grain distribution; Treatment of materials according to more than one of the groups C04B14/00 - C04B18/00 specially adapted to enhance their filling properties in mortars, concrete or artificial stone; Expanding or defibrillating materials
  • C04B20/10—Coating or impregnating
  • C04B20/1018—Coating or impregnating with organic materials
  • C04B20/1022—Non-macromolecular compounds
• • 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
  • C04B22/00—Use of inorganic materials as active ingredients for mortars, concrete or artificial stone, e.g. accelerators, shrinkage compensating agents
  • C04B22/06—Oxides, Hydroxides
  • C04B22/062—Oxides, Hydroxides of the alkali or alkaline-earth metals
  • C04B22/064—Oxides, Hydroxides of the alkali or alkaline-earth metals of the alkaline-earth metals
• • 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
  • C04B28/00—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements
  • C04B28/02—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements containing hydraulic cements other than calcium sulfates
  • C04B28/06—Aluminous cements
• • 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
  • C04B40/00—Processes, in general, for influencing or modifying the properties of mortars, concrete or artificial stone compositions, e.g. their setting or hardening ability
  • C04B40/0028—Aspects relating to the mixing step of the mortar preparation
  • C04B40/0039—Premixtures of ingredients
  • C04B40/0046—Premixtures of ingredients characterised by their processing, e.g. sequence of mixing the ingredients when preparing the premixtures
• • 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
  • C04B7/00—Hydraulic cements
  • C04B7/32—Aluminous cements
• • 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
  • C04B7/00—Hydraulic cements
  • C04B7/36—Manufacture of hydraulic cements in general
  • C04B7/43—Heat treatment, e.g. precalcining, burning, melting; Cooling
  • C04B7/47—Cooling ; Waste heat management
• • 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
  • C04B7/00—Hydraulic cements
  • C04B7/36—Manufacture of hydraulic cements in general
  • C04B7/48—Clinker treatment
  • C04B7/52—Grinding ; After-treatment of ground cement
• • 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
  • C04B2103/00—Function or property of ingredients for mortars, concrete or artificial stone
  • C04B2103/10—Accelerators; Activators
  • C04B2103/12—Set accelerators

Definitions

• the present invention relates to the field of ultrafast cements for the preparation of mortar or concrete.
• the present invention relates to an amorphous calcium aluminate based ultra-fast setting cement composition having a surface treatment to improve its service life, as well as to its manufacturing process.
• the present invention also relates to the use of the aforementioned cement composition to accelerate the intake of Portland cements or to optimize the formation of ettringite.
• CN 102 765 738 describes an amorphous calcium aluminate composition and its method of production.
• Amorphous calcium aluminate can be used as a cementitious composition additive to improve its setting time or as an additive for the manufacture of steel.
• amorphous calcium aluminate comprises, by weight, by relative to its total mass, from 40 to 60% of CaO (C), from 30 to 60% of Al 2 O 3 (A), from 0.01 to 1% of S, from 1 to 10% of SiO 2 , from 0.05 to 3% of Fe 2 O 3 , from 0.01 to 5% of CaF 2 , from 1 to 10% of MgO, from 0 to 3% of TiO 2 and from 0.01 to 1% of P.
• the ultra reactivity of the amorphous cements is itself allowed thanks to a very high speed of dissolution of this type of cement when they come into contact with water. Nevertheless, this high affinity with water poses the problem of maintaining the reactivity of these ultra-reactive cements, and the formulations containing them, during their storage especially in humid conditions.
• the object of the present invention is thus to propose a new high-speed cement composition, especially based on amorphous calcium aluminate, combined or otherwise with other inorganic binders such as Portland cement or calcium sulphate which avoids, at least in part, the aforementioned disadvantages.
• the object of the present invention is to provide a new high-speed cement composition having an improved service life and does not further deteriorate the properties of the mortar or concrete obtained from the cement composition.
• the present invention proposes a high-speed cement composition
• a high-speed cement composition comprising at least amorphous calcium aluminate comprising, by weight, relative to the total weight of amorphous calcium aluminate: (a) 35 to 55% calcium oxide CaO (C), (b) 19 to 55% alumina Al 2 O 3 (A), the molar ratio C / A being greater than or equal to 1.5, preferably greater than or equal to 1.7, characterized in that the amorphous calcium aluminate is coated with a surface treatment, in particular an anti-aging treatment, comprising an organic compound comprising at least two hydrophilic functions and a hydrophobic chain.
• cement means a hydraulic binder, that is to say a finely ground mineral material which, mixed with water, forms a paste which sets and hardens as a result. reaction and hydration process and which, after hardening, retains its strength and stability even under water “(Standard NF EN 197-1).
• the indication of a range of values "from X to Y” or “between X and Y” in the present invention means as including the X and Y values.
• amorphous calcium aluminate means that the calcium aluminate comprises a level of at least 60% of amorphous phase and therefore a crystallization phase rate of less than or equal to 40% of phase crystalline.
• a level of at least 60% amorphous phase means at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, at least 97%, at least 98%, at least 99%.
• the crystalline phases can be CaO.Al 2 O 3 , CaO 2 Al 2 O 3 , 3CaO.Al 2 O 3 , 3CaO.3Al 2 0 3 + CaF 2 , 1 1 CaO.7Al 2 0 3 .CaF 2 , 12CaO. 7AI 2 0 3 or 3CaO.3AI 2 0 3 + CaSO 4 or a mixture thereof.
• the crystalline phases are CaO.AI203 or 12CaO.7AI 2 0 3 or a mixture thereof.
• the invention also relates to a process for producing a high-speed cement composition as described above comprising the following steps:
• the invention also relates to the use of the high-speed cement composition to accelerate the setting of Portland cements, as well as to form ettringite, especially when the amorphous calcium aluminate is combined with sulphate. of calcium in the presence or absence of Portland cement.
• FIG. 1 is a graph showing the percentage mass recovery of six cement compositions: three according to the invention (B1, B2 and B3) and three according to the prior art (A1, A2 and A3 which have the same compositions of B1, B2 and B3, respectively, except that B1, B2 and B3 further comprise anti-aging treatment) as a function of time in days;
• FIG. 2 is a graph illustrating the mass recovery variations of the cement compositions illustrated in FIG. 1, namely between B1 versus A1, between B2 versus A2 and between B3 versus A3 after 13 days of exposure at 20 ° C. / 70% relative humidity;
• FIG. 3 is a graph showing the initial reactivity of the A1 and B1 cements ("initial pure paste") and the initial reactivity of two mortar compositions respectively comprising A1 or B1 cements ("initial formulated").
• FIG. 4 is a graph showing the impact of aging on the reactivity in pure paste (expressed in minutes) of the cement compositions A1 and B1 during the aging time (expressed in days);
• FIG. 5 is a graph showing the impact of aging on the reactivity in formulation (expressed in minutes) of cement compositions A1. and B1 integrated within a mortar composition during the aging time (expressed in days).
• the applicant company has focused on the development of new highly reactive amorphous calcium aluminate cement compositions adapted to the requirements of building professionals, ie having high mechanical strengths and good storage stability, while making the pouring concrete or mortar obtained from this type of easy cement.
• the present invention relates to a high-speed cement composition (hydraulic binder) comprising at least amorphous calcium aluminate comprising by weight relative to the total weight of amorphous calcium aluminate:
• the molar ratio C / A is greater than or equal to 1, 5, preferably greater than or equal to 1, 7, ideally greater than or equal to 2 , and in particular ranging from 1.5 to 3,
• amorphous calcium aluminate is coated with an anti-aging surface treatment comprising an organic compound having at least two hydrophilic functions and a hydrophobic chain.
• an organic compound comprising at least two hydrophilic functions and a hydrophobic chain makes it possible to improve the lifetime of an amorphous calcium aluminate cement while not affecting the reactivity. or the mechanical strength of the cement obtained.
• the weight concentration of this organic compound in the cement composition is advantageously between 0.025% and 5% by weight relative to the weight of the cement composition, preferably between 0.05% and 2.5%, advantageously between 0, 1% and 1%.
• hydrophilic function means functions that make it possible to obtain compatibility with a medium containing water.
• these hydrophilic functions advantageously have the capacity to react with the cations or metal elements present in the hydraulic binder.
• Suitable functions for the invention include carboxylic acid functions, acid anhydrides, acid halides, primary amines.
• the preferred functions of the invention are the acid functions, or acid anhydrides.
• the hydrophobic nature of the organic product is provided by an aliphatic, aromatic, alkylaromatic or arylaliphatic hydrocarbon chain.
• the linear or cyclic, branched or substituted aliphatic, arylaliphatic chains are preferred for the invention. They advantageously comprise between 2 and 13 carbon atoms.
• the organic compound is according to a first embodiment introduced into the cement composition according to the invention during a co-grinding step between said organic compound. in the form of powder and an amorphous calcium aluminate clinker (ie, having undergone a rapid cooling step after firing).
• the organic compound is hot-mixed with an amorphous calcium aluminate cement at a temperature above the melting point of said organic compound and at a temperature below its decomposition temperature before being crushed. .
• an organic non-film-forming but wetting and adsorbing compound on the hydraulic binder grains is also suitable for the invention.
• Suitable organic compounds for the invention include polycarboxylic acids such as dicarboxylic acids such as glutaric acid, succinic acid, adipic acid, octanedioic acid, decanedioic acid, dodecanedioic acid, brassylic acid and the like. their anhydrides and acid halides, phthalic acids such as orthophthalic acid, terephthalic acid, isophthalic acid or a mixture thereof. In particular, adipic acid is preferred.
• dicarboxylic acids such as glutaric acid, succinic acid, adipic acid, octanedioic acid, decanedioic acid, dodecanedioic acid, brassylic acid and the like. their anhydrides and acid halides, phthalic acids such as orthophthalic acid, terephthalic acid, isophthalic acid or a mixture thereof.
• adipic acid is preferred.
• acids in a mixture and more particularly to use a mixture of adipic, succinic and glutaric acid.
• This mixture is a by-product in industrial processes for the manufacture of adipic acid.
• Such organic compounds may correspond in particular to those described in document WO 03/010109 relating to non-amorphous (crystalline) hydraulic binders.
• amorphous calcium aluminates according to the invention have surface properties very different from crystalline hydraulic binders and in particular a much higher dissolution rate, making it not obvious that the cement composition according to the invention could be covered with these organic compounds as an anti-aging surface agent.
• the amorphous calcium aluminates thus coated with the anti-aging organic compound in accordance with the invention are less sensitive to moisture uptake, thus making it possible to increase their shelf life in the various packages such as silos, bags, containers, for example.
• the flowability of the powder is improved during the operation of emptying the packages.
• the shelf life of the formulations containing calcium aluminates coated with the organic anti-aging compound according to the invention are also increased.
• formulation is meant formulations in which the binder phase comprises amorphous calcium aluminate or calcium aluminate combined with other binders including Portland cement and / or calcium sulfate.
• the amorphous calcium aluminate comprises by weight relative to its total weight of: (a) 35 to 55%, preferably 42 to 52%, and even more preferably 47 to 51% of oxide of calcium.
• the cement composition according to the invention is less reactive; while when the calcium oxide content is greater than 55%, it becomes more difficult to melt the compound in a melt furnace and particularly in a reverberatory furnace.
• the amorphous calcium aluminate may comprise by weight relative to its total weight of (b) 19 to 55%, preferably 25 to 48%, and even more preferably 34 to 42% of alumina .
• alumina content is in particular a function of the calcium oxide content so that the molar ratio C / A is greater than or equal to 1.5, preferably greater than 1.7, and ideally greater than or equal to 2 and in particular from 1.5 to 3.
• amorphous calcium aluminate comprises other transition metal or metalloid oxides.
• the amorphous calcium aluminate comprises, by weight, relative to the weight of the amorphous calcium aluminate of 3 to 16%, preferably 5 to 10%, ideally 5 to 8% of iron oxide (Fe 2 O 3 ).
• At least 5% Fe 2 O 3 iron oxide includes the following mass percentages: 5%, 5.5%, 6%, 6.5%, 7%, 7.5% , 8%, 8.5%, 9%, 9.5%, 10%, 10.5%, 1 1%, 1 1, 5%, 12%, 12.5%, 13%, 13.5% , 14%, 14.5%, 15%, 15.5%, 16%.
• the Applicant has also unexpectedly discovered that a particular Fe 2 0 3 iron oxide content makes it possible to regulate the reaction kinetics of amorphous calcium aluminates, while not affecting the mechanical strength of the cement obtained and especially its initial resistance.
• the cement composition according to this embodiment variant has the advantage of being free of such a setting regulator and of obtaining good initial mechanical strength.
• the cement composition according to the invention has the advantage of reducing production costs due to the use of less expensive raw materials than those used for conventional cement compositions, especially those based on amorphous calcium aluminate with an accelerator and a set retarder. Indeed, according to the invention, it is no longer It is necessary to add a setting inhibitor or to select raw materials that are very rich in alumina and calcium oxide (ie with little impurities).
• the calcium aluminate present in the cement composition is thus rich in iron.
• a relatively high iron oxide content in the cement composition does not deteriorate the ultra-reactivity of the amorphous calcium aluminate, but simply allows to regulate its grip while allowing to obtain a mortar composition having excellent robustness.
• the amorphous calcium aluminate may comprise, by weight relative to the total weight of amorphous calcium aluminate: from 1 to 10% and more particularly from 3 to 6% of SiO 2 silica.
• the amorphous calcium aluminate according to the invention may comprise impurities ranging from 0 to 5%, preferably from 0 to 3% by weight, relative to the total weight of calcium aluminate.
• impurities may be for example a titanium oxide (TiO 2 ) or magnesia (MgO).
• the amorphous calcium aluminate present in the cement composition of the invention has a dissolution rate in water higher measured or equal to 15.10 "6, preferably greater than or equal to 20 mol .S "1 .m-2. This rate is measured by assaying the calcium released into the water in 5 minutes by the calcium aluminate in a suspension at 0.5 gl "1. The calcium concentration is divided by 300 seconds (5 minutes) and by the surface calcium aluminate calculated by the product of the BET surface expressed in m 2 .g -1 by the mass of material (0.5 g per liter).
• the amorphous calcium aluminate has a Blaine specific surface area measured according to the NF EN 196-6 standard ranging from 2000 to 7000 cm 2 / g and preferably from 3000 to 5000 cm 2 / g. .
• the cement composition comprises a density ranging from 2 to 5, preferably ranging from 2.5 to 3.5 and ideally ranging from 2.7 to 3.1 g / cm 3 .
• the cement composition comprises, in addition to amorphous calcium aluminate, calcium sulphate.
• the calcium sulphate is in the form of anhydrite, gypsum or hemihydrate, of natural or synthetic origin.
• the calcium sulfate is in the form of type I or type II anhydrite.
• the cement composition comprises, by weight relative to the total weight of the cement composition: from 30 to 70% of amorphous calcium aluminate as defined above and from 30 to 70% of calcium sulphate, in particular the cement composition according to the invention may comprise from 45 to 55% of amorphous calcium aluminate and from 45 to 55% of calcium sulphate.
• a mortar or concrete composed of this type of compounds, namely amorphous calcium aluminate as described above and calcium sulphate, has many advantages over a conventional composition, the main being a setting time. and developing fast resistors and compensation for shrinkage. These advantages are related to hydration and in particular to the presence of calcium sulphate.
• the present invention also relates to a method for producing the cement composition according to the invention.
• the method of manufacturing a high-speed, improved aging cement composition as described above comprises the following steps:
• ii) firing in the melting furnace at a minimum temperature permitting the melting of the composition generally around 1250 ° C to 2300 ° C (for example, around 1400 ° C) for a period of time to obtain complete melting raw materials, usually 10mn to 10h, depending on the process and raw materials used.
• step vi) may be carried out at the same time as step v) by co-grinding the amorphous calcium aluminate clinker with an organic compound (as defined above) lying in the form of a powder, for example of average particle size less than or equal to 300 ⁇ m, so as to obtain a calcium aluminate cement comprising an anti-aging surface treatment.
• an organic compound as defined above
• step vi) may be carried out by hot mixing the calcium aluminate cement obtained in step v) with an organic compound (as defined above) at a temperature greater than the melting temperature of said organic compound and at a temperature below its decomposition temperature.
• organic compound as defined above
• the coating of the amorphous calcium aluminate grains is carried out at a low temperature, for example at ambient temperature, and more generally in a range of ambient temperature in which the compound organic is in the solid state.
• the organic compound used for the mixture may be in the form of granules or powder whose grains may be fine or coarse.
• the temperature is determined to be greater than the melting temperature of said organic compound and lower than its decomposition temperature.
• this temperature is between 140 ° C. and 270 ° C.
• the source of calcium can be chosen from: limestone, lime and by-products from processes consumers of limestone and lime, such as slags or slags from iron and steel or electrometallurgy, or a mixture thereof; while the source of alumina or even of iron oxide may be chosen from: bauxite (bauxite monohydrate and / or bauxite trihydrate), corundum wheels, catalyst supports, refractory bricks, hydroxides, aluminas metallurgical materials, calcined and melted aluminas, by-products of the aluminum die and non-compliant high-alumina manufacturing or mixtures thereof.
• bauxite bauxite monohydrate and / or bauxite trihydrate
• corundum wheels bauxite monohydrate and / or bauxite trihydrate
• catalyst supports refractory bricks
• hydroxides aluminas metallurgical materials
• calcined and melted aluminas by-products of the aluminum die and non
• the bauxite trihydrate may comprise by weight 46 to 50% alumina, 14 to 20% iron oxide and 7 to 12% silica. It is thus both a source of alumina and iron oxide.
• These raw materials sources of calcium oxide, aluminum or iron are generally in the form of blocks, such as bauxite blocks or limestone blocks.
• alumina source bauxite block
• the melting furnace used in the process according to the invention is generally a reverberatory furnace.
• a reverberatory furnace has for example an L-shaped section, namely a vertical portion and a horizontal portion that communicate with each other.
• the vertical part can reach ten meters high.
• the limestone blocks and bauxites are introduced into the melting furnace through an opening disposed on the upper portion of the vertical portion. These blocks are loaded into the furnace to fill the entire volume of this vertical portion and thus form, at a junction between the horizontal portion and the vertical portion, a slope of blocks. The latter is then attacked by a flame disposed in the horizontal part of the furnace, facing the slope. The flame heats at a temperature above 1500 ° C, or even 2000 ° C. It brings the necessary calories to melt the limestone blocks and bauxites forming a liquid bath of materials. The temperature of the raw materials in the oven in general reaches 1400-1500 ° C. The materials, a melted bis, out through a taphole disposed in the horizontal part of the oven.
• flue gases form and take a counter-current path to that of the blocks. They are then evacuated by a chimney located on the upper portion of the vertical part of the oven. These gases, having a temperature of the order of 1500 ° C, thus collapse between the blocks disposed above the slope and preheat by heat transfer.
• the blocks of raw materials from their introduction in contact with the flame, thus undergo beforehand: drying, then dehydration and decarbonation by the combustion gases rising up the vertical part of the furnace.
• the preheating of the raw materials by the combustion gases is made possible because of the porous stacking of bauxite blocks and limestone of fairly large diameter able to let the gases pass.
• the firing of raw materials sources of at least calcium oxide, alumina and iron oxide is carried out at a temperature preferably ranging from 1250 to 2300 ° C., preferably from 1300 to 2000 ° C. C and in general from 1400 to 1600 ° C, for a duration preferably from 5 to 12 hours, in particular from 6 to 10 hours.
• a calcium aluminate clinker is thus obtained.
• This clinker is cooled very rapidly just after baking so as to lower the temperature of the calcium aluminate clinker to a temperature below its crystallization temperature so as to obtain an amorphous calcium aluminate clinker.
• the cooling can be carried out at a gradient of 10 to 25 ° C / second, preferably 15 to 20 ° C / second.
• the sudden cooling can be carried out by dipping the liquid clinker with air having a temperature not higher than 500 ° C., preferably not higher than 100 ° C. for a shorter or equal period of time. at 1 minute, advantageously less than or equal to 15 seconds.
• a horizontal air jet will be disposed out of the oven to blow and disperse the clinker to accelerate its cooling.
• the amorphous calcium aluminate clinker can be finely ground to obtain an amorphous calcium aluminate cement (binder Hydraulic) having a Blaine specific surface area of 2000-7000 cm 2 / g and preferably from 3000 to 5000 cm 2 / g.
• the process comprises a step in which calcium sulfate is co-milled with calcium aluminate clinker in step v) or in which calcium sulfate is mixed with the calcium aluminate cement before or after the step of mixing with the organic compound.
• the calcium aluminate clinker can be co-milled with calcium sulfate to form an amorphous calcium sulfaluminate cement.
• the calcium sulphate may be mixed with the amorphous calcium aluminate cement previously ground at the end of step v).
• the cement composition preferably comprises by weight relative to the total weight of the cement composition of 30 to 70% amorphous calcium aluminate (as defined above) and from 30 to 70% of calcium sulphate, in particular the cement composition according to the invention may comprise from 45 to 55% of amorphous calcium aluminate and of 45 to 55% of calcium sulphate.
• This method makes it possible, for example, to produce a cement composition based on amorphous calcium aluminates rich in Fe 2 O 3 iron oxide, as described above.
• the cement composition produced according to this process has the same characteristics as those of the composition according to the invention. To the extent that they have already been described, they will not be further detailed below.
• the cement composition according to the invention can be used for the manufacture of mortar, concrete or other usual compositions based on inorganic binders. It is remarkable that the presence of the organic compound does not affect the conditions of realization of these compositions such as mortar, concrete or their mechanical and rheological properties. On the contrary, it may, in certain applications, improve the methods of implementation and the mechanical properties of the products or articles made with these compositions.
• a mortar composition is generally in the form of a dry powder, ready for use and may comprise at least the composition of cement as described above as a hydraulic binder and at least one granulate, as well as optionally a current additive and / or adjuvant.
• a composition of the mortar or dry concrete comprises, by weight, relative to the total weight of said mortar composition:
• hydraulic binder such as the cement composition according to the invention and / or a Portland cement and / or a calcium sulphate,
• the cement composition according to the invention can be rich in iron oxide capable of regulating the setting of the hydraulic binder (calcium aluminate with or without calcium sulphate), it does not It is not necessarily necessary to add a retarding agent within the mortar or dry concrete composition.
• a mortar or concrete composition may comprise setting regulators, such as setting accelerators or setting inhibitors, superplasticizers or hardening accelerators. These additives are known from the state of the art and their proportion can be adapted by those skilled in the art.
• the mortar comprises a mixture of cement and sand / fillers, while the concrete may further comprise aggregates, each in proportions known to those skilled in the art.
• the present invention also relates to the use of the high-speed setting cement composition as described above to accelerate the setting of Portland cements.
• Any Portland cement such as normal Portland cement, fast setting Portland cement, super fast cure Portland cement, white Portland cement, etc., can be used as cement.
• the amount of cement composition according to the invention to be added for such use preferably varies from 2 to 10% by weight of the weight of the Portland cement depending on the nature of the other constituents used and the characteristics sought.
• the nature of Portland mainly its C3A content, its fineness, the types of additions and the nature of the calcium sulphate when it is present in the cement composition according to the invention or that present in Portland, will influence the quantity to add.
• the present invention is directed to the use of the high speed setting cement composition as described above to form ettringite when it comprises calcium sulfate.
• the comparative compositions A1, A2 and A3 are amorphous calcium aluminate cements not comprising anti-aging agents, while the cement compositions B1, B2 and B3 according to the invention comprise such an anti-aging agent.
• the mass recovery test is carried out on cement alone (A1 or B1) using an aluminum cup in which 25 grams of cement to be tested are positioned. The cup thus prepared is weighed and placed at 20 ° C. and 70% relative humidity. The mass recovery test consists of following the evolution of the weight of the cup as a function of the exposure time. The result is expressed in% of mass recovery with respect to the mass of cement.
• the mortar or cement alone is mixed with the amount of water required (35% water for cement-only tests and 14% for formulation tests) for thirty seconds by hand using a lowering agent. language.
• the dough thus prepared is then immediately placed in a plastic container (diameter 25 mm, height 100 mm) into which is inserted a type K thermocouple connected to a Testo mark recorder (Testo 177).
• the stated reactivity values correspond to the time required to reach the maximum temperature. Reactivity measurements are carried out both on fresh cement (cement alone or in formulation) and on aged cement.
• the cement to be studied is placed in a 5 mm thin layer plastic tank in a climatic chamber regulated at 20 ° C. and 50% relative humidity.
• the cements thus conditioned are maintained in this climatic condition until the various deadlines for desired measurements. At these deadlines, and for the formulations tests, these cements are mixed with a Turbula mixer to the other constituents of the formula having been maintained at 23 ° C and 50% humidity.
• cement compositions according to the invention comprising an anti-aging agent have a mass recovery much lower than those of cement compositions according to the prior art.
• cement compositions according to the invention have a lower sensitivity to moisture and therefore an improved life compared to cement compositions according to the prior art.
• the reactivity of the pure calcium aluminates or in the mortar formulation is not affected by the addition of the anti-aging agent according to the invention.
• the material B1 containing amorphous calcium aluminate cement coated anti-aging treatment according to the invention has excellent retention of reactivity even after 13 days of aging.
• the amorphous calcium aluminate cement according to the prior art sees its reactivity go from 0.08 minute to 440 minutes.
• the amorphous calcium aluminate cement according to the invention therefore makes it possible to increase the shelf life of the formulations containing them.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Ceramic Engineering (AREA)
• Structural Engineering (AREA)
• Materials Engineering (AREA)
• Organic Chemistry (AREA)
• Inorganic Chemistry (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Civil Engineering (AREA)
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• Thermal Sciences (AREA)
• Curing Cements, Concrete, And Artificial Stone (AREA)
• Compounds Of Alkaline-Earth Elements, Aluminum Or Rare-Earth Metals (AREA)

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• 2014
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