COMPOSITION OF MILK-BASED MORTAR ACTIVE BY A BY-PRODUCT

The present invention relates to a dry mortar composition comprising as hydraulic binder a derivative of calcium aluminosilicate activated by an industrial by-product. The present invention also relates to a process for preparing an adhesive mortar by mixing said dry mortar composition.

Mortar formulations, in particular for tile adhesive, exist on the market today, which include hydraulic binders based on calcium aluminosilicate derivatives such as activated blast furnace slags. These binders make it possible in particular to limit the quantity of Portland cement in the formulations of adhesive mortar and consequently also to reduce the carbon footprint of these products. In fact, the clinker manufacturing processes require decarbonation, calcination, clinkerization and heating operations, in particular at very high temperatures of the order of 150 ° C. Portland cements and aluminous cements are for example at the origin of the emission of about 800 kg of C0 2per tonne of cement produced. They are also consumers of energy and natural resources. Formulations poor in Portland cement, for example comprising less than 1% by weight of cement relative to the total composition, make it possible to greatly reduce the C0 2 footprint and to dispense with the “corrosive product” safety marking. On the other hand, certain formulations based on blast furnace slag activated by Portland cements and / or aluminous cements may have limited performance at low temperatures, due to low reactivity, in particular at cold temperatures, below 10 ° vs. It is therefore sought to further improve this low temperature reactivity.

It is in this context that the present invention falls within the scope of the present invention, which provides a dry mortar composition based on calcium aluminosilicate derivatives, which comprises as activator a slag rich in aluminum element, hereinafter referred to as aluminous slag, which is a by-product of industry.

The present invention relates to a dry mortar composition comprising:

- a hydraulic binder comprising at least one derivative of calcium aluminosilicate, at least one ground granulated aluminous slag comprising less than 30% by weight of silica, and at least one source of calcium sulfate,

- aggregates and / or fillers, and

- at least one base in an amount less than or equal to 0.5% of the total weight of the dry mortar composition.

For the purposes of the present invention, the term “aluminous slag” is understood to mean a slag in which alumina is the most abundant constituent.

In this document, the elementary chemical compositions are given in equivalent% by mass of oxide. For example, to say that a substance contains X% alumina means that this substance contains the element aluminum in an amount equivalent to that provided by X% alumina; it does not necessarily mean that the substance contains alumina as a chemical or mineralogical component.

A slag is a by-product of an industrial process involving the fusion of a starting material, fusion intended to separate metals from an oxide phase, the latter being called "slag".

For the purposes of the present invention, the term granulated means that the molten aluminous slag has undergone thermal quenching with water, the consequence of which is to obtain grains which are generally predominantly amorphous. The granulated slag is then ground in order to activate it, as explained in more detail below in the text.

The ground granulated aluminous slag preferably comprises between 30% by weight and 60% by weight, in particular from 30 to 50% by weight, preferably between 32 and 45% by weight, of alumina, or even between 35 and 43% by weight alumina.

Advantageously, the silica content of the ground granulated aluminous slag is between 5 and 25% by weight, or even between 10 and 20% by weight, relative to all the components of the granulated aluminous slag. Preferably, the ground granulated aluminous slag comprises between 12 and 18% by weight of silica.

Preferably, the granulated aluminous slag also comprises lime (CaO). The lime content is lower than the alumina content -as indicated above; it is preferably between 20 and 40% by weight, in particular between 25 and 35% by weight.

In order not to negatively impact the activating properties of the aluminous slag, the iron oxide content in the aluminous slag is preferably less than 5% by weight, in particular less than 3% by weight, and even less than 2% by weight. weight.

The ground granulated aluminous slag is advantageously predominantly, or even completely, amorphous. The level of amorphous material, as determined by X-ray diffraction according to the Rietveld method, is preferably at least 66%, in particular 90%, and even 95% or 98% by mass.

The ground granulated aluminous slag is preferably obtained from the recycling by total melting of catalysts used for the desulphurization of petroleum products, in particular of catalysts based on molybdenum and / or cobalt. These catalysts are recycled and a number of wastes or by-products are obtained during the recycling cycles. One of the by-products obtained is an aluminous slag, the silica content of which is less than 30% by weight. The aluminous slag preferably comprises molybdenum or cobalt, in a weight content of at most 0.5% expressed by weight of oxide.

This by-product is, after recycling the catalyst, in the form of aggregates of an average size generally between 2 and 5 mm. At this diameter, the aluminous slag aggregates are generally inert. In order to make them reactive, it is better to grind them to obtain fine particles. This grinding operation is to be taken into consideration to calculate the carbon footprint during the manufacture of the binder. However, if we compare it to the carbon footprint of a

manufacturing an aluminous or sulphoaluminous cement, the grinding operation reduces C0 2 emissions by more than 90%.

The ground granulated aluminous slag is preferably in the form of ground granules having a particle diameter D50 less than 20 μιτι, preferably less than 15 μητι. The diameter D50 is the diameter such that 50% by mass of the particles have a diameter smaller than this D50 value. This fineness of the particles makes it possible in particular to give the granulated aluminous slag good reactivity, allowing it to be used in a glue-adhesive composition and to obtain the expected properties in terms of setting time and mechanical strength.

The aluminous slag, by its activator action, makes it possible in particular to improve the reactivity of the binder at relatively low temperatures, such as for example at 5 ° C.

The base also participates in the activation of the hydraulic binder. However, the quantities of base required are very low, which makes it possible to consider the activation system as a gentle activation system compared to systems where it is necessary to add an alkaline activator in a much larger quantity, causing a pH. high which may cause severe skin irritation when handling the products. Its content is preferably less than 0.3% by weight relative to the weight of the dry mortar composition.

The base is preferably chosen from alkali metal or alkaline earth metal hydroxides, alkali metal or alkaline earth metal carbonates or alkali metal or alkaline earth metal silicate derivatives. Mention may in particular be made of KOH, Ca (OH) 2 , Na 2 C0 3 , K 2 C0 3 , Li 2 C0 3 , Na 2 Si0 3 . It may be a mixture of bases, such that the total amount of the mixture of bases is less than 0.5%, in particular 0.3%, of the total weight of the mortar composition.

The calcium aluminosilicate derivative is preferably a by-product of industry. Advantageously, alumina is not the most abundant constituent of the calcium aluminosilicate derivative.

The calcium aluminosilicate derivative is preferably chosen from granulated blast furnace slags, fly ash such as silico-aluminous fly ash, calcined clay and / or expanded clay dust, or silico ash. -calco-aluminous in particular of coal, in particular of lignite, of subbituminous coal, of hard coal, etc.

Preferably, at least one calcium aluminosilicate derivative has a fineness of less than 6000 Blaine. The term “Blaine” is a unit of measurement for the fineness of grinding of a solid ingredient expressed in cm 2 per gram of solid. This unit is used to measure the useful surface of the grains of solid.

The hydraulic binder can also comprise microparticles of granulated and ground blast furnace slag, the fineness of which is between 6000 and 15000 Blaine.

The source of calcium sulphate is advantageously chosen from plaster, hemihydrate, gypsum and / or anhydrite, alone or as a mixture.

The hydraulic binder can also comprise alkali metal sulfates such as lithium, sodium and / or potassium, preferably in an amount less than or equal to 0.5% of the total weight of the dry mortar composition.

The hydraulic binder can also comprise Portland cement, an aluminous cement and / or a sulphoaluminous cement, preferably in an amount less than or equal to 1% of the total weight of the dry mortar composition.

The hydraulic binder preferably represents from 5 to 70%, in particular from 10 to 60% of the total weight of the dry mortar composition. The total amount of calcium aluminosilicate derivative (other than aluminous slag) is preferably between 5 and 60%, especially between 20 and 50% by weight relative to the dry mortar composition. The total amount of ground granulated aluminous slag is preferably between 0.1 and 5%, in particular between 0.5 and 3% of the total weight of the dry mortar composition. The total amount of calcium sulfate source is preferably between 0.5 and 4%, especially between 1 and 3% of the total weight of the dry mortar composition.

The fillers are finely ground inert mineral materials of the limestone or siliceous type. Their content is generally between 0 and 30% by weight relative to the dry mortar composition. The aggregates generally used in the mortar compositions have a diameter of less than 8 mm. The aggregates are mineral grains, in particular grains of stone, gravel, gravel, pebbles and / or sands. The aggregate content preferably varies between 20 and 95% by weight relative to the dry mortar composition.

The composition is a dry composition since the majority of its constituents are in powder form. The percentages of each of the constituents are given as percentages by weight relative to all of the components of said composition.

The composition can also comprise one or more additives, chosen from rheological agents, water retaining agents, air entraining agents, thickening agents, biocidal protection agents, dispersing agents, pigments, accelerators and / or retarders, polymeric resins. The total content of additives and adjuvants conventionally varies between 0.001 and 10% by weight relative to the total weight of the dry mortar composition.

The presence of these different additives makes it possible in particular to adapt the setting time or the rheology of the wet mortar composition, that is to say after mixing with water, so as to meet the expectations depending on the product. wish.

The present invention also relates to a process for preparing a wet mortar composition, in particular an adhesive mortar composition, by mixing the dry mortar composition according to the invention with water. The presence of aluminous slag as activator advantageously makes it possible to accelerate the kinetics of curing of the composition.

of mortar, both at 20 ° C and at a lower temperature, for example at 5 ° C.

The examples below illustrate the invention without limiting its scope.

A ground granulated aluminous slag, resulting from the recycling by total melting of catalysts for the desulphurization of petroleum products based on cobalt and molybdenum, is used in the following examples. The main constituents of this slag are alumina (41%), lime (32.6%), silica (12.6%), magnesium oxide (8.9%), iron oxide (1.6%) and sulfur (1.6%). Other oxides, in particular of molybdenum, nickel, cobalt, chromium, vanadium, zinc, manganese, phosphorus, potassium, titanium, as well as chlorine are also present in the slag, but in levels minimal, less than 0.5%.

The granules of this aluminous slag, which have a maximum diameter of 5 mm, were ground, to obtain a fineness equivalent to that of a cement. The particle size distribution of the ground granulated aluminous slag is as follows: Di 0 of 0.7 μιτι, D 50 of 10 m and D 90 of 34 μητι.

This ground granulated aluminous slag was used in the following examples as an activator of the hydraulic binder.

Different formulations of mortar compositions were prepared by mixing the constituents in the proportions indicated below in Table 1. Composition 1 is given for comparison and does not contain the ground granulated aluminous slag playing the role of activator. Compositions 2 and 3 are mortar compositions according to the present invention.

Components in% Composition 1 Composition 2 Composition 3

Slag (4500 35 35 35

Blaine)

Slag (Blaine 4.5 4.5 0.0> 6500)

Fine limestone filler 5 5 9.5

Cellulose ether 0.40 0.40 0.40

Polymer 3.50 3.50 3.50 powder

(copolymer

acetate

ethylene vinyl)

Siliceous sand 48.9 47.4 47.4

1, 5 1, 5 1, 5 calcium sulphate

Alkali sulphate 0, 1 0, 1 0, 1

Alkaline carbonate 0, 1 0, 1 0, 1

Portland cement 0.9 0.9 0.9

Aluminous slag 0 1, 5 1, 5 ground granulate

Lime 0, 1 0, 1 0, 1

Table 1

These powder mixtures were mixed with water with a mixing rate of 26%, at a temperature of 20 ° C.

Tests were carried out on the mortars of dry compositions given in Table 1; they are summarized in Table 2 below.

The consistency of the adhesive mortar is evaluated by measuring the Brookfield viscosity.

The initial adhesion corresponds to a tensile strength test carried out according to the method described in standard EN 12004. The tear strength expressed in MPa is measured by tearing after 24 hours, according to the method described in standard EN 1348 § 8.2.

The setting times are given by measuring the start of setting and the end of Vicat setting.

The grouting time is the time after which the tiles are sufficiently maintained to allow the room to be put back into circulation and the joints to be made. In order to estimate it under the most unfavorable conditions, it is carried out at 5 ° C and by simulating a renovation test on old non-porous tiles. Tiles are glued with a comb 9 * 9 * 9 mm 3 on an enameled earthenware model. The jointing time is defined by qualitatively determining the moment when it becomes impossible to move the tiles by applying a shear force.

Table 2

Activation by ground granulated aluminous slag makes it possible to greatly accelerate the hardening kinetics at 20 ° C. and also at 5 ° C. The grouting time, even under very unfavorable conditions (application at 5 ° C on old tiles) is reduced from 72 hours to less than 24 hours, i.e. to a level of performance equivalent to that of a conventional formulation of adhesive based adhesive. of Portland cement.

CLAIMS

1. Dry composition of mortar comprising:

- a hydraulic binder comprising at least one derivative of calcium aluminosilicate, at least one ground granulated aluminous slag comprising less than 30% by weight of silica, said aluminous slag being a slag in which alumina is the most abundant constituent, and at least one source of calcium sulfate,

- aggregates and / or fillers, and

- at least one base in an amount less than or equal to 0.5% of the total weight of the dry mortar composition.

2. Mortar composition according to the preceding claim, such that the ground granulated aluminous slag comprises between 30% by weight and 60% by weight of alumina, preferably between 32 and 45% by weight of alumina.

3. Mortar composition according to one of the preceding claims, in which the silica content of the ground granulated aluminous slag is between 5 and 25% by weight, in particular between 10 and 20%.

4. Mortar composition according to one of the preceding claims, such that the ground granulated aluminous slag is predominantly amorphous.

5. Mortar composition according to one of the preceding claims, such that the ground granulated aluminous slag is in the form of ground granules having a particle diameter D50 less than 20 μιτι, preferably less than 15 m.

6. Mortar composition according to one of the preceding claims, such that the ground granulated aluminous slag results from the recycling by total melting of catalysts used for the desulphurization of petroleum products, in particular of catalysts based on molybdenum and / or cobalt.

7. Mortar composition according to one of the preceding claims, such that the total amount of ground granulated aluminous slag is between 0.1 and 5% of the total weight of the dry mortar composition.

8. Mortar composition according to one of the preceding claims, such that the calcium aluminosilicate derivative is chosen from blast furnace slags, crushed granules, fly ash such as silico-aluminous fly ash, calcined clay and / or expanded clay dust, or silico-calco-aluminous ash, in particular of coal, in particular of lignite, of subbituminous coal or of hard coal.

9. Mortar composition according to the preceding claim, such that at least one calcium aluminosilicate derivative has a fineness of less than 6000 Blaine.

10. Mortar composition according to one of the preceding claims, such that the binder comprises microparticles of granulated and ground blast furnace slag, the fineness of which is between 6000 and 15000 Blaine.

1 1. Mortar composition according to one of the preceding claims, such that the hydraulic binder comprises Portland cement, in an amount of less than 1% of the total weight of the dry mortar composition.

12. Mortar composition according to one of the preceding claims, in which the source of calcium sulphate is chosen from plaster, hemihydrate, gypsum and / or anhydrite, alone or as a mixture.

13. Mortar composition according to one of the preceding claims, in which the base is chosen from alkali metal or alkaline earth metal hydroxides, alkali metal or alkaline earth metal carbonates or alkali metal or alkaline metal silicate derivatives. earthy.

1. Mortar composition according to one of the preceding claims, further comprising one or more additives, chosen from rheological agents, water-retaining agents, air entraining agents, thickening agents, biocidal protection agents, dispersants, pigments, accelerators and / or retarders, polymeric resins.

15. A process for preparing a wet mortar composition, in particular an adhesive mortar composition, by mixing with water the dry mortar composition according to one of the preceding claims.