The present invention relates to the stabilization of the alkanolamines used in the grinding processes, in particular in the hydraulic binder grinding processes, in particular clinker.

It is known to use alkanolamines when grinding clinker. Alkanolamines are also known to improve the mechanical strengths of cement-based hydraulic compositions.

It has therefore been proposed to combine these effects and to use the alkanolamines at the time of grinding the hydraulic binder, in particular cement, in order to benefit from the grinding properties of alkanolamines while introducing active agents into the hydraulic binder allowing the improvement of mechanical resistance during the preparation of hydraulic binder compositions.

However, certain alkanolamines, in particular triisopropanolamine (TIPA), used during grinding, will be degraded by temperature and will therefore no longer be available to participate in obtaining good mechanical strengths during the preparation of hydraulic binder compositions. To overcome this problem, it has been envisaged to add a larger quantity of alkanolamine in order to compensate for their degradation. However, the increase in the concentration of alkanolamine in certain mills results in an excessively high grinding efficiency and the superfluidification of the cement powder leads to emptying of the mill, which is not desired.

It is also known from FR 3 002 162 the use of AMP (2-amino-2-methyl-propanol), in particular in the form of an organic salt, during the grinding of the clinker. However, this results in an increase in the fluidity of the cement and therefore in insufficient grinding of the clinker.

There is therefore an interest in providing a process allowing the use of alkanolamines during the grinding of a hydraulic binder, in particular cement, while not degrading the grinding conditions, in particular by not emptying (or not emptying) the mill. .

There is also an interest in providing such a process which makes it possible to reduce the fluidity of the hydraulic binder and consequently to increase its passage time in the mill, in order to obtain a finer powder also making it possible to obtain good mechanical strengths.

There is also an interest in providing a process which makes it possible, during the step of grinding the hydraulic binder, to provide the compounds necessary for improving the

mechanical strength properties, in particular mechanical strength at 28 days, of the hydraulic binder compositions, while not degrading the grinding conditions, in particular by not emptying the crusher.

An objective of the present invention is therefore to provide a process making it possible to stabilize the alkanolamines used in a mill.

Another objective of the invention is to provide such a process making it possible at the same time to maintain an impact on improving the mechanical strengths, in particular at 28 days, of hydraulic binder compositions.

Yet another objective of the present invention is to provide a means making it possible to control the performance of the grinding agent for alkanolamines while retaining the properties of improving the mechanical strengths, in particular at 28 days during the preparation of the hydraulic binder compositions. . The object of the present invention is particularly advantageous in all situations where the required grinding performance is low (nature of the clinker, co-grinding of the clinker with soft materials - for example limestone filler, natural pozzolans -, inefficient grinders, open grinders. without separation system, closed grinding systems with e.g. constant air flow separators, process with cement transfer by inclined conveyor belt, open bucket elevators,

The object of the present invention is particularly advantageous during the co-grinding of clinker and limestone for the manufacture of OEM II / A or OEM II / B LL, which require, for the improvement of the mechanical strengths at 28 days, high dosages of amine. (for example 120 g of triisopropanolamine (TIPA) per tonne of cement). When such dosages are used on certain plants, rapid emptying of the crusher is observed as well as critical dust phenomena at the outlet of the crusher and at the level of the elevator.

Surprisingly, it has been observed that the use of amines in the form of salts makes it possible to control the grinding performance of the amines, while retaining all of the performance for improving the mechanical strengths at 28 days.

All these objectives are fulfilled by the present invention, which relates to a process for using an alkanolamine, preferably secondary or tertiary alkanolamine, for grinding at least one hydraulic binder, preferably cement, comprising:

- Putting alkanolamine in the form of a salt, preferably an inorganic acid salt;

- The addition of the alkanolamine in the form of a salt in a mill.

The method preferably further comprises grinding said hydraulic binder.

Preferably, the present invention relates to a process for using secondary or tertiary alkanolamine, for grinding at least one hydraulic binder comprising:

- The setting in the form of an inorganic acid salt of the alkanolamine;

- The addition of the alkanolamine in the form of a salt in a mill.

The method preferably further comprises grinding said hydraulic binder.

Preferably, the alkanolamine is an alkanolamine of formula (I) N (R 1 OH) (R 2 ) (R 3 ) (I) in which the R 1 , which are identical or different, represent a linear or branched alkyl group comprising of 1 to 10 carbon atoms, preferably 1 to 5 carbon atoms, R 2 represents H or a group R 1 -OH, R 3 represents H, a linear or branched alkyl group comprising from 1 to 10 carbon atoms, preferably from 1 to 5 carbon atoms, a group R 4 -OH in which R 4represents a linear or branched alkyl group comprising from 1 to 10 carbon atoms, preferably from 1 to 5 carbon atoms, or an (alkyl) -N (alkyl-OH) 2 group , the alkyl being linear or branched and comprising from 1 to 5 carbon atoms, preferably (OH2-OH2) -N (OH2-OH 2 -OH) 2, at least one of R 2 and R 3 being different from H.

Preferably, the alkanolamine is an alkanolamine of formula (I) N (R 1 OH) (R 1 OH) (R 3 ) (I) in which the R 1 , which are identical or different, represent a linear or branched alkyl group comprising from 1 to 10 carbon atoms, preferably from 1 to 5 carbon atoms, R 3 represents H, a linear or branched alkyl group comprising from 1 to 10 carbon atoms, preferably from 1 to 5 carbon atoms, a group R 4 -OH in which R 4 represents a linear or branched alkyl group comprising from 1 to 10 carbon atoms, preferably from 1 to 5 carbon atoms.

The process of the present invention does not cover the use of salts of acetic acid. The process of the present invention does not cover the use of AMP (2-amino-2-methyl-propanol).

The present invention also relates to a process for improving the mechanical strengths of a hydraulic binder composition comprising the use of an alkanolamine salt, preferably an inorganic alkanolamine salt, preferably an alkanolamine of formula ( I), when grinding the hydraulic binder. In a particularly advantageous manner, the process makes it possible to improve the mechanical strengths of the hydraulic binder composition without affecting the performance of the grinding of hydraulic binder, in particular clinker.

Preferably, in the context of the invention, when reference is made to the mechanical strengths, it is preferably the mechanical strengths at 28 days.

The inorganic alkanolamine salts of formula (I) are chosen from acid halide salts, sulfuric acid, phosphoric acid, phosphonic acid or hydrogen sulphate salts.

Preferably, the alkanolamine salt is a salt of sulfuric acid, phosphoric acid or phosphonic acid, preferably sulfuric acid.

Preferably, the alkanolamine salt is an acid halide salt. In particular, a hydrochloric acid salt.

The process of the present invention can be applied to any type of alkanolamine, preferably secondary or tertiary, preferably of formula (I), in particular to any type of secondary or tertiary alkanolamine of formula (I) used in mills, especially in clinker and hydraulic binders crushers. More particularly, mention may be made of triisopropanolamine (TIPA), diisopropanolamine (DIPA), diethanolisopropanolamine (DEIPA), ethanoldiisopropanolamine (EDIPA), N, N, N ', N'-tetrakis (2-hydroxyethyl) ethylenediamine (THEED) and methyldiethanolamine (MDEA). Preferably, the alkanolamine is chosen from triisopropanolamine (TIPA), diethanolisopropanolamine (DEIPA) and ethanoldiisopropanolamine (EDIPA). Preferably, the alkanolamine is triisopropanolamine (TIPA).

The preparation of the alkanolamine salt is preferably carried out by stoichiometric mixing between the alkanolamine and the acid. Since the reaction may be exothermic, it may be necessary to cool the medium during the reaction. For this reason, the synthesis of the alkanolamine salt is preferably carried out in a glass vessel immersed in a cold water bath and the temperature as well as the pH are continuously measured.

The present invention also relates to a method of reducing the fluidity of the hydraulic binder in a mill comprising the use of an inorganic salt of secondary or tertiary alkanolamine, preferably of formula (I), during the grinding of the hydraulic binder. .

In the context of the present invention, any type of crusher can be used. In particular, the invention relates to the use in vertical mills, ball mills, roller mills, open without a separation system, closed grinding systems with separators with constant air flow or not, process with transfer of the cement by inclined conveyor belt, open bucket elevators, poorly performing or near saturation dust filters (high differential pressure, worn bag filters). Preferably, the mill is a ball mill, or a vertical mill.

The object of the present invention is particularly advantageous during co-grinding of clinker and mineral additions for the manufacture of OEM ll / A or OEM ll / B or OEM III, which require for the improvement of the mechanical strengths at 28 days. , high dosages of amine (for example 120 g of TIPA per tonne of cement). When such dosages are used on certain plants, it is observed a rapid emptying of the crusher, critical dust phenomena at the outlet of the crusher and at the level of the elevator.

The present invention deals with the grinding of any type of hydraulic binder and in particular of clinker and / or mineral additions.

In the context of the present invention, the term “hydraulic binder” is understood to mean any compound having the property of hydrating in the presence of water and the hydration of which makes it possible to obtain a solid having mechanical characteristics, in particular a cement. such as Portland cement, aluminous cement, pozzolanic cement or else an anhydrous or semi-hydrated calcium sulphate. The hydraulic binder can be a cement according to standard EN197-1 (2001) and in particular a Portland cement, mineral additions, in particular slag, or a cement comprising mineral additions.

“Cement” is understood to mean a cement according to standard EN 197-1 (2001) and in particular a cement of the OEM I, OEM II, OEM III, OEM IV or OEM V type according to the Cement standard NF EN 197-1 (2012). . The cement can include mineral additions.

The expression “mineral additions” designates slags (as defined in the Ciment NF EN 197-1 (2012) paragraph 5.2.2), steelworks slags, pozzolanic materials (as defined in the Ciment NF standard. EN 197-1 (2012) paragraph 5.2.3), fly ash (as defined in the Cement standard NF EN 197-1 (2012) paragraph 5.2.4), calcined shale (as defined in the Ciment NF standard EN 197-1 (2012) paragraph 5.2.5), limestones (as defined in the Cement standard NF EN 197-1 (2012) paragraph 5.2.6) or silica fumes (as defined in the Cement standard NF EN 197-1 (2012) paragraph 5.2.7) or their mixtures. Other additions, not currently recognized by the Cement standard NF EN 197-1 (2012), can also be used. These include metakaolins,

Particularly advantageously, the inventors have shown that the salt form of the alkanolamine according to the invention made it possible to reduce its vapor pressure and consequently to protect it from degradation, in particular due to temperature, in the mill. . The inventors have shown that against all expectations, despite this setting in the form of a salt, the alkanolamine retained its properties for improving the mechanical properties of a hydraulic binder composition, in particular its properties for improving the mechanical strengths, in particular the strengths. mechanical at 28 days. Furthermore, and surprisingly, the inventors have shown that the setting in the form of inorganic acid salts, unlike the examples known from the literature with organic acid salts,

Thus, the present invention makes it possible in a particularly advantageous manner to add the alkanolamine at the time of grinding without it degrading and while improving grinding and while retaining its properties for improving the mechanical properties of hydraulic binder compositions.

Preferably, the alkanolamine salt is used during grinding in a content of 0.003 to 0.025% by weight of the hydraulic binder, preferably 0.005 to 0.015%.

Particularly advantageously, the alkanolamine salt used during the grinding can be used in combination with other additives generally used in hydraulic compositions or during the grinding of the hydraulic binder, mention may in particular be made of alkanolamines other than those of formula (I), salts such as sodium chloride, calcium chloride, sodium thiocyanate, calcium thiocyanate, sodium nitrate and calcium nitrate and their mixtures, glycols, glycerols, adjuvants water reducers and top water reducers, surfactants, carboxylic acids such as acetic, adipic, gluconic, formic, oxalic, citric, maleic, lactic, tartaric, malonic acids and their mixtures.

The alkanolamine salt can also be used in combination with setting retarders.

In the context of the present invention, among the setting retarders, mention may in particular be made of setting retarders based on sugar, molasses or vinasse.

Preferably, the water-reducing and high-water-reducing adjuvants are chosen from:

- Sulphonated salts of polycondensates of naphthalene and formaldehyde, commonly called polynaphthalene sulphonates or even naphthalene-based superplasticizers;

- Sulphonated salts of polycondensates of melamine and formaldehyde, commonly called melamine-based superplasticizers;

- Lignosulfonates;

- Sodium gluconate and sodium glucoheptonate;

- Polyacrylates;

- Polyaryl ethers (PAE);

- Products based on polycarboxylic acids, in particular comb polycarboxylate copolymers, which are branched polymers whose main chain carries carboxylic groups and whose side chains are composed of polyether type blocks, in particular polyethylene oxide, such as, for example, poly [(meth) acrylic acid - grafted - polyethylene oxide]. The superplasticizers of the CHRYSO ® Fluid Optima, CHRYSO ® Fluid Premia and CHRYSO ® Plast Omega ranges marketed by CHRYSO can in particular be used;

- The products based on polyalkoxylated polyphosphonates in particular described in patent EP 0 663 892 (for example CHRYSO®Fluid Optima 100).

Particularly advantageously, the alkanolamine salt used during grinding can be used in combination with one or more anti-foaming agents, in particular chosen from ethoxylated fatty amines. The inventors have in particular shown that the setting in the form of salt of the alkanolamine makes it possible to obtain a pH zone allowing the solubilization of the ethoxylated fatty amines while retaining their effectiveness in applications, in particular concrete which are in pH zones where they are present. become active.

The present invention also relates to a composition comprising:

- At least one hydraulic binder;

- An alkanolamine salt as described above.

The composition can also comprise at least one additive as described above.

The present invention also relates to a hydraulic composition comprising:

- Some water ;

- At least one hydraulic binder;

- An alkanolamine salt;

- An aggregate.

The hydraulic composition can also comprise at least one additive as described above.

The term “aggregates” is understood to mean a set of mineral grains with an average diameter of between 0 and 125 mm. Depending on their diameter, aggregates are classified into one of the following six families: fillers, sands, sands, gravels, chippings and ballast (XP P 18-545 standard). The most used aggregates are:

- Fillers, which have a diameter of less than 2 mm and for which at least 85% of the aggregates have a diameter of less than 1.25 mm and at least 70% of the aggregates have a diameter of less than 0.063 mm;

- Sands with a diameter between 0 and 4 mm (in standard 13-242, the diameter can go up to 6 mm);

- The bass with a diameter greater than 6.3 mm;

- Chippings with a diameter of between 2 and 63 mm;

- Sands are therefore included in the definition of aggregate according to the invention;

- The fillers can in particular be of limestone or dolomitic origin.

The hydraulic composition may also comprise other additives known to those skilled in the art, for example a mineral addition and / or additives, for example an anti-air entrainment additive, an anti-foaming agent, a setting accelerator or retarder. , a rheology modifying agent, another plasticizer (plasticizer or superplasticizer), in particular a superplasticizer, for example a superplasticizer CHRYSO®Fluid Premia 180 or CHRYSO®Fluid Premia 196.

The present invention will now be described with the aid of non-limiting examples.

Figure 1 is a top view of the inclined plane for the rolling bottle test of Example 2.

Figure 2 is a side view of the inclined plane for the rolling bottle test of Example 2.

In these examples, a hydrochloric acid salt of triisopropanolamine (TIPA) is used. This salt is obtained according to the following process: a mass of 1 13 g of triisopropanolamine (TIPA) at a mass concentration of 63% in water was kept under stirring with a magnetic stirrer and 35 g of 37% hydrochloric acid. mass were added over 30 minutes to obtain about 150 g of solution. The stoichiometric ratio between TIPA and HCl is 1: 1. During formulation, the temperature did not exceed 40 ° C. The solution obtained is clear. The conductivity and pH measurements as a function of the volume of HCl titrated show a strong variation in values ​​at the time of the end of the reaction between TIPA and HCl, which confirms the chemical reaction between the two reagents. Indeed, it is possible to prove the formation of protonated TIPA by reverse acid-base assay. If sodium hydroxide (0.1 mol / L) is added to the TIPA + HCl solution, a pH jump is noted at a volume of sodium hydroxide characteristic of the acidity constant of this chemical compound. (Tl PA / Tl PA + HCI). At half the equivalent volume, the pH is equal to the pKa of this chemical compound (Tl PA / Tl PA + HCl) which is close to 8. Conversely, TIPA does not show a jump in pH since the amine is already in basic form.

According to the same type of chemical reaction, it is possible to prepare a hydrochloric acid salt of diethanolisopropanolamine (DEIPA). This salt is obtained according to the following process: a mass of 80 g of diethanolisopropanolamine (DEIPA) at a concentration by mass of 87% in water was kept under stirring with a magnetic stirrer and 42 g of hydrochloric acid at 37% by mass. were added over 30 minutes to obtain about 150 g of solution. The stoichiometric ratio between DEIPA and HCl is 1: 1. During formulation, the temperature did not exceed 40 ° C. The solution obtained is clear. The formation of the protonated amine DEIPA + HCl can be confirmed by reverse acid-base titration. The DEIPA + HCI compound does exhibit a pH jump characteristic of the acid-base compound DEIPA / DEIPA + HCI when adding sodium hydroxide,

According to the same type of chemical reaction, it is possible to prepare a sulfuric acid salt of triisopropanolamine (TIPA). This salt is obtained according to the following process: a mass of 129 g of triisopropanolamine (TIPA) at a concentration by mass of 61% in water was kept under stirring with a magnetic stirrer and 21 g of sulfuric acid at 95% by mass. were added over 30 minutes to obtain about 150 g of solution. The stoichiometric ratio between TIPA and H2SO4 is 2: 1. During formulation, the temperature did not exceed 40 ° C. The solution obtained is clear. The formation of the protonated TIPA + H2SO4 amine can be confirmed by reverse acid-base titration. The TIPA + H2SO4 compound does exhibit a pH jump characteristic of TIPA, close to 8.

EXAMPLE 1:

On a 42.5 N CEM ll / AV cement which contains 15% by mass of fly ash with a Blaine specific surface area target of 4000 cm 2 / g, a dosage of 90 ppm of TIPA makes it possible to increase the throughput of the cement mill. of 1 1%. On the other hand, a dosage of 120 ppm of TIPA creates harmful effects by superfluidifying the cement powder which becomes very volatile. TIPA + HCI does not have a negative impact on cement grinding (no overfluidification) and leads to improved mechanical strengths.

* Emptying the crusher

** Equivalent to 120 ppm TIPA + 23 ppm HCl.

This example demonstrates the fact that, in the grinder, too high a TIPA content impacts the grinding efficiency and leads to a drop in mechanical performance, the salt form of the TIPA makes it possible to overcome these disadvantages.

EXAMPLE 2:

Laboratory tests were carried out with a ball mill on 5 kg of clinker in the presence of various amines. The fluidity of the powder thus obtained was analyzed using the "rolling bottle test (RBT)", the principle of which is to measure the distance traveled by a cylindrical bottle 9.3 cm long, diameter 2.74. cm, of empty mass with lid of 1 19.14 g, containing 40 g of crushed clinker which rolls on an inclined plane, like that shown in figure 1. The greater the distance traveled, the more the sample is conducive to fluidity suitable for industrial scale.

The following table shows that the clinker ground in the presence of TIPA does not promote the fluidity of the clinker powder. This effect is explained by a distribution of the size of the particles which has a negative impact on the flow of the clinker powder contained in the flask, which denotes an over-efficiency of TIPA which is not favorable to grinding. On the other hand, when the clinker is ground with TIPA + HCI, the distance traveled by the vial is higher, showing that TIPA + HCI avoids the known superfluidification effect for TIPA and brings the clinker sample back to a lower level. behavior favorable to the flow of the powder on an industrial scale.

EXAMPLE 3:

In a ball mill to single chamber (combined closed circuit between a roller press, a ball mill connected to a separator 3 rd generation) is introduced 77 tons per hour of slag and 150 g / t of agent grinding (composition 1).

The Blaine specific surface target at the outlet of the mill is 5100 cm 2 / g. A dosage of 150 g / t of grinding agent (composition 1) which provides 41 g / t TIPA generates

adverse effects by superfluidifying the cement powder which becomes very volatile. The ball mill must be stopped because the dust filters saturate. This saturation is followed by measuring the pressure at the filter inlet - mill outlet which increases significantly with composition 1 comprising TIPA. Used at a dosage close to TIPA of 36 g / t in the grinding agent (composition 2), TIPA + HCI has no negative impact on the grinding of the cement (no overfluidification). The protonated amine makes it possible to maintain a rejection of the separator and a dust level of the filter equivalent to the reference. By increasing the dosage of composition 2 containing this amine salt (from 36 to 84 g / t TIPA), the Blaine surface of the slag increases thanks to the effect of the grinding agent. However, despite the reduction in the particle size of the slag, the fine particles do not saturate the filter, maintaining a separator rejection and a dust level of the filters equivalent to that of the reference. Thus, the TIPA salt makes it possible to promote the grinding of the slag, while maintaining the particles in an agglomerated state and therefore without risk of dusting and overfluidification.

* Emptying the crusher

** Equivalent to 36 ppm TIPA + 7 ppm HCl.

*** Equivalent to 48 ppm of TIPA + 9 ppm of HCl

**** Equivalent to 60 ppm of TIPA + 1 1 ppm of HCl

***** Equivalent to 84 ppm TIPA + 16 ppm HCl

This example highlights the fact that, in the mill, the use of TIPA can lead to overfluidification of the slag with a dust filter which quickly saturates. The salt form of TIPA overcomes these drawbacks. The inlet flow rate of the grinder can be kept constant while promoting the grinding of the slag and without risk of overfluidification.

EXAMPLE 4:

A CEM ll / A LL 42.5 N cement containing 10% by mass of limestone is ground with a double-chamber ball mill (so-called open circuit configuration without coupling to a separator) to obtain a target with a Blaine specific surface area of ​​3300 cm 2/ g. The use of an adjuvant containing TIPA. HCl (composition 4) makes it possible to reduce even more than with an adjuvant containing TIPA (composition 3) the 45 and 25 μm rejection at the outlet of the ball mill compared to the reference. The TIPA salt form therefore makes it possible to reduce the particle sizes of the cement more effectively and thus to have a gain in compressive strengths compared to the control which is higher at 2 days. In addition, the replacement of TIPA by a TIPA salt maintains a marked activating effect in the long term, with compressive strengths at 28 days markedly higher than those of the reference.

* Equivalent to 163 ppm TIPA + 31 ppm HCl.

This example demonstrates the fact that, in the mill, the use of TIPA in salt form instead of TIPA makes it possible to improve the grinding efficiency resulting in a reduction in rejects at 25 and 32 μm. This leads to the conclusion that the residence time in the grinder of the CEM II / A LL 42.5 N cement has been extended.

EXAMPLE 5:

In a double-chamber ball mill combined with 2 first generation separators installed in parallel, 108 tonnes per hour of a CEM I type cement are introduced in the presence of an activator comprising TIPA (composition 5) to obtain a specific Blaine surface area of ​​around 360 m 2/ kg. CEM I 42.5 N type cement is composed of 90.5% m clinker, 4.5% m limestone and 5.0% m gypsum. The use of an activator containing TIPA + HCl (composition 6) instead of TIPA (composition 5) with an amine iso-dosage makes it possible to improve the grinding efficiency. For the same inlet flow rate of the mill, the specific surface of the cement is higher and the rejection 45 μm lower in the presence of chlorinated salt of TIPA than of TIPA. Even if the inlet flow rate of the mill is increased from 108 to 11 1 tph, the TIPA + HCI-based admixture remains a very effective grinding agent since it maintains a high Blaine surface. The TIPA acetate used in a grinding agent (composition 6) for its part makes it possible to obtain a specific surface area of ​​the ground cement equivalent to that of TIPA. Nevertheless, the TIPA acetate leads to a clogging of the grinder filter which can be detected by increasing the cleaning time of the filter and the number of purges per hour. Conversely, TIPA + HCI makes it possible to form less dust during grinding and therefore to reduce the purge time of the filters. At 2 days, the compressive strengths are higher in the presence of TIPA + HCI because the cement is ground more finely than in the presence of TIPA or TIPA acetate. Finally, the compressive strengths at 28 days are equivalent for all the adjuvants. compressive strengths are higher in the presence of TIPA + HCI because the cement is ground more finely than in the presence of TIPA or TIPA acetate. Finally, the compressive strengths at 28 days are equivalent for all the adjuvants. compressive strengths are higher in the presence of TIPA + HCI because the cement is ground more finely than in the presence of TIPA or TIPA acetate. Finally, the compressive strengths at 28 days are equivalent for all the adjuvants.

* Equivalent to 74 ppm of TIPA + 15 ppm of HCl.

** Equivalent to 79 ppm of TIPA + 38 ppm of acetic acid.

This example demonstrates the fact that, in the mill, the use of TIPA + HCI makes it possible to improve the grinding efficiency of a CEM I cement compared to TIPA and acetate.

SUBSTITUTE SHEET (RULE 26)

of TIPA, by limiting the clogging of filters and therefore the time spent cleaning them. The use of TIPA + HCI instead of TIPA allows a slight gain in compressive strengths at 2 days and maintenance of compressive strengths at 28 days.

EXAMPLE 6 Stability of antifoam formulation +% air

Triisopropanolamine is known to entrain air in mortars and concrete, which can lead to reduced compressive strengths. Diethanolisopropanolamine (DEIPA) has a similar effect to TIPA on air entrainment. Likewise, the adjuvants containing the protonated amines TIPA + HCI or even DEIPA + HCI promote the entrainment of air in the cements. It is therefore interesting to combine TIPA + HCI and DEIPA + HCI with anti-foaming agents. Nevertheless, antifoams are by their nature chemical species that are poorly soluble in water, which makes their use in the formulation of grinding agents or activators complicated. They tend not to dissolve in solutions mainly consisting of water.

Formulations were produced by combining TIPA + HCI and DEIPA + HCI with an ethoxylated fatty amine type defoamer (ADMA® 10 AMINE and ADMA® 12 AMINE from ALBEMARLE) at different dosages. The formulas obtained are stable, the ethoxylated fatty amine dissolving in the protonated amine solutions according to the invention having a pH of less than 7.5.

The air entrained in a cement of CEM I type added to 120 ppm of protonated amine was then measured for an anti-foam dosage of 6 or 7 ppm. The addition of defoamer makes it possible to reduce the entrainment of air induced by the presence of amines and to return to a value equivalent to that of the reference for a concentration of 6 - 7 ppm in the cement.

* Equivalent to 120 ppm TIPA + 23 ppm HCl.

** Equivalent to 120 ppm DEIPA + 27 ppm HCl.

It is therefore possible to formulate adjuvants which are stable in solution based on a protonated amine and an antifoam of ethoxylated fatty amine type. Adding an anti-foam to

SUBSTITUTE SHEET (RULE 26)

the hydrochloric salt amine significantly reduces the entrainment of air in the mortar or concrete when using cement.

EXAMPLE 7:

In a vertical mill with 3 servo-controlled rollers, 200 tonnes per hour of an OEM ll / BV 42.5 R type cement containing 24% fly ash (added at the mill outlet) are introduced to obtain a cement of targeted final fineness with a particle size distribution defined by the parameters d50 of 12.5 (median diameter at 50%; expressed in pm) and d90 of 31.0 (median diameter at 90%; expressed in pm). In the presence of an activator comprising TIPA (composition 8), the performance of the mill (production rate in tonnes per hour) is established by setting the following process parameters:

- Separator speed (in rpm / revolutions per minute) to control the fineness of the cement.

- Differential pressure in the crusher (in mbar) reflecting the quantity of material present in the crusher and therefore the efficiency of the grinding.

- Water injected into the crusher (in m 3 / h) to control the stability of the crusher and the vibrations.

The use of an adjuvant containing TIPA. HCl (composition 9) makes it possible to have a direct impact on the efficiency of the grinding by generating a cement with improved fineness (decrease in the parameters d50 and d90) without impact on the process parameters. The setting in the form of salt of TIPA therefore makes it possible to reduce the particle sizes of the cement more effectively.

* Equivalent to 100 ppm TIPA + 19 ppm HCl.

This example demonstrates the fact that, in the vertical mill, the use of TIPA in the form of hydrochloric acid salt instead of TIPA makes it possible to improve the grinding efficiency resulting in a reduction in the parameters d50 and d90.

This grinding efficiency can also translate into mill productivity gains (tonnes per hour) while adjusting process parameters and maintaining the vertical mill in an optimized operating zone to ensure the targeted fineness of the cement.

CLAIMS

1.- Process for using secondary or tertiary alkanolamine for grinding at least one hydraulic binder comprising:

- The setting in the form of an inorganic acid salt of the alkanolamine;

- The addition of the alkanolamine in the form of a salt in a mill.

2. A process for improving the mechanical strengths of a hydraulic binder composition comprising the use of an inorganic acid salt of a secondary or tertiary alkanolamine in the grinding of the hydraulic binder.

3. A method according to claim 2 characterized in that it allows the improvement of the mechanical strengths of the hydraulic binder composition without affecting the performance of the grinding.

4. A method according to any one of claims 1 to 3, wherein the alkanolamine salt is an acid halide salt or a salt of sulfuric acid, phosphoric acid, phosphonic acid or hydrogen sulphate. .

5. A method according to any one of claims 1 to 3, wherein the alkanolamine salt is an acid halide salt or a sulfuric acid salt.

6. A method according to any one of claims 1 to 3, wherein the alkanolamine salt is a salt of hydrochloric acid.

7. A method according to any one of claims 1 to 6, wherein the alkanolamine is an alkanolamine of formula (I) N (R10H) (R2) (R3) (I) in which the R1, identical or different, represent a linear or branched alkyl group comprising from 1 to 10 carbon atoms, preferably from 1 to 5 carbon atoms, R2 represents H or an R1 -OH group, R3 represents H, a linear or branched alkyl group comprising from 1 to 10 carbon atoms, preferably from 1 to 5 carbon atoms, an R4-OH group in which R4 represents a linear or branched alkyl group comprising from 1 to 10 carbon atoms, preferably from 1 to 5 carbon atoms, or an (alkyl) -N (alkyl-OH) 2 group, the alkyl being linear or branched and comprising from 1 to 5 carbon atoms, preferably (CH2-CH2) -N (CH2-CH2-OH) 2, at the minus one of R2 and R3 being different from H.

8. A method according to any one of claims 1 to 6, wherein the alkanolamine is chosen from triisopropanolamine (TIPA), diisopropanolamine (DIPA), diethanolisopropanolamine (DEIPA), ethanoldiisopropanolamine (EDIPA), N , N, N ', N'-tetrakis (2-hydroxyethyl) ethylenediamine (THEED) and methyldiethanolamine (MDEA).

9. A method according to any one of claims 1 to 6, wherein the alkanolamine is chosen from triisopropanolamine (TIPA), diethanolisopropanolamine (DEIPA) and ethanoldiisopropanolamine (EDIPA).

10. A method according to any one of claims 1 to 6, wherein the alkanolamine is triisopropanolamine (TIPA).

1 1 .- A method according to any one of claims 1 to 10, wherein additives selected from alkanolamines other than those according to one of claims 1 to 8, salts such as sodium chloride, calcium chloride , sodium thiocyanate, calcium thiocyanate, sodium nitrate and calcium nitrate and their mixtures, glycols, glycerols, water-reducing and high-water-reducing adjuvants in particular chosen from the sulfonated salts of polycondensates naphthalene and formaldehyde, commonly called polynaphthalene sulfonates or even naphthalene-based superplasticizers; sulfonated salts of polycondensates of melamine and formaldehyde, commonly called melamine-based superplasticizers; lignosulfonates; sodium gluconate and sodium glucoheptonate; polyacrylates; polyaryl ethers (PAE); products based on polycarboxylic acids, in particular comb polycarboxylate copolymers, which are branched polymers whose main chain bears carboxylic groups and whose side chains are composed of blocks of polyether type, in particular polyethylene oxide, such as for example poly [(meth) acrylic acid - grafted - polyethylene oxide]; products based on polyalkoxylated polyphosphonates; surfactants, carboxylic acids such as acetic, adipic, gluconic, formic, oxalic, citric, maleic, lactic, tartaric, malonic acids, setting retarders in particular based on sugars, molasses or vinasse, and their mixtures are used in complement of the alkanolamine salt. products based on polycarboxylic acids, in particular comb polycarboxylate copolymers, which are branched polymers whose main chain bears carboxylic groups and whose side chains are composed of blocks of polyether type, in particular polyethylene oxide, such as for example poly [(meth) acrylic acid - grafted - polyethylene oxide]; products based on polyalkoxylated polyphosphonates; surfactants, carboxylic acids such as acetic, adipic, gluconic, formic, oxalic, citric, maleic, lactic, tartaric, malonic acids, setting retarders in particular based on sugars, molasses or vinasse, and their mixtures are used in complement of the alkanolamine salt. products based on polycarboxylic acids, in particular comb polycarboxylate copolymers, which are branched polymers whose main chain bears carboxylic groups and whose side chains are composed of blocks of polyether type, in particular polyethylene oxide, such as for example poly [(meth) acrylic acid - grafted - polyethylene oxide]; products based on polyalkoxylated polyphosphonates; surfactants, carboxylic acids such as acetic, adipic, gluconic, formic, oxalic, citric, maleic, lactic, tartaric, malonic acids, setting retarders in particular based on sugars, molasses or vinasse, and their mixtures are used in complement to the alkanolamine salt. which are branched polymers whose main chain carries carboxylic groups and whose side chains are composed of blocks of polyether type, in particular polyethylene oxide, such as for example poly [(meth) acrylic acid - graft - polyoxide d ethylene]; products based on polyalkoxylated polyphosphonates; surfactants, carboxylic acids such as acetic, adipic, gluconic, formic, oxalic, citric, maleic, lactic, tartaric, malonic acids, setting retarders in particular based on sugars, molasses or vinasse, and their mixtures are used in complement of the alkanolamine salt. which are branched polymers whose main chain carries carboxylic groups and whose side chains are composed of blocks of polyether type, in particular polyethylene oxide, such as for example poly [(meth) acrylic acid - graft - polyoxide d ethylene]; products based on polyalkoxylated polyphosphonates; surfactants, carboxylic acids such as acetic, adipic, gluconic, formic, oxalic, citric, maleic, lactic, tartaric, malonic acids, setting retarders in particular based on sugars, molasses or vinasse, and their mixtures are used in complement to the alkanolamine salt. such as, for example, poly [(meth) acrylic acid - grafted - polyethylene oxide]; products based on polyalkoxylated polyphosphonates; surfactants, carboxylic acids such as acetic, adipic, gluconic, formic, oxalic, citric, maleic, lactic, tartaric, malonic acids, setting retarders in particular based on sugars, molasses or vinasse, and their mixtures are used in complement to the alkanolamine salt. such as, for example, poly [(meth) acrylic acid - grafted - polyethylene oxide]; products based on polyalkoxylated polyphosphonates; surfactants, carboxylic acids such as acetic, adipic, gluconic, formic, oxalic, citric, maleic, lactic, tartaric, malonic acids, setting retarders in particular based on sugars, molasses or vinasse, and their mixtures are used in complement of the alkanolamine salt.

12. A method according to any one of claims 1-1 1, wherein one or more antifoam compounds are used in combination with the alkanolamine salt.

13.- Composition comprising:

- At least one hydraulic binder;

- An alkanolamine salt as defined in claims 1 to 10.

14. A composition according to claim 13 further comprising one or more antifoam compounds.

15.- Hydraulic composition comprising:

- Some water ;

- At least one hydraulic binder;

- An alkanolamine salt as defined according to claims 1 to 10;

- An aggregate.

16. A composition according to claim 15 further comprising one or more antifoaming compounds.