EP3863984A1

EP3863984A1 - Method for using alkanolamine in a grinder

Info

Publication number: EP3863984A1
Application number: EP19782633.2A
Authority: EP
Inventors: Bruno Pellerin; Martinho DUARTE AMARO CORREIA
Original assignee: Chryso SAS
Current assignee: Chryso SAS
Priority date: 2018-10-10
Filing date: 2019-10-10
Publication date: 2021-08-18
Also published as: JP7353362B2; AU2023202421A1; CN112823146A; BR112021006735A2; AU2019356954A1; MA52918B1; PH12021550768A1; MX2021003988A; TN2021000070A1; CN112823146B; JP2022512677A; ZA202102280B; FR3087196A1; EA202190756A1; CA3115389C; MA52918A1; US20210387909A1; WO2020074633A1; FR3087196B1; KR102604067B1

Abstract

The present invention relates to a method for using a secondary or tertiary alkanolamine for grinding cement, comprising: - forming an inorganic acid salt of the alkanolamine; - adding the salified alkanolamine to a grinder.

Description

Method of using alkanolamine in a mill

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

It is known to use alkanolamines when grinding the 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 during the grinding of the hydraulic binder, in particular cement, in order to benefit from the grinding properties of the alkanolamines while introducing into the hydraulic binder active agents allowing the improvement of the 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 the hydraulic binder compositions. To overcome this problem, it has been envisaged to put a larger amount of alkanolamine in order to compensate for their degradation. However, the increase in the alkanolamine concentration in certain mills results in too high a grinding efficiency and the overfluidification of the cement powder leads to an emptying of the mill, which is not desired.

It is also known from FR 3 002 162 the use of AMP (2-amino-2-methylpropanol), 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 an insufficient grinding of the clinker.

There is therefore an advantage in providing a method making it possible to use the 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 crusher .

There is also an advantage in providing such a process which makes it possible to reduce the fluidity of the hydraulic binder and therefore to increase its passage time in the mill, to obtain a finer powder also allowing good mechanical strengths to be obtained.

There is also an advantage in providing a process which makes it possible during the grinding step of the hydraulic binder to provide the compounds necessary for improving the mechanical resistance properties, in particular mechanical resistance at 28 days, hydraulic binder compositions, while not degrading the grinding conditions, in particular by not emptying the crusher.

An object of the present invention is therefore to provide a process for stabilizing the alkanolamines used in a mill.

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

Yet another objective of the present invention is to provide a means making it possible to control the performances of grinding agent of the alkanolamines while retaining the properties for 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 mills, open mills without separation system, closed grinding systems with, for example, constant air flow separators, process with cement transfer by inclined conveyor belt, open bucket elevators, dust filters not very efficient or close to saturation (high differential pressure , worn bag filters)).

The object of the present invention is particularly advantageous during the co-grinding of clinker and limestone for the manufacture of OEM ll / A or OEM ll / 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 ton of cement). When such dosages are used in certain factories, rapid emptying of the mill is observed as well as critical dust phenomena at the outlet of the mill and at 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 the entire performance of improving the mechanical strength at 28 days. All these objectives are fulfilled by the present invention which relates to a process for using alkanolamine, preferably secondary or tertiary alkanolamine for grinding at least one hydraulic binder, preferably cement, comprising:

- The salt form, preferably an inorganic acid salt, of the alkanolamine;

- Adding alkanolamine as a salt in a grinder.

The method further preferably includes grinding said hydraulic binder.

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

- The form of the inorganic acid salt of the alkanolamine;

- Adding alkanolamine as a salt in a grinder.

The method further preferably includes 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 , identical or different, represent a linear or branched alkyl group comprising 1 to 10 carbon atoms, preferably from 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, of 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, or an (alkyl) group ) -N (alkyl-OH) ₂ , 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 the 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 , 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 of alkanolamine of formula ( I), during the grinding of the hydraulic binder. In a particularly advantageous manner, the method allows the mechanical strengths of the hydraulic binder composition to be improved 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 resistances, it is preferably the mechanical resistances at 28 days.

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

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 grinders, especially in clinker and hydraulic binder crushers. More particularly, triisopropanolamine (TIPA), diisopropanolamine (DIPA), diethanolisopropanolamine (DEIPA), ethanoldiisopropanolamine (EDIPA), N, N, N ', N'-tetrakis (2-hydroxyethyl) ethylenediamine (THEED) may be mentioned 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. The reaction can 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 container immersed in a cold water bath and the temperature as well as the pH are measured continuously.

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 a 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 grinder can be used. In particular, the invention relates to the implementation in vertical mills, ball mills, cylinder mills, open without separation system, closed grinding systems with separators with constant or non-constant air flow, process with transfer of cement by inclined conveyor belt, open bucket elevators, dust filters which are ineffective or close to saturation (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 mechanical strengths to 28 days , high dosages of amine (for example 120 g of TIPA per ton of cement). When such dosages are used in certain factories, rapid emptying of the mill is observed, critical dust phenomena at the outlet of the mill and at 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 even 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 dairy additives, or a cement comprising mineral additions. “Cement” means a cement according to standard EN 197-1 (2001) and in particular a cement of type OEM I, OEM II, OEM III, OEM IV or OEM V according to standard Cement NF EN 197-1 (2012) . Cement may include mineral additions.

The expression “mineral additions” designates slag (as defined in the Cement standard NF EN 197-1 (2012) paragraph 5.2.2), steelworks slag, pozzolanic materials (as defined in the Cement standard NF 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 shales (as defined in the Cement standard NF 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 even 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, such as type A metakaolins conforming to standard NF P 18-513 (August 2012), siliceous additions, such as siliceous additions of oz mineralogy conforming to standard NF P 18-509 (September 2012), aluminosilicates, in particular of the inorganic geopolymer type.

In a particularly advantageous manner, the inventors have shown that the salt form of the alkanolamine according to the invention makes it possible to reduce its vapor pressure and therefore to protect it from degradation, in particular due to the temperature, in the mill. . The inventors have shown that, against all expectations, despite this salt form, the alkanolamine retains its properties for improving the mechanical properties of a hydraulic binder composition, in particular its properties for improving the mechanical strengths, especially the strengths mechanical at 28 days. Furthermore, and surprisingly, the inventors have shown that the placing in the form of inorganic acid salts, unlike the known examples of the literature with organic acid salts, allows better grinding and results in a decrease in the fluidity hydraulic binder.

Thus, the present invention makes it particularly advantageous to add the alkanolamine at the time of grinding without it degrading and while improving the grinding and retaining its properties for improving the mechanical properties of the 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 from 0.005 to 0.015%. In a particularly advantageous manner, the alkanolamine salt used during grinding can be used in combination with other additives generally used in hydraulic compositions or during grinding of the hydraulic binder, mention may in particular be made of alkanolamines other than those of formula (I), the 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 high water reducers, surfactants, carboxylic acids such as acetic, adipic, gluconic, formic, oxalic, citric, maleic, lactic, tartaric, malonic acids and mixtures thereof.

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 especially be made of setting retarders based on sugar, molasses or vinasse.

Preferably, the water reducing and high water reducing additives are chosen from:

- The sulfonated salts of polycondensed naphthalene and formaldehyde, commonly called polynaphthalene sulfonates or superplasticizers based on naphthalene;

- The sulfonated salts of polycondensed melamine and formaldehyde, commonly called melamine-based superplasticizers;

- Lignosulfonates;

- Sodium gluconate and sodium glucoheptonate;

- Polyacrylates;

- Polyarylethers (PAE);

- Products based on polycarboxylic acids, in particular polycarboxylate comb copolymers, which are branched polymers in which the main chain carries carboxylic groups and in which the 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 sold by CHRYSO can in particular be used;

- Products based on polyalkoxylated polyphosphonates especially described in patent EP 0 663 892 (for example CHRYSO®Fluid Optima 100). In a particularly advantageous manner, the alkanolamine salt used during grinding can be used in combination with one or more defoamers, in particular chosen from ethoxylated fatty amines. The inventors have in particular shown that the salt form of the alkanolamine makes it possible to obtain a pH zone allowing the solubilization of ethoxylated fatty amines while retaining their effectiveness in applications in particular concrete which are in pH zones where they 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.

By "aggregates" is meant a set of mineral grains with an average diameter of between 0 and 125 mm. According to their diameter, the aggregates are classified into one of the following six families: fillers, sand, sand, gravel, gravel and ballast (standard XP P 18-545). 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 being up to 6 mm);

- Bass with a diameter greater than 6.3 mm; - Gravel with a diameter 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 can also comprise other additives known to a person skilled in the art, for example a mineral addition and / or additives, for example an anti-air entraining additive, an anti-foaming agent, a setting accelerator or retarder. , a rheology modifying agent, another fluidifier (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 nonlimiting 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 in 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 stirring with a magnetic stirrer and 35 g of hydrochloric acid at 37% mass were added in 30 minutes to obtain approximately 150 g of solution. The stoichiometric ratio between TIPA and HCl is 1: 1. During the 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 titrated HCl show a large variation in the 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 an inverse acid-base assay. If sodium hydroxide (0.1 mol / L) is added to the TIPA + HCI solution, a jump in pH is noted at a volume of soda equivalence characteristic of the acid 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 + HCI) 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 mass concentration of 87% in water was kept stirring with a magnetic stirrer and 42 g of hydrochloric acid at 37% by mass were added in 30 minutes to obtain approximately 150 g of solution. The stoichiometric ratio between DEIPA and HCl is 1: 1. During the formulation, the temperature did not exceed 40 ° C. The solution obtained is clear. The formation of DEIPA + HCI protonated amine can be confirmed by reverse acid-base titration. The compound DEIPA + HCI clearly exhibits a jump in pH characteristic of the acid-base compound DEIPA / DEIPA + HCI when adding sodium hydroxide, which indicates a pKa close to 8. In fact, TIPA and DEIPA are amines with very similar acid constants, with a pKa around 8. Conversely, unprotonated DEIPA does not show a jump in pH when adding sodium hydroxide.

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

EXAMPLE 1:

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

^* Emptying the crusher

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

This example highlights the fact that, in the mill, a too high content of TIPA impacts the efficiency of the grinding and leads to a decrease 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 different 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 of 9.3 cm long, diameter 2.74 cm, of empty mass with cover of 1 19.14 g, containing 40 g of crushed clinker which rolls on an inclined plane, like the one shown in Figure 1. The greater the distance covered, the more the sample is conducive to fluidity adapted to the industrial scale.

The table below 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 particle size distribution which negatively impacts the flow of clinker powder contained in the bottle, which indicates an over-efficiency of TIPA which is not favorable for grinding. On the other hand, when the clinker is ground with TIPA + HCI, the distance traveled by the bottle is greater, showing that TIPA + HCI avoids the effect of overfluidification known for TIPA and reduces the clinker sample to a behavior favorable to the flow of 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 3 ^rd generation separator) was charged 77 tons per hour of slag and 150 g / t of agent grind (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 of TIPA generates harmful effects by overfluidifying the cement powder which becomes very volatile. The ball mill must be stopped because the dust filters are saturated. This saturation is followed by the measurement of the pressure at the inlet of the filter - mill outlet, which increases significantly with composition 1 comprising TIPA. Used at a dosage close to TIPA of 36 g / t in the milling agent (composition 2), TIPA + HCI has no negative impact on the grinding of the cement (no overfluidification). The protonated amine maintains a rejection of the separator and a dust rate 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 milling agent. Nevertheless, despite the reduction in the particle size of the slag, the fine particles do not saturate the filter, maintaining a separator rejection and a dusting rate 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 the risk of dusting and overfluidification.

^* Emptying the crusher

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

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

* ^*** Equivalent to 60 ppm TIPA + 1 1 ppm HCl _***** Equivalent to 84 ppm TIPA + 16 ppm HCl

This example highlights the fact that, in the grinder, the use of TIPA can lead to over-leaching of the slag with a quickly saturated dust filter. The TIPA salt form overcomes these drawbacks. The inlet flow rate of the mill can be kept constant while promoting the grinding of the slag and without the 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 Blaine specific surface target 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 rejection 45 and 25 μm at the outlet of the ball mill compared to the reference. The salt form of TIPA therefore makes it possible to more effectively reduce the particle sizes of the cement and thus to have a gain in resistance to compression compared to the control higher at 2 days. In addition, replacing TIPA with a TIPA salt maintains a marked long-term activating effect, with resistance to compression at 28 days significantly higher than that of the reference.

^* Equivalent to 163 ppm of TIPA + 31 ppm of HCl.

This example highlights the fact that, in the mill, the use of TIPA in the form of salt in place of TIPA makes it possible to improve the grinding efficiency, resulting in a reduction in rejections at 25 and 32 μm. This leads to the conclusion that the residence time in the CEM ll / A LL 42.5 N cement grinder 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 type cement are introduced CEM I in the presence of an activator comprising TIPA (composition 5) to obtain a Blaine specific surface of approximately 360 m ² / kg. CEM I 42.5 N cement is composed of 90.5% m clinker, 4.5% m limestone and 5.0% m gypsum. The use of an activator containing TIPA + HCI (composition 6) in place of TIPA (composition 5) with iso-dosage in amine 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 input flow rate of the mill is increased from 108 to 1 1 1 tph, the additive based on TIPA + HCI remains a very effective milling agent since it maintains a high Blaine surface. The TIPA acetate used in a grinding agent (composition 6) makes it possible to obtain a specific surface of the ground cement equivalent to that of the TIPA. However, TIPA acetate leads to fouling of the grinder filter detectable by increasing the filter cleaning time and the number of purges per hour. Conversely, TIPA + HCI makes it possible to form less dust during grinding and therefore to reduce the purging 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 adjuvants.

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

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

This example highlights 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) TIPA, by limiting the clogging of the filters and therefore the time spent cleaning them. The use of TIPA + HCI instead of TIPA allows a slight gain in resistance to compression at 2 days and a maintenance of resistance to compression at 28 days.

EXAMPLE 6 Stability of anti-foam formulation +% air

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

Formulations have been made by combining TIPA + HCI and DEIPA + HCI with an ethoxylated fatty amine 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 CEM I type cement adjuvanted with 120 ppm of protonated amine was then measured for an antifoam dosage of 6 or 7 ppm. The addition of antifoam 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 of TIPA + 23 ppm of HCl.

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

It is therefore possible to formulate stable adjuvants in solution based on protonated amine and an ethoxylated fatty amine defoamer. Adding an anti-foam to

SUBSTITUTE SHEET (RULE 26) 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 rollers, 200 tonnes per hour of an OEM ll / BV 42.5 R cement containing 24% fly ash (added at the mill outlet) are introduced to obtain a cement with 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 mill (in mbar) reflecting the amount of material present in the mill and therefore the efficiency of the grinding.

- Water injected into the mill (in m ³ / h) to control the stability of the mill 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 grinding by generating a cement with improved fineness (drop in parameters d50 and d90) without impact on process parameters. The salt form of TIPA therefore makes it possible to more effectively reduce the particle sizes of the cement.

^* Equivalent to 100 ppm TIPA + 19 ppm HCl.

This example highlights the fact that, in the vertical mill, the use of TIPA in the form of hydrochloric acid salt in place 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 productivity gains for the crusher (tonnes per hour) while adjusting the process parameters and keeping the crusher vertical in an optimized operating zone to guarantee the targeted fineness of the cement.

Claims

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

- The form of the inorganic acid salt of the alkanolamine;

- Adding alkanolamine as a salt in a grinder.

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

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

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 sulfate .

5.- 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.- Method according to any one of claims 1 to 3, wherein the alkanolamine salt is a salt of hydrochloric acid.

7.- Method according to any one of claims 1 to 6, in which 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 a group R1 -OH, 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 least one of R2 and R3 being different from H.

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

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

1 1 .- Process according to any one of Claims 1 to 10, in which additives chosen 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 sulfonated polycondensed salts naphthalene and formaldehyde, commonly called polynaphthalene sulfonates or superplasticizers based on naphthalene; sulfonated salts of polycondensates of melamine and formaldehyde, commonly called melamine-based superplasticizers; lignosulfonates; sodium gluconate and sodium glucoheptonate; polyacrylates; polyarylethers (PAE); products based on polycarboxylic acids, in particular polycarboxylate comb 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]; 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.- Method according to any one of claims 1 to 1 1, wherein one or more anti-foaming compounds are used in combination with the alkanolamine salt.

13.- Composition including:

- At least one hydraulic binder;

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

14.- Composition according to claim 13 further comprising one or more antifoam compounds.

15.- Hydraulic composition including:

- 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 anti-foaming compounds.