Patent Grant
8629202
This is the U.S. National Stage of PCT/FR2010/051569, filed Jul. 23, 2010, which in turn claims priority to French Patent Application No. 09/03862, filed Aug. 5, 2009 and French Patent Application No. 09/05863, filed Dec. 4, 2009, the entire contents of all applications are incorporated herein by reference in their entireties.
The present invention relates to the use of a composition in the production of cement comprising at least one sacrificial molecule in order to protect the dispersing agents during the grinding operation of the clinker.
Dispersing agents are generally organic molecules, for example polymers. One of their uses may be to fluidize hydraulic compositions or other mineral charges. Practically, they are most often added to hydraulic compositions or to other mineral charges during the mixing phase, either in the mixing water or at the same time as the different components.
It may be advantageous to add the dispersing agents directly during the production of cement. The clinker is ground with calcium sulphate, which may for example, be added in the form of gypsum or anhydrite, to obtain the cement.
It is known that such dispersing agents can partially or even totally lose their fluidizing effect when used in a grinding operation. This grinding effect on the activity of the dispersing agents does not allow introducing the dispersing agents during the grinding operation in the production of cement.
In order to meet the requirements of users and ensure the efficiency of the dispersing agents, it has become necessary to find a new means to protect the dispersing agents submitted to a grinding operation in the production of cement, and to hence retain their fluidizing properties.
Therefore, the problem which the invention intends to solve is to provide a new means adapted to protect the dispersing agent against a partial or total decrease of their fluidizing property during a grinding operation in the production of cement, in other words, to partially or totally retain their fluidizing properties during the grinding operation.
Unexpectedly, the inventors have shown that it is possible to use a sacrificial molecule, for example an antioxidant, to protect the dispersing agent during the grinding operation.
With this aim the present invention provides the use of a composition in the production of cement, said composition
The invention has the advantage of being able to be used in all industries using a grinding process, in particular the construction industry, the chemical industry (admixture suppliers), the cement industry, or grinding plants.
Other advantages and characteristics of the invention will clearly appear after reading the following description and examples provided for purely illustration and non-limiting purposes.
The expression <<sacrificial molecule>> is to be understood according to the present invention as a molecule which can function according to one of the two following manners in order to partially or totally retain the fluidizing properties of a dispersing agent when it is submitted to a grinding operation: either decompose instead of the dispersing agent or react with the dispersing agent in order to protect it. Preferably, the sacrificial molecule decomposes instead of the dispersing agent. A preferred sacrificial molecule is an antioxidant.
The term <<antioxidant>> is to be understood according to the present invention as a molecule adapted to capture electrons or free radicals and then to stabilise.
The term <<dispersing agent>> is to be understood according to the present invention as an organic molecule used in the field of hydraulic compositions or other mineral charges in order to fluidize the said hydraulic compositions or the said other mineral charges. A dispersing agent according to the present invention may in particular be a plasticizer/water-reducer or a superplasticizer/high water-reducer as defined in the EN 934-2 Standard in paragraphs 3.2.2 and 3.2.3. The fluidity of a hydraulic composition may in particular be evaluated by measuring the spread according to the procedure described hereinafter.
The expression <<polyoxy ethylene polycarboxylate/polyoxy propylene polycarboxylate>> or <<PCP>> is to be understood according to the present invention as a copolymer of acrylic acids and/or methacrylic acids, of their esters of polyoxy ethylene/polyoxy propylene (POE/POP) or their ethers of POE/POP. The expression <<polyoxy ethylene/polyoxy propylene>> is to be understood in the present description as polyoxy ethylene, or polyoxy ethylene and polyoxy propylene.
The term <<grinding>> is to be understood according to the present invention, as the operation consisting in dividing a solid to reduce the size of the particles and/or to increase their specific surface (developed surface of the powder per unit by mass).
The expression <<hydraulic composition>> is to be understood according to the present invention as a composition which comprises a hydraulic binder. Preferably, the hydraulic composition is a mortar or a concrete.
The expression <<hydraulic binder>>, is to be understood according to the present invention as a compound which has the property of becoming hydrated in the presence of water and the hydration of which makes it possible to obtain a solid having mechanical characteristics. Preferably, the hydraulic binder is a cement.
The term <<cement>> is to be understood according to the present invention as cements as defined in the EN 197.1 Standard and the aluminous cements. Preferably, the cement is a Portland cement.
The term <<clinker>>, is to be understood according to the present invention as the product obtained after burning (clinkerisation) of a mix (raw meal) composed of, among others, limestone and for example clay. Preferably, the clinker is a Portland clinker as defined in the NF EN 197.1 Standard.
The expression <<mineral charges>> is to be understood according to the present invention as any mineral product in the powder form, the use of which may require the presence of a dispersing agent and/or which may be used in a hydraulic composition.
The term <<emulsion>> is to be understood according to the present invention as a homogeneous mix of two liquid non-miscible substances, one substance being dispersed in the second substance in the form of little droplets the size of which is in the order of the micrometer.
The term <<suspension>> is to be understood according to the present invention as a colloidal dispersion wherein a finely divided product, in liquid or solid form, is combined with another product in liquid form, the first product being in the form of droplets or particles having a size greater than the micrometer but small enough so that the said first product does not settle quickly.
An aspect of the present invention is the use of a composition in the production of cement, said composition
Preferably, an aspect of the invention is the use of at least one sacrificial molecule, the said sacrificial molecule being adapted to either decompose instead of the dispersing agent or to react with the dispersing agent in order to protect it.
Preferably, the dispersing agent and the sacrificial molecule are in the form of a liquid solution.
Preferably, the dispersing agent and the sacrificial molecule are not in the form of a solid solution.
Preferably, the dispersing agent and the sacrificial molecule are not added separately. In other words, they are not added in sequence. They are preferably added simultaneously.
A variant of the aspect according to the present invention is the use of a composition in the production of cement, said composition
By way of example, in the case where the dispersing agent is submitted to a grinding operation at 100° C. for 1 hour 30 minutes, the sacrificial molecule may be present in a quantity greater than or equal to 5%, preferably 10%, more preferably 15%, most preferably 20% by dry mass relative to the dry mass of the dispersing agent.
Preferably, the sacrificial molecule is soluble in a solution of the dispersing agent.
Preferably, the sacrificial molecule is an antioxidant. The antioxidant may be a hydrogen donor, a decomposer of hydroperoxides, an alkyl radical scavenger, or a reducer in an oxidation-reduction reaction. Preferably, the antioxidant comprises a reactive group, for example an OH group or a NH group, preferably associated to a phenolic or aromatic cycle.
The antioxidant may in particular be selected from the following compounds, alone or mixed:
in which TNPP is tris(nonylphenyl)phosphite.
Preferably, the sacrificial molecule is selected from phenols, polyphenols, phenolic acids and their associated esters, secondary aromatic amines, organophosphorous compounds, organosulfurous compounds except salts of sulphurous acid, organic acids and their associated esters, hydroxylamines, reducers of oxidation-reduction reactions, their associated salts and mixtures thereof.
In particular, the sacrificial molecule is preferably selected from phenols, polyphenols, phenolic acids and their associated esters, secondary aromatic amines, hydroxylamines, their associated salts and mixtures thereof.
Preferably, the sacrificial molecule is selected from hydroquinone, methyl gallate, propyl gallate, gallic acid and hydroxylamine.
Preferably, the sacrificial molecule is 4-methoxyphenol or also called MEHQ.
According to a variant, another aspect of the invention is the use of a composition in the production of cement, said composition
Preferably, the dispersing agent is selected from polyoxy ethylene/polyoxy propylene polycarboxylates, poly naphtalene sulfonates, lignosulfonates, polymelamines sulfonates and mixtures thereof. In particular, the dispersing agent is preferably a polyoxy ethylene polycarboxylate.
According to a variant of the invention, the dispersing agent may be used in liquid form, the sacrificial molecule may be used in powder or liquid form and the sacrificial molecule may be soluble in a solution of the dispersing agent. The solubility of the sacrificial molecule in a solution of the dispersing agent provides a homogeneous mixing of these two compounds which are then in the form of a liquid solution.
According to another variant of the invention, the sacrificial molecule may not be soluble in a solution of the dispersing agent, and the dispersing agent and the sacrificial molecule may be used in the form of an emulsion or of a suspension. In order to obtain a stable emulsion/suspension, it is possible to further use a stabilizer.
According to another variant of the invention, it is possible to copolymerize the sacrificial molecule and the dispersing agent, in order to directly integrate the sacrificial molecule in the skeleton of the dispersing agents. The sacrificial molecule and the dispersing agent may be copolymerised. In particular when the dispersing agent is a polymer, it may then be possible to graft the sacrificial molecule onto this polymer. This grafting may be carried out during the synthesis of the polymer, for example by radical polymerisation. Antioxidant monomers may then be integrated by radical copolymerisation in a structure of the PCP type. For example, the monomers may be selected from the molecules described in Table 1 herein below
The dispersing agent may comprise one or more types of dispersing agents. Likewise, the sacrificial molecule may comprise one or more types of sacrificial molecules.
Other typical admixtures may also be used with the dispersing agent and the sacrificial molecule, for example a setting accelerator, a setting retarder or an anti-foaming agent.
Preferably, the quantity of sacrificial molecule is at least 5%, more preferably at least 10%, even more preferably at least 15% by dry mass relative to the dry mass of the dispersing agent.
Preferably, the quantity of sacrificial molecule is less than or equal to 40%, more preferably less than or equal to 20%, by dry mass relative to the dry mass of the dispersing agent.
Preferably, the concentration of the mix comprising the sacrificial molecule and the dispersing agent in a cement is from 0.05 to 5% by mass relative to the mass of cement.
It is to be noted that the dosage of sacrificial molecule relative to the dispersing agent to be protected may depend on the nature of the sacrificial molecule and on the nature of the dispersing agent.
According to a particular embodiment of the invention, the composition comprising at least one sacrificial molecule and at least one dispersing agent may be used during the production of cement, said cement comprising mineral additions, to partially or totally retain the properties of the dispersing agent. According to this variant, the mineral additions are added during the production of the cement before or during the grinding of the clinker.
The expression <<mineral additions>>, is to be understood according to the invention as slags (as defined in the <<Cement>> NF EN 197-1 Standard, paragraph 5.2.2), steel industry slags, pozzolanic materials (as defined in the <<Cement>> NF EN 197-1 Standard, paragraph 5.2.3), fly ash (as defined in the <<Cement>> NF EN 197-1 Standard, paragraph 5.2.4), calcined shale (as defined in the <<Cement>> NF EN 197-1 Standard, paragraph 5.2.5), limestones (as defined in the <<Cement>> NF EN 197-1 Standard, paragraph 5.2.6), or silica fume (as defined in the <<Cement>> NF EN 197-1 Standard, paragraph 5.2.7) or mixtures thereof.
Preferably, the quantity of mineral additions comprised with the clinker is from 10 to 70% of mineral additions, more preferably from 10 to 60%, even more preferably from 10 to 50%, % by mass relative to the total mass of clinker.
Another aspect according to the invention is the use of a cement with the composition as described herein above for the production of a hydraulic composition. Another aspect according to the invention is the use of a mineral charge as described herein above for the production of a hydraulic composition. Within the scope of these two uses according to the invention, the sacrificial molecule and the dispersing agent have the same characteristics as those described in relation to the first use according to the invention.
Measurement of the Spread and Rheology Monitoring
The spread of a mortar is measured using a mini Abrams cone, the volume of which is 800 mL. The dimensions of the cone are the following:
The cone is placed on a dry glass plate and filled with fresh mortar. It is then levelled. A slump of the mortar on the glass plate is provoked by lifting the cone. The diameter of the obtained disk is measured in millimeters+/−5 mm. This is the spread of the mortar.
These operations, repeated at several intervals (5, 15 and 30 minutes), make it possible to monitor the rheological evolution of the mortar for 30 minutes.
The following examples illustrate the invention without limiting its scope.
Different mortars were made and their rheologies were measured. These mortars were made with either a cement comprising the composition used according to the invention (that is to say, the composition is added during the grinding of the clinker), or they were made with a typical cement, the dispersing agent and optionally the sacrificial molecule having been added into the mortar (control).
The dispersing agents which were tested are PCPs, and in particular a PCP coming from a laboratory synthesis having 30% content of MMPEG 1100 ester (methoxy polyethylene glycol methacrylate having a molar mass of 1100 g/mol), a PCP coming from a laboratory synthesis having 20% content of MMPEG 1100, Premia 180 (supplier: Chryso), Premia 196 (supplier: Chryso), Optima 200 (supplier: Chryso) and Optima 203 (supplier: Chryso).
The PCPs coming from a laboratory synthesis which were tested in the different examples of the present description were synthesized by radical polymerisation in water between the methacrylic acid and the methoxy polyethylene glycol methacrylate having a molar mass of 1100 g/mol. Depending on the desired content of ester, the initial quantities of the two monomers were modified.
The reactants used in the present test and their quantities were the following:
The operating procedure for the production of the tested PCPs was the following:
The sacrificial molecules tested in the present example were methyl gallate, propyl gallate, hydroquinone, hydroxylamine and gallic acid (supplier: Aldrich), 4-methoxyphenol (supplier ECEM).
The cement was ground according to the procedure described herein below. The grinder which was used was a grinder capable of containing 5 kg of material to be ground and having 60 kg of metal balls, by the order of 27 kg of balls, the average diameter of which was between 40 and 60 mm, 18 kg of balls, the average diameter of which was between 25 and 35 mm et 15 kg of balls, the average diameter of which was between 20 and 25 mm. The grinder was used at a speed of 40 rpm. The grinding steps were the following:
After the grinding the cement was used for the production of a mortar, for which the rheology was monitored in order to highlight the effect of the sacrificial molecule.
The formulation of the tested mortar was the following:
The cement was a CEM 152.5 N cement.
The ISO sand was a siliceous sand (supplier: Societe Nouvelle du Littoral).
The tested mortar was produced according to the procedure described herein after:
Tables 1 and 2 herein after give the results of the tests carried out with different sacrificial molecules. The composition used according to the invention comprising at least one sacrificial molecule and at least one dispersing agent was either added during the grinding of a clinker or added to a mortar (control).
According to Table 1 herein above, the effect of the different sacrificial molecules has been shown because the fluidizing power of the PCP submitted to grinding at 20° C. is improved by the presence of a sacrificial molecule. For example, the spread at 5 minutes of a mortar comprising a PCP alone, submitted to grinding at 20° C. was 220 mm, while it was 275 mm in the presence of 10% of methyl gallate, or 285 mm in the presence of 20% of propyl gallate.
According to Table 2 herein above, the effect of the different sacrificial molecules has been shown because the fluidizing power of the PCP submitted to grinding at 100° C. improved by the presence of a sacrificial molecule. For example, the spread at 5 minutes of a mortar comprising a PCP alone, submitted to grinding at 100° C. was 200 mm, while it was 270 mm in the presence of 30% of gallic acid, or 265 mm in the presence of 10% of hydroxylamine.
Table 3 herein after gives the results of the spread tests carried out with different sacrificial molecules. The composition used according to the invention comprising at least one sacrificial molecule and at least one dispersing agent was either added during the grinding of a clinker or added to a mortar (control).
According to Table 3 herein above, the effect of a sacrificial molecule has been shown on 5 different dispersing agents. The fluidizing power of the tested dispersing agents submitted to grinding at 100° C. indeed improved by the presence of a sacrificial molecule. For example, the spread at 5 minutes of a mortar comprising Premia 180 submitted to grinding at 100° C. in the absence of a sacrificial molecule was 210 mm, whilst it was 275 mm in the presence of 20% of methyl gallate. Likewise, the spread at 5 minutes of a mortar comprising a PCP having 20% content of MMPEG 1100 ester submitted to grinding at 100° C. in the absence of a sacrificial molecule was 220 mm, whilst it was 255 mm in the presence of 20% of methyl gallate.
The cement was ground according to the procedure described herein below. The grinder which was used was a grinder capable of containing 5 kg of material to be ground and having 60 kg of metal balls, by the order of 27 kg of balls, the average diameter of which was between 40 and 60 mm, 18 kg of balls, the average diameter of which was between 25 and 35 mm et 15 kg of balls, the average diameter of which was between 20 and 25 mm. The grinder was used at a speed of 40 rpm. The grinding steps were the following:
After the grinding the cement was used for the production of a mortar (identical to the one in Example 1), for which the rheology was monitored in order to highlight the effect of the sacrificial molecule.
Table 4 herein after gives the results of the spread tests carried out with different dispersing agents. The composition used according to the invention comprising at least one sacrificial molecule and at least one dispersing agent was either added during the grinding of a clinker or added to a mortar (control).
According to table 4, the minimum dosage of sacrificial molecule to ensure protection of the dispersing agent during a grinding operation of clinker was at least 5%. The best efficiency was obtained for a dosage comprised from 10 to 20%.
Table 5 herein after gives the results of the spread tests carried out on different forms of use of the dispersing agent and of the sacrificial molecule: liquid solution, suspension of the sacrificial molecule in the dispersing agent and separate addition, during a grinding operation at 100° C.
According to Table 5 herein above, the sacrificial molecule and the dispersing agent must be in contact with each other before being used. The fluidizing power of the dispersing agent submitted to grinding at 100° C. indeed improved by the presence of a sacrificial molecule and of a dispersing agent which were either in the form of a solution or in the form of a suspension before being added to the cement. For example, the spread at 5 minutes of a mortar comprising Optima 203 submitted to grinding at 100° C. in the absence of a sacrificial molecule was 205 mm, whilst it was 250 mm in the presence of 20% of methyl gallate in solution with the dispersing agent, or 230 mm in the presence of 20% of methyl gallate in suspension with the dispersing agent. In contrast, the spread at 5 minutes of a mortar comprising Optima 203 submitted to grinding at 100° C. in the presence of 20% of methyl gallate, the dispersing agent and the sacrificial molecule being added separately to the cement was 200 mm, a value very close to the 205 mm value of the mortar ground without a sacrificial molecule.
Copolymer 1 containing the sacrificial molecule TAA-OL was prepared with the following reactants:
The following operating procedure was used for the production of the tested PCPs:
Copolymers 2 to 5 were prepared according to the same operating procedure by replacing the TAA-OL with the monomer to be tested according to the molar percentages given in Table 6:
Table 7 herein below, gives the results of the spread tests carried out using different dispersing copolymers. The copolymer used according to the invention comprising at least one monomer with an antioxidant was either added during the grinding operation of a clinker or added to a mortar (control).
According to Table 7, it can be seen that the copolymer containing the antioxidant in the polymer chain retained all or part of its fluidizing property compared to the PCP 30% ester MMPEG 1100 not containing the antioxidant which lost all its fluidizing property.
| Number | Date | Country | Kind |
|---|---|---|---|
| 09 03862 | Aug 2009 | FR | national |
| 09 05863 | Dec 2009 | FR | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/FR2010/051569 | 7/23/2010 | WO | 00 | 2/2/2012 |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO2011/015761 | 2/10/2011 | WO | A |
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|---|---|---|---|
| 6709508 | Dietrich et al. | Mar 2004 | B2 |
| 6869476 | Shin et al. | Mar 2005 | B2 |
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| 0 605 318 | Jul 1994 | EP |
| 605318 | Jul 1994 | EP |
| 2 776 285 | Sep 1999 | FR |
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| 2 917 401 | Dec 2008 | FR |
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| WO 2005076858 | Aug 2005 | WO |
| WO 2009004348 | Jan 2009 | WO |
| WO 2009004348 | Jan 2009 | WO |
| Entry |
|---|
| Written Opinion of the International Searching Authority for PCT/FR2010/051569. |
| International Search Report for PCT/FR2010/051569. |
| Han, Seongok et al.; “Thermal/oxidative degradation and stabilization of polyethylene glycol”; Polymer, vol. 38, No. 2, 1997, pp. 317-323. |
| Number | Date | Country | |
|---|---|---|---|
| 20120136096 A1 | May 2012 | US |
