Method for using alkanolamine in a grinder

Abstract

Disclosed is a method for using a secondary or tertiary alkanolamine for grinding cement, the method including: forming an inorganic acid salt of the alkanolamine; and adding the salified alkanolamine to a grinder.

Claims

1. A method for reducing the fluidity of at least one hydraulic binder in a grinding mill, the method comprising: forming an inorganic acid salt of triisopropanolamine (TIPA); adding the inorganic acid salt of triisopropanolamine into the grinding mill, wherein the fluidity of the hydraulic binder is reduced.

2. The method according to claim 1, wherein the inorganic acid salt of triisopropanolamine is an acid halide salt or a salt of sulfuric acid, phosphoric acid, phosphonic acid, or hydrogen sulphate.

3. The method according to claim 1, wherein the inorganic acid salt of triisopropanolamine is an acid halide salt or a sulfuric acid salt.

4. The method according to claim 1, wherein the inorganic acid salt of triisopropanolamine is a hydrochloric acid salt.

5. The method according to claim 1, wherein the inorganic acid salt of triisopropanolamine is combined with at least one additive selected from the group consisting of alkanolamines other than inorganic acid salts of triisopropanolamine; sodium chloride, calcium chloride, sodium thiocyanate, calcium thiocyanate, sodium nitrate, calcium nitrate and mixtures thereof; glycols; glycerols; water reducing adjuvants/admixtures and high water reducing adjuvants/admixtures; sulphonated salts of melamine-formaldehyde polycondensates, commonly known as melamine-based superplasticisers; lignosulfonates; sodium gluconate and sodium glucoheptonate; polyacrylates; polyaryl ethers (PAE); polycarboxylic acids; products based on polyalkoxylated polyphosphonates; surfactants, carboxylic acids; setting retarders; and mixtures thereof.

6. The method according to claim 1, wherein one or more anti-foaming (defoamer) compounds are used in combination with the inorganic acid salt of triisopropanolamine.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

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

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

(3) FIG. 2 is a side view of the inclined plane for the rolling bottle test of Example 2.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

(4) In these examples, a triisopropanolamine hydrochloric acid salt (TIPA) is used. This salt is obtained according to the following method: a mass of 113 g of triisopropanolamine (TIPA) at a mass concentration of 63% in water was maintained under agitation with a magnetic agitator (or stirrer) and 35 g of hydrochloric acid at 37% mass concentration were added over 30 minutes to obtain about 150 g of solution. The stoichiometric ratio between TI PA and HCl is 1:1. During formulation, the temperature did not exceed 40 C. The solution obtained is clear. The measurements of conductivity and pH as a function of the volume of titrated HCl show a strong variation in values at the time of the end of the reaction between TI PA 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 solution of TIPA+HCl, a jump in pH is noted at an equivalence volume of sodium hydroxide that is characteristic of the acidity constant of this chemical compound. (TIPA/TIPA+HCl). At half the equivalent volume, the pH is equal to the pKa of this chemical compound (TIPA/TIPA+HCl) which is close to 8. Conversely, TIPA does not show a jump in pH since the amine is already in basic form.

(5) Based on 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 method: a mass of 80 g of diethanolisopropanolamine (DEIPA) at a mass concentration of 87% in water was maintained under agitation with a magnetic agitator and 42 g of hydrochloric acid at 37% mass concentration 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+HCL. compound does indeed exhibit a pH jump that is characteristic of the acid-base compound DEIPA/DEIPA+HCl during the adding of sodium hydroxide, which indicates a pKa close to 8. Indeed, TIPA and DEIPA are amines with very similar acidity constants, with a pKa around 8. Conversely, non-protonated DEIPA does not show a jump in pH during the adding of sodium hydroxide.

(6) Based on 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 method: a mass of 129 g of triisopropanolamine (TIPA) at a mass concentration of 61% in water was maintained under agitation with a magnetic agitator and 21 g of sulfuric acid at 95% mass concentration were added over 30 minutes to obtain about 150 g of solution. The stoichiometric ratio between TIPA and H.sub.2SO.sub.4 is 2:1. During formulation, the temperature did not exceed 40 C. The solution obtained is clear. The formation of the protonated TIPA+H.sub.2SO.sub.4 amine can be confirmed by reverse acid-base titration. The TIPA+H.sub.2SO.sub.4 compound does indeed exhibit a jump in pH that is characteristic of TIPA, of close to 8.

Example 1

(7) On a cement CEM II/AV 42.5 N which contains 15% mass concentration of fly ash with a Blaine specific surface area target of 4000 cm.sup.2/g, a dosage of 90 ppm of TI PA makes it possible to increase the throughput of the cement mill by 11%. On the other hand, a dosage of 120 ppm of TIPA creates harmful effects by superfluidifying the cement powder which becomes very volatile. The TIPA+HCL does not have a negative impact on the grinding of cement (no super-fluidification) and leads to improved mechanical strengths.

(8) TABLE-US-00001 Dosage Mill throughput Rc 2 d Rc 28 d Description (ppm) rate (tph) (MPa) (MPa) Reference 0 70 24.0 55.2 TIPA 90 78 24.5 61.3 TIPA 120 ppm NA* TIPA + HCl 143 ppm** 76 25.1 63.1 *Emptying of grinding mill **Equivalent to 120 ppm of TIPA + 23 ppm of HCl.

(9) This example evidently demonstrates the fact that, in the grinding mill, an excessively high TIPA content impacts the grinding efficiency and leads to a drop in mechanical performance; the forming of salt of the TIPA makes it possible to overcome these drawbacks.

Example 2

(10) Laboratory tests were carried out with a ball mill on 5 kg of clinker in the presence of various different amines. The fluidity of the powder thus obtained was analyzed by using the rolling bottle test (RBT), whereof the underlying principle is to measure the distance travelled by a cylindrical bottle having 9.3 cm length, diameter of 2.74. cm, empty mass with lid of 119.14 g, and containing 40 g of ground clinker which rolls over an inclined plane, like that shown in FIG. 1. The greater the distance travelled, the more the sample is conducive to a fluidity that is suitable for industrial scale.

(11) 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 bottle, which denotes an over-efficiency in respect of TIPA that is not favourable to grinding. On the other hand, when the clinker is ground with TIPA+HCL, the distance travelled by the bottle is greater, while showing that TIPA+HCL prevents the known superfluidification effect for TIPA and brings back the clinker sample to a behaviour that is favourable to the flow of the powder on an industrial scale.

(12) TABLE-US-00002 Control TIPA TIPACH Distance travelled by the 34.0 28.7 36.7 bottle of clinker (cm)

Example 3

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

(14) The Blaine specific surface area target at the outlet of the mill is 5100 cm.sup.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 filtres become saturated. This saturation is followed by measuring of the pressure at the filtre inletmill 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), the TIPA+HCL has no negative impact on the grinding of the cement (no super-fluidification). The protonated amine makes it possible to maintain a discharge from the separator and a dust formation rate of the filtre 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 size of particles of the slag, the fine particles do not saturate the filtre, maintaining a separator discharge and a filtre dusting rate 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 super-fluidification.

(15) TABLE-US-00003 Discharge Pressure TIPA Mill from (mBar) at the Dust from the Blaine Specific Dosage throughput separator Filtre Inlet - Mill Filtre Surface Area Description (ppm) rate (tph) (tph) Mill Outlet broyeur (g/m.sup.3) (g/cm.sup.2) Reference 0 77 160 9.2 8 500 Composition 1 41 77 120 10.5 11 500 comprising TIPA Composition 2 36* 77 140 9.1 9 517 comprising TIPA + HCl Composition 2 48** 78 130 9.2 12 521 comprising TIPA + HCl Composition 2 60*** 79 120 9.4 17 524 comprising TIPA + HCl Composition 2 84**** 79 110 9.8 38 524 comprising TIPA + HCl *Emptying of the grinding mill **Equivalent to 36 ppm of TIPA + 7 ppm of 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 of TIPA + 16 ppm of HCl

(16) This example evidently demonstrates the fact that, in the grinding mill, the use of TIPA could lead to super-fluidification of the slag with a dust filtre which rapidly saturates. The forming of salt of the TIPA makes it possible to overcome these drawbacks. The inlet throughput flow rate of the grinding mill may be kept constant while also promoting the grinding of the slag and without the risk of super-fluidification.

Example 4

(17) A cement CEM II/A LL 42.5 N containing 10% mass concentration 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 area target of 3300 cm.sup.2/g. The use of an adjuvant containing TIPA.Math.HCl (composition 4) makes it possible to reduce even more than with an adjuvant containing TI PA (composition 3) the 45 and 25 m discharge at the outlet of the ball mill as compared to the reference. The forming of the salt of TIPA therefore makes it possible to more effectively reduce the particle dimensions of the cement and thus to obtain a gain in compressive strengths which is higher at 2 days as compared to the control. 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 that are clearly greater than those of the reference.

(18) TABLE-US-00004 TIPA Discharge Discharge Dosage 45 m 25 m Rc 2 d Rc 28 d Description (ppm) (% m) (% m) (MPa) (MPa) Reference / 20.9 37.0 27.8 46.6 Composition 3 163 16.9 33.2 26.6 60.1 comprising TIPA Composition 4 163* 15.1 23.6 29.1 58.2 comprising TIPA + HCl *Equivalent to 163 ppm of TIPA + 31 ppm of HCl.

(19) This example evidently demonstrates the fact that, in the grinding mill, the use of TIPA in salt form instead of TIPA makes it possible to improve the grinding efficiency resulting in a reduction in 25 and 32 m discharges. This makes it possible to conclude that the residence time in the grinding mill of the cement CEM II/A LL 42.5 N has been extended.

Example 5

(20) 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 Blaine specific surface area of around 360 m.sup.2/kg. The CEM I 42.5 N type cement is composed of 90.5% mass concentration of clinker, 4.5% by mass of limestone and 5.0% by mass of gypsum. The use of an activator containing TIPA+HCl (composition 6) instead of TIPA (composition 5) with amine iso-dosage makes it possible to improve the grinding efficiency. For the same inlet throughput flow rate of the mill, the specific surface area of the cement is greater and the 45 m discharge is lower in the presence of chlorinated salt of TIPA than of TIPA. Even if the inlet throughput flow rate of the mill is increased from 108 to 111 tph, the TIPA+HCL based adjuvant/admixture remains a very effective grinding agent since it maintains a high Blaine surface area. 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. However, the TIPA acetate leads to a clogging of the grinder filtre which can be detected by increasing the cleaning time of the filtre and the number of purges per hour. Conversely, TIPA+HCL provides the means to form less dust during grinding and therefore to reduce the time of purging of the filtres. At 2 days, the compressive strengths are higher in the presence of TIPA+HCL 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/admixtures.

(21) TABLE-US-00005 TIPA Mill Blaine Specific Discharge Cleaning Number Dosage Throughput Surface Area 45 m Time of Purges Rc 2 d Rc 28 d Description (ppm) Rate (tph) (g/cm.sup.2) (% m) (s/h) per h (MPa) (MPa) Composition 5 74 108 362 9.9 1114 13 32.6 59.0 comprising TIPA Composition 6 74* 106 370 8.5 1172 14 34.3 58.9 comprising TIPA + HCl Composition 6 74* 111 364 9.8 Not Not 31.3 58.9 comprising mesured mesured TIPA + HCl Composition 7 79** 108 358 9.8 1552 18 33.3 60.5 comprising TIPA acetate *Equivalent to 74 ppm of TIPA + 15 ppm of HCl. **Equivalent to 79 ppm of TIPA + 38 ppm of acetic acid.

(22) This example evidently demonstrates the fact that, in the grinding mill, the use of TIPA+HCL makes it possible to improve the grinding efficiency of a CEM I cement as compared to TIPA and TIPA acetate, by limiting the clogging of filtres and therefore the time require for cleaning the latter. The use of TIPA+HCL instead of TIPA makes it possible to obtain a slight gain in compressive strengths at 2 days and to maintain the compressive strengths at 28 days.

Example 6: Stability of Antifoam Formulation+% Air

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

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

(25) The air entrained in a CEM I type cement with 120 ppm of protonated amine admixture was then measured for a dosage of 6 or 7 ppm of anti-foaming agent. The addition of anti-foaming agent 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.

(26) TABLE-US-00006 Amine Dosage of Entrained Dosage Anti-Foaming Air Description (ppm) Agent (ppm) (%) Reference 0 0 4.0 TIPA 120 0 5.1 DEIPA 120 0 5.1 TIPA + HCl 120* 0 4.8 TIPA + HCl 120* 6 4.0 with Anti-Foamer DEIPA + HCl 120** 0 5.1 DEIPA + HCl 120** 7 3.9 with Anti-Foamer *Equivalent to 120 ppm of TIPA + 23 ppm of HCl. **Equivalent to 120 ppm DEIPA + 27 ppm of HCl.

(27) It is therefore possible to formulate adjuvants/admixtures which are stable in solution based on a protonated amine and an ethoxylated fatty amine type antifoaming agent. Adding an antifoaming agent with hydrochloric salt amine provides the means to significantly reduce air entrainment in the mortar or concrete when using cement.

Example 7

(28) In a vertical roller mill with 3 servo-controlled rollers, 200 tonnes per hour of a cement of type CEM II/BV 42.5 R containing 24% fly ash (added at the mill outlet) are introduced to obtain a cement having the targeted final fineness, with a particle size distribution defined respectively by the parameters d50 (median diameter at 50%; expressed in m) of 12.5 and d90 (median diameter at 90%; expressed in m) of 31.0. In the presence of an activator comprising TI PA (composition 8), the performance of the mill (production throughput rate in tonnes per hour) is established by setting the following method parameters: Speed of the separator (in rpm/revolutions per minute) in order to control the fineness of the cement. Differential pressure in the grinding mill (in mbar) reflecting the quantity of material present in the grinding mill and therefore the efficiency of the grinding. Water injected into the grinding mill (in m3/h) in order to control the stability of the grinding mill and the vibrations.

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

(30) TABLE-US-00007 Mill TIPA Mill Separator Differential Injected Dosage d50 d90 Throughput Speed Pressure Water Description (ppm) (m) (m) Rate (tph) (rpm) (mbar) (m.sup.3/h) Composition 8 100 12.5 31.0 200 1450 17.0 5.8 comprising TIPA Composition 9 100* 11.2 29.5 200 1450 16.5 5.8 comprising TIPA + HCl Composition 9 100 12.0 30.5 215 1350 17.2 4.9 comprising TIPA + HCl *Equivalent to 100 ppm of TIPA + 19 ppm of HCl.

(31) This example evidently 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.

(32) This grinding efficiency may as well translate into grinding mill productivity gains (tonnes per hour) while also adjusting the method parameters and maintaining the vertical mill in an optimised operating zone so as to ensure the targeted fineness of the cement.