Industry Versus Laboratary Clinker Processing Using GA

See discussions, stats, and author profiles for this publication at: https://www.researchgate.net/publication/287360073 Industrial versus Laboratory Clinker Processing Using Grinding Aids (Scale Effect) Article in Advances in Materials Science and Engineering · December 2015 Impact Factor: 0.74 · DOI: 10.1155/2015/938176 READS 18 1 author: Joseph J. Assaad Notre Dame University 64 PUBLICATIONS 636 CITATIONS SEE PROFILE All in-text references underlined in blue are linked to publications on ResearchGate, letting you access and read them immediately. Available from: Joseph J. Assaad Retrieved on: 01 May 2016 Accepted 11 November 2015 Academic Editor: Luigi Nicolais Copyright © 2015 Joseph Jean Assaad. . It is to be noted that the Blaine measurement cannot effectively represent the entire PSD. However. it provides a preliminary assessment of GA effects on cement fineness and properties. therefore creating a socalled circulating load (CL). the Ec reduction due to GA is around twofold higher when grinding is performed in real-scale mill. the results obtained cannot be directly transposed to industrial mills. and 1. which permits unrestricted use. This paper seeks to evaluate the scale effect by comparing the results obtained from a closed-circuit tube mill operating at 90 ton/hr to those determined using a 50-liter laboratory mill.O. while the latter is more and more demanded with today’s constraints regarding the reduction of usable energy [5]. provided the original work is properly cited. Baabda.1155/2015/938176 Research Article Industrial versus Laboratory Clinker Processing Using Grinding Aids (Scale Effect) Joseph Jean Assaad Holderchem Building Chemicals. P. Article ID 938176.e. Their chemical basis mostly includes ethanolamines such as triethanolamine (TEA) and triisopropanolamine (TIPA) as well as glycols such as diethylene glycol (DEG) and propylene glycol (PG) [1–3].doi. The practical consequences of such additions to the cement industry can broadly be divided into two aspects including an increase in cement Blaine fineness and compressive strength for given specific energy consumption (Ec) and/or savings in electrical energy and Ec together with improved mill productivity for given fineness. ASTM C150 Type III [4]). the clinker processing in real-scale mills is a continuing process. It is to be noted that GAs blended with TIPA molecules are known by their capability to promote cement hydration reactions. the results obtained cannot be directly transposed to industrial mills.. volume change. This is an open access article distributed under the Creative Commons Attribution License. Yet. and hydration processes such as heat release. The evaluation of GA effect on clinker processing in laboratory grinding mills is relatively simple. The CL is defined as the average number of times that the material circulates through the grinding system before becoming the product [11]. laboratory grinding mills operated over given time interval do not account for CL. Tests results have shown that the decrease in specific energy consumption (Ec) due to glycol or amine-based GA can be evaluated under laboratory conditions. screening. Box 40206.Hindawi Publishing Corporation Advances in Materials Science and Engineering Volume 2015. setting time. 10].edu. 6–8]. 12]. For instance. ventilation. given the fundamentally different operational modes and grinding parameters such as comminution forces. setting time. and clinker temperature [9. thereby leading to increased compressive strengths [2.org/10. therefore leading to different cement particle size distribution (PSD) curves [11. The evaluation of grinding aid (GA) effect on clinker processing in laboratory grinding mills is relatively simple. and reproduction in any medium. All particles larger than the cut size would be sent to a reject stream. 1.and 28-day compressive strengths. This led to remarkable changes in water demand. the cement particle size distribution curves widened and shifted towards higher diameters when grinding was performed under laboratory conditions. whereby the grinding forces are applied to the coarse particles while the fine ones are discharged as soon as they have been reduced to the required cut size. jassaad@ndu. Introduction Grinding aids (GAs) are incorporated during clinker processing to reduce electrostatic forces and agglomeration of cement grains. and strength development [13. Yet.lb Received 14 September 2015. Compared to industrial tests. particularly with GA additions. Unlike industrial mills. 12 pages http://dx. Lebanon Correspondence should be addressed to Joseph Jean Assaad. The former direction is relevant when producing cement possessing increased fineness necessary for high early strength requirements (i. distribution. rheology. given the fundamentally different operational modes and grinding parameters. This consequently alters cement properties such as water demand. 14]. such tests underestimate the actual performance that could be achieved in real-scale mills. 16].8.5 16 2.13 Gypsum 2. . and pH were 64%. ASTM C465 Standard Specification for GAs related such changes to cement flowability and mill retention time (MRT) during grinding [17].595 mm 0.51 mm 4. Its main components include TIPA and TEA.5%.2 given the fact that two cements with different ratios of fineto-coarse particles and described by different PSD can possess the same Blaine value [15. % Al2 O3 . and researchers dealing with processing and testing procedures of cement and clinker materials.4 22. natural pozzolan meeting the requirements of ASTM C618 Class N [19].3 64.3 4. the laboratory tests yielded significantly wider PSD curves than those experienced in practice.2. The cement PSD curves were deducted by fitting the laser diffraction data into the Rosin-Rammler-Sperling-Bennett (RRSB) function given as [21] ? (?) = 1 − exp [− ( ? ? ) ].3 13 25. respectively.4% from standard samples. SiO2 . 1. 2.2 7.01 Advances in Materials Science and Engineering Table 1: Chemical composition and grading of clinker. 8. and 7. and 5%.1 14. 12]. % SO3 .297 mm 0. The equipment generates high-speed data processing at 5000 cycles per second within an entire measuring time less than 2 minutes and yields high-accuracy measurements that deviate by not more than ±0.e.22 Pozzolan 73. ?(?) is the cumulative fraction passing function.5%.5 16.96. Results obtained were compared with those determined using a 50-liter laboratory grinding mill. Using the same cement paste produced for normal consistency. the Vicat initial and final setting times were then determined as per ASTM C191 Test Method [23]. This research project was initiated following an industrial grinding test undertaken to validate the effect of glycol and amine-based GAs on Ec and cement performance.5 43. % MgO. 2. The cubes were demolded the second day from casting and stored side by side in saturated limewater until the testing time of 1 and 28 days. were determined using a mechanical shaker.2% cumulative passing value on the distribution curve. to properly evaluate GA effect on cement properties. In the literature.2 1. The apparatus complies with ISO 13320 technical requirements. 1350 g of normalized sand (EN 196-1). and fixed w/c of 0. ?0 (1) ? refers to the measured particle size in ?m. it is commonly used as grinding aid and strength enhancer in the cement industry. and ?0 indicates the powder fineness in ?m that corresponds to 63. Hence. 1. Industrial clinker used for the production of ASTM C150 Type I cement [4]. and 7. 10.08.6 3.149 mm 0. respectively. The resulting correlation coefficients (?2 ) of the regression lines built throughout this project between ln(?) and ln[ln(1/1 − ?(?))] varied between 0. A laser particle size diffraction analyzer (Analysette 22 NanoTec Plus) capable of measuring particle sizes varying from 0.485. and gypsum materials were employed.6 6. % Percent retained on 9.1 1. Its active chemicals determined by Karl Fischer method. limited attempts have been made to quantify the scale effect (i. ? is the slope of size distribution reflecting the narrowness or wideness of PSD (the higher ? means a narrower PSD).5 1. The Blaine was determined using the air permeability apparatus as per ASTM C204 Test Method [20].1.53 0.7 0.32 4.3 3. % Fe2 O3 .8 5 0 0. The materials chemical composition and PSD are presented in Table 1. the active chemicals. The glycol-based GA is composed by DEG and PG chemicals. This paper can be of particular interest to cement manufacturers. Testing Methods. The MRT can be defined as the average time necessary for the bulk material to pass through the tube mill [18].19 mm 0. pozzolan. respectively.1 to 2000 ?m was used for cement particle measurements. GA suppliers. The differences in PSD curves determined under laboratory and industrial mill conditions were noticed by several researchers in the cement and mineral grinding industries [8. Their ratio in the cement produced was maintained at 86. % CaO. with reproducibility (?50 ) less than 1%. and pH were 60%. Tests were performed using mortars prepared with 450 g of ground cement.92 and 0.6 20. The compressive strength was determined as per ASTM C109 Test Method [24]. as per ASTM C187 Test Method [22]. and PSD curve.7 26 11.5 14 7.2 12. industrial versus laboratory mill) that could result from GA additions on cement fineness and properties.8 2..4 2. It presents data collected over 2 consecutive days of clinker grinding in real-scale closed-circuit tube mill operating at around 90 ton/hr.2. The water demand required to achieve normal consistency was determined by mixing 650 g of ground cement with a measured quantity of water.86 0. respectively. sieve residue.38 mm 1.6 6.09.074 mm Pan Clinker 20. and gypsum.2 15. it is referred to as grinding aid and pack-set inhibitor in the cement industry.5 26. specific gravity. Materials. the standard recommends the realization of fullscale tests over enough time to ensure reaching equilibrium conditions and stable CL [17].76 mm 2.8 24. specific gravity.5 8. The second GA is amine-based.8 2 3 5. Materials Used and Testing Methods 2. while the 45 and 90 ?m residues referred to as R-45 and R-90. Two commercially available GAs were tested in this study. The cement fineness characteristics were evaluated using the Blaine measurement.39 32.25 0. 1. separator motor power. 3. % Charge weight.7 8. Description of Mill Employed. The fresh feed rate (B0). mill sound.6 3. m Filling degree. an elevator conveys the entire ground material (B1) to a rotor separator where it is divided into two fractions. After grinding. mm Mill motor power. and pozzolan is introduced in the mill. Control of Grinding Mill Parameters. since neither accumulation nor generation of new material takes place inside the mill. The coarse fraction constitutes the separator rejects (B2) that is sent back to the mill for an additional cycle of grinding. A measured fresh feed mixture (B0) of precrushed clinker. During steady-state operation.1.5 43 20 to 50 Rotor separator 2 3. rejects (B2). Tube ball mill Internal diameter. gypsum. rpm Fan motor power.06 110 260 280 1500 becomes the final product (B3).1. Data Obtained from Industrial Tube Mill 3. The CL is calculated as B1/B3 = (B0+B2)/B0. ton Ball size. The design parameters of the industrial tube mill and rotor separator are given in Table 2. ton/hr Compartment 1 3. m3 /min 2 1. separator air flow rate. Test Results and Discussion 3. m Motor power. kW Rotor speed. kW Production rate. Table 2: Design parameters for the tube ball mill and separator. This stage was pursued over 3 hours. kW Air flow. The first stage of testing consisted in ensuring uniformity of grinding parameters and sampling cement at regular time intervals for use as control mixtures. The industrial mill was operating without any GA. The clinker initially passes through a double-deck screen. the mill productivity is equal to B0 (or B3). where all particles larger than 10 mm are sent to a precrusher. and CL were equal .Advances in Materials Science and Engineering 3 Clinker storage Cement (B3) Separator Double-deck screen Gypsum storage Separator feed (B1) Clinker crusher Rejects (B2) Pozzolan storage Crushed clinker storage Ball grinding mill Fresh feed (B0) Figure 1: Various stages during industrial closed-circuit grinding tube mill. the data collected are summarized in Table 3. kW Mill speed.2. whereas the fine fraction Rotor diameter.4 34 138 15 to 20 3200 17 150 90 (design value) 3.6 29. m Internal length. Industrial closed-circuit tube (or ball) mill schematically presented in Figure 1 was used for cement production. m Rotor height. rpm Fan power.1. mill motor power consumption. Then.9 dB and 79% ± 0. 25].8 140.2 kWh/ton. Air flow rate. Rejects (B2).7 141. 79.81 ± 0. Further increases in B0 would not be desirable as this may abuse the mill motor capacity (an 80% threshold value was placed by the cement company). this can be directly attributed to the organic GA molecules adsorbed on clinker surfaces.4 ± 1.9 39.62 1. and 1.6 97. 25.5 105.9 76.1 79. whereas the increased amounts of clinker will dampen the clanking noise and result in lower decibel (dB) values.45 1. increasing the rotor speed will elevate the product’s fineness and increase the rejects (B2).3 81.91 ± 0. mostly attributed to a decrease in MRT and improved cement flowability [11.3.8 63.5 91.4 Advances in Materials Science and Engineering Table 3: Data collected over time during industrial grinding without or with GA.2 135. respectively.1 85 85. For instance.73 1. ton/hr Mill sound.7 85.8 75 76. Glycol-based GA was used in the first testing day.2 105.1 80. 26].3 134 142. The product’s temperature leaving the mill (B1) hovered around 97 ± 3∘ C.4 78.4 105.92 and stabilized at around 1. Hence.6 108 108.1 ton/hr (Table 3). The corresponding CL ranged from 1. In other words. % 1/0:00 1/1:00 1/2:00 1/3:00 1/3:30 1/4:00 1/5:00 1/6:00 1/7:00 1/8:00 1/9:00 1/10:00 1/11:00 2/0:00 2/0:30 2/1:00 2/2:00 2/3:00 2/4:00 2/5:00 2/6:00 2/7:00 0 0 0 0 530 530 530 530 530 530 530 530 530 460 460 460 460 460 460 460 460 460 90.81 1.7 72 69.75 1.8 79.8 83 86.43 1.4 78.1% of ultimate capacity is another indicator of improved clinker processing.4 66 65.9 84 83.4 82 83.01. 107. Blaine of 3850 ± 75 cm2 /g).63 1. The B2 varied between 83 and 97 ton/hr during the first 4 hours and thereafter stabilized at around 89. The decrease in motor power consumption from 79% to 74.7 121 128.7 78.3 ± 3.3 86. Day/time. The increase in CL due to GA additions is a common phenomenon in the cement grinding industry.3 79.77 1.92 kWh/ton.7 81.2 79 74 75. by increasing gradually B0 to 110.3 80.69 1.1 82.5 ± 1 dB.58 1.3 126.5 91 90.8 Rotor motor.2 88 54. The corresponding Ec decreased from 27.62 1. since more particles will be returned back to mill.90 1.5 79. and Blaine fineness was within 3850 ± 35 cm2 /g. 26].9 113.6 97 86.5 63.6 110 109.75 to 1.9 CL Blaine.8 40.5 78.1 79.8 79.1%.4 111. The grinding parameters were adjusted over time to maximize mill productivity under stable conditions while achieving similar Blaine fineness as the control mix (i.6 ± 2 kW. thus reflecting improved clinker processing and reduced MRT (Table 3). while amine-based one was used in the second day.7 38.5 ton/hr.2 135.e.5 138. Conversely.5 107 108.5 60. ton/hr kW m3 /min 108.9 83. to 91 ± 0. rotor motor power.2 114 110. 82. 3. the mill sound is an indicator of filling state in mill compartments during operation [10.8 122 120. hr:min GA. cm2 /g 1. respectively.5 ton/hr.5 126 1366 1380 1365 1294 1423 1325 1290 1264 1255 1268 1290 1302 1277 1310 1406 1415 1340 1303 1304 1283 1294 1291 38. 1350 ± 50 m3 /min.6 79. 8].6 99 100.1 130 126. Around 4 hours was necessary to regulate B0.6 136.3 81.44 ± 0.5 87..43 1.6 81 78. 39.61 1.83 1.82 1.7 86. Hence.3 110.3 75. higher air flow inside the separator would carry particles of larger size into the fine stream.9 82. dB Mill motor power. The resulting Ec calculated as the ratio between the consumed mill motor power and B0 was around 27.6 90.80 1. thus reducing cement agglomeration with direct consequences on B0 and Ec [2.92 1. g/ton Feed (B0).5 113. thereby requiring increased number .7 80.43 1. therefore decreasing cement fineness with reduced B2.2% ± 0.61 3820 3840 3885 3850 4020 3745 3770 3820 3905 3790 3880 3820 3745 3660 3835 4105 4000 3860 3825 3905 3880 3845 Values in bold correspond to stable mill conditions. this index sharply increased to around 90 dB during the first hour of GA addition.3 79.91 kWh/ton when grinding was performed without GA to 22.5 ± 1 ton/hr. the use of GA makes coarser the product that leaves the mill (B1). The separator’s rotor speed (or motor power) and air flow rate are crucial parameters for controlling cement fineness and residue [10.7 82 77.7 63.78 1.5 97. sprinkling of glycol-based GA over the fresh feed introduced in the mill started at a rate of 530 g/ton using an automatic dispenser. The mill sound and power consumption were readjusted to around 83 ± 0. an emptier mill will produce a louder sound.6 104 103.4 82. and air flow rate in order to obtain stable mill conditions delivering cement fineness close to that of the control mix. 11.56 1.3 104. 18.2%.3 91.1 103.6 104.4 90 87. 4 kW. respectively. 1293 ± 11 m3 /min.48%) 0. Effect of GAs on Cement Fineness and Properties: Industrial Grinding. kWh/ton Blaine.28%) 28. (amine GA) Figure 2: PSD curves obtained under industrial and laboratory grinding conditions of control cement and those containing GAs. 79.35%) 220 (2.81%) 52.5 (1. the B0 reached 104.13 (1.89%) 14. (control cement) Poly.9 (5.46 (3. Table 4 summarizes the properties of control cement and those containing GAs that resulted from industrial grinding after reaching stable conditions (the Ec values are also given).2 (4. dispensing of the amine-based GA started at relatively reduced rate of 460 g/ton (this was due to economic reasons established by the cement company).17 (9. separator air flow.47%) 17.04%) 14.09%) 3810 (1.3.78%) 1. (glycol GA) Poly.69%) 19. MPa 28-day compression. (glycol GA) Poly.83 (5.92%) 1.42%) 28.8 (0. the grinding tests were pursued for 4 additional hours.07 (5. The dispensing of glycol-based GA was stopped overnight.71 m/s when the glycol. After reaching stable mill conditions.87 (3.041 (0.65%) 24. It is to be noted that the data reported in Table 4 are averages of 3 to 4 measurements collected after reaching stable mill conditions. The coefficient of variation (COV) for each measurement determined as the ratio between standard deviation and mean values. cm2 /g R-90.93%) 22. and 1.55%) 13.26 (1. motor power consumption. The Ec that resulted from the amine-based GA was 24.8%) 245 (7.43%) 1. min 1-day compression.56%) 3850 (0. The PSD curves of cement mixtures sampled after reaching stable mill conditions are plotted in Figure 2 (this figure also plots the various PSD curves determined under . 100 100 Laboratory grinding (50-liter mill) Blaine = 3850 ± 75 cm2 /g 60 80 Passing (%) Passing (%) 80 40 20 60 Industrial grinding Blaine = 3850 ± 50 cm2 /g 40 20 0 0 0.052 (0. % Final setting. whereby samples of cement were taken at regular time intervals.39 (0.71%) 2.92 (1.69%) 54.52%) 16. separator motor power.33%) The COV values are given between parentheses. B2.79%) 3865 (0.3. 64 ± 4 ton/hr.58 m/s when grinding was realized without GA to 1.1. and CL were equal to 79.1 1 10 100 Sieve diameter (?m) Poly.73 and 1. is given.7 (0. of passages through the system to reach the targeted fineness level. while mill sound.67 (2.86%) 12.14%) 16.and amine-based GAs were used.91 (0.9 ± 1.76 (3.77%) 28.8 (6. and industrial testing resumed the second day using the amine-based one.61 ± 0. Ec. MPa Control cement Cement with glycol-based GA at 530 g/ton Cement with amine-based GA at 460 g/ton 27.946 (0.Advances in Materials Science and Engineering 5 Table 4: Ec and cement properties after reaching stable conditions in industrial mill grinding. (control cement) Poly.06%) 56.39 kWh/ton. % R-45.4%. The product’s temperature leaving the mill (B1) hovered around 102 ± 4∘ C.6 ± 2.38 ± 1 ton/hr. multiplied by 100. 3. After around 4 hours of grinding.57 (3. (amine GA) 0. the tube mill and separator parameters were adjusted to ensure stable grinding conditions delivering cement fineness close to that determined on the control mix (Table 3).76 (5. % ? ?0 .5 dB. It is to be noted that the air speed within the tube mill varied from around 1. 127.75%) 266 (2.56 (4.45%) 0. ?m Water demand.6% ± 1.1 1 10 Sieve diameter (?m) 100 Poly. after assuring stability of mill conditions. As earlier. respectively.73%) 14. Again. The increase in 28day compressive strength was more accentuated (i. The temperature of cement obtained right after the end of grinding hovered around 32 to 36∘ C... Although the Blaine values are quite close to each other and varied within 3850 ± 50 cm2 /g. ? increased from 0.2%. and rotational speed of 400 mm. This can be attributed to the TIPA existing in the former GA. that is. and sampling around 100 grams to check whether the Blaine became close to the targeted value. The control mix was found to require an Ec of 43. Two other grinding tests were then realized by sprinkling the preselected glycol. Because of similar reasons.9% and 1.5 min). was used in this testing program (Figure 3). The water demand necessary to achieve normal consistency of various sampled mixtures remained almost invariable at 28. 7].15% (Table 4).27 kW/ton for the control mix to 39.67 MPa for the one made using cement ground with glycol-based GA.and amine-based GA. thus making a filling degree equal to 34.2. stopping the mill. Grinding Tests Performed under Laboratory Conditions 3.23 and 40. 400 mm. 28]. 8].76% for the control mix to 0. Initially. The mill operated in a room where ambient temperature and relative humidity were 23 ± 2∘ C and 55 ± 5%.76 and 17.and amine-based GA concentrations of 530 or 460 g/ton onto the 6 kg feed materials. 56.17% with the addition of glycol.2.1.13 MPa for the control mortar to 54. pozzolan.2. The approach consists in grinding the materials for a certain elapsed time. where Tc refers to the amount of electricity in kWh consumed during the grinding time interval and mill factor equal to 3 as per the manufacturer calibration procedure. Concurrent to the enhancement in PSD.2 to 16. given the reduced Ec applied . the remarkable increase in compression up to 56. The narrowing of PSD curves due to GAs is well proven in the cement industry. Approach Used for Clinker Grinding. this can be attributed to a combination of different phenomena including the reduction of cement particles finer than around 5 ?m that mainly influence the setting [14]. As expected.946 for the control cement to 1. The setting time that resulted from cement containing amine-based GA was relatively lower than the one obtained using glycol GA (i. respectively.6 laboratory conditions that will be discussed later in text). those molecules are known by their capacity to promote cement hydration reactions with consequently reduced setting times [2. respectively.). It is to be noted that each test was repeated twice to evaluate the COV of various measurements.33 kWh/ton for those containing glycol. additional grinding is performed.2. 27].052 and 1. The mill was connected to an electric counter for monitoring Ec in kWh/ton Advances in Materials Science and Engineering Figure 3: Photo of the 50-liter laboratory grinding mill..56 ?m. and gypsum in the ground mix were maintained similar to those used in industrial tests. grinding time of 29. the R-90 decreased from 2. a control mix was prepared by grinding 6 kg of materials without any GA until achieving a Blaine fineness similar to that obtained from industrial testing. the addition of GA led to reduced Ec. Nevertheless. 6. that is.83 MPa. Grinding stopped when the cement mixtures reached Blaine fineness equivalent to the control mix. respectively. The corresponding ?0 decreased from 19. 3.3. For example.041 when grinding was performed using the glycol. If not. as summarized in Table 5.and aminebased GA. respectively.46 MPa for the control mortar to 12. Hence. The resulting 1-day compressive strength slightly increased to 14. just like what happens with the use of water reducers in concrete mixtures [3. The 28-day compressive strength increased from 52. and 50 rpm. The GA addition was associated with an increase in R-45 and R-90 values (Table 5). 3. For given Blaine fineness. the adsorption of glycol monolayers onto cement grains can partly block hydration reactions. A 50-liter laboratory grinding mill having a drum diameter. 6. respectively. Additionally. it is clear that GA additions affected PSD curves including a reduction in the percentage of very fine particles smaller than around 5 ?m as well as those retained on coarser sieve diameters. the 1day compressive strength decreased from 14. 245 versus 266 min. respectively. the setting time remarkably increased from 220 min for the control cement to 266 min when the glycol-based GA was used. resp. 3850 ± 75 cm2 /g.27 kWh/ton (i.e.8 MPa) when the amine-based GA was used.e.8 MPa can be related to the TIPA molecules that improve cement hydration reactions and lead to increased strengths [2. length.26 MPa for that prepared using cement containing glycol GA (Table 4). Description of Laboratory Mill.and amine-based GA.65% ± 0. This resulted in narrower PSD curves together with their shifting towards smaller diameters. Effect of GAs on Cement Fineness and Properties: Laboratory Grinding. it is related to an improvement in cement flowability [12. This strength improvement can be related to enhanced cement PSD possessing increased amount of fraction grains varying from around 5 to 25 ?m [14]. The percentages of clinker. given the decrease in cement agglomeration. A total of 80 kg steel balls (36 kg of 20 mm diameter and 44 kg of 30 mm diameter) were used for grinding. determined as (Tc × 1000)/(mass of ground mix in kg × mill factor).e. 3. 7.2. from 43. remarkable increase in early strength occurred when both GAs were used (i.6 0.7 27.65%) 5.7 205 44. 14.7 MPa were measured for mortars made using cement containing glycol and amine GA. ?m 40.55 (6.9 3790 3835 (1. % 2 Cement with glycol-based GA at 530 g/ton 1 2 54. the ? parameter decreased from 0.8 0.7 17.748 29 14.25%) 1-day compression. resp.4 MPa for glycol and amine GA.75%) 45.8% when the glycol.81 27.48%) 27.7 23 23.8 (8.8 16.7 3775 23.82%) 5.4 ?m. Control cement Test number Ec. albeit still substantially higher than those registered from industrial grinding.75 (0. 8.. during processing [8]. 14]. as compared to the control mortar that exhibited strength of 45.Advances in Materials Science and Engineering 7 Table 5: Ec and cement properties following laboratory grinding.771 0.15% and 20. especially knowing that glycol chemicals added at relatively low to moderate rates do not affect the development of compressive strength [7. The decrease in 28-day compression that resulted from glycol-based GA could be related to increased percentage of cement particles coarser than 25 ?m. Compared to industrial tests.35 and 27.37%) 16.9 42 17 15.1 (1. respectively.7 (1.8 28-day compression.35 (2.3 25. respectively (Table 5).3. 7]. For instance. respectively.3 to 27.5 (1. Comparison of Data Obtained from Industrial versus Laboratory Tests 3.66%) 27.).5 225 22 20.796 and 0.and aminebased GA.891 for the control cement to 0. 6.759 (2.39%) 40. values of 43.4 (8. 7]. Compared to the control mix. those measurements varied within 27.33 (0%) 7.61%) 190 197.7 0.3 0. respectively.6 3825 3810 5.37%) 18.2 43. thus promoting cement hydration reactions and resulting in higher late-age strengths [2.14%) 27. resp. Nevertheless.8 27. The increase in 1-day compression could mostly be attributed to an increase in the amount of fine cement particles.2%) 26.17%) 44. % R-45.05 (8. The addition of glycol.3 6.3 49.15% and 210 ± 15 min. respectively.9 kWh/ton needed for industrial grinding of the control mix increased to 43. 3. Nevertheless. The COV is given between parentheses.16%) 27. The variations in Ec due to GA additions that resulted from industrial and laboratory grinding are plotted in Figure 4.796 (2. the incorporation of GA did not remarkably alter water demand and setting time. Effect of GAs on Mill Performance.2 51.31%) 3848 (0. the Ec of 27. % 1 43. The corresponding ?0 increased from 24.03%) 215 16.1 (3.891 (0.95%) 0.3 38.).759 for those prepared with glycol. MPa 46.02%) 18 (2.27 43. Hence.8 15.87 Cement with amine-based GA at 460 g/ton 1 2 39.1 and 51. cm2 /g R-90.27 (0%) ? Water demand.3 5.02%) 215 6.5 (1.27 3870 39.and amine-based GA led to reduced Ec to 39. the R-45 increased from 18% for the control cement to 23. The 28-day compression was differently affected by GA additions.888 27.5 0. The significantly reduced absolute Ec values that resulted from industrial grinding could be related to a combination of phenomena including improved grinding energy due to the presence of 2 compartments with different ball sizes and .97%) The mean of two values is considered for analysis.4 6.6% ± 0.5 (5.33 kWh/ton. For example. excessively high Ec was required to secure a cement Blaine of 3850 ± 75 cm2 /g when grinding was realized in the laboratory mill.7%) 14.33 40.32%) 212.21%) 14.3 (4.6 MPa (i.4 0.48%) 25.3.7 (6. min 43.e. as a consequence of GA additions [6.8 27.. MPa 7.and amine-based GA was used.36%) ?0 .15 (0.893 Final setting.92 27.5 (1.65%) 27.27 kWh/ton in laboratory grinding. the increase in compressive encountered with the use of amine-based GA can be attributed to the presence of TIPA molecules.4 (5.33 3792 (0. a certain amount of fine material was produced during grinding of mixtures containing GA due to reduced level of agglomeration.1 210 3880 23.5 MPa for the control mortar compared to 16.1 and 16.26%) 220 (3.23 and 40.782 24.05 (7.6 (2. kWh/ton Blaine. Conversely. thus widening the PSD curves while maintaining similar Blaine fineness (refer to Figure 2).23 (1.1.e.3 27.91%) 0.4 19. 10. [27] reported that GAs added during clinker processing in industrial mills lead to narrow PSD. industrial versus laboratory).891 when grinding was realized in industrial or laboratory conditions. ? of 1. Katsioti et al.92 12. respectively. setting time.3. respectively. lower ? factor) [8.15% compared to 28.e. Yet.34% to 6. unlike the steeper trend that resulted from industrial tests. The remarkable changes in cement PSD curves generated during industrial and laboratory grinding are well documented in the literature.3.79% in the laboratory mill.54% when industrial grinding was realized using the glycol. that is. it is clear that laboratory grinding widens the cement PSD curve and shifts it towards higher diameters.e. respectively. 13]. Comparison of Cement Fineness.65% ± 0. the decrease in Ec varied from 17. 265 min) .796 with laboratory grinding.35 ?m.4 22. and ? determined on control cement and those containing glycol. Additionally.. Among the most influential parameters that may lead to increased Ec variations in industrial mills could be the ventilation system that helps optimizing the MRT at which the product passes through the tube as a result of reduced cement agglomeration [11. In other words. ?0 . 27. 3.and amine-based GA following industrial or laboratory grinding are plotted in Figure 5.15% in industrial grinding). This phenomenon is mostly attributed to different mill operational modes (i. laboratory grinding led to reduced water demand (i. For example.9 24. which could be related to enhanced packing density resulting from increased PSD wideness (i.6% ± 0. as compared to laboratory mill. 3. The variations in R45.2 to 24. Compared to data obtained from industrial tests.34 10 10 40. it is important to note that the widening of PSD and shifting towards larger diameters were particularly accentuated with GA additions during laboratory grinding. 25. For example.or amine-based GA. this suggests that the assessment of GA influence on Ec under laboratory conditions is adequate for comparison purposes of various GAs within each other.052 obtained from industrial test realized with glycol-based GA dropped considerably to 0.33 39..8 Advances in Materials Science and Engineering 50 50 43. 12]. 18]. however. Comparison of Cement Properties. Conversely.e.946 to 0. such tests underestimate the actual performance that could be achieved in real-scale mills.e.23 40 40 6..27 27. while the corresponding ?0 increased from 16.3.2.8 to 27.. Generally speaking. For example. respectively. enhanced screening efficiency associated with the CL [9. respectively.9 20 17. with the exception of two cement mixtures including the one industrially ground with glycol-based GA (i.54 Ec variations due to GA additions Ec variations due to GA additions 30 30 20 9. and compressive strength is plotted in Figure 6. given the reduced percentage of very fine particles lower than around 1 ?m. Regardless of the grinding conditions (i. it is important to note that the decrease in Ec due to GA is around twofold higher when grinding was performed in industrial mill.79 0 0 Control Glycol GA Industrial mill Amine GA Ec (kWh/ton) Decrease in Ec due to GA addition (%) Control Glycol GA Amine GA Laboratory mill Ec (kWh/ton) Decrease in Ec due to GA addition (%) Figure 4: Ec and its rate of decrease due to GA additions during industrial and laboratory grinding. For instance. The setting time remained almost unchanged at 220 ± 10 min. The corresponding ?0 increased from 19. 29]. when grinding is realized in laboratory mills. mainly the CL) that directly influence amount of fine particles including the overall PSD curves.92% to 12. the use of glycol-based GA showed enhanced reduction in Ec as compared to the amine-based one (Figure 4). The comparison between industrial and laboratory grinding following GA addition on water demand. the ? parameter of the control cement decreased from 0.3 ?m. the percentage of such fine particles increases due to reduced cement agglomeration resulting from the presence of GAs [8..e. Such variation was from 9. and late-age compressive strengths are differently affected by the grinding method.7 0.e.1 MPa in laboratory grinding. the 1-day compression for the mortar containing cement ground with glycol-based GA varied from 12.7 Control Glycol GA Industrial mill Amine GA Control Glycol GA Laboratory mill 30 30 25 R-90 = 2. while the highest 28-day values were obtained from industrial grinding.17% 15 Cement fineness characteristics Cement fineness characteristics R-90 = 7.759 0.05% 20 Amine GA 25 R-90 = 6.Advances in Materials Science and Engineering 9 Blaine = 3850 ± 75 cm2 /g 1. the reduced setting encountered in the latter case could be associated with increased fine cement particles generated during laboratory grinding and acceleration of hydration reactions due to the TIPA molecules [2. For instance. the highest 1day strengths were achieved from laboratory grinding. 197.8 0.891 0.041 1 Slope of PSD (n factor) 1 Slope of PSD (n factor) Blaine = 3850 ± 75 cm2 /g 1.55% 20 15 10 10 Control Glycol GA Industrial mill Amine GA R-45 (%) d0 (?m) Control Glycol GA Amine GA Laboratory mill R-45 (%) d0 (?m) Figure 5: Comparison of cement fineness characteristics that resulted from industrial and laboratory grinding mills due to GA additions. The early. Conversely.9 0.. hence.946 0.1 0. As already noted. In the former case.5 min). The corresponding 28-day compression varied from 54.1 MPa. respectively.796 0.67 to 43.9% R-90 = 1. and the one ground in laboratory using the amine-based GA (i. this .8 0.052 1.26 MPa in industrial grinding to 16.76% R-90 = 0. the excessive lengthening in setting can be attributed to the couple effect of reduced fine particles as well as adsorption of glycol molecules onto cement grains that could retard hydration reactions over time [8]. 6].1 1.05% R-90 = 5.9 0. 28-day comp.6% ± 0. ventilation. Glycol GA Laboratory mill Amine GA 1-day comp. Grinding was realized for fixed Blaine fineness of 3850 ± 75 cm2 /g.15% 280 280 245 240 220 220 Setting time (min) Setting time (min) 265 260 260 Water demand = 27. 300 300 Water demand = 28. It mainly seeks to evaluate the scale effect by comparing the results obtained from the closed-circuit tube mill operating at around 90 ton/hr to those determined using a 50-liter laboratory mill. 4. given the adapted operational mode for enhanced clinker processing such as the presence of 2 compartments and improved screening associated with the rotor separator.and aminebased GAs on mill performance and cement properties.10 Advances in Materials Science and Engineering 18 65 Blaine = 3850 ± 75 cm2 /g 65 Blaine = 3850 ± 75 cm2 /g 60 14 50 12 1-day compressive strength (MPa) 55 28-day compressive strength (MPa) 1-day compressive strength (MPa) 60 16 16 55 14 50 12 45 45 10 10 40 Control Glycol GA Industrial mill 28-day compressive strength (MPa) 18 Amine GA 40 Control 1-day comp. .5 197. Summary and Conclusions This research project was initiated following an industrial test undertaken to validate the effect of glycol.65% ± 0. Compared to laboratory tests. and CL. 28-day comp. can be related to variations in the fine-to-coarse cement particles generated from each grinding method and their influence on cement hydration reactions and strength development over time. remarkably reduced Ec was required during industrial grinding.15% 240 220 220 212.5 200 200 180 180 Control Glycol GA Industrial mill Amine GA Control Glycol GA Laboratory mill Amine GA Figure 6: Comparison of cement properties that resulted from industrial and laboratory grinding mills due to GA additions. J. 29–36. M. G. pp. Canevet. E. J. [14] D.” ASTM C191-08. no. however. Ergun. E. Springer. “Modelling cement grinding circuits. pp. 2011. Benzer.” Cement and Concrete Research. 63.e. The setting time remained almost unchanged at 230 ± 15 min. “Why TIPA leads to an increase in the mechanical properties of mortars whereas TEA does not. Middle East Technical University (METU). and C. or [50-mm] cube . 1995. West Conshohocken. 1. Tsimas. “Mechanisms and effects of additives from the dihydroxy-compound class on Portland cement grinding. Haecker.” in Proceedings of the Petrochem Conference. Zhang and T. L. 217. Miller. 2003. Buchanan. 191. 1. vol. the highest 1-day compressive strength was achieved from laboratory grinding. Quality. with the exception of the cement industrially ground with glycol GA (i. [5] J. “Use of cement grinding aids to optimise clinker factor. On the other hand. Mejeoumov. pp. Assaad and C. 265 min) and the one ground in laboratory using amine GA (i. as compared to laboratory mill. Tex. ASTM C187-11e1. 2015.” National Institute of Standards and Technology Report 6883. Ankara. unlike the steeper trend that resulted from industrial tests.” ACI Materials Journal. 2001. Pa. Doncaster. Pourchet. Issa. pp. “Standard test methods for fineness of hydraulic cement by air-permeability apparatus. ASTM International.” Cement and Concrete Research. compared to those ground in industrial scale. 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This suggests that the assessment of GA influence on Ec under laboratory conditions is adequate for comparison purposes of various GAs. J. Baabda. while the highest 28-day strength was obtained from industrial grinding. surface area and chemical composition on Portland cement strength. pp. 1663–1671. 2008. “Standard specification for coal fly ash and raw or calcined natural pozzolan for use in concrete. “Standard test method for amount of water required for normal consistency of hydraulic cement paste. no. Assaad. Harb. Nonat. Perez. Garrault. Compared to industrial tests. “Analysis of the ASTM Round-Robin test on particle size distribution of portland cement: phase I. 6. 2010. Asseily. [10] G. such tests underestimate the actual performance that could be achieved in real-scale mills. vol. Lynch et al. [24] ASTM C109. USA. 9–15. Russia. no. US Department of Commerce. Pa. 1–11. no.” Minerals Engineering. J. 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