scholarly journals Effects of Calcination Conditions on the Formation and Hydration Performance of High-Alite White Portland Cement Clinker

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 494 ◽  
Author(s):  
Lei Huang ◽  
Geling Cheng ◽  
Shaowen Huang
Keyword(s):  
Portland Cement ◽  
Mineral Composition ◽  
Sintering Temperature ◽  
Cement Clinker ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Free Lime ◽  
Sintering Time ◽  
Portland Cement Clinker ◽  
White Portland Cement

The purpose of this study was to evaluate the effects of sintering temperature and sintering time on mineral composition of high-alite white Portland cement clinker and hydration activity of the clinker. Effects of sintering temperature and sintering time on clinker mineral composition, C3S polymorph and size and hydration heat release rate were analyzed by X-ray diffraction (XRD), scanning electron microscope (SEM), differential scanning calorimetry&Thermogravimetric Analysis (DSC-TG) and isothermal heat-conduction calorimetry. Results shown that, with the increase of sintering temperature (1450–1525 °C) and sintering time (60–240 min), free lime (f-CaO) in clinker decreased, C3S grain size increased, and C3S crystal type changed from T3 to M type and R type, which exhibits higher symmetry. The hydration activity of different C3S crystals ranged from high to low as follows: T3→M1→M3→R@.

Effects of CaF2 on the Formation Kinetics of Portland Cement Clinker

2011 ◽  
Vol 306-307 ◽  
pp. 966-969
Author(s):  
Chun Fang Wang ◽  
Zong Hui Zhou ◽  
Cai Xia Liu ◽  
Xin Cheng
Keyword(s):  
Portland Cement ◽  
Formation Rate ◽  
Reaction Rate Constant ◽  
Cement Clinker ◽  
X Ray Diffraction ◽  
Free Lime ◽  
X Ray ◽  
Formation Kinetics ◽  
Portland Cement Clinker ◽  
Kinetics Of

Through testing the amount of the free lime and the Loss ignition, the clinker formation rate, the reaction-rate constant (K) and the activation energy (Ea) were calculated according to the Gentling equation and Arrhenius equation. The effects of CaF2on the formation kinetics of Portland cement clinker were investigated by analyzing theKandEa. X-ray diffraction (XRD) and scanning electron Microscope (SEM) were used to characterize the phase composition and the morphology of the resulting samples. The results show that the silicate minerals formation is promoted when a proper amount of CaF2is doped into the raw meal. TheKincreased from 0.7450 ×10-5s-1to 7.1588 ×10-5s-1and theEadecreased from 386 kJ/mol to 122 kJ/mol when the amount of CaF2increased from 0.0% to 2.0% in mass. However, the results were reversed at the amount of CaF2exceeding 2%.

Effect of ZnO on the whiteness of white Portland cement clinker

2021 ◽  
Vol 143 ◽  
pp. 106372
Author(s):  
Jinzhen Li ◽  
Geling Cheng ◽  
Shaowen Huang ◽  
Pinghua Lian
Keyword(s):  
Portland Cement ◽  
Cement Clinker ◽  
Portland Cement Clinker ◽  
White Portland Cement

scholarly journals Evaluation of the reactivity of artificial mixtures of Portland cement clinker obtained by flame spray pyrolysis

2019 ◽  
Vol 16 (2) ◽  
pp. 110-117 ◽  
Author(s):  
Andrés Felipe Pinto ◽  
Jorge Iván Tobón ◽  
Natalia Betancur-Granados ◽  
Oscar Jaime Restrepo-Baena
Keyword(s):  
Portland Cement ◽  
Spray Pyrolysis ◽  
Cement Clinker ◽  
Flame Spray Pyrolysis ◽  
Mechanical Resistance ◽  
Flame Spray ◽  
X Ray Diffraction ◽  
Fundamental Properties ◽  
Portland Cement Clinker ◽  
Reaction With Water

The Portland cement clinker consists of 95% calcium oxide, silicon, aluminium and iron and 5% impurities of magnesium, sodium, potassium, titanium, sulfur, phosphorus and manganese. From the combination of two or more of the main oxides, the constituents of the white clinker are formed, corresponding to alite(3CaO.SiO2 or C3S), belite (2CaO.SiO2 or C2S) and celite (Ca3Al2O6 or C3A), which give cement its characteristic properties. The fundamental properties of cement are its mechanical resistance, chemical resistance, the speed of reaction with water and the heat given off in hydration. In this work, the reactivity of an artificial mixture of white clinker, formed from alite, belite and celite prepared by flame spray pyrolysis was evaluated. The phases were characterized by X-ray diffraction, scanning electron microscopy and microcalorimetry, to evaluate their formation and reactivity. The characterization showed that during the synthesis of belite, a greater amount of the polymorph alpha was produced, with some impurities. On the other hand, the synthesis of celite allowed the production of the polymorph CII. The reactivity was evaluated by microcalorimetry.

scholarly journals Morphological Analysis of White Cement Clinker Minerals: Discussion on the Crystallization-Related Defects

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Mohamed Benmohamed ◽  
Rabah Alouani ◽  
Amel Jmayai ◽  
Abdesslem Ben Haj Amara ◽  
Hafsia Ben Rhaiem
Keyword(s):  
Morphological Analysis ◽  
Xrd Analysis ◽  
Mineral Elements ◽  
Cement Clinker ◽  
Free Lime ◽  
X Ray ◽  
White Cement ◽  
Portland Cement Clinker ◽  
White Portland Cement ◽  
Mineralogical Phases

The paper deals with a formation of artificial rock (clinker). Temperature plays the capital role in the manufacturing process. So, it is useful to analyze a poor clinker to identify the different phases and defects associated with their crystallization. X-ray fluorescence spectroscopy was used to determine the clinker’s chemical composition. The amounts of the mineralogical phases are measured by quantitative XRD analysis (Rietveld). Scanning electron microscopy (SEM) was used to characterize the main phases of white Portland cement clinker and the defects associated with the formation of clinker mineral elements. The results of a study which focused on the identification of white clinker minerals and defects detected in these noncomplying clinkers such as fluctuation of the amount of the main phases (alite (C3S) and belite (C2S)), excess of the free lime, occurrence of C3S polymorphs, and occurrence of moderately-crystallized structures are presented in this paper.

Effect of Phosphogypsum on the Clinkerization Temperature of Portland Cement Clincker

2012 ◽  
Vol 730-732 ◽  
pp. 94-99 ◽  
Author(s):  
Maria Margarida Rolim Augusto Lima ◽  
L.F.C. Braz ◽  
Regina da Conceição Corredeira Monteiro ◽  
J.P. Veiga
Keyword(s):  
Compressive Strength ◽  
Portland Cement ◽  
Raw Materials ◽  
Cement Clinker ◽  
X Ray Diffraction ◽  
X Ray ◽  
Portland Cement Clinker ◽  
Alternative Material ◽  
Heating Up ◽  
Mineralogical Compositions

Phosphogypsum (PG) is a pollutant residue resulting from the production of phosphoric acid in the phosphated fertilizers industry. About 180 millions of tons of PG are generated worldwide per year, which originates storage problems because of the environmental restrictions and the high costs of storage spaces. Taking into account the mineralizer properties of PG it has been studied a way to valorize this residue as an alternative material in the production of Portland cement clinker. The PG and the raw-materials (limestone, marl, sand and iron oxide) were chemical, mineralogical and thermally characterized by X-ray fluorescence (XRF), X-ray diffraction (XRD) and differential thermal analysis and termogravimetric analysis (DTA/TGA). After milling, the phosphogypsum was mixed with the raw-materials in different amounts up to 10% weight. The raw mixtures were submitted to two types of firing schedules, heating up to 1500°C without any holding time or heating up to 1350°C and holding for 20 minutes. After firing, the clinkers were analyzed by optical microscopy, milled and characterized in terms of chemical and mineralogical compositions. The clinkers were used to produce cement mortar according to NP EN 196-1 standard. The resultant test specimens were mechanically tested at 2 and 28 days according to the same standard. The obtained results show a reduction of about 140°C in the clinkerization temperature, when a raw mixture with 5% phosphogypsum was used. Standard clinkers, without phosphogypsum addition, which were fired at 1500°C, originated test specimens with a compressive strength of 48.1MPa at 28 days. Test specimens produced with clinker containing 5% phosphogypsum present higher compressive strength values at 28 days, being 55.1MPa for clinkers produced at 1500°C, and 49.4 MPa for clinkers produced at 1350°C.

Study on Sintering Technology and Performance of Alite-Rich Cement Modified by C1.5Sr2.5A3S Mineral

2011 ◽  
Vol 306-307 ◽  
pp. 970-974
Author(s):  
Gui Qiang Li ◽  
Shou De Wang ◽  
Chao Nan Yin ◽  
Ling Chao Lu
Keyword(s):  
Compressive Strength ◽  
Low Temperature ◽  
Sintering Temperature ◽  
Test Method ◽  
Cement Clinker ◽  
X Ray Diffraction ◽  
Sintering Time ◽  
Orthogonal Test Method ◽  
New Type ◽  
And Performance

The effects of the sintering temperature, sintering time and contents of calcium strontium suphoaluminate (C1.5Sr2.5A3) on the sintering technology of the alite-rich cement clinker modified by C1.5Sr2.5A3were researched by the orthogonal test method. X-ray diffraction, scanning electron microscope-energy dispersive spectroscopy (SEM-EDS) and lithofacies analysis were used to investigate the compositions and structure of cement. The experimental results show that the optimal sintering temperature and sintering time of alite-rich cement clinker modified by C1.5Sr2.5A3are 1350 °C and 60 min, and the appropriate content of C1.5Sr2.5A3in the clinker is 2%. The introduction of C1.5Sr2.5A3in clinker can promote the formation of alite mineral at low temperature and decrease the sintering temperature of clinker by 100°C approximately. This new-type cement shows excellent mechanics properties. The compressive strength at 3d is up to 64.3MPa, which is increased by 26.7% comparing to that of alite-rich cement and the compressive strength at 28d is almost the same as that of alite-rich cement. For alite-rich cement clinker modified by C1.5Sr2.5A3calcinated at low temperature, alite still can be mass-formed, but the size decreases.

scholarly journals Use of Design of Experiments (DoE) to Model the Sulphate Agent Amount of (Ultra)Finely Ground and Fast Hardening Portland Cement Clinker

Materials ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 5573
Author(s):  
Tim Schade ◽  
Bernhard Middendorf
Keyword(s):  
Design Of Experiments ◽  
Portland Cement ◽  
Calcium Sulphate ◽  
Cement Clinker ◽  
X Ray Diffraction ◽  
Resource Saving ◽  
X Ray ◽  
Portland Cement Clinker ◽  
Material Sciences

This paper presents a model to calculate the sulphate agent amount and sulphate agent ratio for fine grounded and fast hardening Portland cement clinker. Despite sufficient knowledge about the influence of calcium sulphate on the hydration process of cement, the sulphate agent amount is mostly adjusted empirically. As a result, often a wide and unfeasible experimental matrix has to be tested. In this work, Design of Experiments (DoE) was used in combination with in-situ X-ray diffraction (XRD) tests to accurately adjust the sulphate agent of different finely ground cement by calculation. With only 42 tests, it was possible to analyse in total the influence of the sulphate agent, the grinding fineness and the use of C-S-H-seeds for the use in fast-hardening Portland cement-based systems. In addition, it was found that a hemihydrate to anhydrite content of 25/75 leads to a stabilisation of the hydrated system in the first 24 h of hydration. A model for the optimisation of the sulphate agent composition in dependency of the cement fineness could be determined. Furthermore, it was shown that the DoE also provides optimal results in material sciences in a resource-saving way.

scholarly journals Biocompatibility and setting time of CPM-MTA and white Portland cement clinker with or without calcium sulfate

2013 ◽  
Vol 21 (1) ◽  
pp. 32-36 ◽  
Author(s):  
Clovis Monteiro BRAMANTE ◽  
Marcia Magro KATO ◽  
Gerson Francisco de ASSIS ◽  
Marco Antonio Hungaro DUARTE ◽  
Norberti BERNARDINELI ◽  
...  
Keyword(s):  
Portland Cement ◽  
Calcium Sulfate ◽  
Setting Time ◽  
Cement Clinker ◽  
Portland Cement Clinker ◽  
White Portland Cement

̅̅Research on Calcination Condition of Alite-Rich Portland Cement Clinker with C2.75B1.25A3 S

2012 ◽  
Vol 450-451 ◽  
pp. 392-396
Author(s):  
Shou De Wang ◽  
Xiang Yang Guo ◽  
Ling Chao Lu
Keyword(s):  
Portland Cement ◽  
Mechanical Performance ◽  
Sintering Temperature ◽  
Test Method ◽  
Cement Clinker ◽  
Sintering Time ◽  
Cooling Method ◽  
Orthogonal Test Method ◽  
Calcium Sulphoaluminate ◽  
And Performance

Calcination condition and mechanical performance of alite-rich Portland cement with barium calcium sulphoaluminate mineral(C2.75B1.25A3S ) were investigated by the orthogonal test method in which the influencing factors included sintering temperature, sintering time and cooling method. The composition, structure and performance of the clinker were analyzed by the means of X-ray diffraction, scanning electron microscopy-energy dispersive spectroscopy and metallographic microscope. The results show that C2.75B1.25A3S mineral and alite can coexist in one clinker system. The introduction of C2.75B1.25A3S mineral to clinker system is benefit to promote the formation of alite at lower temperature. The optimal sintering temperature, sintering time and cooling method are 1380°C, 60 min and two-stage cooling, respectively. Under these processing conditions, the compressive strength of alite-rich Portland cement with barium calcium sulphoaluminate reaches 43.4, 80.6 and 123.8 MPa at 3d, 7d and 28d curing ages, respectively, which shows excellent performance of mechanical strength.

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