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.

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%.

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.

Preparation of Portland Cement with Pumice

2011 ◽  
Vol 99-100 ◽  
pp. 733-738
Author(s):  
Shi Cai Cui ◽  
Xing Jun Lv ◽  
Jing Liu
Keyword(s):  
Mechanical Property ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Portland Cement ◽  
Cement Clinker ◽  
X Ray Diffraction ◽  
Calcine Temperature ◽  
X Ray ◽  
Portland Cement Clinker ◽  
Scanning Electron

The portland cement clinker was successfully produced using pumice as the principal materials. Effects of different calcine temperature on cement clinker were studied. Phase compositions of clinker were confirmed by combining the phase diagram with X-ray diffraction. Microstructures of clinker were analyzed by scanning electron microscope. From the result of mechanical property showed that the compression strength of clinker can be reached 35MPa. The result of scanning electron microscope showed that the main hydrating products were CSH gels, AFt and CH crystals, the morphology of which were normal. With the prolongation of hydrating age, the hydrating products were richer and the cement paste was densified.

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@.

Determination of amorphous phase levels in Portland cement clinker

2002 ◽  
Vol 17 (3) ◽  
pp. 178-185 ◽  
Author(s):  
Phe Man Suherman ◽  
Arie van Riessen ◽  
Brian O’Connor ◽  
Deyu Li ◽  
Dick Bolton ◽  
...  
Keyword(s):  
Portland Cement ◽  
Cement Clinker ◽  
Rietveld Refinements ◽  
Amorphous Component ◽  
X Ray ◽  
Absolute Phase ◽  
Portland Cement Clinker ◽  
External Phase ◽  
Long Time

The existence of glass or amorphous component in Portland cement clinker has been questioned for a long time. However, besides the crystalline phases, there are reports in the literature of noncrystalline material in cement clinker, which is considered to be the residue of the melt that has failed to crystallize. Absolute phase abundances were determined in this study by Rietveld refinements with laboratory X-ray data, using both internal and external phase composition standards. The results clearly demonstrate the existence of an amorphous component in Portland cement clinker. The presence of an amorphous component was also apparent from diffraction data for clinker from which the silicate phases had been chemically removed, using both laboratory X-ray and synchrotron radiation patterns.

Fabrication of Baking-free Bricks from Iron Ore Tailings

2020 ◽  
Vol 13 ◽  
Author(s):  
H. J. Chen ◽  
Zi Wang ◽  
Lizhai Pei ◽  
Z. Y. Xue ◽  
C. H. Yu ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Iron Ore ◽  
Raw Materials ◽  
X Ray Diffraction ◽  
Safety Hazard ◽  
Xrd Pattern ◽  
X Ray ◽  
Iron Ore Tailings ◽  
Brick Powder ◽  
Micro Morphology

Aims: The aim is to prepare baking-free bricks using iron ore tailings as the main raw materials. Objective: Iron ore tailings have increased dramatically in recent decades. The storage of the iron ore tailings has potential environmental and safety hazard. Therefore, it is urgent to use the tailings to produce valuable products. Objective: The objective of the research is to treat the tailings by preparing the baking-free bricks. Method: The phases and micro-morphology of the baking-free bricks have been investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The optimal components and preparation parameters of the baking-free bricks were determined by controlling the ratio of the raw materials and forming pressure. The physical properties of the baking-free bricks including compressive strength and density have been analyzed by controlling the forming pressure and curing time. Result: The optimal components of the baking-free bricks is 65wt.% tailings, 5wt.% titanium gypsum, 17wt.% slag, 5wt. Conclusion: Baking-free bricks have been successfully prepared from the iron ore tailings adding a small amount of cementing materials including titanium gypsum, slag, acetylene sludge and waste brick powder. Other: The XRD pattern and SEM observation show that 28 d tailing bricks are mainly composed of irregular particles and a large number of ettringite (Aft) nanorods. The analyzed results revealed that the formed irregular particles and Aft nanorods contribute to the improvement of compressive strength and compactness of the tailing bricks.

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