Effect of Fly Ash Composition and Structure on the Formation of Cement Clinker

2016 ◽  
Vol 680 ◽  
pp. 429-434 ◽  
Author(s):  
Ya Li Wang ◽  
Su Ping Cui ◽  
Gui Ping Tian ◽  
Ming Zhang Lan ◽  
Zhi Hong Wang
Keyword(s):  
Fly Ash ◽  
Empirical Formula ◽  
Liquid Phase Sintering ◽  
Cement Industry ◽  
Cement Clinker ◽  
Thermal Calculation ◽  
Chemical Thermodynamics ◽  
Solid Phase Reaction ◽  
Phase Reaction ◽  
Formation Heat

In the view of scarce of natural mineral resources and requirement of energy-saving/emission-reducing for cement industry, the natural silicon-aluminum clay as one cement raw material has been gradually replaced by silica-rich industrial wastes, such as, fly ash, a principal solid waste discharged from coal-fired power plants, composed mainly of silica- and alumina-rich glass bead-shaped mineral. Using fly ash to produce cement raw materials, the formation and chemical reactions of cement clinker are affected by the chemical and mineral composition as well as the texture of the fly ash and the paper was focused on it. The empirical formula for formation heat of fly ash-doped cement clinker is revised on the basis of chemical thermodynamics. The results show that with the use of fly ash, in contrast with the traditional ingredients, the formation of varieties of clinker minerals as well as the formation sequence and types of intermediates varied little, while the maximum decomposition temperature of carbonate was lowered by 50 °C approximately, so that both the solid phase reaction temperature and liquid phase sintering point were decreased, which is favorable to the reduction of clinker formation heat. The revised formation heat empirical formula of fly ash-doped clinker could facilitate the thermal calculation of furnaces and the evaluation of thermal efficiency.

scholarly journals Структурные фазовые превращения при твердофазной реакции в тонких двухслойных пленках Al/Pt

2018 ◽  
Vol 60 (7) ◽  
pp. 1397
Author(s):  
Р.Р. Алтунин ◽  
Е.Т. Моисеенко ◽  
С.М. Жарков
Keyword(s):  
Thin Films ◽  
Electron Diffraction ◽  
Phase Transformations ◽  
Solid Phase ◽  
Structural Phase ◽  
Solid Phase Reaction ◽  
Phase Reaction ◽  
Formation Heat ◽  
Structural Phase Transformations

AbstractA sequence of phases forming during the solid-phase reaction in Al/Pt bilayer thin films has been investigated by in situ electron diffraction. It is shown that the amorphous PtAl_2 phase forms first during the solid-phase reaction initiated by heating. Upon further heating, PtAl_2, Pt_2Al_3, PtAl, and Pt_3Al crystalline phases sequentially form, which is qualitatively consistent with an effective formation heat model. The content of phases forming during the reaction has been quantitatively analyzed and the structural phase transformations have been examined.

Pressureless Sintering and Characterization of Al2O3-SiO2-ZrO2 Composite

2012 ◽  
Vol 329 ◽  
pp. 113-128 ◽  
Author(s):  
G. Mebrahitom Asmelash ◽  
Othman Mamat
Keyword(s):  
Fracture Toughness ◽  
Flexural Strength ◽  
Sintering Temperature ◽  
Liquid Phase Sintering ◽  
Pressureless Sintering ◽  
Oxide Ceramic ◽  
Solid Phase Reaction ◽  
Phase Reaction ◽  
X Ray Diffraction ◽  
X Ray

An Oxide Ceramic-Based Composite in the Al2o3-Sio2-Zro2(ASZ) System Was Developed and Investigated Using a Pressureless Sintering Route. the Effect of the Content of each Component and Sintering Temperature upon the Microstructure, Density, Hardness and Strength Was Studied. X-Ray Diffraction (XRD) and Field Emission Scanning Electron Microscopy (FESEM) Were Used to Investigate the Phase Transformation Sequences of the ASZ Composite System. the Flexural Strength Was Measured Using Three-Point Bending Method on a Universal Testing Machine, while the Indentation Fracture (IF) Method Was Used to Determine the Fracture Toughness of the Composite. the Results Showed that, with Varying Zro2Content, Keeping the Silica Content Constant and the Alumina as a Matrix, Densification Tends to Decrease as the Content of Zirconia Increases from 20 Wt. % of the Composition. X-Ray Diffraction Peaks Indicated Fully Developed Alumina, Mullite and Zirconia Phases due to Solid-Phase Reaction and Liquid-Phase Sintering of the System. the Experimental Results Also Revealed that, for a Sintering Temperature of 1500°C, the Hardness Value Ranged from 12 Gpa to 14 Gpa and the Flexural Strength Was 420±31MPa.The Fracture Toughness (KIc) Was Also Reported to Be between 4.5 and 5.1 Mpa.m1/2, for Samples Sintered at a Temperature of 14500C.

scholarly journals The use of ternary cements to reduce the environmental impact of concrete

2016 ◽  
Vol 1 ◽  
pp. 88 ◽  
Author(s):  
Kim-Séang Lauch ◽  
Vinciane Dieryck ◽  
Valérie Pollet
Keyword(s):  
Fly Ash ◽  
Environmental Impact ◽  
Carbon Capture ◽  
International Energy Agency ◽  
Carbon Capture And Storage ◽  
Cement Industry ◽  
Cement Clinker ◽  
Energy Agency ◽  
Blended Cements ◽  
The World

In the current context of climate change, reducing the greenhouse gas emissions is one of the greatest challenges of our society. As concrete is the second most used material in the world after water, its environmental impact is significant, especially because of the production of cement. Clinker substitution is according to the International Energy Agency and the World Business Council for Sustainable Development one of the four main reductions levers for the cement industry. Unlike Carbon Capture and Storage technology, replacing clinker with by-products such as fly ash and blast-furnace slag is technically feasible and applicable today. The use of blended cements is nowadays more and more commonly widespread. Ternary cements is particularly advantageous to benefit the synergetic action of two substitutes such as fly ash and limestone filler. Cement standard EN 197-1 is evolving towards more ternary binders but their impact on concrete properties are not thoroughly investigated yet. This paper presents some effects of newly developed ternary cements on concrete. The use of composite cements is a compelling solution to reduce the environmental impact of concrete but it is necessary to always assess their suitability in concrete.

scholarly journals Synthesis and Characterization of a Hybrid Cement Based on Fly Ash, Metakaolin and Portland Cement Clinker

Materials ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1084 ◽  
Author(s):  
Adriagni C. Barboza-Chavez ◽  
Lauren Y. Gómez-Zamorano ◽  
Jorge L. Acevedo-Dávila
Keyword(s):  
Fly Ash ◽  
Portland Cement ◽  
Ordinary Portland Cement ◽  
Cementitious Materials ◽  
Cement Industry ◽  
Supplementary Cementitious Materials ◽  
Cement Clinker ◽  
Dense Matrix ◽  
X Ray ◽  
Reduction Of Co2

Hybrid cement has become one of the most viable options in the reduction of CO2 emissions to the environment that are generated by the cement industry. This could be explained by the reduction of the content of clinker in the final mixture and substitution of the remaining percentage with supplementary cementitious materials with the help of an alkaline activation. Following that, properties that are provided by an Ordinary Portland Cement and of a geopolymer are mixed in this type of hybrid material and could be achieved at room temperature. Thereafter, the main objective of this research was to synthesize hybrid cements reducing the clinker content of Portland Cement up to 20% and use metakaolin and fly ash as supplementary cementitious materials in different proportions. The mixtures were alkaline activated with a mixture of sodium silicate and sodium hydroxide, calculating the amounts according to the percentage of Na2O that is present in each of the activators. The samples were then characterized using Compressive strength, X-ray diffraction, Fourier Transform Infrared Spectroscopy, and Scanning Electron Microscopy with energy-dispersive X-ray spectroscopy. The results indicated that the hybrid cements have similar mechanical properties than an Ordinary Portland Cement, and they resulted in a dense matrix of hydration products similar to those that are generated by cements and geopolymers.

scholarly journals Investigation of fly ash properties with purpose of its utilization as a secondary raw material for portland cement clinker production

2006 ◽  
Vol 60 (9-10) ◽  
pp. 245-252 ◽  
Author(s):  
Zvezdana Bascarevic ◽  
Miroslav Komljenovic ◽  
Ljiljana Petrasinovic-Stojkanovic ◽  
Natasa Jovanovic ◽  
Aleksandra Rosic ◽  
...  
Keyword(s):  
Fly Ash ◽  
Portland Cement ◽  
Power Plants ◽  
Building Materials ◽  
Thermal Power ◽  
Cement Industry ◽  
Raw Material ◽  
Cement Clinker ◽  
Physical Chemical ◽  
Portland Cement Clinker

In this paper the results of the investigated properties of fly ash from four thermal power plants in Serbia are presented. The physical, chemical, mineralogical and thermal characterization of fly ash was carried out, in order to determine the possibility to utilize this material in the building materials industry, foremost in the cement industry. It was determined that, although there are differences concerning the physical, chemical, and mineralogical characteristics of the investigated samples, they are very similar concerning their thermal characteristics. It was concluded that using fly ash as one of the raw components in the mixture for Portland cement clinker synthesis, not only enables the substitution of natural resources, but it might have a positive effect on the lowering of the sintering temperature.

scholarly journals Fe3O4@C Nanoparticles Synthesized by In Situ Solid-Phase Method for Removal of Methylene Blue

Nanomaterials ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 330
Author(s):  
Hengli Xiang ◽  
Genkuan Ren ◽  
Yanjun Zhong ◽  
Dehua Xu ◽  
Zhiye Zhang ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Solid Phase ◽  
Raw Materials ◽  
Phase Method ◽  
Maximum Adsorption Capacity ◽  
High Catalytic Activity ◽  
Solid Phase Reaction ◽  
Phase Reaction ◽  
High Concentrations

Fe3O4@C nanoparticles were prepared by an in situ, solid-phase reaction, without any precursor, using FeSO4, FeS2, and PVP K30 as raw materials. The nanoparticles were utilized to decolorize high concentrations methylene blue (MB). The results indicated that the maximum adsorption capacity of the Fe3O4@C nanoparticles was 18.52 mg/g, and that the adsorption process was exothermic. Additionally, by employing H2O2 as the initiator of a Fenton-like reaction, the removal efficiency of 100 mg/L MB reached ~99% with Fe3O4@C nanoparticles, while that of MB was only ~34% using pure Fe3O4 nanoparticles. The mechanism of H2O2 activated on the Fe3O4@C nanoparticles and the possible degradation pathways of MB are discussed. The Fe3O4@C nanoparticles retained high catalytic activity after five usage cycles. This work describes a facile method for producing Fe3O4@C nanoparticles with excellent catalytic reactivity, and therefore, represents a promising approach for the industrial production of Fe3O4@C nanoparticles for the treatment of high concentrations of dyes in wastewater.

The Effect on Cement Mortar and Concrete by Admixture of Spray Drying Absorption Products

1989 ◽  
Vol 178 ◽  
Author(s):  
Kirsten G. Jeppesen
Keyword(s):  
Grain Size ◽  
Fly Ash ◽  
Cement Mortar ◽  
Setting Time ◽  
Mineralogical Composition ◽  
Cement Clinker ◽  
Strength Development ◽  
Fall Meeting ◽  
Freeze Thaw ◽  
Spray Dried

AbstractSpray dried absorption products (SDA) having special characteristics are used as substitutes for cement in the preparation of mortars; the qualities of the resulting mixed mortars are described. Conditions are described for mortar mixes, data for which were presented at the MRS Fall Meeting 1987.The influence of the composition of the SDA on water requirement and setting time has been studied. A full scale project involving 3 precast, reinforced concrete front-elements containing 20 and 30 wt.% SDA is described. Strength development, mineralogical composition and corrosion were monitored for two years.A non-standard freeze-thaw experiment was performed which compares mortars containing SDA and fly ash (FA) and also shows the effect of superplasticizer.The possibility of improving the SDA by grinding has been tested and a limited improvement has been found. The strength of the mixed mortars seems slightly influenced by the grain size of SDAGypsum (CaSO4·2H2O), synthetic calcium-sulphite (CaSO3·½H2O) and 2 SDAs have been used as retarders for cement clinker. Mortar test prisms have been cast and comparative strengths after curing for 3 years are reported

Microstructure and Mechanical Properties of ZrB2/h-BN Multiphase Ceramics by Low-Temperature Reactive Sintering

2016 ◽  
Vol 697 ◽  
pp. 510-514 ◽  
Author(s):  
Feng Rui Zhai ◽  
Ke Shan ◽  
Ruo Meng Xu ◽  
Min Lu ◽  
Zhong Zhou Yi ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Relative Density ◽  
Fracture Strength ◽  
Solid Phase ◽  
Raw Materials ◽  
Solid Phase Reaction ◽  
Phase Reaction ◽  
Microstructure And Mechanical Properties ◽  
Multiphase Ceramics ◽  
Strength And Toughness

In the present paper, the ZrB2/h-BN multiphase ceramics were fabricated by SPS (spark plasma sintering) technology at lower sintering temperature using h-BN, ZrO2, AlN and Si as raw materials and B2O3 as a sintering aid. The phase constitution and microstructure of specimens were analyzed by XRD and SEM. Moreover, the effects of different sintering pressures on the densification, microstructure and mechanical properties of ZrB2/h-BN multiphase ceramics were also systematically investigated. The results show that the ZrB2 was obtained through solid phase reaction at different sintering pressures, and increasing sintering pressure could accelerate the formation of ZrB2 phase. As the sintering pressure increasing, the fracture strength and toughness of the sintered samples had a similar increasing tendency as the relative density. The better comprehensive properties were obtained at given sintering pressure of 50MPa, and the relative density, fracture strength and toughness reached about 93.4%, 321MPa and 3.3MPa·m1/2, respectively. The SEM analysis shows that the h-BN grains were fine and uniform, and the effect of sintering pressure on grain size was inconspicuous. The distribution of grain is random cross array, and the fracture texture was more obvious with the increase of sintering pressure. The fracture mode of sintered samples remained intergranular fracture mechanism as sintering pressure changed, and the grain refinement, grain pullout and crack deflection helped to increase the mechanical properties.

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