Investigation Of Pozzolanic Binders Using Sulpho-Calcic Fly Ashes

1988 ◽  
Vol 136 ◽  
Author(s):  
J. Pera ◽  
A. Sadr Momtazi ◽  
J. Dejean
Keyword(s):  
Blast Furnace Slag ◽  
Ambient Conditions ◽  
X Ray Diffraction ◽  
Fly Ashes ◽  
Hydrothermal Conditions ◽  
X Ray ◽  
Ambient Temperatures ◽  
Slaked Lime ◽  
Hydrated Product ◽  
Furnace Slag

ABSTRACTBecause of their high SO3 content (∼11%), sulfo-calcic fly ashes cannot be used as a cement admixture without pretreatment. The fly ashes contain mainly quicklime (CaO), anhydrite (CaSO4) and larnite (BC2S). At ambient temperatures and at normal consistency, their hydration leads to the formation of ettringite, slaked lime and gypsum. As a result, cracking and splitting of the hydrated product quickly occurs due to the crystallization of the ettringite.The ability of these fly ashes to produce Portlandite, Ca(OH)2, led the authors to investigate pozzolanic binders by the addition of artificial pozzolans — siliceous fly ashes, slag and clay minerals — which had been calcined at moderate temperatures.The sulfo-calcic fly ashes are ground, then slaked either in ambient or hydrothermal conditions (2 or 6 hours at 130°C). In the case of slaking under ambient conditions, ettringite is quickly produced with a definitive crystallographical structure. As a result, no volume change is observed after re-hydration of the material. By comparison, autoclave slaking does not lead to this phenomenon, and only slaked lime is produced.The rate of hydration is studied through the development of compressive strength and by analyses of the products by differential thermal analysis (DTA) and X-ray diffraction (XRD) at various hydration times. The best results are obtained using calcined laterite or blast furnace slag.

scholarly journals The Effects of Temperature on the Hydrothermal Synthesis of Hydroxyapatite-Zeolite Using Blast Furnace Slag

Materials ◽  
2019 ◽  
Vol 12 (13) ◽  
pp. 2131 ◽  
Author(s):  
G.U. Ryu ◽  
G.M. Kim ◽  
Hammad R. Khalid ◽  
H.K. Lee
Keyword(s):  
Blast Furnace ◽  
Hydrothermal Synthesis ◽  
Blast Furnace Slag ◽  
Raw Material ◽  
X Ray Diffraction ◽  
X Ray ◽  
Different Temperatures ◽  
Type Zeolite ◽  
Effects Of Temperature ◽  
Furnace Slag

Blast furnace slag, an industrial by-product, is emerging as a potential raw material to synthesize hydroxyapatite and zeolite. In this study, the effects of temperature on the hydrothermal synthesis of hydroxyapatite-zeolite from blast furnace slag were investigated. Specimens were synthesized at different temperatures (room temperature, 50, 90, 120, or 150 °C). The synthesized specimens were analyzed qualitatively and quantitatively via X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), BET/BJH, and scanning electron microscopy/energy dispersive using X-ray analysis (SEM/EDX). It was found that the hydroxyapatite phase was synthesized at all the reaction temperatures, while faujasite type zeolite appeared in the specimens synthesized at 90 and 120 °C. Moreover, faujasite was replaced by hydroxysodalite in the specimens synthesized at 150 °C. Additionally, the crystals of the hydroxyapatite tended to become larger and total crystallinity increased as the reaction temperature increased.

Development and Characterization of Cementing Composites with Blast Furnace Slag Replacement

2014 ◽  
Vol 976 ◽  
pp. 246-250
Author(s):  
Reyna Sánchez-Ramírez ◽  
Manuela Diaz-Cruz ◽  
Sebastían Díaz de La Torre ◽  
Enrique Rocha-Rangel
Keyword(s):  
Blast Furnace ◽  
Blast Furnace Slag ◽  
Bending Strength ◽  
Isothermal Calorimetry ◽  
Oil Wells ◽  
X Ray Diffraction ◽  
Hydration Kinetics ◽  
X Ray ◽  
Furnace Slag

In this work, they were produced and characterized cementing composites made with blast furnace slag replacement, for their use in the construction of oil wells. To this, slurries were prepared with a replacement of 20 and 30% slag, as well as a slurry with 100 % slag and a slurry with 100% H-cement were prepared. Starting materials were characterized by chemical analysis, X-ray diffraction and Fourier Transformed Infra Red. Slurries also were activated with sodium silicate in order to study theirs hydration kinetics, driving by isothermal calorimetry. These studies were complemented by the preparation of specimens of 4 X 4 X 16 cm to which they determine its compressive and bending strength during 2 and 28 days of curing. From the results it can be concluded that it was obtained a product that can be effectively used in the construction of oil wells.

Effect of Oxidation on Phase Transformation in Ti-Bearing Blast Furnace Slag

2013 ◽  
Vol 641-642 ◽  
pp. 363-366 ◽  
Author(s):  
Wu Zhang ◽  
Li Zhang ◽  
Nai Xiang Feng
Keyword(s):  
Phase Transformation ◽  
Blast Furnace ◽  
Blast Furnace Slag ◽  
Glass Phase ◽  
Perovskite Phase ◽  
Rutile Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Furnace Slag ◽  
Scanning Electron

Abstract. Effect of oxidation on phase transformation in Ti-bearing blast furnace slag is studied. The slag is analyzed by X-ray diffraction (XRD) and scanning electron microscope (SEM), EDX and metallographic microscope. The experiment results indelicate that the phase composition of the oxidized slag is simpler which are only rutile and glass phase. The titanaugite, Ti-rich diopside and perovskite phase are vanished and most of the Ti components were enriched in the rutile phase.

Influence of SiO2/Al2O3 Content on Structure and Hydration Activity of Granulated Blast Furnace Slag

2014 ◽  
Vol 633 ◽  
pp. 240-244 ◽  
Author(s):  
Su Ping Cui ◽  
Ling Ling Liu ◽  
Jing Chen ◽  
Ya Li Wang ◽  
Jian Feng Wang ◽  
...  
Keyword(s):  
Absorption Spectrum ◽  
Blast Furnace ◽  
Mechanical Testing ◽  
Infrared Radiation ◽  
Blast Furnace Slag ◽  
Actual Process ◽  
X Ray Diffraction ◽  
X Ray ◽  
Granulated Blast Furnace Slag ◽  
Furnace Slag

Granulated blast furnace slag (GBFS) is a by-product of manufacturing iron. Samples of GBFS with different ratio of SiO2/Al2O3 were prepared by simulating the actual process of GBFS in laboratory. This study investigated the influence of SiO2/Al2O3 content on structure and hydration activity of GBFS which were characterized by X-ray fluorescence (XRF), powder X-ray diffraction (XRD), infrared radiation (IR) and mechanical testing. It is found that the vitreous content of each sample is above 97% and the hydration activity indexes of 7d and 28d of samples significantly decrease with the increase of SiO2/Al2O3 ratio. The IR characteristic absorption spectrum shows that the silicates mainly exist in [SiO4]-tetrahedra and the aluminum atoms are in different coordination states and the bonding strengths rise with the increase of SiO2/Al2O3 ratio.

scholarly journals Autogenous Deformation of Alkali-Activated Blast Furnace Slag Concrete Subjected to Variable Curing Temperatures

2019 ◽  
Vol 2019 ◽  
pp. 1-8 ◽  
Author(s):  
Katalin Orosz ◽  
Abeer Humad ◽  
Hans Hedlund ◽  
Andrzej Cwirzen
Keyword(s):  
Blast Furnace ◽  
Diffraction Analysis ◽  
Sodium Silicate ◽  
Blast Furnace Slag ◽  
Curing Temperature ◽  
X Ray Diffraction ◽  
X Ray ◽  
Activated Slag ◽  
Furnace Slag ◽  
Alkali Activated

Deformations of alkali-activated slag concrete (AASC) with high MgO and Al2O3 content, subjected to variable curing temperature were studied. Sodium silicate and sodium carbonate were used as alkali activators. The obtained results showed development of deformations consisting of both shrinkage and expansion. Shrinkage appeared not to be affected by the activator type, while the expansion developed after the cooling down phase in stabilized isothermal conditions and did not stop within the duration of the tests. X-ray diffraction analysis performed shortly after the cooling down phase indicated the formation of crystalline hydrotalcite, which was associated with the observed expansion. A mixture with a higher amount of sodium silicate showed less expansion, likely due to the accelerated hydration and geopolymerization leading to the increased stiffness of the binder matrix.

The Occurrence of Special Components in Blast Furnace Slag of Baotou Iron and Steel Company

2012 ◽  
Vol 220-223 ◽  
pp. 117-122
Author(s):  
Guo Ping Luo ◽  
Yan Ban ◽  
Yi Ci Wang ◽  
Wen Wu Yu ◽  
Qi Jiang
Keyword(s):  
Blast Furnace ◽  
Blast Furnace Slag ◽  
Glass Ceramics ◽  
Optical Microscope ◽  
Aluminum Silicate ◽  
X Ray Diffraction ◽  
Silicate Mineral ◽  
Iron And Steel ◽  
X Ray ◽  
Furnace Slag

The mineral composition of the solidified blast furnace slag and the occurrence of special components CaF2, K2O, Na2O, RexOy and ThO2 were researched by optical microscope analysis, X-ray diffraction analysis and scanning electron microscopy and energy spectrum analysis. The results showed that the major minerals in solidified furnace slag are akermanite and gehlenite; the special component CaF2 is not hosted in the cuspidine (3CaO•2SiO2•CaF2), but in the magnesium and aluminum silicate mineral; the special components K2O，Na2O is hosted in akermanite, magnesium and aluminum silicate mineral and perovskite; the element thorium cannot form an independent mineral, but coexist with the rare earth element Ce in the perovskite. The results will lay a foundation for further study on the influence of these special components on the crystallization behavior of glass-ceramics.

Use of Angang Slag for the Production of Glass-Ceramic Materials

2008 ◽  
Vol 368-372 ◽  
pp. 1426-1428
Author(s):  
Hong Xia Lu ◽  
Tie Cui Hou ◽  
Zhang Wei ◽  
Li Jian Li ◽  
Rui Zhang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Blast Furnace ◽  
Blast Furnace Slag ◽  
Glass Ceramics ◽  
Ceramic Materials ◽  
Clay Brick ◽  
X Ray Diffraction ◽  
X Ray ◽  
Glass Ceramic Materials ◽  
Furnace Slag

The characteristic of Angang blast furnace slag was studied by X-ray fluorescence spectrometry, DSC, X-ray diffraction and SEM. SiO2-Al2O3-CaO system glass-ceramics have been obtained successfully from slag with other additives. The properties of slag-based glass-ceramics were analyzed in this paper. It has been found that nucleation temperature is in the range of 600~700 °C, and crystallization temperature is in the range of 850~950 °C. The crystals phase is 2 CaO⋅ Al2O3⋅ SiO2. The chemical and mechanical properties of slag-based glass-ceramics are superior to the properties of clay brick.

Temperature- and moisture-dependent powder X-ray diffraction studies of kanemite (NaSi2O4(OH)·3H2O)

2015 ◽  
Vol 79 (1) ◽  
pp. 103-120 ◽  
Author(s):  
Daniela Schmidmair ◽  
Volker Kahlenberg ◽  
Daniel M. Többens ◽  
Herwig Schottenberger ◽  
Jochem De Wit ◽  
...  
Keyword(s):  
Rietveld Method ◽  
Single Layer ◽  
Significant Loss ◽  
Monoclinic Space Group ◽  
Ambient Conditions ◽  
X Ray Diffraction ◽  
Orthorhombic Space Group ◽  
Space Group ◽  
X Ray ◽  
Ambient Temperatures

AbstractThe high-temperature- and moisture-dependent behaviour of synthetic kanemite (NaSi2O4(OH)·3H2O orSKS-10) has been studied byin situpowder X-ray diffraction. Heating experiments in the range between ambient temperatures and 250°C confirm earlier investigations that the dehydration of kanemite occurs in two steps. According to our results the two different reactions start at ∼30 and 75°C. The dehydration products have the following compositions: NaSi2O4(OH)·H2O (monohydrate) and NaSi2O4(OH), respectively. The crystal structures of both phases have been solved at ambient conditionsab initiofrom laboratory powder diffraction data using samples that have been carefully dehydrated at 60 and 150°C, respectively, and refined subsequently by the Rietveld method. Basic crystallographic data are as follows: NaSi2O4(OH)·H2O: orthorhombic, space groupPna21,a= 7.2019(1),b= 15.3252(2),c= 4.8869(1) Å,V= 539.37(1) Å3,Z= 4; NaSi2O4(OH): monoclinic, space groupP21,a= 6.3873(1),b= 4.8876(1),c= 7.1936(1) Å, β = 93.36(1)°,V= 224.19(1) Å3,Z= 2. Both compounds belong to the group of single-layer silicates based on Si2O4(OH) sheets. The sodium cations are located between the tetrahedral sheets and are surrounded by oxygen atoms from silicate anions and/or water molecules. Depending on the dehydration step the coordination numbers of the alkali ions vary between six (kanemite) and five (NaSi2O4(OH)). Kanemite and its two dehydration products show structural similarities which are discussed in detail. Moisture-dependent diffraction studies at ambient temperatures indicate that kanemite is stable between 10% and at least 90% relative humidity. Below the lower threshold a transformation to the monohydrate phase was observed. Dehydration and rehydration as a function of humidity is reversible. However, this process is combined with a significant loss of crystallinity of the samples.

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