Secondary Sintering Cement Clinker in SO2 Atmosphere: Composition and Structure Effects

2021 ◽  
Vol 1036 ◽  
pp. 208-213
Author(s):  
Rui Kang ◽  
Su Hua Ma ◽  
Xiao Dong Shen
Keyword(s):  
Cement Clinker ◽  
Phase Content ◽  
Mixed Gas ◽  
Solid Reaction ◽  
Reaction Method ◽  
X Ray ◽  
Composition And Structure ◽  
Portland Cement Clinker ◽  
Different Temperatures ◽  
M1 Type

A gas-solid reaction method was adopted in this work to explore the influence of SO2 gas on the composition and structure of secondary sintering cement clinker. In this process, the Portland cement clinker was secondarily sintered at different temperatures and a mixed gas mixed with SO2 was introduced simultaneously in a tube furnace. X-ray powder diffraction (XRD) combined with rietveld refinement was used to determine the phase composition of the cement clinker and the corresponding phase content. The experimental results showed that the increase in temperature conduced to increasing the content of SO3 solid solution, C2S and CaO, but decreasing the C3S content. Moreover, as the ratio of SO3/MgO (by mass) increases, the content of M1-type alite also increased. And the result of hydration heat release was positively correlated with the content of alite in the clinker. If the content of alite was low, the heat flow was low, as well as the cumulative heat, and vice versa.

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%.

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.

Luminescence Behavior of Tm3+ Activated GdAlO3 Phosphors Synthesized Using Solid-Reaction Method

2014 ◽  
Vol 602-603 ◽  
pp. 32-37 ◽  
Author(s):  
Nan Wu ◽  
Xiao Dong Li ◽  
Shao Hong Liu ◽  
Yu Dong ◽  
Ji Guang Li ◽  
...  
Keyword(s):  
Decay Curve ◽  
Exchange Interactions ◽  
Solid State Reaction Method ◽  
X Ray Diffraction ◽  
Nanosized Powders ◽  
Reaction Method ◽  
X Ray ◽  
Pure Phase ◽  
Different Temperatures ◽  
High Color Purity

Trivalent thulium ions (Tm3+) doped GdAlO3 (Gd1-xTmxAlO3) phosphors which show a blue luminescence of high color purity have been synthesized by using solid-state reaction method starting from nanosized powders. X-ray diffraction (XRD) measurements were used to analyze the phase transformations that take place during the preparation of the phosphors. The morphologies of the powders calcined at different temperatures were studied by using scanning electron microscopy (SEM). The luminescence properties of the compounds were investigated. Pure phase of orthorhombic type GdAlO3 (GAP) was yielded by calcining the phosphors at 1200°C for 8 h. The PL spectra showed representative Tm3+ emission. The strong band centered at ~488 nm and the weak one centered at 697 nm were attributed to the 1D2-3F4 and 1G4-3F4 transitions of Tm3+, respectively. The quenching concentration of Tm3+ was estimated to be ~0.75at.% (x=0.0075), for which can be ascribed to the exchange interactions. The decay curve was fitted to be a single exponent and the estimated fluorescent lifetime of the GdAlO3:Tm3+ phosphor was 1.73±0.08 ms.

Adaptive Nanocomposite Films Exhibiting Low Friction in a Broad Temperature Range

2005 ◽  
Author(s):  
C. Muratore ◽  
A. A. Voevodin ◽  
J. J. Hu ◽  
J. S. Zabinski
Keyword(s):  
Photoelectron Spectroscopy ◽  
Multilayer Film ◽  
Solid Lubricants ◽  
Deposition Process ◽  
Nanocomposite Films ◽  
X Ray Diffraction ◽  
Low Friction ◽  
X Ray ◽  
Composition And Structure ◽  
Different Temperatures

A hybrid magnetron sputtering/pulsed laser deposition process was used to grow nanocrystalline yttria stabilized zirconia (YSZ) embedded in an amorphous YSZ/metal matrix. This nanocomposite design reduced friction and improved the toughness of YSZ. Films containing both silver and molybdenum exhibited friction coefficients between 0.2 and 0.4 in air (40% relative humidity) against silicon nitride balls at temperatures between 25° C and 700 °C. Additional solid lubricants reduced the friction coefficient to <0.2 for over 10000 cycles at all temperatures. A multilayer film architecture was developed to further enhance the lifetime of the adaptive coatings. Electron microscopy, x-ray diffraction and x-ray photoelectron spectroscopy were used to correlate adaptive behavior at different temperatures to the composition and structure of the films.

Structural and Dielectric Properties of Na0.5Bi0.5TiO3 Ferroelectric Ceramics

2012 ◽  
Vol 585 ◽  
pp. 219-223
Author(s):  
Rekha Kumari ◽  
N. Ahlawat ◽  
Ashish Agarwal ◽  
M. Sindhu ◽  
N.N. Ahlawat
Keyword(s):  
Dielectric Properties ◽  
Solid State Reaction Method ◽  
Wide Frequency Range ◽  
Ferroelectric Ceramics ◽  
Frequency Range ◽  
X Ray Diffraction ◽  
Conventional Solid State Reaction ◽  
Reaction Method ◽  
X Ray ◽  
Different Temperatures

Na0.5Bi0.5TiO3 (NBT) ceramics were synthesized by conventional solid state reaction method. Structural and dielectric properties of these ceramics were investigated. Crystalline phase of sintered ceramics was investigated by X-ray diffraction (XRD). The Rietveld refinement of powder X-ray diffraction revealed that the prepared ceramics exhibit the rhombohedral space group R3c. Dielectric properties of Na0.5Bi0. analyzer.5TiO3 (NBT) ceramics were studied at different temperatures in a wide frequency range using impedance

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