scholarly journals Comparative Analysis of Recycled Plaster Composition Determined by X-ray Powder Diffraction and Thermogravimetric Analyses

2021 ◽  
Vol 1 (2) ◽  
pp. 105-121
Author(s):  
Heloísa Cristina Fernandes Cordon ◽  
Mariana Silva Ferreira ◽  
Fabio Furlan Ferreira
Keyword(s):  
Comparative Analysis ◽  
Thermogravimetric Analysis ◽  
Powder Diffraction ◽  
Rietveld Method ◽  
Setting Time ◽  
Recycling Process ◽  
Solubility In Water ◽  
X Ray ◽  
Rapid Setting

Plaster is primarily used as a building material obtained by the calcination of gypsum. Its rapid setting time (time for the mixture to solidify) and the low quality of labor generate a large amount of nonused material. Due to its solubility in water, wasted gypsum cannot be disposed of in the environment, and its recycling process is encouraged. In this work, quantitative phase analyses (QPA) using X-ray powder diffraction (XRPD) data and the Rietveld method were carried out to determine the amounts of each compound present in commercial, hydrated, and laboratory-recycled plasters, and the results compared with those obtained by thermogravimetric analysis (TGA). It was inferred that the Rietveld method associated with XRPD data is quite efficient since it identifies compounds not seen in the TGA. Furthermore, the amount of water used in the preparation of hydrated samples influences the proper hydration of the material and, consequently, the recycled composition of the samples.

Rietveld Structure Refinement of Metastable Lithium Disilicate Using Synchrotron X-Ray Powder Diffraction Data From the Daresbury SRS 8.3 Diffractometer

1990 ◽  
Vol 5 (3) ◽  
pp. 137-143 ◽  
Author(s):  
R.I. Smith ◽  
A.R. West ◽  
I. Abrahams ◽  
P.G. Bruce
Keyword(s):  
Crystal Structure ◽  
Powder Diffraction ◽  
Diffraction Data ◽  
Rietveld Method ◽  
Structure Refinement ◽  
Powder Diffraction Data ◽  
X Ray ◽  
New Instrument ◽  
Diffraction Peaks

AbstractThe crystal structure of metastable Li2Si2O5, Fw = 150.05, has been refined by the Rietveld method using high resolution X-ray powder diffraction data recorded at the Daresbury Synchrotron Radiation Source on the new 8.3 diffractometer. Li2Si2O5, in keeping with many compounds of interest to the materials scientist, exhibits relatively broad diffraction peaks. It is important to establish the quality of crystal structure data that may be obtained from such materials on this new instrument. Various functions were used to model the peak shape from this instrument; a split-Pearson VII function appeared to be marginally superior to Pearson VII or Pseudo-Voigt functions. Refinement was carried out using the split-Pearson VII in the space group Pbcn (60) and terminated with a = 5.6871(6), b = 4.7846(5), c = 14.645(1) Å, V = 398.50 Å3, Z=4, Dc= 2.502 gcm−3, Rwp = 17.06, Rex = 14.48 and Χ2 = 1.39. The refined parameters are compared with those obtained from a previous single crystal X-ray determination.

Crystallographic study of ternary ordered skutterudite IrGe1.5Se1.5

2010 ◽  
Vol 25 (3) ◽  
pp. 247-252 ◽  
Author(s):  
F. Laufek ◽  
J. Návrátil
Keyword(s):  
Crystal Structure ◽  
Powder Diffraction ◽  
Diffraction Data ◽  
Rietveld Method ◽  
Crystallographic Data ◽  
Powder Diffraction Data ◽  
X Ray ◽  
Crystallographic Study ◽  
Related Phase ◽  
The Ideal

The crystal structure of skutterudite-related phase IrGe1.5Se1.5 has been refined by the Rietveld method from laboratory X-ray powder diffraction data. Refined crystallographic data for IrGe1.5Se1.5 are a=12.0890(2) Å, c=14.8796(3) Å, V=1883.23(6) Å3, space group R3 (No. 148), Z=24, and Dc=8.87 g/cm3. Its crystal structure can be derived from the ideal skutterudite structure (CoAs3), where Se and Ge atoms are ordered in layers perpendicular to the [111] direction of the original skutterudite cell. Weak distortions of the anion and cation sublattices were also observed.

Rietveld refinement of the solid-solution series: (Cu,Mg)SO4·H2O

1995 ◽  
Vol 10 (3) ◽  
pp. 189-194 ◽  
Author(s):  
C. L. Lengauer ◽  
G. Giester
Keyword(s):  
Solid Solution ◽  
Rietveld Refinement ◽  
Powder Diffraction ◽  
Rietveld Method ◽  
Structure Refinement ◽  
Solid Solution Series ◽  
Cation Site ◽  
Tg Analysis ◽  
X Ray ◽  
Solution Series

The kieserite-type solid-solution series of synthetic (Cu,Mg)SO4·H2O was investigated by TG-analysis and X-ray powder diffraction using the Rietveld method. Representatives with Cu≥20 mol% are triclinic distorted () analogous to the poitevinite (Cu,Fe)SO4·H2O compounds. Cation site ordering with preference of Cu for the more distorted M1 site was additionally proven by the structure refinement.

Rietveld Refinement of the BaTiO3 from X-Ray Powder Diffraction

2009 ◽  
Vol 79-82 ◽  
pp. 593-596
Author(s):  
Feng Sun ◽  
Yan Sheng Yin
Keyword(s):  
Rietveld Refinement ◽  
Powder Diffraction ◽  
Diffraction Data ◽  
Rietveld Method ◽  
Structural Parameters ◽  
Ferroelectric Ceramic ◽  
Powder Diffraction Data ◽  
Ceramic Powders ◽  
Space Group ◽  
X Ray

The ferroelectric ceramic BaTiO3 was synthesized at 1000 °C for 5 h. The structure of the system under study was refined on the basis of X-ray powder diffraction data using the Rietveld method. The system crystallizes in the space group P4mm（99）. The refinement of instrumental and structural parameters led to reliable values for the Rp, Rwp and Rexp.We use the TOPAS software of Bruker AXS to refine this ceramic powders and show its conformation

Crystal structure of potassium tetraperoxomolybdate (VI) K2[Mo(O2)4]

2005 ◽  
Vol 20 (3) ◽  
pp. 203-206 ◽  
Author(s):  
M. Grzywa ◽  
M. Różycka ◽  
W. Łasocha
Keyword(s):  
Crystal Structure ◽  
Low Temperature ◽  
Diffraction Pattern ◽  
Powder Diffraction ◽  
Rietveld Method ◽  
Structure Refinement ◽  
Crystal Structure Refinement ◽  
Unit Cell Parameters ◽  
X Ray ◽  
Cell Parameters

Potassium tetraperoxomolybdate (VI) K2[Mo(O2)4] was prepared, and its X-ray powder diffraction pattern was recorded at low temperature (258 K). The unit cell parameters were refined to a=10.7891(2) Å, α=64.925(3)°, space group R−3c (167), Z=6. The compound is isostructural with potassium tetraperoxotungstate (VI) K2[W(O2)4] (Stomberg, 1988). The sample of K2[Mo(O2)4] was characterized by analytical investigations, and the results of crystal structure refinement by Rietveld method are presented; final RP and RWP are 9.79% and 12.37%, respectively.

scholarly journals Structural Properties Analysis of Mg-β-TCP by X-ray Powder Diffraction with the Rietveld Refinement

2020 ◽  
Vol 9 (4) ◽  
pp. 1562-1568
Keyword(s):  
Powder Diffraction ◽  
Rietveld Method ◽  
Quantitative Phase Analysis ◽  
Structural Refinement ◽  
Osteoporosis Therapy ◽  
X Ray ◽  
Cell Parameters ◽  
Biomineralization Process ◽  
Resultant Powder ◽  
Rapid Reaction

The incorporation of magnesium in the synthetic apatite has been associated with the biomineralization process and osteoporosis therapy in humans and animals. β-tricalcium phosphate (β-TCP) is one of the most common bioceramics widely applied in bone cement and implants. In this work, Ca-deficient apatite (CDA) with a theoretical 0.08 Mg/(Ca+Mg) ratio was synthesized by the rapid reaction between Ca(OH)2, MgCl2.6H2O and H3PO4 at 40°C and the resultant powder calcined at 650 °C for 10h. X-ray powder diffraction analysis (XRD), in combination with the Rietveld method (Fullprof-suite), was employed for quantitative phase analysis and structural refinement. The results of XRD indicate that magnesium can substitute for calcium into a β-TCP structure inducing a reduction of the cell parameters and the compound crystallizes in the rhombohedral R3c structure, with the following unit cell constants: a = b = 10.3560 Å, c = 37.1718 Å, and cell volume V = 3452.44. The analysis indicated that the substitution of Mg2+ on the M(4) and M(5) sites were, approximately, 2.61 and 6.97 mol%, corresponding to the Ca2.72(MgIV0.07, MgV0.21)(PO4)2 stoichiometric formula and 0.09 Mg/(Ca+Mg) ratio.

Powder X-ray diffraction study of disilver(1+) pentacyanonitrosylferrate(2−)

1999 ◽  
Vol 14 (3) ◽  
pp. 219-221 ◽  
Author(s):  
V. Venegas ◽  
A. Gómez ◽  
E. Reguera
Keyword(s):  
Crystal Structure ◽  
Thermogravimetric Analysis ◽  
Diffraction Study ◽  
Powder Diffraction ◽  
Lattice Parameters ◽  
X Ray Diffraction ◽  
Density Measurements ◽  
X Ray

The crystal structure of disilver(1+) pentacyanonitrosylferrate(2−) was studied by X-ray powder diffraction. IR and Mössbauer spectroscopies, thermogravimetric analysis and density measurements were also carried out. This compound is monoclinic, and its lattice parameters are: a=10.986(3) Å, b=6.4080(10) Å, c=7.4545(19) Å, α=δ=90°, β=102.54°(2).

Structure Refinements of the Layered Intergrowth Phases SbIIISbV x A 1−x TiO6 (x≃0, A = Ta, Nb) Using Synchrotron X-ray Powder Diffraction Data

1997 ◽  
Vol 53 (6) ◽  
pp. 861-869 ◽  
Author(s):  
C. D. Ling ◽  
J. G. Thompson ◽  
S. Schmid ◽  
D. J. Cookson ◽  
R. L. Withers
Keyword(s):  
Single Crystal ◽  
Powder Diffraction ◽  
Diffraction Data ◽  
Homologous Series ◽  
Rietveld Method ◽  
Powder Diffraction Data ◽  
X Ray Diffraction ◽  
Synchrotron Source ◽  
X Ray ◽  
The Family

The structures of the layered intergrowth phases SbIIISb^{\rm V}_xAl-xTiO6 (x \simeq 0, A = Ta, Nb) have been refined by the Rietveld method, using X-ray diffraction data obtained using a synchrotron source. The starting models for these structures were derived from those of Sb^{\rm III}_3Sb^{\rm V}_xA 3−xTiO14 (x = 1.26, A = Ta and x = 0.89, A = Nb), previously solved by single-crystal X-ray diffraction. There were no significant differences between the derived models and the final structures, validating the approach used to obtain the models and confirming that the n = 1 and n = 3 members of the family, Sb^{\rm III}_nSb^{\rm V}_xA n−xTiO4n+2 are part of a structurally homologous series.

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