scholarly journals Determination of Fe2+/Fe3+ mole ratio based on the change of precursor lattice parameters of wustite based iron catalysts for the ammonia synthesis

2019 ◽  
Vol 21 (3) ◽  
pp. 48-52
Author(s):  
Artur Jurkowski ◽  
Zofia Lendzion-Bieluń

Abstract In the presented article, oxide forms of iron catalysts with the wustite structure and with a R = Fe2+/Fe3+ molar ratio in the range from 3.78 to 8.16 were investigated. The chemical composition of the tested catalyst precursors was determined by inductively coupled plasma optical emission spectrometry (ICP-OES). The X-ray diffraction (XRD) technique was used to determine the phase composition and location of reflections characteristic of the Fe1−xO phase. The molar ratio of iron ions R = Fe2+/Fe3+ was determined by manganometric titration. The distribution of promoters in the structure of iron catalyst precursors with different R = Fe2+/Fe3+ ratio was determined by a selective etching method. The dependence of the lattice parameter ao value in the crystal structure Fe1−xO on the molar ratio R = Fe2+/Fe3+ was determined. On the basis of the determined dependence, R can easily be calculated in catalyst precursors of the wustite structure.

2020 ◽  
Vol 11 (1) ◽  
pp. 8034-8042

The incorporation of magnesium (Mg) in tricalcium phosphate (TCP) was prepared through a precipitation method followed by calcination at 850 °C in air. Calcium hydroxide, (Ca(OH)2), phosphoric acid, (H3PO4), and magnesium chloride (MgCl2.6H2O) with a Ca/P ratio of 1.5, were mixed as the precursor materials. The concentration of added Mg was varied with respect to calcium (Ca) precursor molarity as such Mg/(Ca +Mg) molar ratio was 0.05, 0.10, and 0.15, while the (Ca+Mg)/P ratio was maintained at 1.50 throughout the experiment. The influence of Mg-doped TCP on phase composition, chemical structure, and a functional group at different weight percentages were accomplished through X-ray diffraction (XRD), inductively coupled plasma optical emission spectroscopy (ICP-OES) and Fourier Transform Infrared Spectroscopy (FTIR) analyses. Based in the results of this research, the presence of magnesium led to the formation of Mg-doped calcium-deficient apatite (MgCDA) at 80°C and Mg-doped β-TCP at 850°C; the incorporation of Mg into the TCP phase causing an expansion of the lattice and increase in the lattice parameter. This result could be considered rather unusual.


Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3680
Author(s):  
Bo Li ◽  
Yaowu Wang ◽  
Bingliang Gao

A selective liquation process to extract Al from a coarse Al–Si alloy, produced by carbothermal reduction, was investigated on the laboratory scale. The products obtained by selective liquation–vacuum distillation were analyzed by X-ray diffraction, inductively coupled plasma optical emission spectrometry and scanning electron microscopy. During the selective liquation process with the use of zinc as the solvent, the pure aluminum in the coarse Al–Si alloy dissolved in the zinc melt to form an α-solid solution with zinc, and most of the silicon and iron-rich phases and Al–Si–Fe intermetallics precipitated and grew into massive grains that entered into the slag and separated with the Zn–Al alloy melt. However, some fine silicon particles remained in the Zn–Al alloy. Thus, Al–Si alloys conforming to industrial application standards were obtained when the Zn–Al alloys were separated by a distillation process.


Author(s):  
Masoud Aghahoseini ◽  
Gholamhassan Azimi ◽  
M. K. Amini

Determination of traces of Cd, Co, Cu, Mn and Pb elements in zirconium and its alloys by inductively coupled plasma optical emission spectrometry (ICP OES) suffers from severe spectral interferences...


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