Studies on the kinetics of the carbothermic reduction of chromium oxide using the evolved gas analysis technique

1995 ◽  
Vol 262 ◽  
pp. 145-155 ◽  
Author(s):  
M.P. Antony ◽  
R. Vidhya ◽  
C.K. Mathews ◽  
U.V.Varada Raju
2007 ◽  
Vol 1047 ◽  
Author(s):  
James Pawel Lewicki ◽  
Deborah Todd ◽  
Perrine Redon ◽  
John Liggat ◽  
Lorraine Gibson

AbstractReported here is the development of a novel evolved gas analysis technique; Sub-Ambient Thermal Volatilization Analysis (SATVA) and its application in characterizing key analyte species from conservation artifacts. In this work SATVA has been applied to the study of volatiles evolution processes occurring in number of model conservation artifacts. The evolution of volatile species from cured formaldehyde resin, leather and metallic artifacts has been studied by SATVA. The specific analytes making up the total quantity of evolved material in each case have been separated and identified using sub-ambient differential distillation and a combination of online mass spectrometry, gas phase IR spectroscopy and GC-MS. The data gathered has been used to provide information on both the degradation processes occurring within the artifacts and the environmental history of the artifacts themselves.


2021 ◽  
Vol 9 ◽  
Author(s):  
Wasif Farooq ◽  
Imtiaz Ali ◽  
Salman Raza Naqvi ◽  
Mohd Sajid ◽  
Hassnain Abbas Khan ◽  
...  

This study investigates the efficacy of a prepared Ni/θ-Al2O3 catalyst during the pyrolytic conversion of Parachlorella kessleri HY-6 and compares the results with non-catalytic conversion. The catalyst was characterized by techniques such as Brunauer–Emmett–Teller (BET) for surface area, acidity, and X-ray powder diffraction (XRD). Isoconversional and combined kinetic methods were used to study the pyrolytic kinetics of the process. Ni/θ-Al2O3 was used at 10, 20, and 30% of the algal biomass. The addition of Ni/θ-Al2O3 facilitated the conversion by lowering the mean activation energy during pyrolysis. The catalytic effect was more pronounced at lower and higher conversions. The presence of the catalyst facilitated the pyrolysis as indicated by the lower value of activation energy and ∆H, and ∆G. Gases evolved during pyrolysis were qualitatively analyzed by FTIR to see the effect of catalyst on evolved gas composition during the pyrolysis process.


Minerals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 824
Author(s):  
Eulalia Zumaquero Silvero ◽  
Jessica Gilabert Albiol ◽  
Eva María Díaz-Canales ◽  
María Jesús Ventura Vaquer ◽  
María Pilar Gómez-Tena

Mineralogical characterization of clays used in manufacturing of traditional ceramic products is critical for guarantee the quality of the final product, but also for assessing the environmental impact of the industrial process in terms of atmospheric emissions. In fact, the presence of impurities even in low-level concentrations can have a big impact. So, it is very important to carry out an accurate mineral quantification of those minerals which are related to carbon dioxide and acid emissions (hydrogen fluoride, hydrogen chloride or sulfur dioxide). The development of hyphenated techniques coupling thermal analysis equipment with mass spectrometry and Fourier-transform infrared spectroscopy provides more valuable information and lower limit quantification than other primary techniques, such as X-ray diffraction or infrared spectroscopy. The main objective of this work is to develop an analytical procedure using evolved gas analysis to identify and quantify minerals such as chlorides, sulfides, carbonaceous materials and minor clay minerals. In addition to this, the study includes the analysis of acid emissions during the ceramic firing treatment even if they are present at low quantitative levels. This methodology was applied to reference materials so that it allows the identification of sulfur, chlorine, fluorine and carbonaceous compounds in concentrations lower than 1%.


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