Thermal behaviour of Moroccan phosphogypsum

Sebbahi, Saloua; Chameikh, Mohamed Lemine Ould; Sahban, Fatima; Aride, J.; Benarafa, L.; Belkbir, L.

doi:10.1016/s0040-6031(97)00159-7

Cited by 65 publications

(18 citation statements)

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“…Finally, an endothermic peak at $1217°C takes place due to the total decomposition of calcium sulphate into calcium oxide (CaO) and sulphur dioxide (SO 2 ). The results are in concordance with the results obtained by XRD and with other researchers [42,43]. Fig.…”

Section: Materials Characterisationsupporting

confidence: 93%

Influence of the addition of phosphogypsum on some properties of ceramic tiles

Contreras

Teixeira

Santos

et al. 2018

Construction and Building Materials

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Section: Materials Characterisationsupporting

confidence: 93%

Influence of the addition of phosphogypsum on some properties of ceramic tiles

Contreras

Teixeira

Santos

et al. 2018

Construction and Building Materials

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“…This is evidence of calcium sulfate formation after the collapse of the ettringite structure, which is consistent with Lea's work [42]. In addition, this fact demonstrates that the release of SO 3 did not occur by heating an ettringite sample up to 820 K. According to Sebbahi et al [59] and Ingo et al [60], the release of sulfur trioxide gas (SO 3 ) during calcium sulfate thermal decomposition starts slowly at temperatures above 1400 K and practically finishes around 1700 K.…”

Section: (C)supporting

confidence: 90%

Kinetic and thermal decomposition of ettringite synthesized from aqueous solutions

Guimarães

Oliveira

Leão

2016

J Therm Anal Calorim

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The kinetics of the thermal decomposition of a synthetic ettringite sample was studied between 298 and 820 K in an inert atmosphere for the present work. The ettringite and its thermal decomposition products were characterized using X-ray diffraction, infrared spectroscopy, and scanning electron microscopy. Four endothermic events were observed with thermogravimetry curves, the maxima of which occurred at 366, 397, 537, and 641 K. All events were associated with the loss of water molecules with different degrees of interaction within the ettringite structure. Chemical equations for each decomposition step were proposed based on the percentages of mass loss observed. In addition, for the first time, the activation energies of each ettringite decomposition events were determined by the isoconversional methods of Ozawa-Flynn-Wall, Friedman, and Kissinger-AkahiraSunose. The modeling revealed that the activation energy varied from *50 kJ mol -1 , characteristic of mass transfer control steps, to *150 kJ mol -1 , which is typical of chemical control, as the temperature increased and the ettringite structure lost water. A total of 32 mol of water was released equivalent to 43.1 % of the initial sample mass.

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“…Step 2 [20]. Although many studies about the decomposition of gypsum have been reported, we have not noticed any work about the kinetics of thermal decomposition of borogypsum.…”

Section: Resultsmentioning

confidence: 87%