Influence of troilite on the decomposition of ammonium jarosite and estimated activation energy

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Department of Materials Science and Engineering


Jarosite method is most widely employed to remove iron through the zinc hydrometallurgical process, and ammonium jarosite sediment is produced. The low-temperature thermal decomposition of the ammonium jarosite sediment is desirable to recover natural resources and protect the environment. Herein, we aimed to study the influence of troilite addition on thermal decomposition of hydrothermally synthesized ammonium jarosite. The ammonium jarosite gets decomposed at 300 °C and results in a hematite crystal phase. The hematite, pyrite and magnetite phases have been observed at 400 °C. Furthermore, the hematite and magnetite are present as major phases and pyrrhotite phase has been detected as the minor phase at 500 °C. In addition, the amount of magnetite and hematite exhibited linear and inverse relationships with heat treatment temperature, respectively, in the temperature range of 500–800 °C. Also, the sulfur has been completely decomposed during the jarosite process after roasting at 500 °C and the estimated activation energy value (Ea) of 503.4 kJ mol−1 has been obtained from ln (v/T2p) versus 1/Tp plots. Troilite can improve sulfur elimination from ammonium jarosite at low temperature.

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© Akadémiai Kiadó, Budapest, Hungary 2019. Publisher’s version of record: https://doi.org/10.1007/s10973-019-08480-6

Publication Title

Journal of Thermal Analysis and Calorimetry