Thermoanalytical studies of silver and lead jarosites and their solid solutions

Ray L. Frost, Sara J. Palmer, János Kristóf, Erzsébet Horváth

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

Dynamic and controlled rate thermal analysis has been used to characterise synthesised jarosites of formula [M(Fe)3(SO4) 2(OH)6] where M is Pb, Ag or Pb-Ag mixtures. Thermal decomposition occurs in a series of steps. (a) dehydration, (b) well defined dehydroxylation and (c) desulphation. CRTA offers a better resolution and a more detailed interpretation of water formation processes via approaching equilibrium conditions of decomposition through the elimination of the slow transfer of heat to the sample as a controlling parameter on the process of decomposition. Constant-rate decomposition processes of water formation reveal the subtle nature of dehydration and dehydroxylation. CRTA offers a better resolution and a more detailed interpretation of the decomposition processes via approaching equilibrium conditions of decomposition through the elimination of the slow transfer of heat to the sample as a controlling parameter on the process of decomposition. Constant-rate decomposition processes of non-isothermal nature reveal separation of the dehydroxylation steps, since in these cases a higher energy (higher temperature) is needed to drive out gaseous decomposition products through a decreasing space at a constant, pre-set rate.

Original languageEnglish
Pages (from-to)73-79
Number of pages7
JournalJournal of Thermal Analysis and Calorimetry
Volume101
Issue number1
DOIs
Publication statusPublished - Jul 1 2010

Keywords

  • Controlled rate thermal analysis
  • Jarosite
  • Thermal analysis
  • Thermogravimetry

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Physical and Theoretical Chemistry

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