Table 1.

Temperature at Which the Sulfate Ion Begins to Decompose to Give Sulfur Dioxide during Thermal Decomposition of Different Sulfate Species

Mineral	Formula	T at which sulfate decomposition begins (°C)	Decomposition atmosphere
Jarosite	KFe3(OH)6(SO4)2	501a	Nitrogen
Natrojarosite	NaFe3(OH)6(SO4)2	555a	Nitrogen
Hydronium jarosite	H3OFe3(OH)6(SO4)2	557b	Nitrogen
Ammonium jarosite	NH4Fe3(OH)6(SO4)2	510c	Nitrogen
Plumbojarosite	Pb0.5Fe3(OH)6(SO4)2	531a	Nitrogen
Argentojarosite	AgFe3(OH)6(SO4)2	548d	Nitrogen
Alunite	KAl3(OH)6(SO4)2	610e	Air
Natroalunite	NaAl3(OH)6(SO4)2	590e	Air
Hydronium alunite	H3OAl3(OH)6(SO4)2	680e	Air
Ammonium alunite	NH4Al3(OH)6(SO4)2	660e	Air
Ferric sulfate	Fe2(SO4)3	494f	Nitrogen
Aluminum sulfate	Al2(SO4)3	580f	Nitrogen
Lead sulfate	PbSO4	759a	Nitrogen
Magnesium sulfate	MgSO4	780f	Nitrogen
Sodium sulfate	Na2SO4	1100g	Nitrogen
Calcium sulfate	CaSO4	1200h	Nitrogen

^aFrost et al. (2005a).

^bFrost et al. (2006a).

^cFrost et al. (2006b).

^dFrost et al. (2005b).

^eRudolph et al. (2003).

^fMu and Perlmutter (1981).

^gSamadhi et al. (2001).

^hWest and Sutton (1953).