Abstract— A sample of natural alunite of the composition K0.6Na0.4Al3(SO4)2(OH)6 was studied by powder X-ray diffraction, infrared spectroscopy, electron microprobe, and thermal analysis. The enthalpy of formation of the alunite from elements ∆fH0(298.15 K) = −5149 ± 13 kJ/mol was determined by the method of melt …
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