In this study, dehydroxylation of alunite was studied. On the basis of thermogravimetric results and sulfur loss, dehydroxylation of alunite occurs from 508 to 577 degrees C. In this temperature range, temperature and time, as well as their interaction, have the greatest effect on alunite conversion (dehyroxylation) with 99.85% contribution, while the contribution of particle size was only 0.11%. Dehydroxylation increase with time up to a maximum and reached a plateau beyond that time. The time require (t(max)) for maximum dehydroxylation (i.e., maximum conversion) for various temperatures was different and showed decreasing trend with increasing temperature. Kinetic studies below t(max) showed that dehydroxylation of alunite follows Avrami-Erofeev models with different reaction indexes. In the temperature range of 508-534 degrees C, dehydroxylation occurs according to the model alpha = e(((-1.77x1011e-133314/T)(t-0.9r1/3)1.5), while in the 534-575 degrees C temperature range, the alpha = e(((-11065.64e-9934/T)(t-0.213r1/3)) is applicable.