The reaction of ammonium nitrate with pyrite

Abstract

The reaction of ammonium nitrate with pyrite ore was studied using thermal analysis, qualitative and quantitative analyses of the reaction products, and combustion calorimetry. When the mixture of pyrite ore is heated in an argon atmosphere, an exothermic reaction takes place at about 190°C. Reaction products when heated up to 300°C are Fe 2O 3 and a small amount of (NH 4) 2Fe(SO 4) 2, and the main reaction is the oxidation of pyrite to Fe 2O 3 by ammonium nitrate as described by Eq. (4). The combustion reaction is somewhat different from the above thermal reaction. The combustion residue contained Fe 2O 3, Fe 3O 4 and (NH 4)Fe(SO 4) 2 as reaction products, and the overall combustion reaction for the equivalent mixture with regard to Eq. (3) is described by Eq. (5). Ammonium nitrate also reacts with pyrite ore at a relatively low temperature, even near room temperature. During long-term storage at around room temperature, the oxidation of pyrite proceeds gradually and (NH 4) 3Fe(SO 4) 3 is recognized as a reaction product.