Co-recrystallisation, characterisation, and thermal analyses of ammonium nitrate based mixed salts: effect of additives on nitrogen oxides emissions

Ammonium nitrate remains a widely utilise ingredient in civil explosives, and fertilizers around the world. In civil explosive application, ammonium nitrate (AN) serves as a feedstock for making emulsion explosives as well as ammonium nitrate and fuel oil (ANFO) explosives, both commonly applied in open-cut mining operations. In recent years in Australia, demand for ammonium nitrate has increased significantly due to mining activities, the so called mining boom. However, the use of ammonium nitrate based explosives in civil applications may release orange clouds of nitrogen oxides under some condition of use and explosive formulations. Although AN-based explosives are formulated under stoichiometric compositions to produce only H₂O, CO₂, and N₂, in practice, CO, NO, and NO₂ gases are released when the formulation deviates from ideal conditions. Formation of carbon monoxide and nitrogen oxides poses risks to both people and the environment. In Australia, emissions of NOₓ (NO and NO₂) during blasting in mining operations have come under intense scrutiny by regulatory bodies and concerned citizens, as such emissions pose environmental and health risks; in particular, when orange clouds, characteristic of high levels of NO₂ and NO, do not dissipate rapidly and drift into populated areas surrounding the mines. Thus, there is a great interest in industries to find practical solutions to remedy the problems of NOₓ emissions from blasting of ammonium nitrate based explosives.