Towards “Green” ANFO: Impact of perchlorates and inorganic peroxides on detonation parameters

The use of explosives, particularly during blasting operations in mining is associated with a significant impact on human health and the environment. While this issue has long been neglected in favour of augmenting the performance of explosives, recent years have brought about increased awareness and interest in developing “green” explosives. Particular emphasis is being placed on open-pit mining, in which ammonium nitrate - fuel oil (ANFO) explosives are extremely common, due to their low unit cost and facile preparation. ANFO, however, not only exhibits low detonation performance (low brisance and velocity of detonation, high critical diameter), but also emits large amounts of toxic post-detonation gases. In this work, we have studied additives to ANFO—two perchlorates (traditionally used for improving detonation performance) and two alternative, “green” oxidising agents—in terms of their effect on both detonation performance and toxic gas emissions of ANFO. These studies have revealed sodium carbonate peroxyhydrate (SPC) as an extremely promising additive, leading to a drastic reduction in the environmental footprint of ANFO.