Computational Studies on the Environmental Usefulness of Zeolites and Other Oxide-Type Materials as Modifiers of Ammonium Nitrate-Based Energetic Materials

ANFO (Ammonium Nitrate Fuel Oil) is widely used in the mining sector due to its efficient, cost-effective production process, favorable energetic characteristics, and adaptability to modification. Thermodynamic modeling was carried out to assess the effect of adding selected compounds to ANFO on carbon and nitrogen oxide emissions among post-decomposition fumes. The investigated additives include zeolites, hydroxides, layered aluminosilicates, and oxides. Thermodynamic analyses of ANFO thermal decomposition, with particular emphasis on post-decomposition fume emissions, revealed that incorporating any type of oxide material reduced carbon dioxide formation. Additionally, non-zeolite modifiers were found to lower the generation of toxic post-decomposition fumes such as carbon monoxide and nitrogen oxides. The extent of hazardous fume reduction correlated with increasing modifier content in these ANFO-based samples. For instance, the addition of 8% wt. vermiculite and hematite to ANFO reduced the sum of CO and NOx emissions by 36 and 57%, respectively. Consequently, the obtained results from thermodynamic calculations suggested that it is possible to develop eco-friendly energetic materials as a viable low-emission energy source for raw material extraction in quarrying. Moreover, the literature-based calculations suggested that utilizing zeolites and other types of oxide-type modifiers in ANFO could mitigate annual CO2 emissions by thousands of cubic meters, representing a substantial advancement in sustainable environmental protection efforts. Nevertheless, the optimal modifier depends on whether the priority is greenhouse-gas-related CO2 reduction or acute toxic fume (CO + NOx) reduction. From the thermodynamic calculation results, it may be concluded that zeolites are better modifiers concerning CO2 mitigation, whereas non-zeolite additives efficiently reduce overall toxicity formed during ANFO thermal decomposition.