Safety assessment of Ammonium Nitrate Fuel Oil (ANFO) manufactory
The work presents the final results from a safety analysis of a typical manufactory of the commercial explosive known as ANFO—ammonium nitrate and fuel oil. ANFO is a commercial explosive whose fundamental characteristics in terms of industrial production are low cost and ease to produce. As a general rule, ANFO is a mechanical mixture of an oxidizer (role played by the ammonium nitrate) and a source of carbon/fuel. The later role is where the composition usually varies across manufacturers, thus these are not a single composition for the ANFO. In our case study, we selected the most common process of producing ANFO, as well as considered the most effective (in terms of explosive performance) and environmentally friendly formulation. Then we applied a preliminary hazard analysis to the case study, whose results are consolidated in Table 4. The PHA indicated that the most critical risk scenarios are those related to possibility of explosion, and the cause attached to the highest risk relates to metal contamination within the Ammonium nitrate, reason why we strongly advise any manufacturer to implement metal detection screening prior to dose the Ammonium Nitrate into the mixer.