2022 Miron Research on the evaluation of the level of detonability of chemical fertilizers based ammonium nitrate regarding certification for safe use in agriculture
Ammonium nitrate used as fertilizer is classified, according to Orangebook, as a hazardous substance in Class 5 Division 1 (5.1), oxidizing substances. Although, under fire conditions, ammonium nitrate burns in certain situations, the transition from combustion to detonation can occur. Such accidents have occurred in several countries, with significant quantities, including in Romania. Such catastrophic scenarios can occur in the case of nitrogen-based chemical fertilizers, in which case the manufacturing recipe (dolomite inhibitor additive, respectively silicone antiglutinant) is not made correctly. Exposure of nitrogen fertilizers to repeated temperature fluctuations during storage and transport leads to recrystallization of the substance as a result of these thermal cycles. This recrystallization promotes an increase in sensitivity to detonation, which is unacceptable for a chemical fertilizer intended for widespread use in agriculture. In order to verify this aspect (sensitivity to detonation), under laboratory conditions, successive thermal cycles of heating and cooling of a quantity of about 8 kg of ammonium nitrate fertilizer with a high nitrogen content must be carried out in an specialized installation with a thermal conditioning bath with predefined cycles, the duration of the entire thermal conditioning process being approximately 35 hours. INSEMEX Petroșani, has purchased a suitable equipment for this conditioning, namely water bath, with heating and cooling system, respectively, programmable. In order to achieve a high level of automation, the water bath is controlled by a computer, on which the specialized NEScom 4.0 software runs. The results of the use of this automated system are appropriate for the purpose for which it was put into operation.