The Influence of Microstructured Charcoal Additive on ANFO’s Properties

Abstract

The verification of the blasting parameters of Ammonium Nitrate Fuel Oil (ANFO) with the addition of microstructured charcoal (MC) produced by destructive wood distillation was performed. Additional investigation of specific surface and pore distribution by the nitrogen adsorption of the two granulations of MC was also carried out. High-resolution scanning electron microscopy was used for morphology evaluation and revealed smoothening of the initially developed external surface of carbon with intensive milling. In addition, the analysis of the thermal properties of the studied samples (TG/DSC) indicated that the size of the microstructured charcoal additives influenced the decomposition temperature of the prepared materials. The explosives containing microstructured charcoal grains of −90 μm underwent decomposition at lower temperatures in comparison with those containing higher sizes of microstructure charcoal grains (−1.18 mm), for which the decomposition temperature reached 292 °C. The obtained results of blasting parameters compared to the results derived from thermodynamic simulation showed the non-ideal character of the explosives (much lower values of blasting parameters than in established thermodynamic models). It was indicated that higher velocities of detonations (VOD) were obtained for non-ideal explosives where finer MC grains were added. Blasting tests confirmed that the studied type of MC can be applied as an additive to the ANFO.

Variously Prepared Zeolite Y as a Modifier of ANFO

“…In our recent work [ 47 ], we reported that the maximum of DSC peak responsible for the decomposition of AN can depend on both the size of the microstructured charcoal (MC) grains and the chemical composition of the prepared samples. Generally, higher MC content and smaller MC grains lowered ANFO decomposition temperature (from 292 to 272 °C).…”

“…Post-blast fumes analysis was conducted according to the procedure described in [ 44 ], which was based on regulations reported in [ 45 ]. The description of blasting tests has also been reported in our previous works [ 41 , 46 , 47 ]. In each experiment, 600 g of non-ideal ANFO charge was placed inside the steel mortar locked in the blasting chamber.…”

Explosion Risks during Firefighting Operations in Storage Rooms and the Transport of Ammonium Nitrate-Based Fertilizers

“…The rates of heat energy release are in this case significantly higher than for the pure components of the mixture alone. The charcoal addition as an ANFO component was investigated in [25,26]. The effect of chemically bound carbon on the properties of thermal decomposition of AN was investigated in [27].…”

Novel Sensitizing Agent Formulation for Bulk Emulsion Explosives with Improved Energetic Parameters

“…Interpretation of the results of the analysis is conducted based on the fact that the concentrations of carbon monoxide (CO) and carbon dioxide (CO 2 ) is constant after the initial mixing period (homogenization of the post-detonation gas mixture). Due to the occurrence of consecutive reactions between the detonation products, the initial concentrations of nitrogen oxides (NO, NO X and NO 2 ) are determined by plotting a dependence of the concentration of each substance over time that has elapsed since detonation and extrapolating the experimental curve to the moment of detonation [ 30 ]. The initial concentrations of post-detonation gases ( C G ) are used to calculate the quantity of each gas ( Q G ) at normal conditions (273 K, 760 mm Hg ) via Equation ( 2 ): where: p 1 —measured pressure in the chamber after detonation [mm Hg ] T 1 —measured temperature in the chamber after detonation [K] V ch —volume of the experimental chamber [dm 3 ] m —mass of the detonated explosive sample [kg] …”