## 2 Review of Influence of Sensitizers on Detonation Properties of Emulsion Explosives  
### Chemical Density Reduction  
This process involves the addition of substances into the matrix that decompose to release nitrogen or other gases in the form of microbubbles. These substances include N N,N-dinitrosopentaethyl-ethylenetetramine; hydrogen peroxide; azodicarbonamide; sodium, potassium, and barium inorganic peroxides; bicarbonate of alkali metals and alkaline earth metals; nitrates (III) of alkali metals or chemical systems of sodium nitrate-urea; alkali hydroborides-urea [8,9]; or a mixture of potassium manganate (VII) and hydrogen peroxide [10]. The encapsulated gas microbubbles act as \"hot spots\", facilitating the initiation and propagation of the EE detonation process. The aeration of the emulsion using the sodium nitrate (III)-urea chemical system occurs due to the release of gases (carbon dioxide and nitrogen) according to the following reaction (Equation (1)):  
\[3\text{NaNO}_{2}+3\text{HNO}_{3}+2(\text{NH}_{2})_{2}\text{CO}\to 3\text{NaNO}_{3}+2 \text{CO}_{2}+4\text{H}_{2}\text{O}+3.5\text{N}_{2}\uparrow \tag{1}\]  
The nitric acid (V) involved in the reaction acts as a pH-regulating agent. If NaNO\({}_{2}\) alone is used to sensitize the matrix, it will react with ammonium nitrate (V) according to Equations (2) and (3):  
\[\text{NaNO}_{2}+\text{NH}_{4}\text{NO}_{3}\to\text{NH}_{4}\text{NO}_{2}+\text{ NaNO}_{3} \tag{2}\]  
\[\text{NH}_{4}\text{NO}_{2}\to 2\text{H}_{2}\text{O}+\text{N}_{2}\uparrow \tag{3}\]  
In total,  
\[\text{NaNO}_{2}+\text{NH}_{4}\text{NO}_{3}\to\text{NaNO}_{3}+2\text{H}_{2} \text{O}+\text{N}_{2}\uparrow \tag{4}\]  
In practice, if NaNO\({}_{2}\) is used as a stand-alone gassing agent, compounds containing thiocyanate anions are additionally dosed to increase the decomposition efficiency of the sodium derivative. The decomposition of NaNO\({}_{2}\) in the presence of ionic thiocyanate compounds follows Equation (5):  
\[\text{H}^{+}+\text{SCN}^{-}+\text{HONO}\to\text{NOSCN}+\text{H}_{2}\text{O} \tag{5}\]  
NOSCN is formed, which is more active than nitric (III) or nitric (V) acids, and reacts in solution with amines or inorganic ammonium salts. Another aerating substance is sodium bicarbonate. It already decomposes easily at 65 \({}^{\circ}\)C, and at 270 \({}^{\circ}\)C, carbon dioxide is released completely. The decomposition reaction is more intense under humid conditions. The aqueous solution of sodium bicarbonate has a slightly alkaline pH, and when acetic acid is added, decomposition occurs with the release of carbon dioxide. Therefore, in order to gasify the EE matrix, sodium bicarbonate and acetic acid are dosed simultaneously. The effect of the degree of gasification, achieved through the application of sodium nitrate (III), on the density and detonation velocity of EEs was determined by [PERSON] et al. [10]. Experiments were performed for 30 min at different temperatures (31 \({}^{\circ}\)C, 47 \({}^{\circ}\)C, and 70 \({}^{\circ}\)C) and at five concentrations of gassing agent solution (2%, 4%, 6%, 8%, and 10%). At 31 \({}^{\circ}\)C, there was a monotonic decrease in density for 25 min, followed by stabilization for another 25 min. At temperatures of 47 and 70 \({}^{\circ}\)C, density stabilization occurred after 20 min. The minimum densities for temperatures of 3 \({}^{\circ}\)C 1, 47 \({}^{\circ}\)C, and 70 \({}^{\circ}\)C, reached values of 1.14, 0.92, and 0.94 g/cm\({}^{3}\), respectively. The density of the EE (1.15 g/cm\({}^{3}\)) atwhich the maximum detonation velocity of 4381 m/s was achieved was determined. The maximum density at which the process disappeared was 1.27 g/cm\({}^{3}\). An original gassing agent was proposed by [PERSON] et al. [11; 12], through the addition of sodium perchlorate to an aqueous solution of ammonium nitrate (sensitizers BK-1 and BK-2, Table 1). They were used to sensitize the commercial EE Emulinit 8L.