title: Analysis of an explosion accident of nitrogen trichloride in a waste liquid containing ammonium ion and platinum black.
abstract: Five liters of sodium hypochlorite aqueous solution (12 mass%) was poured into 300 L of liquid waste containing ammonium ion of about 1.8 mol/L in a 500 L tank in a plant area; then, two minutes later the solution exploded with a flash on March 30th, 2005. The tank cover, the fluorescent lamp and the air duct were broken by the blast wave. Thus, we have conducted 40 runs of laboratory-scale explosion tests under various conditions (solution concentrations of (NH4)2SO4 and NaClO, temperatures, Pt catalysts, pH, etc.) to investigate the causes for such an explosion. When solutions of ammonium sulfate and sodium hypochlorite are mixed in the presence of platinum black, explosions result. This is ascribable to the formation of explosive nitrogen trichloride (NCl3). In the case where it is necessary to mix these 2 solutions (ammonium sulfate and sodium hypochlorite) in the presence of platinum black, the following conditions would reduce a probability of explosion; the initial concentration of NH4(+) should be less than 3 mol/L and the pH should be higher than 6. The hypochlorite solution (in 1/10 in volume) to be added at room temperature is recommended to be less than 0.6 mol/L.
authors: Research Institute of Science for Safety and Sustainability (RISS), National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan. Electronic address: ken.okada@aist.go.jp.
authors: Ken
authors: K
authors: Okada
authors: Research Institute of Science for Safety and Sustainability (RISS), National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan.
authors: Miyako
authors: M
authors: Akiyoshi
authors: Tanaka Kikinzoku Kogyo K. K., 2015-7, Kouya, Ichikawa, Chiba 272-0013, Japan.
authors: Keiko
authors: K
authors: Ishizaki
authors: Tanaka Kikinzoku Kogyo K. K., 2015-7, Kouya, Ichikawa, Chiba 272-0013, Japan.
authors: Hiroyasu
authors: H
authors: Sato
authors: Research Institute of Science for Safety and Sustainability (RISS), National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan.
authors: Takehiro
authors: T
authors: Matsunaga
mesh_terms: D000645:Ammonium Sulfate / Q000737:chemistry*; D055884:Chemical Hazard Release; D002712:Chlorides / Q000737:chemistry*; D005107:Explosions; D008401:Gas Chromatography-Mass Spectrometry; D017672:Nitrogen Compounds / Q000737:chemistry*; D010984:Platinum / Q000737:chemistry*; D012973:Sodium Hypochlorite / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D014866:Waste Products
chemical_list: D002712:Chlorides; D017672:Nitrogen Compounds; D014866:Waste Products; D010984:Platinum; D012973:Sodium Hypochlorite; D000645:Ammonium Sulfate; C037454:nitrogen chloride
keywords: Ammonium salt; Explosion accident; Nitrogen trichloride; Platinum black; Reaction hazard