Two topics of explosive accidents were mentioned in this paper. One is ion exchange resin, the other is silver compounds. An explosion occurred while ion exchange resin (IER) was being used in the analytical pretreatment. To clarify the cause of the accident and go/no-go criteria of the explosion, elemental analysis of the IER, DSC analysis, SIKAREX analysis (a screening tool for runaway reactions), and Raman spectroscopy were performed. Finally, experiments on the same scale as the accident were conducted in an explosion chamber. When HClO4 was added to IER-NO3, the IER violently exploded without any heating nor metal ions such as uranium. It was confirmed that the accident was caused by an incorrect procedure in the chemical process. From the standpoint of explosion safety, IER-NO3 in particular should be kept away from perchloric acid in the laboratory. In the silver mirror reaction using ammoniacal silver solution, silver nitride (Ag3N) is generated, when the solution is allowed to stand. This compound is highly explosive. Thus, for a recycling process of silver compounds from ammoniacal silver solution, it is required to establish safety treatment of the solution. In the present study, various conditions for the safety treatment have been investigated on a laboratory scale. When an aqueous solution of Ag2O/NH3 was allowed to stand in the open air at ambient temperature, Ag3N was finally generated, as expected.
Keywords:explosion accident, explosive compound, thermal analysis
Publication Date: 2018-10-20