Molten Salt Destruction of Energetic Material Wastes as an Alternative to Open Burning

Abstract

The Lawrence Livermore National Laboratory in conjunction with the Energetic Materials Center (a partnership of Lawrence Livermore and Sandia National Laboratories), is developing methods for the safe and environmentally sound destruction of explosives and propellants as a part of the Laboratory’s ancillary demilitarization mission. As a result of the end of the Cold War and the shift in emphasis to a smaller stockpile, many munitions, both conventional and nuclear, are scheduled for retirement and rapid dismantlement and demilitarization. Major components of these munitions are the explosives and propellants, or energetic materials. The Department of Energy has thousands of pounds of energetic materials which result from dismantlement operations at the Pantex Plant. The Department of Defense has several hundred million pounds of energetic materials in its demilitarization inventory, with millions more added each year. In addition, there are vast energetic materials demilitarization inventories world-wide, including those in the former Soviet Union and eastern Bloc countries. Although recycling and reusing is the preferred method of dealing with these surplus materials, there will always be the necessity of destroying intractable or unusable energetic materials. Traditionally, open burn/open detonation (0B/OD) has been the method of choice for the destruction of energetic materials. Public concerns and increasingly stringent environmental regulations have made open burning and open detonation of energetic materials increasingly costly and nearly unacceptable. Thus, the impetus to develop environmentally sound alternatives to dispose of energetic materials is great.

The Molten Salt Destruction (MSD) Process has been demonstrated for the destruction of HE and HE-containing wastes (1,2,3). MSD converts the organic constituents of the waste into non-hazardous substances such as carbon dioxide, nitrogen and water. Any inorganic constituents of the waste, such as binders and metallic particles, are retained in the molten salt. The destruction of energetic material waste is accomplished by introducing it, together with oxidant gases, into a crucible containing a molten salt, such as sodium carbonate, or a suitable mixture of the carbonates, chlorides or sulfates of sodium, potassium, lithium and calcium.

We destroyed the following pure component DOE and DoD explosives in the experimental in our High Explosives Applications Facility (HEAF): Ammonium Picrate, HMX, K-6, NQ, NTO, PETN, RDX, TATB, and TNT. In addition, we destroyed the following formulations: Comp-B, LX-10, LX-16, LX-17, and PBX-9404. We continued our investigation into the destruction of the liquid gun propellant XM-46 for the US Army. In all these cases, the fractions of carbon converted to CO and of chemically bound nitrogen converted to NOx were found to be well below 1%. The details of the experiments are contained in the attached paper. In addition, we have completed construction of the next MSD unit, incorporating our advanced design. This unit, currently under installation, is nominally rated at 5 kg/hr of HMX.

This work was performed under the auspices of the U. S. Department of Energy by the Lawrence Livermore National Laboratory under contract number W-7405-ENG-48.