Objective
The objective of this project is to eliminate the reliance on emerging chemicals of environmental concern as solvents in the processing of certain aluminized high-performance combined effects explosives. Currently, they are required because aqueous processing of aluminized explosives does not produce an acceptable granulated product required for pressing operations. Obtaining the proper particle size and geometry will require study of the aqueous suspension and interaction of CL-20 and aluminum with the added organic lacquer phase of binder components. Currently, the particular solvent used is under scrutiny and production may be phased out in coming years. The Department of Defense is pursuing environmentally or recycle-friendly processes in particular explosive formulation procedures.
Technical Approach
Aqueous slurry optimization will proceed with various approaches as listed below. Two metrics will measure the quality of granulated product from the aqueous slurry workup:
- Particle uniformity by sieve fraction, derived from current state of the art explosive specifications.
- Dispersion of aluminum powder within granules as measured directly by Scanning Electron Microscope and Energy Dispersive X-ray analysis.
Provided both of these metrics are met, the aqueous workup will be deemed a success and the project team will demonstrate pilot runs at a government partner as a transition. In order to obtain these two objectives, it is hypothesized that two approaches should yield success in obtaining the metrics above:
- Since the aluminum and CL-20 possess drastically different wettability in aqueous solutions, the proper understanding of such surfaces is needed. Then, by proper implementation of the correct surfactant, improved dispersion and uptake into the binder should be realized. The project team will determine the optimum solution pH and cationic, anionic, or nonionic surfactants required for uniform dispersion of CL-20 and aluminum within the granules formed during slurry operations.
- To further enhance the uptake of the very hydrophilic aluminum particles, the project team will modify surface of aluminum using organosilanes, which are well- known, commercial off the shelf materials. Proper selection should facilitate uptake of the aluminum with the CL-20 into the binder system.
In the above approaches, particular attention will be given to scale-up and industrialization constraints. This is important for transition and implementation into the constraints of commercial slurry coating operations.
Benefits
Benefits of this project include cost savings for the aluminized explosives formulation process, elimination of lifecycle issues associated with the use of these solvents (procurement from outside the contiguous United States, disposal, and limited vendor availability), and applicability to other explosives made with these processing fluids.