Demilitarization of Hexachloroethane-containing Smoke Ammunition by Sublimation and Carbonization

Dr. Matthew Davis | Naval Air Warfare Center China Lake

WP20-1020

Objective

This limited-scope, core standard project, plans for risk reduction and feasibility studies in removal of hexachloroethane (HC) directly from smoke ammunition by solid to gas phase transition followed by carbonization of the recovered HC by reaction with calcium carbide (CaC2) or alkali metals. The end product from this HC smoke demilitarization (demil) process will be graphite and calcium chloride.

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Technical Approach

Authentic HC filler will be studied to determine safe operating conditions including initiation temperature. Optimal conditions for sublimation of HC from free HC filler will be identified through experimentation. The sublimation rate of HC from free HC filler (grams/hour/inch) will be determined. Possible thermite reaction between the recovered metals (zinc oxide, aluminum) from the HC filler will be determined by differential scanning calorimetry (DSC) or bomb calorimetry. Dismantling of HC smoke grenades by physical methods (decrimping, sawing, water jet) and configurations will be studied. The sublimation of HC directly from a dismantled smoke grenade will be carried out to collect rate and yield data based on dismantled configuration. The metathesis reaction of pure and recovered HC with calcium carbide and other alkali metals in various stoichiometric ratios will be studied in a steel bomb calorimeter on small scale. The enthalpy of reaction, elemental analysis and yield of products and will be measured for selectivity and conversion of HC to metal chloride salts and carbon allotropes.

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Benefits

The Department of Defense (DoD) has nearly 200 million pounds of hexachloroethane (HC) smoke ammunition which are obsolete and costly to keep in storage. The proposed 2-stage demilitarization process fills a technology gap for demil of HC ammunition. The process may be an environmentally responsible method to irreversibly remove the military functionality of HC smoke ammunition. This 2-stage demil process will dispose of these obsolete DoD products without open-burn or open detonation (OB/OD) with their high environmental burden. The graphite and calcium chloride end-products from the process are commodities with many domestic uses. The energy output from the exothermic metathesis reaction could be harnessed to power the sublimation for low or even zero net energy use.

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Points of Contact

Principal Investigator

Dr. Matthew Davis

Naval Air Warfare Center China Lake

Phone: 760-939-0196

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