Electrochemical Waste Recycling for Cannon Production

Mr. Christopher Humiston | Benet Laboratories



To meet mission needs, the Department of Defense (DoD) is increasingly incorporating advanced materials that are difficult to machine with traditional methods, creating a gap between performance and quality. Nonā€conventional manufacturing methods such as electrochemical machining (ECM) provide superior surface finish, dimensional stability and accuracy that are more suitable to machining complex shapes from difficult to machine materials. However, the generation of heavy metal sludge from ECM requires costly infrastructure and high disposal costs to handle and treat the waste stream.

This project will combine the ECM operation with electrowinning to plate the metal ions and prevent heavy metal sludge formation. The metal will be recycled and the cleaned electrolyte will be reused offering a high quality machining process with limited waste. Demonstration objectives for this fully recyclable, sustainable manufacturing process include: (1) reduces hazardous waste streams up to 90%, (2) recovers 100% of wasted salts and water, and (3) improves surface finish as compared to conventional machining processes.

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Technology Description

The combined ECM and electrowinning process will recover the anodically dissolved metals from the work piece by electroplating them back out of solution onto a recycling cathode. The combined ECM and electrowinning process avoids the need to employ exotic electrolytes by using different high frequency electric waveform pulses for machining and electrowinning operations. This waveform is the enabling technology to allow a single aqueous electrolyte to function in both roles without having to resort to strong acidic or basic solutions. 

This project will demonstrate a sustainable manufacturing process for ECM to reduce the burden of heavy metal sludge generation, enabling manufacturing centers to replace machining cells that have high environmental costs.

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The combined ECM and electrowinning process will reduce heavy metal sludge by 90% and generate a metal recycling stream. Several hundred pounds of salt will be recovered and water consumption will be reduced by 60%. The combined ECM and electrowinning process aligns the DoD organic manufacturing centers (arsenals, depots, and shipyards) with established strategic sustainable manufacturing goals and reduces the environmental burden and expense. Additionally, no coolants or cutting oils will be used for the operations replaced by the ECM operation. (Anticipated Project Completion - 2018)

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Points of Contact

Principal Investigator

Mr. Christopher Humiston

Benet Laboratories

Phone: 518-266-3938