Sustainable Electrochemical Machining for Metal Recovery, Elimination of Waste, and Minimization of Water Usage

摘要

This paper will discuss progress in development by Faraday of an integrated technology to recover and recycle metals from electrochemical machining (ECM). ECM is suited for low mass removal, high value-added manufacturing steps that cannot be easily performed using conventional machining, whether due to workpiece material properties, tooling limitations, or high surface integrity requirements. Sludge byproducts formed during conventional ECM processes are difficult to recover from the electrolyte, and discarding the sludge results in the loss of potentially valuable "waste" metal as well as entrained electrolyte salts and water. Results will be presented demonstrating a "Recycling ECM" technology, which is based upon patented cell designs and pulsed waveforms, targeting alloys including: C18000 copper, SAE4150 alloy steel, 316L stainless steel, and INCONEL~®718. These metals were machined in electrolyte to concentrations between 800-3500 ppm and subsequently recovered by electrowinning in solid, metallic form devoid of hydroxides/hydrated oxides, without intermediate electrolyte processing.