A Novel and Eco‑friendly Approach for the Simultaneous Recovery of Copper and Diamond from Waste Cutting Segments via Electrodissolution/Deposition

Abstract

A new approach is brought to diamond recovery from waste cutting segments. Unlike the commonly used hydrometallurgical processes, this approach offers the simultaneous recovery of copper with diamond. Besides, instead of strong acids, this work involves use of a dilute acid solution, reducing the evolution of toxic vapors. Copper base segments of waste diamond tools were used as anode, which were dissolved by applying potentials above the dissociation voltage of Cu. Simultaneously, the diamond grits detached from the segments and gathered at the bottom of the cell. Then, the dissolved Cu2+ cations were reduced, and Cu powders were electrodeposited at cathode without affecting the accumulated diamond particles. Eventually, the diamond particles could be collected from the bottom of the cell, providing the simultaneous recovery. In this work, the effect of individual process parameters on the outcome of presented approach is studied. The process parameters were then optimized, and mathematical models were developed for response variables by response surface methodology. Also, a mini-prototype was designed and operated at the optimized conditions to check the possibility of converging the proposed approach to industrial applications. Prototype tests show that all detached diamond could be recovered in 3 h and simultaneously with Cu powders.