E-Waste Recycling

ewaste - Pyrometallurgy and electrorefining vs digestion and electrowinning

To enhance profitability, reduce costs, and promote sustainability, businesses can recover valuable metals from e-waste like Copper, Silver, Gold, Nickel, and Cobalt. This not only generates sustainable revenue but also minimizes environmental impact by diverting e-waste from landfills and supporting circular economies.

Smelting, commonly used for treating PCBs, incinerates and melts crushed PCBs in furnaces. However, this process only partially removes impurities, resulting in a low-concentration PGM alloy. Base metals need to be removed before processing the PGMs. Smelting has high energy consumption and poses risks of dioxin formation and toxic releases.

An additional required step in e-waste processing is electrorefining. The anodes are casted from smelted alloy, and pure copper cathodes are produced in electro-refining cells along with anode slime containing precious metal. This process takes about 3 weeks to liberate the precious metals and requires recasting spent anodes after electrorefining. Additionally, bleeding is necessary to maintain the quality of copper cathodes and remove impurities.

conventional process for metal recovery from electronic waste

An alternative route offered by emew is a simple two-step process. The first step involves leaching the base metals, leaving the precious metals behind as residue in less than 24 hours. The second step is emew electrowinning, which produces high-purity copper cathodes from the electrolyte. Additionally, this step regenerates the acid, allowing it to return to the leaching circuit for the next batch, creating a closed-loop process.

emew process for copper recovery from electronic waste

There are many advantages and disadvantages in every processing route:

Pyrometallurgy + Electrorefining
(third party)
Digestion + Electrowinning
Rapid realization of precious metals No Yes
Accurate sampling and assay No Yes
High-purity Copper recovered Yes Yes
Low working capital No Yes
Tin value realization No Yes
High shipping time and cost Yes No
Long processing time Yes No
High carbon footprint Yes No
Difficult process control Yes No
Slag by-products Yes No
Hazardous emissions Yes No