[Report] Extracting Copper from Electronic Waste... A Visit to Korea Zinc Ulsan Plant

Crushing and Sorting Printed Circuit Boards Containing Gold and Copper
Producing 30,000 Tons of Copper Annually... Additional Construction Due to Soaring Demand

The world's largest non-ferrous metal smelting company, Korea Zinc, is being reborn as a "secondary battery material goldmine." The source of this goldmine is the electronic waste processing plant within the Onsan Smelting Plant 3 at Korea Zinc in Ulsan. On the 2nd, upon entering the entrance wearing dust masks and safety helmets, the heavy mechanical sounds of "wing~ wing~" were heard incessantly.

In a corner of the factory, an excavator was at work. The excavator pushed piles of discarded electronic products?from washing machine buttons and laptop and mobile phone parts to industrial reactor controllers?into a shredder. These parts are printed circuit boards (PCBs) removed from discarded electronic devices.

Electronic waste piled up on one side of the factory just before demolition
Photo by Choi Seoyoon

PCBs are insulating substrates made of glass fiber and epoxy resin (PP) layered with conductive copper; simply put, they are boards that electrically connect components. They contain various precious metals such as gold, silver, and copper. Choi Tae-woo, head of Smelting Team 2, said, "Last year, we processed 18,000 tons of waste PCBs annually," adding, "We are continuously increasing our raw material processing capacity internally to expand waste PCB processing volume."

After shredding and grinding the waste PCBs into small pieces, iron and aluminum are first separated using magnetism and magnetic force. The iron scrap is fed into the lead smelting process, and the aluminum is sold externally.

Crushed waste PCBs entering the sorter
Photo by Choi Seoyoon

The waste PCBs, after removing iron and aluminum, are baked and hardened in a high-temperature calciner (kiln) at 700?800 degrees Celsius. This process hardens the PCB and converts it into a powdered calcined product from which precious metals can be extracted.

The produced calcined product is sent to the copper smelting plant for precious metal recovery. This is a form of "urban mining," extracting precious metals from end-of-life electronic products. Team leader Choi said, "We can recover precious metals at a lower cost than mining from conventional mines," adding, "There is no loss as no metal is discarded."

At the copper smelting plant located across from Plant 3, copper is produced. Through the copper smelting process, including the calcined products from the previous process, zinc?Korea Zinc's main product?and by-products remaining after lead smelting, about 30,000 tons of copper are produced annually. Korea Zinc's strength lies in producing copper through recycled resources without using copper ore.

Copper attached to the cathode plate after electrolysis
Photo by Choi Seoyoon

The copper is graded according to its condition, and clean, defect-free Grade A copper is supplied to KZAM, a subsidiary that manufactures copper foil?a core material for secondary batteries?or to wire manufacturers. KZAM plans to produce 60,000 tons of copper foil annually by the end of 2027, making the proactive securing of raw materials crucial.

Kang Seong-ho, head of the Convergence Innovation Team, said, "Copper foil is the most widely used raw material in electronic products, and with the growth of the electric vehicle market, global demand is surging," adding, "To meet the increasing demand, we plan to add a copper smelting plant within the Onsan Plant by the first half of next year."