Overview

Turning wastewater into gold is not a mythical alchemical feat but rather the latest implementation of a circular economy by UMC. UMC recycles waste copper sulfate and refines it into pure copper through an electrolytic reduction process, subsequently using it to produce copper pipes. This initiative not only reduces the generation of chemical waste but also regenerates usable resources for the planet, effectively mitigating overall environmental impacts. Moreover, by lowering wastewater treatment expenses and generating additional revenue from the sale of copper pipes, the Company realizes increased income, resulting in a win-win scenario for both corporate operations and environmental sustainability.

UMC recycles waste copper sulfate to produce copper pipes, implementing a circular economy

Copper sulfate, used as an electroplating solution in the Electrical Copper Plating (ECP) process of semiconductor manufacturing, unavoidably generates waste. In just UMC's Fab 12A facility located in the Southern Taiwan Science Park, an annual production of approximately 1,680 metric tons of waste copper sulfate required an annual expenditure of NT$16 million for outsourcing disposal. However, since the introduction of the "Tubular Electrolytic Reduction System" in 2022, processing 150 metric tons of copper-containing waste liquid can yield around 4 metric tons of pure copper. Estimated over the course of a year, this translates to a net profit of nearly NT$13 million.

Using recycled copper sulfate waste to create copper pipes and new profits

The copper pipes produced through the "Tubular Electrolytic Reduction System"

UMC's "Copper Electrowinning Technology" is built on a simple principle. By placing an anode and a cathode into an electrolytic cell and pouring in high-concentration waste copper sulfate, electricity is applied. The positively charged copper ions then adhere to the cathode. Through a reduction reaction, copper metal is deposited, and by removing the cathode and separating the material, a copper pipe with a purity as high as 99.9% can be obtained. After electrolysis, the low-concentration waste copper sulfate is further processed by diverting it to an ion exchange resin system, where the concentration is raised again before returning to the electrolytic cell for copper extraction. Through multiple cycles of this process, the plant no longer generates copper sludge. Meanwhile, other low-concentration copper-containing waste liquid is treated through the ion exchange resin system to remove copper ions, making it suitable for use in secondary manufacturing processes. This not only reduces wastewater discharge but also significantly enhances water resource utilization efficiency.

Through multiple electrolytic treatments, blue waste copper sulfate transforms into transparent sulfuric acid

Through in-house recycling and reuse of waste, UMC has achieved a 30% reduction in waste generation per dollar earnings compared to previous years. This approach has also led to a decrease in the transportation carbon footprint associated with outsourcing waste disposal. As a result, UMC has achieved an annual carbon reduction effect of over 6,000 metric tons.

UMC continues to assess various potential circular economy business models, developing resource recycling products, and integrating them into the Company's sustainability strategy blueprint. Moreover, UMC is investing NT$1.8 billion in establishing the "Circular Economy & Recycling Innovation Center," expected to be officially operational by 2025. As the first waste resource recycling research center in the Southern Taiwan Science Park, it aims to convert approximately one-third of waste into recyclable products annually, thus contributing around NT$100 million to the green economy.