TAIPEI (Taiwan News) — A National Taiwan University team has developed a new method to recycle difficult-to-treat fluoride wastewater from semiconductor manufacturing and convert it into a reusable industrial resource.
Taiwan is a major semiconductor production hub, where many manufacturing processes use fluoride-based compounds that generate wastewater. Current treatment methods typically produce calcium-based sludge with limited reuse value, which is most often transported off-site for disposal, according to Service and R&D of Innovative Water Technology.
To address this challenge, a team led by National Taiwan University Distinguished Professor Hou Chia-hung (侯嘉洪) developed a concentration technology that upgrades low-concentration fluoride wastewater into medium- and high-concentration streams. These can then be further processed into cryolite, an industrial material used in aluminum production that helps reduce energy consumption, according to CNA.
Hou said conventional treatment makes it difficult to recover useful materials while increasing the burden of sludge handling, transportation and related carbon emissions. While high-concentration fluoride wastewater can already be converted into cryolite, low-concentration wastewater has lacked an economically viable recovery method due to low efficiency and high processing costs.
The team worked with Retech Environmental Solutions Co., which specializes in fluoride wastewater recycling in the semiconductor industry. Together, they applied membrane capacitive deionization, an electric field–based separation technology that removes and concentrates charged particles in water without added chemicals.
In testing, the team built a laboratory-scale system capable of treating about 100 liters of fluoride wastewater per day, successfully concentrating it to levels suitable for cryolite production. To test scalability, the researchers expanded the system tenfold into a pilot unit capable of processing one ton of wastewater per day, marking a step toward industrial deployment.
