The Korea Institute of Ocean Science & Technology (KIOST) announced on the 6th that it has developed ultrasonic washing equipment capable of effectively removing salt (NaCl) from beach sand and has proven its performance for the first time in the world.
Sand is an essential material used in various social infrastructure, including roads, ports, and bridges. To use beach sand, a salt removal process must be undertaken. If the salt is not properly removed, it can cause corrosion of rebar within cement concrete and premature damage to structures, significantly affecting structural safety. The allowable salt content for beach sand recommended by the Ministry of Land, Infrastructure and Transport is below 0.04%. Until now, the method of using a large amount of water to remove salt from beach sand has been utilized. Approximately 4 tons of water are used to wash 1 ton of beach sand.
A research team led by Senior Researcher Yun Gil-lim from KIOST's marine space development and energy research department developed a new type of ultrasonic washing equipment that can efficiently remove salt from beach sand compared to existing methods. This technology features the use of ultrasound to enhance particle removal force and penetration capability, allowing for non-contact washing. It can remove salt accurately and quickly even in narrow spaces, dramatically reducing water use and processing time during washing. It has been confirmed that mixing beach sand with freshwater in a 1:2 ratio and applying ultrasonic waves of over 300W for 3 minutes can lower the salt concentration to below the standard of 0.04%.
KIOST President Lee Hee-seung noted, "This research is significant as it presents an alternative to the ongoing shortage of river sand issues both domestically and internationally, while also ensuring the safety and economic efficiency of structures. We plan to continuously enhance related technologies to facilitate faster and more precise processing of large amounts of beach sand in the future."
The results of this research were published in the international journal Scientific Reports on the 30th.
References
Scientific Reports (2025), DOI:https://doi.org/10.1038/s41598-025-12764-3