Project nominated for the Excellence in sustainability Steelie Award 2020

JFE Steel has developed marine products using slag, a co-product of steel production to protect or restore coastal ecosystems and thereby make local communities more resilient.

These innovative and sustainable products are hydrated steel slag (Frontier Rock™ and Frontier Stone™), carbonated steel slag (Marine Block™), and steel slag with adjusted particle sizes (Marine Stone™).

The products were used to develop artificial reefs in Yokohama, create an artificial shoal in Seto Inland Sea, install a base for transplanted corals in Okinawa Prefecture, and install seabed in Fukuyama port.

The use of these recycled materials has had significant positive impacts on the marine ecosystem as well as bringing tangible benefits to the local communities.

A five-year monitoring study demonstrated that the number of species in Yokohama port area, where steel slag artificial reefs have been installed, has increased from 4 to 38 species due to a cleaner marine environment. More than 4 million citizens in Yokohama and Fukuyama have indirectly benefitted from the improved marine water quality.

The 36,000 m2 of artificial shoal in Yamaguchi Prefecture helped to increase the amount of seaweed and the number of fish catches by 2-3 times compared to pre-construction. The annual total carbon capture by the seaweed from the installed shoal was estimated to be 4,658kg CO2.

It was also confirmed that corals are growing and spawning robustly in the seas around Okinawa Prefecture’s Miyakojima island, where the company’s Marine Block was used to create a base to regenerate coral.

The 67,500 m2 of the seabed created by 39,000 tonnes of Marine Stone has effectively reduced generation of hydrogen sulphide and improved the habitat for bottom dwelling organisms, resulting in improved water quality and eliminated odours in the enclosed sea in Fukuyama port.