POSCO enables circular economy through recycling of steel slag

A worker asphalts a road inside POSCO's Gwangyang plant in South Jeolla Province using aggregate made with the steelmaker's steel slag in this undated photo. Courtesy of POSCO

POSCO said Wednesday it has recycled byproducts of the steelmaking process to enable a circular economy, which refers to an economic system designed to minimize waste and pollution while maximizing resource efficiency through sharing, reusing, repairing and recycling.

In particular, the steelmaker has made various efforts to add value to steel slag, which accounts for 75 percent of byproducts from the steelmaking process.

Considering the shortage of gravel and sand used in asphalt streets, POSCO has supplied angular steel slag to make paved roads more durable.

Last year, the company's steel slag was used to asphalt five sections of National Route 3, a highway that connects Namhae in South Gyeongsang Province to Chosan County in North Korea's Jagang Province. The material was also used to asphalt roads at the steelmaker's Gwangyang plant in South Jeolla Province in February.

Last December, POSCO and rival steelmaker Hyundai Steel signed a memorandum of understanding with the Korea Expressway Corporation Research Institute and the Korean Recycled Construction Resources Institute to ensure a stable supply of steel slag for asphalting streets.

In April, POSCO held a meeting with representatives from the Ministry of Oceans and Fisheries, the Korea Fisheries Resources Agency and the Research Institute of Industrial Science & Technology (RIST) to discuss their joint project to create underwater forests.

Under a partnership signed among the four institutions in April last year, Triton artificial reefs made with POSCO's steel slag were installed last November off the coast of Pohang in North Gyeongsang Province, covering 2.29 square kilometers of seabed.

During the recent meeting, POSCO proposed managing the reefs with sea fertilizer developed by RIST using the steelmaker's steel slag. According to the company, sea fertilizer refers to materials that promote the growth of seaweed through a stable supply of iron.

"POSCO Group Chairman Chang In-hwa defined the core of the group's competitiveness as achieving absolute superiority in technology," a POSCO official said.

"Amid an unprecedented crisis in the steel industry, POSCO is not only securing its fundamental competitiveness in steelmaking through a technological gap with competitors but also exploring various ways to utilize byproducts. With these efforts, POSCO aims to contribute to conserving natural resources, promoting the circular use of byproducts and adding value to byproducts."