Winner of the Excellence in sustainability Steelie Award 2022

South Korea produces an average of 500,000 tons of shellfish annually, and oysters account for approximately 70%. Oysters are intensively cultured in most coastal areas of Korea. The annual output of oyster shells is approximately 300,000 tons in volume, but only 60-70% is recycled.

Considering the substantial production of shell waste along the south coast, shell waste needs better management. Occurrences of marine pollution, diseases, and odours are particularly concerning in the case of unauthorised dumping into the ocean and open forests.

Given there are multiple side effects of disposing of shell waste from the perspective of environmental, hygienic, social, and financial implications, POSCO set out actively to look for ways to recycle shell waste. After determining that shells are similar in composition to the limestone used for sintering, POSCO studied different ways to substitute shell waste for limestone.

By replacing 1 tonne of limestone with shell waste, up to 460kg of CO2 can be avoided. Moreover, shell waste recycling can cut standardised disposal costs and help address many of the environmental problems caused by indiscriminate dumping. POSCO started utilising shell waste in 2021 and continues to promote resource circulation to achieve environmental, economic, and social sustainability.