Dissolution behavior of elements in steelmaking slag into artificial seawater

Suppression of CO₂ and slag discharged from iron- and steelmaking processes are some of the typical biggest issues for the protection of global environment and sustainable growth of steelmaking industry. Utilization of active phytoplankton propagation will be one of the best options, to stabilize and reduce carbon dioxide with great efficiency. Inorganic minerals such as C, N, Si, P, and Fe are necessary, for phytoplankton to grow. It is crucial for effective supply of nutrition to understand the dissolution mechanism of elements from steelmaking slags into seawater. At first, the morphology of the precipitated phases in steelmaking slags during cooling period was investigated in the present work. It was continued to compare the dissolution behavior of some elements from steelmaking slags and pure substances such as 4CaO·P₂O₅, 3CaO·P₂O₅ and 2CaO·SiO₂-3CaO·P₂O₅ (2.8 mass% P) solid solution phase into artificial seawater for understanding their dissolution possibility. The dissolution behavior of elements such as phosphorus are strongly dependent of phase present in steelmaking slag. It was confirmed that the dissolution of component in steelmaking slag was observed such that enough amount of nutrition for phytoplankton multiplication can be supplied from steelmaking slag.