Abstract
The control of phosphorus release from eutropHicated coastal sediment by a carbonated steelmaking slag was examined. Batch experiments showed the following. Without slag addition, the pH, DO and ORP of seawater easily decreased with the progress of coastal sediment corruption. Moreover, phosphorus release from coastal sediment occurred rapidly. On the other hand, with steelmaking slag addition, the decreases in pH and DO were inhibited and the high ORP values of seawater were maintained. Phosphorus release from coastal sediment was clearly inhibited by slag addition. Even when the carbonated steelmaking slag was compared with sand, phosphorus release from coastal sediment was further improved. In the mechanism of phosphorus release control through steelmaking slag addition, it was considered that a carbonated steelmaking slag promotes calcium hydroxyapatite (HAP) generation induced by the high Ca2+ concentration of seawater. Furthermore, continuous experiments for more than 300 days showed that pH control and phosphorus release control from coastal sediment by carbonated steelmaking slag addition were maintained for a long term.
