Abstract
Seagrass beds and tidal flats are facing massive destruction and so it is highly desirable to restore and conserve them. Steel slags from steelmaking processes are some of the promising alternative materials for marine sands useful for restoration. The release of calcium and alkalis caused by the hydrolysis and elution of calcium oxide from the slags constituted the main reaction arising from aging processes in the marine environment, and it promotes the separation of magnesium hydrate and calcium carbonate and the solidification by pozzolanic reaction. The significant pH increase and solidification would have negative impact on biological activities. However, the mechanism of solidification and the effect of contact ratio of seawater with slag are not fully understood. Therefore, this study aimed to reveal the mechanism of solidification in seawater and the effect of contact rate with seawater. The result indicates that the solidification is affected by the contact speed of seawater, and would be caused by the products with the hydrolysis of magnesium, the calcium oxide and silicate salts produced by pozzolanic reaction in alkaline condition.
