Abstract
Sea grass beds and tidal flats are facing imminent dangers of extinction. Steel slags are one of the promising alternative materials for marine sands to restore sea grass beds and tidal flats. On the other hand, significant pH increase and solidification attributed to dissolving calcium released from the slags are sometimes negative impact on ecosystems. To quantify the dissolved calcium, Japan Cement Association Standard method is conventionally used. However, our study leveled the method underestimate the dissolved calcium from the steel slags. The purpose of this study is to optimize the determination method for maximum calcium releasing potential from steel slags. Powdered sample (0.1 g) was stirred in 40 mL of 99.5% ethyleneglycol-100 mM tris buffer solution for 6 h at 80±5°C. Thereafter, the solution filter through 0.45 μm filter and the dissolved calcium was determined by ICP-AES. The optimized condition proposed in this study recovered the dissolved calcium from the slag in seawater perfectly.
