Metal sorption on blast-furnace slag

The removal of Cu, Ni and Zn-ions from water solution by ungranulated blast-furnace slag has been studied depending on contact time, initial ion concentration, pH and solution temperature. The polymineral composition and the slag specific properties determine its high sorption activity in metal salts solutions. In the range of the concentrations studied (10−4–10−3 M), the sorption data for Cu2+, Ni2+ and Zn2+ have been described using Freundlichʹs parabolic equation. The materialʹs own alkalizing activity creates conditions for effective metal ions sorption in a wide pH range. With the temperature increase the hydrolysis of the sorption matrix intensifies which leads to the sorption improvement. On the basis of both literature data and the authorʹs own data the mechanism of metal ions removed by blast-furnace slag has been discussed.