Sulphate removal from acid rock drainage using steel slag

Abstract

The removal of sulphates from acid rock drainage (ARD) using basic oxygen furnace (BOF) slag was investigated. The results indicated that sulphates removal using BOF-slag increased with temperature increase (25-45C), time (0-24 h) and solid loading (2-12 g BOF-slag/50 ml ARD). The maximum sulphate removal was 65% when 12 g BOF-slag/100 ml ARD was used at 45C and 24 h residence time. Adsorption followed the Langmuir isotherm with maximum adsorption capacities at 25, 35 and 45C of 1.949, 1.967, 4.078 mg/g respectively and RL values less than 0.3, indicating adsorption was thermodynamically favourable. The adsorption kinetics followed the pseudo second order kinetics.