Industrial products and wastes as adsorbents for sulphate and chloride removal from synthetic alkaline solution and mine process water

Two limestones and two solid wastes were tested as adsorbents for chloride and sulphate ion removal from synthetic and real alkaline process mining water. The composition and surface structure of the adsorbents were analysed by ED-XRF, XRD, SEM and MIR spectroscopy and the nitrogen adsorption method. The optimal adsorption time and amount of adsorbent were determined by batch analysis with an anion concentration of 20 mg/L. In synthetic solution adsorbents removed 99% of SO42− and 96% of Cl− and in real process water the removal rate was 85% and 74% for SO42− and Cl−, respectively. It was found that equilibrium could successfully be fitted to the Langmuir, Toth and BiLangmuir adsorption isotherms.