The Application of a Natural Zeolite for Acid Mine Drainage Purification

Abstract

A natural zeolite from Serbia was employed for the removal of heavy metals from acid mine drainage (AMD) generated in the area of copper mine. The efficiency of the natural zeolite samples was tested on AMD that contained manganese, copper, zinc, nickel and cadmium ions in the concentrations above the maximal allowed, according to existing legislation. The results of X-ray diffraction (XRD) analyses of natural zeolite having a particle size of -1 + 0.3 mm, confirmed that the clinoptilolite (Al1.6H30Ca2.06O4756Si164) is a dominant mineral of mine tuff. A dynamic method was used for the experiments in order to simulate real conditions in an industrially relevant environment. The effect of the flow rate of AMD, type of columns and zeolite classes on the degree of adsorption of the heavy metals from AMD was investigated. The results of chemical analyses of treated AMD samples at a flow rate of 0.0033 dm(3)s(-1) which corresponds to the spontaneous outflow from the real accumulation indicate that concentrations of heavy metals are not decreased below that allowed for defined recipient class, except for copper. Also, these results show that the heavy metal ion removal serie for the industrially relevant environment can be given as: Cu > Zn > Cd > Mn > Ni.