Dissolution of heavy metals from electrostatic precipitator (ESP) dust of a coal based sponge iron plant by fungal leaching

Abstract

Coal based sponge iron industries in India generate considerable quantity of solid waste, 40% of which is flue dust produced from the electrostatic precipitator (ESP) connected to rotary kiln. This paper reports the dissolution of Zn, Cu, Pb, Mn and Fe from the ESP dust using three fungal species, Aspergillus niger, Aspergillus fumigatus and Aspergillus flavus at 5 and 10% pulp densities over a period of 28 days. Highest metal leaching was achieved with A. niger followed by A. flavus. The least metal leaching was achieved with A. fumigatus. The pH of the medium declined consistently over the incubation period. Maximum leaching for Zn, Cu, Pb, Mn and Fe were 81, 76, 74, 72 and 52% respectively.

Key words: Fungal leaching, sponge iron, electrostatic precipitator (ESP) dust, metal dissolution.