Production of composite clay bricks: A value-added solution to hazardous sludge through effective heavy metal fixation

摘要

The study explores utilization of hazardous battery sludge in fired clay brick production with the conjoint aim of reducing depletion of fertile clay and heavy metal fixation. Spectroscopic analysis of pulverized clay soil (PCS) and pulverized battery sludge (PBS) revealed presence of fluxing agents viz. K2O, Fe2O3, CaO. MgO. and TiO2. PBS added bricks (B0-B50%, w/w) were casted and fired in the temperature range from 950 to 1050 degrees C and B5 bricks (1050 degrees C) showed the highest compressive strength (74 N/mm(2)) and the lowest water absorption (2.1%). The modified bricks exhibited an improved ductile behavior and porosity restraining its deformation and/or distortion during firing and avoiding sudden failure of masonries. PBS imparted yellow coloration to bricks due to high CaO content, which can be an added benefit in decorative purposes. The bricks were tested for linear shrinkage behavior, volume of open pores, bulk density, and loss on ignition. Furthermore, the toxicity characteristic leaching procedure test confirmed an effective Pb, Cd Ni, and Zn fixation, and B20 bricks complied IS:1077:1992 class 12.5 and ASTM International. (C) 2019 Elsevier Ltd. All rights reserved.