Production of eco-friendly bricks from copper mine tailings through geopolymerization

This paper studies the feasibility of utilizing copper mine tailings for production of eco-friendly bricks based on the geopolymerization technology. The procedure for producing the bricks simply includes mixing the tailings with an alkaline solution, forming the brick by compressing the mixture within a mold under a specified pressure, and curing the brick at a slightly elevated temperature. Unlike the conventional method for producing bricks, the new procedure neither uses clay and shale nor requires high temperature kiln firing, having significant environmental and ecological benefits. In this study, the effects of four major factors, sodium hydroxide (NaOH) solution concentration (10 and 15 M), water content (8-18%), forming pressure (0-35 MPa), and curing temperature (60-120 degrees C), on the physical and mechanical properties of copper mine tailings-based geopolymer bricks are investigated using water absorption and unconfined compression tests. Scanning electron microscopy (SEM) imaging and X-ray diffraction (XRD) analysis are also performed to investigate the microstructure and phase composition of the mine tailings-based geopolymer bricks prepared at different conditions. The results show that copper mine tailings can be used to produce eco-friendly bricks based on the geopolymerization technology to meet the ASTM requirements. (C) 2011 Elsevier Ltd. All rights reserved.