Potential of using zinc processing tailings (ZPT's) in the production of burnt clay bricks

Zinc processing tailings (ZPTs) from the Kharzet Youcef processing complex (Setif-Algeria) are mainly stockpiled in tailings dumps without use, occupying a significant area with potentially influencing the environment and human health. Incorporating ZPTs in building materials manufacturing is an effective solution to meet the dual objectives of environmental protection and economic development. The study investigates the influence of integrating ZPTs to partially replace clays and firing temperature on the physic-mechanical properties of fired clay bricks (FCB). Microstructural, chemical, and mineralogical analyses of ZPT and clays were carried out by SEM-EDS, XRF and XRD, respectively. Seven mixtures were produced with various percentages of ZPTs added to clays (0%, 5%, 10%, 15%, 20%, 25% and 30%) and were fired to three different temperatures (950, 1000 and 1050 °C) at a ramp rate of 5 °C. Physic-mechanical tests were carried out on different brick specimens, and the results obtained showed the FCB incorporated with 30% of ZPTs produced the highest flexural strength of 6.24 MPa, compressive resistance of 29.78 MPa, bulk density of 1.37 g/cm3 and water absorption of 15.1% at 900 °C. Therefore, recycling ZPTs for FCB manufacturing is a feasible alternative waste disposal solution for sustainable development while reducing negative environmental impacts.