Use of steel slag and quartz sand-tailing for the preparation of an eco-friendly permeable brick

In order to effectively utilize industrial solid wastes (ISW), an eco-friendly permeable brick was successfully prepared by using quartz sand-tailing and steel slag. The influence of sintering temperature on the properties including permeability, apparent porosity, water absorption, bulk density, mechanical strengths, and chemical stability was systematically investigated. The research results show that with increasing sintering temperature, the structure of the permeable brick gradually become dense, which may be due to liquid phase sintering caused by a small amount of glass-liquid phase (Ca-Fe-Si-Al-O glass system). The permeability, apparent porosity, and water absorption decrease gradually, while the bulk density and mechanical strengths increase monotonously. Furthermore, the best sintering schedule for the permeable brick is 1320°C for 1 hour, with the optimized parameters, the permeable brick exhibits excellent properties (permeability, 3.65 × 10⁻² cm/s; compressive strength, 34.1 MPa; bending strength, 5.2 MPa; chemical stability, above 99%), wherein the permeability is far beyond Chinese standard (1 × 10⁻² cm/s). The permeable brick in this work provides a promising way for the recycle of ISW. Even better, it can maximize the introduction of quartz sand-tailing and steel slag (reach 100%) and create huge economic benefits while protecting environment.