Characteristics of the fired bricks with low-silicon iron tailings

This paper studies the feasibility of utilizing low-silicon iron tailings for production of eco-friendly fired bricks. In order to improve the bricks quality, we add different proportions of fly ash to the raw materials. Compositions were prepared with additions of 5 wt.%, 10 wt.%, 15 wt.% and 20 wt.% fly ash in tailings. Initially, the iron tailings and fly ash were characterized by their chemical compositions, X-ray diffraction and particle size. The brick pieces were prepared and fired, and then the sintering shrinkage, weight loss on ignition, water absorption, apparent porosity, compressive strength, phase compositions and microstructure of final fired samples were investigated. Results indicated that the firing temperature and fly ash proportion significantly influenced the bricks properties. With different proportions of fly ash added to the bricks, the physical properties at temperatures from 900 °C to 1000 °C were well conformed to Chinese Fired Common Bricks Standard (GB/T5101-2003). The main mineral phases of the product were hematite, quartz, anorthite, diopside and anhydrite, which were principally responsible for the mechanical strength of bricks.