Preparation of permeable ceramic bricks with tungsten tailings by two-stage calcination technology

Taking the waste tungsten tailing sand as the main raw material, using its intrinsic mineral composition and particle gradation, ceramic permeable bricks were prepared by adding binder, and the experimental research on the preparation of high-performance ceramic permeable bricks was carried out, and an effective way for the comprehensive utilisation of tungsten tailing sand was also sought.Permeable ceramic bricks were prepared with waste tungsten tailings and ball clay by a two-stage calcination technology, which involves rapid sintering at high temperature (900–1215 °C) and slow crystallisation at low temperature (<900 °C). The pore structure and flexural strength of permeable bricks were improved synthetically. The composition and sintering parameters were optimised, including the ratio of large (>2 mm) to small (1–2 mm) aggregates (1:1 w/w), content of waste ceramic (20 wt%), binder content (10 wt%), sintering temperature (1215 °C), and sintering time (holding time at the maximum sintering temperature; 60 min). The optimised water-permeable ceramic bricks had high permeability (2.53 × 10−2 cm/s) and excellent flexural strength (4.62 MPa). Therefore, through the recovery of tungsten tailing sand and waste ceramics can protect the environment, save resources, and achieve high-value comprehensive utilisation of tungsten tailing sand, with significant economic and environmental benefits, which is conducive to the sustainable development of the tungsten industry.