Preparation of lead–zinc tailings-based ceramsite using fly ash as supplementary aluminum source

The preparation of ceramsite using lead–zinc tailings (LZT) as the primary raw material, fly ash as a sintering auxiliary material, and coal powder as a flux was investigated. The results indicate that the apparent density and water absorption of ceramsite decrease continuously with increasing sintering temperature, while the cylinder compressive strength shows the opposite trend. As the LZT content increases, the apparent density of ceramsite initially decreases and then slightly increases. Meanwhile, the water absorption rate shows an upward trend, and the cylinder compressive strength continuously declines. The primary crystalline phases of LZT-based ceramsite are anorthite, mullite and quartz, with mullite providing significant support to the strength of the ceramsite. Under the conditions of 50% LZT content and a sintering temperature of 1250°C, the ceramsite with an apparent density of 1165.8 kg/m 3 , a water absorption of 3.1%, and a cylinder compressive strength of 8.5 MPa was successfully produced.