Synthesis of high-performance copper barium silicate composite pigment from waste iron ore tailings

Abstract

Iron ore tailings (IOT) is a kind of solid waste that is a mixture of a variety of non-metallic minerals. However, the research on preparing functional materials by virtue of the endowment characteristics of its non-metallic mineral mixture is still at the beginning. Herein, bright purple copper barium silicate (BaCuSi2O6) composite pigment was prepared by IOT, sodium silicate, Cu2+ and Ba2+ via a simple and mild one-step hydrothermal method. In the process, the structure of IOT was decomposed and acted as a silicate resource and carrier. The presence of IOT enhanced the crystallinity of BaCuSi2O6 and improved its dispersibility. At a Ba:Cu:Si molar ratio of 1:1:8 and hydrothermal temperature of 200 °C, the obtained BaCuSi2O6 composite pigment exhibited the most vivid purple color (L* = 55.7, a* = 25.3, b* = −46.6), which is much better than the commercial cobalt violet pigment (L* = 46, a* = 33, b* = −32). Moreover, the theoretical content of IOT in composite pigment was 36.17 wt%, which significantly reduces the synthesis cost of the purple composite pigment.