Novel red composite pigment with high thermostability from iron ore tailings: Synthesis and coloring mechanism

Abstract

Iron ore tailings (IOTs) are in urgent need of utilization. Here, a series of novel red composite pigments with bright color (L* = 42.6, a* = 35.3, and b* = 25.7) and high thermostability (1000 °C) was prepared from IOTs. The composite pigment was mainly compounded by α-Fe2O3, quartz, and anorthite, and it exhibited an ellipsoidal morphology. Thereinto, α-Fe2O3 was derived from the hydrolysis of Fe3+ ions, and quartz and anorthite were collected as the residue minerals of IOTs after the synthesis reaction. The presence of IOTs exposed more (1 0 4) crystal planes of α-Fe2O3 and doped Al elements in the crystals, resulting in the bright red color of the synthesized pigments. The presence of quartz and anorthite endowed the synthesized pigments with excellent thermal resistance, enabling their preferential decomposition under the action of heat and protecting the composite pigments from any significant changes in color.