High-value upcycling of iron ore tailings into stable, non-toxic turquoise pigments for sustainable applications

Abstract

The transformation of solid waste into high-value-added materials is pivotal for advancing resource circularity and promoting environmental sustainability. In this study, the high-value upcycling of iron ore tailings (IOTs) into environmentally benign, turquoise-colored iron-composite pigments was demonstrated via a facile one-pot hydrothermal synthesis route. Structural and morphological characterization revealed that the as-synthesized pigments exhibit a distinct fusiform microstructure, predominantly composed of giniite and quartz phases, with additional trace elements (Fe, Si, P, Al, and Mg) contributing to their unique chromatic properties. The pigments displayed a vibrant turquoise hue, with Commission Internationale de L’Eclairage (CIE) Lab color coordinates of L*=59.66, a*= −5.98, and b*= −3.57, indicative of stable and aesthetically desirable coloration. Notably, the pigments demonstrated exceptional long-term color stability, maintaining their chromatic properties without significant degradation even after 12 months of ambient atmospheric exposure. Furthermore, the absence of toxic heavy metals and hazardous substances confirms their environmental compatibility and safety for potential industrial applications. This study not only presents a sustainable and scalable strategy for the valorization of IOTs but also contributes to the development of eco-friendly inorganic pigments, aligning with the principles of green chemistry and a circular economy. The findings highlight the potential of mining waste as a valuable resource for high-performance pigment production, offering a promising alternative to conventional synthetic pigments while mitigating the environmental burdens associated with tailings disposal.

Graphical abstract