A low temperature black ceramic pigment prepared from secondary raw materials

This work presents the first systematic investigation of Ruthner‑derived hematite recovered from steelmaking waste streams as a functional precursor for the synthesis of black ceramic pigments. A sustainable approach for the synthesis of black ceramic pigments by substituting conventional Fe sources with recycled hematite derived from steelwork waste. The investigated pigment composition (Cr0.4Fe0.35Co0.25)3O4, was prepared via solid-state synthesis at 1300 °C, 1200 °C, and 1100 °C and compared to a reference one prepared with goethite. Characterization by XRD, SEM-EDS, XAS and SCI colorimetric analysis, revealed that recovered hematite promotes the formation of more rounded and uniformly distributed crystallites, promoting the development of a dark hue, while the incorporation of the pigment into a transparent ceramic glaze showed that recovered-hematite-based pigments provide darker and more saturated black tones with improved optical performance compared to goethite-derived pigments. These findings demonstrate that industrial waste–derived secondary raw materials can effectively reduce the reliance on primary and critical raw materials, enabling lower-temperature, energy-efficient synthesis of high-performance black pigments for ceramic decoration. This approach contributes to reducing the environmental impact of pigment production while maintaining industrially relevant properties.