Color stability of blue aluminates obtained from recycling and applied as pigments

Abstract

Aluminates have been used as synthetic inorganic pigments due to their structural stability. In this context, we report on the synthesis of blue aluminates obtained from the boehmite combination with Co²⁺ and Ni²⁺ ions and calcination at 1000 °C. The boehmite was obtained from recycling aluminum metal from can seals. The aluminates were characterized by X-ray diffractometry (XRD) and Raman spectroscopy. The oxidation state of the ions responsible for the color was evaluated by XPS and UV-vis, suggesting the presence of divalent Co and Ni ions. Colorimetry confirmed the blue coloration and different shades. The colorimetric stability of the blue aluminates in harsh environments for pigments was evaluated. Both pigments were stable after 240 hours of exposure, showing no strong color difference.