Evaluating the Use of Chicken Eggshell Waste for Synthesizing Nano-Sized Calcium Aluminate Powder by Combining High-Energy Milling and Calcination

In recent years, sustainable recycling approaches for chicken eggshell waste have increased significantly worldwide due to environmental and circular economy benefits. This work aimed to synthesize and characterize a new calcium aluminate powder using chicken eggshell waste as an alternative source of calcium carbonate through mechanical activation and subsequent calcination. The starting formulation consisting of the eggshell waste (CaCO3):Al2O3 (1:1) ratio was subjected to a high-energy milling process for 0 h, 15 h and 30 h and subsequent calcination at 1200 °C for 4 h. The resulting calcium aluminate powders have been investigated using X-ray diffraction (XRD), differential thermal analysis (DTA), scanning electron microscopy (SEM), and photoluminescence techniques. After calcination, a calcium aluminate-based composite powder with an average crystallite size between 46.45 nm and 52.27 nm and a predominance of the CaAl2O4 phase was found. The calcium aluminate powders produced (milled for 15 h and 30 h and calcined at 1200 °C) showed a luminescent behavior, emitting characteristic violet light with a wavelength between 380 and 418 nm. Our findings may provide a novel technical pathway for recycling chicken eggshell waste into calcium aluminate powder with luminescent properties.