The valorization of eggshell waste as bio-calcium oxide is crucial for pollution prevention and supporting sustainable development. There are several reports on the thermal conversion of eggshell waste to calcium oxide for the partial or complete substitution of natural lime applications. However, this paper reports the thermal decomposition of large amounts of hatchery eggshell waste on an industrial-scale car bottom furnace for the first time. The hatchery eggshell waste was sundried and placed into five stacked trays in the car bottom furnace. The calcination of the eggshell waste was conducted at 900°C for 3 and 4 h under an atmosphere of air. Both the physical and chemical properties of the eggshell samples and the bio-quicklime products were carefully examined by TGA, SEM, XRD, FTIR, and XRF. The results demonstrate that the purity of calcium oxide in the quicklime products increased from 79% to 87% upon increasing the calcination time from 3 to 4 h. However, the color of the calcined eggshell samples at the surface of the pile was white while the color of the product beneath the surface was black or dark gray. The purity of the calcium oxide of both the black and white calcined samples was 76.4% and 91.5%, respectively. These results indicate the limited efficacy of the car bottom furnace for thermal decomposition of the large amount of eggshell waste to calcium oxide. Additionally, the production cost of bio-calcium oxide is approximately twice the cost of industrial grade lime. For further industrial applications, the furnace should contain the mixing equipment for improving the thermal decomposition of the large pile of eggshell waste. Furthermore, the oil burner system may be used in order to reduce fuel costs.

Quick lime or calcium oxide has attracted significant attention as a sustainable material to be used as fillers and catalysts in a broad range of industries. The quick lime derived from calcination of eggshell waste in a laboratory-scale rotary furnace is reported in this study. The eggshell waste was prepared by washing several times, drying in the sun, grinding and sieving through a 250 micrometers sieve size. Calcination of the sieved eggshells waste was conducted in a single zone rotary tube furnace at 800 °C with 5 degree slope and at 1 rpm. Both physical and chemical properties of the calcium oxide derived from the calcination of eggshell waste were systematically investigated by various scientific instruments. The results from powder X-Ray Diffraction (PXRD) and X-Ray Fluorescence: (XRF) showed that most of the calcium carbonate in the eggshell waste was thermally transformed to nano-calcium oxide with mean crystallite size of 47.5 nm and with a purity of 97.8%. The results from this study indicated the optimum conditions and the possibility for mass production of nano-calcium oxide via rotary furnace and have shown that the obtained nano-calcium oxide is comparable to the commercial chemical.