Spectromicroscopy Analysis of Chicken Egg Shells

ABSTRACT Chicken egg shells, taken from farm and backyard eggs of different suppliers from different regions in Brazil were collected for chemical/structural analysis, in order to try to find if there is a relation between egg shells composition and the type of production (farm or backyard), the egg shell color and the region of production. EDS joined with SEM, XRD and FT‐IR were employed for such characterization. 100% of the egg shell samples showed the presence of calcium carbonate (CaCO 3 ). Traces of other components such as sodium (Na), zinc (Zn), chlorine (Cl), potassium (K) and iodine (I) were found in different sample sets. Cl was found in less than 50% of the egg shell samples, most probably because, in excess, it depresses the eggshell quality. Also, the presence of I associated with Na and Cl was found in 50% of backyard egg shell samples (probably, due to the kitchen salt in the hens' diet). I (in the absence of Na and Cl) and Zn could be associated to the hens' dietary supplementation used for improving the egg shell strength. SEM, spatially resolved EDS and FT‐IR showed that cubic crystals, found in 23% of the samples, can be associated to magnesium oxide (MgO). In summary, all the samples showed similar chemical composition; however, in different quantities. This is affected by the type of production (farm or backyard), the region of production or, even the egg shell color. Then, controlled syntheses of the resulting raw powder material must be taken when using for different recycling applications.