Figure 3. XRD patterns of the materials obtained by calcining (a) chicken, and (b) duck eggshell waste at 900C (Symbols: ♦ CaO)

From

Application of Eggshell Wastes as a Heterogeneous Catalyst for Biodiesel Production

Achanai Buasri, Nattawut Chaiyut, Vorrada Loryuenyong, Chaiwat Wongweang, Saranpong Khamsrisuk

Sustainable Energy. 2013, 1(2), 7-13 doi:10.12691/rse-1-2-1