Eggshell is a rich source of CaCO3 with a high purity content of more than 96.35% w/w and a potential raw material for calcium hydroxyapatite preparation. Mesoporous and nano‐particulate calcium hydroxyapatite was prepared from duck eggshell from the chemical reaction with phosphoric acid followed by the calcinations at 800, 900, and 1000°C for 2 hours. The optimum condition to obtain the high purity calcium hydroxyapatite was by sintering calcium phosphate Ca3(PO4)2 at 1000°C for 2 hours. The average particle size, pore diameter, specific surface, and true density of the sample sintered at 1000°C for 2 hours were 101.93 ± 12.15 nm, 98.96 Å, 2.12 m2/g, and 3.02 g/cm3, respectively, appearing as a soft fine powder with a white color. The raw duck eggshell is a potential candidate as a bio‐ceramic material to prepare calcium hydroxyapatite suitable for use in various bio‐applications such as bone tissue engineering, drug and gene delivery, remineralizing agent in toothpaste, and bone void fillers for orthopedic and restoration.

Calcium hydroxyapatite made from duck eggshell react to phosphoric acid with the Ca/P mole ratio 1.67 and calcined at 800º, 900º, and 1000°C for each temperature 2 hr. Duck eggshell is a source of calcium carbonate having high purity content more than 98.101 %w/w and small amount of other metal oxides. Duck eggshell is a bio-material similar to other calcium sources i.e. coral, animal bone, and seashell. There are many advantages of using duck eggshell as a raw material such as abundant, low price, high purity of calcium carbonate content, easy to calcium phosphate formation, biocompatibility, bioactive, non-toxic for human, and the high percentage of ceramic yield 69.73%w/w. In addition, one of the most important advantages is to reduce the amount of duck eggshell waste from household and food industries as environmental conservation. The optimum condition to obtain high purity hydroxyapatite is sintering calcium phosphate at 1000°C for 2 hr. The average particle size, specific surface are, pore diameter, and true density of sample sintered at 1000°C for 2 hr are 39.92 µm, 2.12 m2/g, 98.96 Å, 3.02 g/cm3, respectively, in soft fine white powder. Furthermore, the results obtained by XRF, SEM, and XRD confirmed of sample fired at 1000°C for 2 hr to be calcium hydroxyapatite (HA, Ca10(PO4)6(OH)2) of Ca/P mole ratio 1.67 and small amount of calcium phosphate (β-TCP, Ca3PO4) of Ca/P mole ratio 1.5. Therefore, the duck eggshell is a potentially bio-ceramic material to prepare calcium hydroxyapatite applied for biomedical, bio-dental, and many industries i.e. pharmaceutical, toothpaste, cosmetic, and nutrient food etc.