Calcination-based direct extraction of hydroxyapatite from bovine bone waste

Area of Science:

• Materials Science
• Biomaterials Engineering
• Biomineralization

Background:

• Waste cow bones are rich in apatite minerals, primarily calcium and phosphorus.
• Hydroxyapatite (HAp) is a key biomaterial with applications in bone regeneration and dental implants.
• Efficient methods for extracting and purifying HAp from biological waste are crucial for sustainable biomaterial production.

Purpose of the Study:

• To investigate the extraction of hydroxyapatite from waste cow bones.
• To determine the optimal calcining conditions (temperature and time) for producing high-purity HAp.
• To characterize the structural and morphological properties of the synthesized HAp powders.

Main Methods:

• Waste cow bones were crushed and calcined at 900°C for varying durations (1-6 hours).
• Powder X-ray Diffraction (XRD) was used for quantitative phase analysis.
• Scanning Electron Microscopy (SEM) and Energy-Dispersive X-ray spectroscopy (EDX) were employed for morphological and elemental analysis.

Main Results:

• Calcining cow bones at 900°C resulted in an average mass loss of 45%.
• Quantitative XRD confirmed the presence of 99.97 wt.% hydroxyapatite and trace amounts of calcite and calcium ferrite.
• SEM revealed aggregate sizes of 0.5-3 µm and crystallite sizes of 70-340 nm.
• EDX analysis indicated a Ca/P ratio exceeding 1.67, suggesting calcium-deficient hydroxyapatite formation.

Conclusions:

• Calcining cow bones at 900°C for 5-6 hours produces a high-purity, nano-crystalline hydroxyapatite powder precursor.
• The synthesized HAp shows potential for biomedical applications due to its purity and controlled morphology.
• Optimized thermal treatment of bone waste offers a sustainable route to valuable biomaterials.