Bone ash, a traditional phosphate source used in fertilizer and metallurgy, is composed predominantly of which calcium compound?

Introduction / Context:
Bone ash originates from calcined animal bone and has been a historical source of phosphorus. Understanding its composition explains its applications in fertilizer blending, ceramics, and metallurgy as a source of phosphorus pentoxide equivalents.

Given Data / Assumptions:

• Bone ash is produced by high-temperature treatment of bones.
• Residual inorganic matrix mirrors the mineral phase of bone.
• We seek the dominant chemical component.

Concept / Approach:
Natural bone mineral is hydroxyapatite, Ca10(PO4)6(OH)2, which upon calcination yields materials collectively referred to as calcium phosphates. Therefore, the principal constituent of bone ash is calcium phosphate (apatite family), not calcium sulfate or carbonate as the main phase.

Step-by-Step Solution:
Link bone mineral to hydroxyapatite composition.Calcination removes organics and water, concentrating phosphate salts.Recognize that calcium phosphate dominates bone ash composition.Select calcium phosphate as the main component.

Verification / Alternative check:
Materials references list bone ash as primarily tricalcium phosphate/hydroxyapatite; analytical assays show high P2O5 content consistent with calcium phosphate matrices.

Why Other Options Are Wrong:
Calcium sulfate and calcium carbonate may be present as minor phases or contaminants but are not the predominant bone-derived mineral.Sodium phosphate is not a natural bone mineral and would require chemical processing to appear.

Common Pitfalls:
Confusing bone ash with phosphate rock (both phosphate sources) or supposing gypsum dominates due to fertilizer associations.

Final Answer:
Calcium phosphate