Thorium in monazite: Indian monazite beach sands typically contain approximately what percentage of thorium (as thorium-bearing minerals)?

Introduction / Context:
India’s thorium resources are largely found in monazite-bearing beach sands, which are strategic for the thorium fuel cycle. Knowing typical thorium content provides context for resource assessments and processing economics.

Given Data / Assumptions:

• “Indian monazite sand” refers to placer deposits along certain coasts.
• Thorium content is asked as an approximate percentage, recognizing natural variability.

Concept / Approach:
Monazite is a phosphate mineral containing rare-earth elements and thorium. Typical thorium content for Indian monazite is on the order of ten percent by weight (often quoted near 9–10% as ThO2 equivalent), though deposits vary by location.

Step-by-Step Solution:

Verification / Alternative check:
Resource summaries and historical data commonly reference ~10% thorium in monazite concentrates, acknowledging variability across beaches and processing stages.

Why Other Options Are Wrong:

• 25%, 60%, 90%: substantially higher than typical monazite thorium content and unrealistic as bulk sand composition.
• 5%: below the commonly cited rounded value for monazite concentrates in India.

Common Pitfalls:
Confusing raw beach sand composition with monazite mineral composition; ignoring deposit-to-deposit variability.

Final Answer:
10