Thorium in monazite: Indian monazite beach sands typically contain approximately what percentage of thorium (as thorium-bearing minerals)?
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A10
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B25
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C60
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D90
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E5
Answer
Correct Answer: 10
Explanation
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:
1) Recall typical reported ranges for Th in Indian monazite.2) Select the closest rounded value from the options.3) Therefore, 10% is the best representative choice.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