According to Rittinger’s law for crushing and grinding, the energy required is directly proportional to which quantity?
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AThe new surface created
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BThe size reduction ratio only
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CThe change in volume of solids
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DNone of these
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EThe square of feed size
Answer
Correct Answer: The new surface created
Explanation
Introduction / Context:Comminution energy models help estimate power requirements across size ranges. Rittinger’s law applies best to fine grinding where surface area increases significantly.
Given Data / Assumptions:
- Focus on the proportionality statement.
- No numeric data required.
Concept / Approach:Rittinger’s postulate: E ∝ ΔA (increase in surface area). It contrasts with Kick’s law (E ∝ ln size ratio) and Bond’s law (E ∝ 1/√d relationships). Therefore, for fine size targets, Rittinger provides the most accurate estimate.
Step-by-Step Solution:Identify the law linking energy to surface area.Select “new surface created.”
Verification / Alternative check:Textbook derivations and experimental evidence in fine milling confirm the proportionality to ΔA.
Why Other Options Are Wrong:Size ratio or volume change are not Rittinger’s basis.
Common Pitfalls:Confusing Bond’s widely used industrial correlations with Rittinger’s fine-grind regime.
Final Answer:The new surface created