Wax sweating — allowable oil content\nTo achieve efficient and satisfactory wax sweating, the upper limit of oil content in the wax should be about ______ %.

Introduction / Context:
Wax sweating is a finishing step where controlled heating allows entrained oil to “sweat” out of a wax cake, improving oil content to meet specifications. Excess oil interferes with crystal networking and drainage.

Given Data / Assumptions:

• Target is efficient sweating performance without excessive cycle time.

Concept / Approach:
For effective sweating, wax cakes must have limited initial oil so the crystalline structure can form a connected matrix and allow oil to drain. Industrial practice limits initial oil content to around 5% or less. Higher oil percentages hinder structure and lead to poor separation and off-spec wax.

Step-by-Step Solution:

Verification / Alternative check:
Specifications for fully refined paraffin and microcrystalline waxes show low oil content limits; process notes advise low initial oil for effective sweating.

Why Other Options Are Wrong:

• 15–60% are far too high for efficient sweating.
• 2% is within spec for finished waxes, not an upper limit for initiating sweating.

Common Pitfalls:
Attempting to sweat wax with very high oil content instead of first deoiling by solvent/cooling methods.

Final Answer:
5