Question

Gravity separation processing method depends on the difference in

• A. colour
• B. temperature
• C. reactivity
• D. density

Hint:

Gravity separation is highly economical and environmentally friendly because it uses water as the primary separating medium and avoids the use of toxic chemical reagents.

Answer 1

The Correct Option is D

Step 1: Understanding the Question:
The question asks for the primary physical property difference exploited in gravity concentration (separation) techniques during mineral processing.

Step 2: Key Formula or Approach:
The efficiency of separation by gravity methods can be estimated using the Concentration Criterion (\( CC \)):
\[ CC = \frac{\rho_h - \rho_f}{\rho_l - \rho_f} \]
where:
\( \rho_h \) is the density of the heavy mineral,
\( \rho_l \) is the density of the light mineral, and
\( \rho_f \) is the density of the fluid medium (usually water or air).
A concentration criterion value greater than \( 2.5 \) indicates that gravity separation is highly efficient.

Step 3: Detailed Explanation:

• Operating Principle: Gravity separation methods separate minerals based on the differences in their specific gravity (density) and their movement in a fluid medium under the action of gravitational or centrifugal forces.
- Heavy minerals (such as gold, hematite, or galena) experience a larger downward gravitational force and settle more rapidly.
- Light minerals (such as quartz or silicate gangue) settle slowly and are carried away by the fluid current.

• Common Equipment: This principle is utilized in various mineral processing units, including jigs, shaking tables, spirals, and dense medium separators (DMS).

• Incorrect Options:
-

Colour (Option A) is used in sensor-based optical sorting.
-

Temperature (Option B) is not a static material property used for separation.
-

Chemical reactivity (Option C) is exploited in leaching and chemical separation, not gravity concentration.


Step 4: Final Answer:
Hence, the gravity separation method depends on the difference in density, which corresponds to Option (D).