Question

Which of the following is a process of gravity concentration where solids are separated based upon the differences in the behavior of particles through a moving fluid which in turn, depends upon densities/specific gravities.

• A. Classification
• B. Sedimentation
• C. Centrifugation
• D. Jigging

Hint:

Jigging uses pulsating fluid motion to separate particles by density, making it a classic gravity concentration method in mineral processing.

Answer 1

The Correct Option is D

Step 1: Understand gravity concentration and the role of a moving fluid.
Gravity concentration is a separation process that uses the differences in density or specific gravity of particles to separate them. The question specifies that the separation occurs in a moving fluid, and the behavior of particles depends on their densities/specific gravities.
Step 2: Analyze each process.
Classification: This process separates particles based on size and settling velocity in a fluid (often air or water). While density plays a role, classification primarily focuses on size differences, not density-based separation in a moving fluid as the primary mechanism.
Sedimentation: This involves particles settling in a fluid due to gravity, often in a static or slowly moving fluid (e.g., in a settling tank). It separates based on density and size, but the fluid is typically not "moving" in the sense of a dynamic flow aiding separation.
Centrifugation: This uses centrifugal force (not gravity alone) to separate particles based on density differences, typically in a rapidly rotating device. It does not rely on a moving fluid in the same way as gravity concentration processes.
Jigging: This is a gravity concentration process where particles are separated in a moving fluid (usually water) through a pulsating motion. The bed of particles is repeatedly lifted and settled by the fluid, allowing heavier (denser) particles to settle faster and separate from lighter particles. The separation directly depends on differences in specific gravity, and the moving fluid (pulsating water) plays a key role.
Step 3: Match the process to the description.
Jigging fits the description perfectly:
It is a gravity concentration process.
It involves a moving fluid (pulsating water).
Separation is based on the behavior of particles, which depends on their densities/specific gravities.
Step 4: Evaluate the options.
(1) Classification: Incorrect, as classification focuses on size-based separation, not primarily density in a moving fluid. Incorrect.
(2) Sedimentation: Incorrect, as sedimentation typically involves a static or slowly moving fluid, not a dynamically moving fluid for separation. Incorrect.
(3) Centrifugation: Incorrect, as it uses centrifugal force, not gravity concentration, and does not involve a moving fluid in the same sense. Incorrect.
(4) Jigging: Correct, as jigging is a gravity concentration process where a moving fluid separates particles based on density differences. Correct.
Step 5: Select the correct answer.
The process of gravity concentration where solids are separated based on differences in behavior in a moving fluid, depending on densities/specific gravities, is jigging, matching option (4).