Which of the following can be used as a stabilizer during ore concentration?

Aniline

The correct answer is option 2. Aniline.

Froth flotation is a method widely used to concentrate ores, particularly sulfide ores. The process involves the following steps:

Crushing and Grinding: The ore is crushed and ground into fine particles to liberate the valuable minerals from the gangue (unwanted minerals).

Mixing with Water: The ground ore is mixed with water to form a slurry.

Addition of Reagents:

Collectors: Chemicals that selectively bind to the surface of the desired mineral particles, making them hydrophobic (water-repellent).

Frothers: Substances added to stabilize the froth formed on the surface of the slurry.

Depressants: Prevent certain types of particles from forming froth.

Air Bubbles Introduction: Air is bubbled through the slurry. The hydrophobic mineral particles attach to the air bubbles and rise to the surface, forming a froth layer.

Froth Collection: The froth, which contains the concentrated ore, is skimmed off the surface, while the gangue remains in the water and is removed.

Role of Stabilizers in Froth Flotation:

Stabilizers are crucial in maintaining the stability and longevity of the froth. They prevent the bubbles from bursting too quickly, ensuring that the froth is stable enough to carry the desired mineral particles to the surface. A stable froth allows for better separation efficiency.

Why Aniline is Used as a Stabilizer:

Aniline is an aromatic amine with the chemical formula \(C_6H_5NH_2\). Its structure allows it to interact with both the aqueous environment and the surface of the mineral particles. Here’s why aniline is effective:

Interaction with Frothers: Aniline can interact with frothers (like pine oil) to enhance froth stability. This interaction ensures that the bubbles in the froth do not collapse prematurely, allowing the mineral particles attached to them to be effectively separated.

Adsorption on Mineral Surfaces: Aniline can adsorb onto the surface of certain minerals, further stabilizing the froth by reducing the surface tension at the air-liquid interface.

Prevents Froth Breakdown: The aromatic ring of aniline provides hydrophobic characteristics, which can contribute to the formation of a more stable froth, preventing it from breaking down before the desired minerals are separated.

Selective Froth Formation: Aniline's selective interaction with certain minerals can help in the flotation process by stabilizing the froth specifically around the particles that need to be concentrated.

Example in Practice: In the flotation of sulfide ores, for example, aniline might be used as a froth stabilizer to ensure that the sulfide mineral particles are efficiently collected in the froth. Without a stabilizer like aniline, the froth might collapse too soon, leading to poor separation and recovery of the valuable minerals.

Summary: Aniline acts as a stabilizer in the froth flotation process, maintaining the stability of the froth and ensuring efficient separation of the desired ore from the gangue. Its ability to interact with frothers, reduce surface tension, and selectively stabilize the froth makes it valuable in ore concentration processes.

Therefore, option 2: Aniline is the correct answer as the stabilizer used during ore concentration.