Froth Flotation

Materials: ★★☆ Available in most school laboratories or specialist stores
Difficulty: ★☆☆ Can be easily done by most teenagers
Safety: ★☆☆ Minimal safety procedures required

Categories: Separating Mixtures, Mining and Resources

Alternative titles: Ore Separation with Froth

Summary

Students simulate the froth flotation process used in mining to separate valuable minerals from waste rock. By adding water, kerosene, and detergent to a mixture of sand and iron filings, they observe how bubbles can help separate materials.

Procedure

Place one spatula of a sand and iron filings mixture into a test tube.
Add 5 ml of water, seal with a stopper, and shake for 10 seconds. Record observations.
Add 5 ml of kerosene to the same mixture, reseal, and shake for 10 seconds. Record observations.
Add one drop of detergent to the mixture, reseal, and shake again. Record observations.
Compare results after each step, focusing on bubble formation, separation of materials, and movement of particles.

Links

📄 Floating Froth Experiment - Oresome Resources: https://www.oresomeresources.com/wp-content/uploads/2010/03/Experiment-Floating-Froth-1.pdf

Variations

Try using different mineral mixtures, such as powdered chalk with sand, to model other ore separations.
Test different detergents or frothing agents to see how they affect separation efficiency.
Scale up the experiment using a beaker and stirrer for group demonstrations.

Safety Precautions

Wear safety glasses and gloves throughout the experiment.
Handle kerosene carefully; keep away from open flames and use in a well-ventilated area.
Dispose of mixtures safely according to teacher or lab technician instructions; do not pour kerosene down sinks.
Wash hands after handling chemicals and mixtures.

Questions to Consider

What happened when only water was added to the mixture? (Sand and iron filings stayed mixed without separation.)
Why was kerosene added? (It attaches preferentially to certain particles, helping them float with bubbles.)
What role did the detergent play? (It acted as a frothing agent, stabilizing bubbles to carry particles to the surface.)
Did all the iron filings separate out? Why or why not? (Not all may separate due to incomplete attachment to bubbles or mixing.)
Why is froth flotation valuable in metal production? (It allows efficient separation of ores from waste, making extraction more economical.)
How might modern techniques improve this process compared to early versions? (Use of more selective chemicals, better bubble control, and larger-scale machinery.)