Bill Frazer, age 13, of Biloxi, MI for his question:

WHAT IS THE FLOTATION PROCESS?

Flotation process is used to separate minerals from each other, or from other materials with which they are mixed.

In this process, the material that contains the minerals is first crushed and ground fine. It is then added to a liquid that contains certain chemicals called flotation reagents. These chemicals form a film around the particles of one of the ores and keep the liquid from wetting it.

As an example, xanthates keep water from wetting sulfide ores.

Other chemicals may also be used which will help or hinder the filming of a certain mineral. The liquid is stirred up with air, which rises in bubbles and forms a froth on top.

The bubbles stick to the film around the dry particles and carry them to the top. Here they may be skimmed off with the froth.

Special flotation machines have been designed to carry out this process.