Mining and ore flotation

As just mentioned, the addition of the proper surfactant to a dispersion can produce a situation in which the solid particles, having a specific gravity much greater that that of water, can be made to float to the top and be easily (relatively speaking) separated from the aqueous phase. In the deinking mentioned above, there is no particular interest in being selective with respect to what is removed. It is essentially an all out proposition. In the mining industry the situation is quite different. 

While the theory of the adsorption of surfactants onto solid surfaces is highly developed and well understood in ideal systems, the reality of the universe is that in such complex multicomponent systems as mining ores, theory soon runs out of steam and success ultimately depends on hands-on laboratory and field trials, inmition, and art (or perhaps black magic). 

Surfactants are also becoming more important in the coal mining industry. Aside from flotation processes, they are also employed as binders for the suppression of coal dust, and as dispersal aids and antifreezes for coal slurries that are pumped through pipelines. 

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