Sulfide ores are first ground to powder, then water and pine oil is added. The mixture is agitated with air. Oil wets the mineral particles and not the gangue. Oil and froth float on the surface along with the sulfide ore. The gangue particles being insoluble in oil remain at the bottom of the water tank. The froth is skimmed off.
Rock salt is the name of a sedimentary rock that consists almost entirely of halite, a mineral composed of sodium chloride, NaCl. It forms where large volumes of sea water or salty lake water evaporate from an aridclimate basin where there is a replenishing flow of salt water and a restricted input of other water.