Foams in mineral flotation and separation processes

Foam flotation is a process used worldwide to separate metallic and nonmetallic minerals from extracted ore. It is probably the single most important operation used in the mining industry in the world today. In the United States, for example, over one-third of the mineral concentrates produced are obtained using flotation [I]. Ninety percent of the world’s copper, lead, zinc, molybdenum, antimony, and nickel are produced by processes employing concentration of ore by flota tion. Although the processing of mineral ores is by far the largest use of flotation separation, numerous other processes have been developed for the separation of other materials. These range from coal flotation processes for upgrading its fuel value to solution processes for separating biomolecules and ions. New applications are being developed in environmental areas such as processing of recycled paper, including particulate flotations for removing ink particles. Table 1 indicates the range of materials separable by flotation techniques.