The popularity of non-mechanically agitated flotation machines (flotation columns) has varied significantly over the last fifty years. There are various philosophies on the use of column flotation. These range from support of the concept of all column flotation plants, to the opposite extreme where the risks are considered to outweigh any potential gains of column flotation. The majority of mineral processing engineers support the installation of columns based on a logical appraisal.
In the Australian coal industry, where flotation columns have almost total dominance, the use of anything other than a column would be questioned. Column flotation is also largely the dominant flotation technology in the coal industry in the USA and China, the phosphate industry in the USA and Brazil and the iron ore industry in Brazil. These areas of dominance represent a substantial installed column capacity, but even so are restricted to specific geographic areas and commodities. Within the base metals industry flotation columns are generally accepted in the smaller capacity cleaner roles worldwide. It should be noted that a number of flotation column installations have been dismal failures, but they represent only a fraction of total column installed capacity.
This paper provides an analysis of over 4000 installed flotation columns, contained in the Amec Foster Wheeler flotation database. Changing trends in column flotation use by type, commodity and geographical region are reviewed. The reasons for the numerous rises and falls in column flotation use are also discussed.