Flotation, that is, foam flotation, is a mineral processing method to separate minerals according to the different physical and chemical properties of the mineral surface.
In the flotation process, the rise and fall of minerals is almost independent of mineral density, such as chalcopyrite and quartz, the relative density of the former is 4.2, the latter is 2.66, but the heavy mineral chalcopyrite is easy to float, and the quartz instead sinks at the bottom. The study found that the buoyancy of the mineral is related to its affinity for water, and those minerals with large affinity for water and easy to be wet by water are difficult to adhere to the bubble and difficult to float. Minerals that have a small affinity with water and are not easily moistened by water are easy to float. Therefore, it can be said that flotation is a mineral processing method based on the different wettability of minerals by water, generally the nature of minerals easy to float and difficult to float is called mineral floatability, flotation is the use of mineral floatability differences to separate minerals. In the modern flotation process, the application of flotation reagents is particularly important. Because after being treated by flotation agents, the floatability of minerals can be changed, so that the minerals to be floated can selectively adhere to the bubbles, so as to achieve the purpose of beneficiation.
Flotation is one of the most important beneficiation methods. According to statistics, 90% of non-ferrous metal ores are treated by flotation. In addition, the flotation method is also widely used in the separation of rare metals, precious metals, ferrous metals, non-metals and coal and other mineral raw materials. In recent years, the flotation method is also used at home and abroad for water purification, sewage treatment, etc. It can be seen that the application range of flotation method is quite wide. Compared with other beneficiation methods, the flotation method has better effect and is more urgent and reasonable. The flotation method is also commonly used to separate the fine parts of coarse-grained or uneven thick-grained disseminated ores.
Flotation is the same as other beneficiation methods, it is necessary to do a good job of material preparation before separation, that is, the ore should be ground and graded to achieve the concentration fineness suitable for flotation. In addition, flotation has the following basic operations.
(1) The adjustment of the pulp and the addition of flotation agents is designed to cause the difference in the surface properties of the mineral, that is, to change the wettability of the mineral surface, to adjust the selectivity of the mineral surface, so that some mineral particles can be attached to bubbles, or to promote the formation of microbubbles in the air dissolved in the pulp.
(3) The mineralization of bubbles The mineral particles are selectively attached to bubbles, which is the most basic behavior in the flotation process.
(4) Formation and scraping of the mineralized foam layer The mineralized bubble rises from the lower part of the flotation cell to the pulp surface to form the mineralized foam layer, and the useful minerals are enriched into the foam and scraped out to become a concentrate (middle ore) product. Non-target minerals are left in the flotation cell to achieve the purpose of separation. Usually, the minerals that float in the flotation operation are useful minerals, and this flotation process is called positive flotation, whereas the minerals that float are gangue, which is called reverse flotation (or reverse flotation).
