Different beneficiation methods or ores of different nature have different concepts for the division of fine mud grades. Flotation fines generally refer to fine fractions of less than 10 microns or less than 5 microns, and froth flotation is suitable for processing finely divided materials. However, the production practice shows that when the material contains more fine mud, the flotation process is seriously deteriorated, and the flotation effect is significantly reduced. The production indicators generally have the problem of “two lows and two highsâ€, that is, the concentrate has low grade, low recovery rate, high consumption of chemicals, and high water content of concentrate. Therefore, flotation of fine mud has become one of the problems in mineral processing research. The problem of fine mud flotation is related to the physicochemical properties of fine mud. The basic characteristics of fine mud are as follows.
(1) The fine mud is small in mass, that is, the fine mud is difficult to collide with the bubbles. Even if it is in contact with the bubbles, the momentum is small because the mass is small, and it is difficult to overcome the hydrated film between the fine mud and the bubbles, so that the fine mud is hard to adhere to the bubbles. However, the fine mud is easy to adhere to the coarse grain surface, or the slime covers the coarse grain surface, which acts as a “suppressing†effect on the coarse flotation, which reduces the floatability of the coarse particles and makes the selection of the flotation process. Sex is bad. However, the mud cover is not all bad, the same composition of the mud cover does not affect its selectivity, carrying the flotation is the use of this principle. It is only the fine mud cover of different minerals that destroys the effective flotation separation.
(2) The ore particles larger than the surface, that is, the unit mass, have a large total surface area. For example, when a cubic ore with a side length of 1 mm is ground to 10 microns, its surface area is increased by a factor of 100. Since the surface area is large, the amount of adsorbed is large, which destroys the normality of the flotation process and consumes a large amount of flotation reagent.
(3) It is larger than the surface energy, that is, there is a large amount of unsaturated surface bond force on the surface of the slime. In other words, the surface activity of the slime is very large, so the surface of the slime will selectively adsorb a large amount of flotation agent, and in addition to increasing the consumption of the agent, it will make the slime difficult to sort.
On the other hand, the large surface activity of the slime makes the slime have a strong hydration ability. So it is very good. This brings great difficulties to the selection, concentration and filtration operations.
The fine mud has the distinction of primary fine mud and secondary fine mud. The primary fine mud is fine mud formed by minerals in the deposit due to natural weathering, such as kaolin and clay. Secondary fine mud refers to the fine mud produced during mining, handling, crushing and grinding. Generally, the primary fine mud is harder to float than the secondary fine mud. In order to reduce the damage of fine mud to the flotation process, it is necessary to minimize secondary sludge.
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