One of the most important methods of flotation operation technology is to observe the foam in the flotation machine and judge the flotation effect according to the change of foam. Based on years of experience, Fodamon engineers would like to share with you the following:
Experienced flotation machine operators can judge the causes of changes from observing various changes in the apparent phenomenon of foam, so as to adjust in time to ensure that the flotation process is carried out under optimal conditions.
Whether the floater can correctly adjust the flotation reagent addition, concentrate scraping and middling circulation depends on the correctness of his judgment on the appearance of flotation foam, and the ability to observe and judge is mainly obtained from continuous and careful summary of operating experience. The appearance of flotation foam includes the virtual and solid, size, color, luster, shape, thickness, strength, fluidity, sound and other phenomena of foam, which are mainly determined by the type, quantity, particle size, color, luster, density, and amount of foaming agent of minerals attached to the surface of foam.
- The Virtual and Real of foam
The mineral particles attached to the surface of the bubble are many and dense, while the foam is solid. The mineral particles attached to the bubble surface are few and thin, and the foam is empty. The raw ore grade is high, the dosage of reagent is appropriate, and the foam is solid. The foam will become empty if the inhibitor is excessive and the collector is too little.
- The size of foam
The size of bubbles on the surface of foam layer often varies with ore properties, reagent system and flotation area.
- Color
The darker the color of the floating minerals in the scavenging area, the greater the metal loss. The darker the color of the floating minerals in the coarse and fine concentration areas, the better the concentrate quality.
- Gloss
For the rough flotation of sulfide minerals, the foam mineralization in the concentration area is good, so its metallic luster is strong, while the foam mineralization in the sweep area is poor, showing the glassy luster of water film. If the scanning foam shows semi metallic luster, it indicates that the metal loss is large.
- Contour
When the foam mineralized by moderately hydrophobic mineral particles is formed on the pulp surface, it has sufficient water, and the contour of each bubble is relatively bright. The foam stays on the pulp surface for a long time, and the mineral is hydrophobic. When the bubble wall is dry and incomplete, the bubble contour is blurred.
- Thick and thin
The thickness of the foam layer is mainly related to the amount of foaming agent and the degree of bubble mineralization. There are many foaming agents, high grade of raw ore, high concentration, and good degree of mineralization. The foam layer is generally thick, on the contrary, it is relatively thin. The floating ore particles are too thick, and it is difficult to form a thick foam layer. The slurry surface in the cleaning area is low, the foam layer is thick, and the concentrate grade is high. The cleaning area maintains a high slurry surface, and the floating minerals can be scraped out in time. The foam layer is thin, and the recovery rate is high.
- Brittleness and viscosity
The foam is too brittle, poor stability, easy to break, and sometimes cannot be scraped out. On the contrary, the foam is too viscous and stable, which will cause the flotation machine to “run off”, damage the normal flotation process, cause difficulty in concentrate transportation, excessive foaming agent, and a large amount of soluble salts such as slime and lead sulfate falling into the oil or ore, all of which can make the foam too stable.
- Audio
When the foam is scraped into the foam tank by the scraper, it makes a sound of “rustling”. It is often because foam contains a large number of minerals with large proportion and coarse particle size.
The above eight points are the flotation operation technology to judge the flotation effect. The appearance of foam varies with different flotation areas, but specific areas often have specific phenomena. To observe the foam situation, we should focus on several flotation cells that have obvious characteristics and have a major impact on the concentrate grade and recovery rate, mainly including: final concentrate flotation cells, several flotation cells before operation, flotation cells with flotation reagents and flotation cells at the end of scavenging.