What are the effects of bubble mineralization on flotation performance

In the flotation process, the flotation machine scrapes out froth with ore particles adhering to it, separating valuable minerals from gangue minerals. In this stage, the froth pulp contains substances in solid, liquid, and gaseous states. The process by which mineral particles in the pulp adhere to the bubbles is called bubble mineralization. Bubble mineralization exhibits a certain selectivity towards mineral particles. During this process, hydrophobic particles adhere to the bubbles, forming gas-solid complexes; hydrophilic particles, however, are difficult to adhere to the bubbles and remain in the pulp. For the flotation process, the degree of particle adhesion to the bubbles directly affects the flotation effect. Therefore, improving the degree of bubble mineralization is one of the key factors in improving the flotation process. How can we improve the flotation effect by improving the bubble mineralization process? Important influencing factors include bubble size, mineral surface properties, particle density, and particle size, etc. Below, we will explore the roles of each of these aspects in affecting the flotation effect.

I. The Influence of Bubble Size

During the adhesion process between bubbles and minerals, bubbles and mineral particles approach and collide. Only after multiple collisions can the bubbles successfully capture the mineral particles. In the stage of mineral particle-bubble adhesion, at least ten collisions occur between the minerals and bubbles. Reducing the bubble diameter increases the probability of collisions between bubbles and mineral particles, making it easier for mineral particles to adhere to the bubbles and facilitating the mineralization process. In production practice, the bubble size should be determined based on the particle size of the minerals. When the mineral particle size is fine, the bubble size can be appropriately reduced, but it should not be too small, otherwise it will reduce the recovery rate and concentrate quality. This increases the probability of collisions between bubbles and minerals, thereby improving the flotation effect.

II. The Influence of Mineral Surface Properties

The mineral surface properties here mainly refer to the surface wettability of the minerals. This determines whether the minerals can selectively adsorb, that is, whether the mineralization process can be completed. Generally, surface wettability is determined by the structural properties of the minerals. The worse the surface wettability, the stronger the hydrophobicity, and the better the natural floatability of the mineral. For this type of mineral, bubbles easily displace the hydration film on its surface, allowing it to adhere stably to the bubble surface, thus facilitating bubble mineralization. Generally, when determining the mineral composition, their floatability can be compared based on the differences in surface wettability of the constituent minerals. When the difference in surface wettability between the useful mineral and the gangue mineral is relatively small, we can widen the difference in floatability by adding suitable media modifiers and collectors, making it easier for one to adhere to the bubbles and facilitating flotation separation.

III. Influence of Mineral Particle Density and Size

After the mineral adheres to the bubbles, the bubbles rise to the surface of the slurry and then enter the froth product. The carrying capacity of the bubbles is limited. How can we ensure that mineral particles do not detach from the bubble surface from the time they complete attachment until they float to the surface of the slurry and are scraped into the froth tank? When mineral particles adhere to the bubbles, the forces acting on the particles include the buoyancy of the bubbles, the weight of the particles themselves, and the adhesion force between the mineral and the bubbles. Therefore, in addition to the surface wettability of the minerals, their density and particle size are also important factors in this process. Analysis reveals that during the ascent of the mineral particles to the froth layer, the adhesion and buoyancy must exceed their own weight. Therefore, under certain gravitational conditions, the lower the density of a mineral, the larger the diameter of the particles that can be floated. Thus, for minerals with poor wettability and low density, the grinding fineness can be appropriately relaxed during flotation, such as graphite and molybdenite. We have explained the impact of bubble mineralization on the flotation process from three aspects. However, the factors mentioned above are controllable; many other factors can affect flotation results, such as the fluid dynamics within the flotation cell, the mechanism of action of flotation reagents, and their appropriate addition. For complex ores, it is crucial to avoid rigidly applying a single process. Determining the appropriate process and parameters through experimentation, tailored to the ore's properties, is a more scientific and reasonable approach. Consulting a mineral processing equipment manufacturer with mineral processing testing qualifications is highly recommended to develop a suitable process for the ore, thus avoiding economic losses and resource waste.