The coarse particle flotation (CPF) and grinding circuit are the cornerstones of current mineral processing. The CPF is the unique extraction of large-sized mineral particles, which can be 150 to 850 microns, by flotation cells that have difficulty dealing with such heavy particles. Grinding circuits are energy-intensive processes of ore milling aimed at the liberation of minerals. It is vital to know how CPF and grinding circuits interrelate to minimize energy consumption and increase mineral extraction.
The recent advancements made in CPF technology have been largely concerned with the fluidized bed flotation cells, including the Eriez HydroFloat, the Jord NovaCell, and the FLSmidth CoarseAIR. These technologies bring about a new approach by combining gravity separation and flotation. Through creating a state of suspension of particles in a fluidized bed characterized by low shearing and turbulent free environment, it becomes possible to separate coarse, partially liberated, and heavy particles without their loss to tailings.
In addition to hydrodynamics, advances in process chemistry are improving the effectiveness of CPF processing. Improvements such as the addition of aerosol collectors improve the thermodynamic conditions of collector adsorption on mineral surfaces. Efficient collisions between bubbles and particles ensure that even large particles are well attached. Additionally, control over bubble coalescence in fluidized beds enables operators to adjust frother concentrations to form the larger bubbles needed to lift heavy mineral agglomerates.
The adoption of CPF will have a dramatic effect on how the grinding circuits are designed. Traditionally, the grinding circuits have been operated so that finely liberated particles are produced at the output. This operation has consumed a lot of power. However, due to CPF’s ability to float the coarser and partially liberated minerals, the comminution circuits can be designed for a much coarser output.
Moreover, the use of CPF makes it possible to reject waste early on. The separation of gangue from the valuable minerals in large-sized particles results in the early rejection of large amounts of worthless ore. This leads to a release of capacity in subsequent grinding mills and enables plants to increase their throughput without building expensive fine grinding facilities.
In summary, advances in coarse particle flotation represent an innovative operating approach that is beneficial for today’s mines. Through the application of advanced fluid mechanics and chemistry, mining facilities will be able to successfully extract coarse particles. As a result, there will be no strain on grinding plants, which implies lower energy consumption and increased efficiency of operations.
