Column Flotation

The Eriez Flotation Division has supplied more than 900 flotation columns throughout the world in mineral concentrating and purification applications that include iron ore, base metals, gold, industrial minerals, fertilizers (phosphate and potash), energy (coal and oil-sands) and speciality applications such as oil/water separation.

EFD’s advantages in Columns include:

  • A large group of knowledgeable engineers throughout the world to design and support your application. This includes more than 20 years of experience in supplying column applications.
  • Offering test-services. We operate a central test lab and test columns that can be brought to site that can be used to predict metallurgical performance and de-risk the installation.
  • Provides a variety of column and sparging technologies so we can recommend and design the most appropriate equipment for the application. In some cases, we have optimized columns for particular mineral systems such as the PhosPro™ for phosphate, the K-Pro™ for potash, the BitPro™ for bitumen, and the CoalPro™ for coal


Stack Cells

StackCell®… Column-like performance in a substantially smaller footprint

These compact, stackable units offer considerable savings for new installations and are ideal for expanding capacity in an existing plant.

A new high-capacity flotation technology, the StackCell, has been developed as an alternative to both conventional and column flotation machines. This technology makes use of a pre-aerated, high-shear feed canister that provides efficient bubble-particle contacting, thereby substantially shortening the residence time required for coal flotation. Other potential advantages of the process include low air pressure requirements, low capital and installation costs, and increased flexibility in plant retrofit applications.

Recent full-scale plant trials suggest that this low-profile technology can provide coal recoveries and product qualities comparable to column flotation systems. Two full-scale approaches were tested including a single unit rougher application as well as a 3-stage, in-series arrangement. In the rougher application, the StackCell was able to successfully offload an existing overloaded flotation circuit which resulted in an increase in combustible recovery in excess of 90%. For the 3-stage circuit, the metallurgical results show that the StackCells, when arranged in-series, are meeting the design requirements at an acceptable combustible recovery, product carrying capacity, and product ash content.

StackCell technology provides an alternate means to efficiently achieve column-like performance when plant space and/or capital is limited. In particular, the small size and low weight of this new technology makes it amenable to low-cost plant upgrades where a single unit can be placed into a currently overloaded flotation circuit with minimal retrofit costs.

StackCell features:

  • Small footprint
  • Gravity feed system
  • High throughput with low residence time
  • Stackable design
  • Low energy input costs
  • High sheer bubble generation



The first in fluidized-bed flotation with more than 50 units installed worldwide!

Eriez, a world leader in separation technology, has designed the new HydroFloat Separator for coarse particle mineral concentration delivering the capacity of a density separator while maintaining the selectivity of a flotation device. Using a novel aeration system to disperse fine bubbles into a fluidized-bed environment, the HydroFloat Separator significantly increases the selective recovery of coarse particles by applying flotation fundamentals to gravity separation.

Can be applied to:

  • Coal
  • Iron ore
  • Industrial minerals
  • Base metals
  • Sulfides

Applications include:

  • Coarse recovery in split-feed flotation circuits
  • Tailings scavenging
  • Flash flotation in grinding circuits
  • Principles of Operation

The HydroFloat Separator is an aerated fluidized-bed (or teeter-bed) separator. The synergistic effect of combining flotation with gravity concentration results in an outcome that cannot be achieved by either approach alone.

Air bubbles are dispersed by the fluidization system, percolate through the hindered-setting zone and attach to the hydrophobic component altering its density and rendering it sufficiently buoyant to float and be recovered. The use of the dense phase, fluidized bed eliminates axial mixing, increases coarse particle residence time and improves the flotation rate through enhanced bubble-particle interactions. As a result, the rate of recovery is high for both fully-liberated and semiliberated particles.

HydroFloat Separators Improve Coarse Particle Recovery through:

  • Increased bubble/particle collision rates
  • Increased bubble/particle sliding time
  • Increased residence time
  • Decreased mixing
  • Decreased turbulence and detachment
  • Decreased buoyancy restrictions


CrossFlow Classifier

A high capacity teeter-bed separator

Eriez’ CrossFlow Separator is a highly efficient hydraulic classifier for the separation of material based on particle size, shape and/or density. This technology can also be used for de-sliming, counter-current washing and acid neutralization of minerals.

The CrossFlow separates particles based on hindered-settling principles providing an economical and efficient means of classifying material such as silica and frac sands, mineral sands and industrial minerals.

Ores containing a mixture of high- and low-density components can also be upgraded based on their difference in specific gravity. Examples include iron ore, and heavy mineral with silica contamination and run-of-mine coal containing various ash-forming components such as rock and pyrite.

The hindered-settling environment creates the optimum conditions for efficient counter-current washing to rinse, clean, and neutralize ore prior to secondary unit operations.

Applications include:

  • Sizing and classification
  • Density separation and concentration
  • Washing and neutralization of minerals
  • Novel feed presentation system improves separation efficiency

Unlike traditional teeter-bed technologies, the Eriez CrossFlow uses a unique “tangential” feed presentation system to introduce feed into the top of the separation chamber. This novel approach can provide unit capacities up to three times that of a conventional classifier and eliminates particle misplacement caused by excessive feed volume and plant fluctuations.

In the CrossFlow, feed particles descend against a rising flow of teetering water established by a uniform system of water injection pipes located in the base of the main separator housing. Based on the settling characteristics of the ore and the water addition rate, a fluidized bed of solids is established in the separator. Particles with a low settling velocity (fine/low density) that cannot penetrate the teeter bed are carried over the top of the separator with the bulk of the fluidizing medium. Particles with a high settling rate (coarse/high density) settle through the fluidized bed and are eventually discharged at a high solids content through the underflow control valve.

CrossFlow Features

  • High capacity
  • Precise, efficient classification
  • Improved efficiency with fluctuating and/or dilute feed streams
  • Easy, on-line cut-point control using true density measurement
  • Fully automated discharge control system
  • Dewatering cone for consistent underflow discharge characteristics
  • Units are all pre-assembled and shop tested to ensure you have no surprises on site
  • Rubber shell liners and lifters for a long life and ease of replacement