Imhoflot™ Pneumatic Flotation

The technology was introduced to the mining industry more than 25 years ago and the technology has since branched into various designs including V-cells, the patented as Imhoflot G-Cell and H-cell as the latest design.

Imhoflot flotation is typically characterised as being a non-impeller flotation system, whereby all the critical tasks are separated in unique and distinct unit operations.

Imhoflot™ Operating Principles

Imhoflot™ technology, distinctive and unique principles of operation:

  • Collection and particle – bubble interaction takes place outside of the cell in proprietary aeration devices.
  • The aeration system is self aspirating
  • Separation and recovery of the floatable constituents takes place in the separation tank
  • The process consists of co-current flow (unlike column flotation) and therefore variable froth crowding can be applied
  • Mechanical agitators to suspend the slurry and disperse the air are not required
  • Residence time is short. Recycle and multi-stage systems enhance the efficiency of the process


Classic Design – Vertical cell lassic Design – Vertical cell

  • Central cell feed is vertical and free draining
  • Self-aspirating aeration device
  • Pulp distributor is located in the separation zone
  • Cylindrical separator with peripheral froth collection
  • Conical froth crowder permits fine control of froth dynamics
  • Tailings flow and discharge through a conical hopper
  • Overflow level control facility, with short-circuit prevention
  • Recycle flow and level control facility

The new design incorporates features for enhancing separation in difficult process applications.

  • Dynamic, centrifugal action improves the mobility of rising air bubbles, promoting disengagement, whilst reducing entrainment; and
  • Smaller volumes allow for more stages, increased separation and lower costs.

Advanced Design – G and H Cells

Operational Design Features and Benefits

  • Imhoflot™ flotation cells are designed for high throughput capacity per unit and can endure wide variations in feed grade;
  • Every Individual Imhoflot™ flotation cell has a constant feed rate as per set feed pump, eliminating sliming and concentrate production caused by fluctuations in feed rates;
  • The process caters for the recovery of all variations of floating minerals, reducing investment and operating costs;
  • The space required is much smaller compared to other flotation systems and on the same level (ground level) as compared to conventional cells cascading from height;
  • Space requirements, compared to other flotation systems are a minimum, limited to the same level;
  • It is a modular design process, therefore:
    • The design of the distribution unit, aeration unit and separating cell allows for the easy assembly and replacement of parts;
    • Imhoflot™ flotation cells can be automatically controlled and require minimum supervision via PLC control;
    • A maintenance friendly process, occasional and simple replacement of parts, confined to the pump and aeration unit;
    • Imhoflot™ flotation excels in coarse and ultra-fine mineral recovery applications; and
    • Critical parts are manufactured from ceramic and wear resistant materials.

The flotation cells are designed for a variety of throughput requirements, ranging from small pilot sized cells with a diameter of 0.8m, processing 6 – 10 m3/h of feed; to cells with a diameter of 6.5m, handling feeds of 1500 m3/h.

The flow rate is dependent on the feed pressure and rate of concentrate removal. A higher concentrate removal requires a higher throughput.

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Modular 3D

Scale-up and Flowsheet Layout

MMS has extensive experience in plant layouts regarding pneumatic flotation systems. Since the conception of pneumatic flotation in the 1980’s, a large database of information has been accumulated. Our design layouts are based on standard laboratory tests. The mineral being floated determines the number and size of cells in series required to achieve optimal recovery, and the desired grade of the mineral will determine the number of steps required.

As per examples:

  • A single unit is sufficient to recover product with a low percentage of ash for fast floating coals;
  • Industrial minerals – applications requiring long flotation times of over 30 minutes – multiple cells are needed.

Considerable savings in energy and cost are achieved when compared to other forms of flotation. Three conventional cleaning stages, required to produce market / smelter grades of a base metal or pyrite, can be replaced with one cleaning stage using the Imhoflot™ process.


Testing of an ore is done by using a pilot scale G08 cell with a throughput of 2 t/h. The ore is tested by milling it to the required size, conditioning with the correct chemicals and processed through the G-cell to achieve flotation. The flotation tailings is passed through the cell a number of times and the assay results of the products and their mass recoveries are used in a flotation simulation package.

Flotation Technical Support

Our engineering staff members are specialists in various types of flotation process operations, from a broad range of industries. We provide a complete range of customer services, from pilot scale testing, process design, manufacturing, installation, commissioning and after-sales service.

Technical backup is exceptional due to a world-wide network of agents and associates with expert advice. Liaison with the client throughout the project stages ensures an optimum solution for the specific application.


The following flotation plants are operating with Imhoflot™ pneumatic flotation cells:

Los Pelambres
Molybdenum/copper sulphides
Lead / zinc sulphides
Kaolin, cleaning step
Fly ash
Kali + Salz
Kali + Salz
Iron Ore, reverse flotation
K+S GmbH
Coal tailings ponds
Coal tailings ponds
Coal / iron ore
CMP Romeral
Iron ore, reverse flotation
Gebr. Dorfner
Titanium Resources
Sierra Leone
Mineral sands, reverse flotation
Fly ash
Pilot units, different ores

Physical Address

1331 Staal Street (corner Spokeshave)
Stormill Ext 2
South Africa

Postal Address

PO Box 2437
South Africa

Contact Details

Tel: +27 11 474 0705
Fax: +27 11 474 5580
Maelgwyn Mineral Services Africa (Pty) Limited | South Africa | Company Reg No: 2003/007416/07
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