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The main scientific results of the project are the following:

- The nature of the gas used for flotation plays only a minor role compared to the role of other parameters such as grinding conditions.
- Froth characteristics play an major role in selectivity and recovery during flotation. New tools have been developed to better study the mechanisms of bubble coalescence and its impact on selectivity, as well as tools to sample froth and to determine its composition.
- The Microcel bubble generator producing finer bubbles without addition of water improves the recovery and the flexibility of industrial operations.
- The respective fields of application of mechanical flotation cells and columns can now be better defined on the basis of mineral liberation and fragility of the association between bubbles and particles to be floated.
- When the conditions for their implementation are fulfilled, the introduction of columns simplifies the circuits, lower operating and investment costs, enables and requires improved control systems and improves metallurgical results.
- A correct evaluation of a column-based circuit requires testing campaigns including flow recirculation.
- Columns can adequately carry out ionic flotation.
- Models for column flotation and SAM grinding have been developed as well as procedures for evaluating and comparing flotation technologies and designing plants according to maximum profit.

The industrial benefits of the project are also important:

- The Microcel bubble generator having proved its advantages will be actively marketed by Control International S.A. and will totally replace the previously established USBM technology.
- BRGM expects an increase of its sales of services and software (USIM PAC), thanks to its improved knowledge and the development of new models.
- The way is now open for the commercial application of ionic flotation.
- On the basis of the project results, Boliden Apirsa has equipped a column in its Pb circuit with the Microcel bubble generator and has proved its profitability. The return on investment is very rapid.
- LKAB has decided to integrate column flotation into its circuits for at least one application. Here also, the return on investment will be very rapid.
- Most of the industrial partners will continue their experimentation to increase the use of column flotation in their plants (LKAB, Ammeberg Mining Corp., and Boliden -Apirsa).
- A mobile pilot column (Control Int. S.A.) and a full pilot plant with three columns, mechanical cells and a vertical regrinding mill (MITU) are now available in Europe to carry out a pilot plant campaign on actual industrial flows.
Columns have fully demonstrated their importance in the field of flotation (improved metallurgical results, decreased investment and operating costs, aptitude for automatisation). Nevertheless the application field in which they are more efficient than mechanical cells is not fully defined and difficulties have been encountered in scaling up and/or industrial operation.

The aims of the project are:

- to use columns to optimise flotation circuits, including new equipment, such as agitated mills.

- to verify if their use as rougher equipment in the flotation circuit can be generalised,

- to take advantage of their low gas consumption to evaluate the effects of gases other than air on flotation results,

- to try alternative bubble generator systems, for the flotation of fine minerals (micas in kaolin) and for ionic flotation.

The project parnership involves seven industrial companies, one center, and three academic laboratories.

Successful completion of the project could result in important energy savings, increased revenues and lower investment. It could also result in new tools for environmental depollution.

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Bureau de Recherches Géologiques et Minières (BRGM)
EU contribution
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Avenue de Concyr
45060 Orléans

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Participants (5)