Froth Flotation (Sulphide & Oxide)

Froth Flotation (Sulphide & Oxide) 2017-04-04T06:57:31+00:00
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Woodgrove flotation reactors a revolution in flotation? (9 replies)

1 year ago
vsrangarajan 1 year ago

Are the Woodgrove flotation reactors the new revolution in flotation? Any comparison of these machines with existing ones?

1 year ago
David 1 year ago
1 like by johnclark

Hi and welcome,

The Woodgrove flotation reactors is very successful in certain applications.  You always need to test your ore to confirm.

According to Woodgrove, the Staged Flotation Reactor (SFR) was developed by going back to the first principles of flotation and examining how best to optimize the different stages of flotation without preconceived limitations. The result is a machine which optimizes the three stages of flotation into three separate zones, so that each zone is mutually exclusive of the requirements of other zones. The back drop of the foam is minimal and tightly controlled. Recovery zone "tight" pulp allows much more control in a scanning SFR, resulting in better recovery and upgrade.

Woodgrove claims its SFR to have for benefits:

  • Reduced energy consumption by approximately 50%
  • The space required is only 60% to 50% of conventional mechanical cells used.
  • Air consumption is reduced by approximately 80%
  • Smaller units required to achieve equivalent results
  • Reduced building height up to 3m in large plants
  • Better control circuit
  • minor instrumentation
  • Less wear and maintenance costs due to the lower tip speed of the impeller
  • Advanced automation control is simpler, faster and less cost and maintenance and installation


For more about Woodgrove' SFR you may want to watch:

And for best full details: Glenn Dobby & Glenn Kosick from


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Jorge Ganoza
1 year ago
Jorge Ganoza 1 year ago
1 like by David

Woodgrove Technologies developed the flotation cell called Staged Flotation Reactor (SFR). David mentioned the main features of the SFR cells. There are other similar flotation cells, but they have some operating and technical problems (e.g. sanding, circulating load is not handled properly, the residence time, etc).

I believe that Woodgrove design is more friendly and robust. Also, there is a very important point to keep in mind, the designers have a lot of experience in flotation, specially in the design of column cells. Some time ago, they established Minnovex, probably the main manufacturer of flotations columns. 

If it is possible to design a flotation circuit equipped with SFR flotation cells. It is a real advantage.

Greg Henderson
1 year ago
Greg Henderson 1 year ago

I have been involved in two projects now that have adopted SFRs, one for gold recovery accompanying a low sulphide content and the other for pyrite recovery from a copper cleaner circuit.  The latter is operating and apparently working well after some hydraulic modifications and the former has yet to be installed.  Bang for buck they are more expensive than tank cells and are probably best suited to smaller plants (<1 Mt/a).  They do however draw less power and have a smaller footprint.  It should be noted though that they need a greater step height between cells than an equivalent tank cell train which is an important consideration for a float plant in a building but no real issue for an outdoors plant.  Overall I think they could be a winner but its hard to get operating data.  They don't have a patent which is why they are understandably close lipped about their products but there are some smart guys behind the technology.  Ore can be piloted at their facility in Canada but there isn't really any small bench scale equivalent (1 or 2 kg) test that can be employed, they need around 80 kg as a minimum.  As a cleaner stage they have a lot of appeal as they can achieve remarkable upgrade ratios which means reducing the number of flotation stages.  Worth a look for your projects, especially for fine particle scenarios.

1 year ago
David 1 year ago

Thanks for this Greg.  

SFR cost > mechanical cells but and likely also > than columns?

Am not sure they want a Patent or if they can obtain a Patent. 

I think the Hoover type of 1916 and the Woodgrove Technology of 2016 are … “similar” in working principle.

Woodgrove Technologies


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Greg Henderson
1 year ago
Greg Henderson 1 year ago
1 like by Charlie

Ha!  I like that, the Hoover cell!  We'll be digging out De Re Metallica next, another classic. 

Yes, I believe it is a case of prior art which is why they guard their technology closely, fair enough.  They claim that most of the energy in a tank cell, especially large ones, is spent on suspending particles rather than inducing collision, the latter being the forte of the SFR.  This make sense when you look at the kW/m3 which falls away with larger cells so less energy must be going into particle attachment.  Most of their blue chips are investing in SFRs so they must be taking them seriously.  Spence mine in Chile tried them out but I never saw the results.  Its worth talking to them to learn more about what they are up to. 

Paul Morrow
4 months ago
Paul Morrow 4 months ago

The SRF Woodgrove reviews are naturally or involuntarily biased by the fact that only SFR successes are published or promoted. When SFR is tested for Ore-A and does not show improvements/gains, the test results are quietly buried.

Nobody goes to the annual CMP to publish a paper entitled "How SFR Failed at ABC Mining Inc." or "How Woodgrove' SFR did not do anything for us at XZY Mining Ltd."

We only hear about the successes which gives us the illusion of a super, can't fail, miracle technology.   

If your flotation circuit needed extra flotation capacity and you test Woodgrove to see it if improves your situation, you are much likely to come out and say Woodgrove is a winner.  Truth is you would have tested old fashion column, Jamesons, or mechanicals cells with a similar positive outcome.

The SFR certainly has its applications. It is by no means the Holy Grail of flotation technologies.

4 months ago
MP 4 months ago

I was involved in the SFR install and commissioning Greg H spoke of. (MRM days Greg) Both as the copper cleaners and latter the Pyrite roughers and cleaners. Like you Paul I was extremely sceptical....not any more. I now have a small involvement in Spence and have seen the test work.

Woodgrove are taking on a massive challenge with this project and its not based on blind faith. The SFR's will do all they say they will do.

They only talk of their successes because they have had no failures, so they are a bit light on for references there.

Any company that does not consider these things as a serious alternative to the normal has way to much money to throw down the tails line.

Disclaimer: I have no affiliation with Woodgrove or their processes, I work for the clients.

4 months ago
David 4 months ago

Interesting conversation...

The fact that SFR work great as cleaners is not surprising. The true difficulty is in rougher, coarse grind applications. 

"They only talk of their successes because they have had no failures"

This may be true in terms of plant applications, but not so in laboratory. I am certain there are many cases where nothing conclusive resulted from lab tests but we, the general public, will not hear about it at the CMP.

Then again, I am not a regular at CMP. Maybe this one have a wall effect discussion.

"Not positive" Lab tests, do not make the SFR technology a failure. That is what lab testing is for; risk reduction.

Sometimes a lower recovery rate in the small SFR pilot unit is seen and attributed to "the wall effect" ie: the adherence of froth to the walls of the test unit leading to coarse particle detachment. This wall effect is significant with small diameter pilot units and ultimately defines the lower limit of froth surface area that can be used for testing -Woodgrove explains.

Time will tell. So far, so good.

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Hugo Delgado
3 months ago
Hugo Delgado 3 months ago

Anyone knows if this SFR is used in Chile?, this technology sounds pretty good.

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