Froth Flotation (Sulphide & Oxide)

Froth Flotation (Sulphide & Oxide) 2017-04-04T06:57:31+00:00
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Making flotation cells work (48 replies)

Gruppen
2 years ago
Gruppen 2 years ago

For a number of years a mine struggled to float a sulfide mineral and was getting less than 50% recovery even after installing a rotor and stator “upgrade”. We did minor modification to the rougher float cells and achieved a 19% increase in recovery. These improvements would apply to all flotation cells.

Tony Verdeschi
2 years ago
Tony Verdeschi 2 years ago

Are you able to share the minor modifications you did to the rougher flotation cells, was the modification meant to increase mixing of reagents and minerals particles. I am interested to know.

Gruppen
2 years ago
Gruppen 2 years ago

We installed a new rotor which we designed and manufactured.

Ace Levy
2 years ago
Ace Levy 2 years ago

Discussions are very interesting even if a 68% recovery in sulfide ore flotation looks very poor the improvement looks great.

As usual in any flotation process the first parameter is liberation size and surface chemistry. May be you did both actions at the same time?
However the fluid hydrodynamics in a flotation cell is also critical mainly when floating at a particle size below 15µ. Is it the case?
Apparently you have increased the turbulence in the cell with probably very high Reynolds number. How was the power demand compared to before? Did you really run testing in two banks in parallel each of them fed with same feed?
The other option is to control the hydrodynamic in order to maximize the probability for a bubble to be in contact with a collected particle. In such a case the size of the bubbles is also critical. See the Jameson Xstrata cell for example
But very interesting discussion and probably there is a potential for improvement in hydrodynamics optimization
I really appreciate.

Sturmbann
2 years ago
Sturmbann 2 years ago

The only thing we did was optimise the fluid dynamics by modifying the mechanism components. Nothing else was changed - liberation, reagent suite, power etc all remained the same. I have always felt flotation machines could be improved and these modifications seem to confirm that. I would also recommend that before extensive trials are done on grind size, reagents etc get your flotation machines operating as best as you can.

Standartenfurer
1 year ago
Standartenfurer 1 year ago

If you are an innovative type of person you may be interested in this. For a number of years a mine struggled to float a sulfide mineral and was getting less than 50% recovery even after installing a rotor and stator “upgrade”. We did minor modifications to the rougher float cells and achieved a 19% increase in recovery. These improvements would apply to all flotation cells regardless of what is being recovered. The mine is now converting all the remaining float cells to incorporate these modifications.

Bill Fraser
1 year ago
Bill Fraser 1 year ago

Would be very interested in discussing your findings in more detail! I personally was involved in grade improvement modifications to a leading brand of flotation cells.

OberstGruppen
1 year ago
OberstGruppen 1 year ago

It's interesting that so many of the gains in float cell design are now being made in the mechanical cells. To the degree that you are confident of such a gain, you might want to consider formally publishing this case study in industry journals.

Raje Singh
1 year ago
Raje Singh 1 year ago

We are interested in your modifications & strongly want to implement those in our mechanical flotation cells for recovering low ash clean coal from ROM raw coal.

Helena Russell
1 year ago
Helena Russell 1 year ago

I think the change you made highlights a very important point: Productivity improvements can be made in most flotation circuits by paying attention to the rotor and stator. I spend a lot of time visiting sites and one (disturbing) trend I’m seeing is that on a lot of sites the insides of flotation cells aren’t well maintained and the mechanisms are run to destruction. As you know the rotor is responsible for not only mixing but bubble formation so high wear can result in a serious drop in metallurgical performance. This is even worse in self aspirating machines where this wear can have a major impact on of the volume of air induced.

A pro-active maintenance program including regular inspections of the internals of cells and timely wear part replacement is usually sufficient to prevent the wear getting to the stage where it can have a negative effect on performance. The cost of inspections and replacing an old worn mechanism with a new one is normally insignificant when a performance improvement of 1%+ recovery can be achieved.

As earlier suggests it would be great if you’d share some more details of this upgrade and the results with us. It would hopefully help to educate some people on the importance of maintaining this vital component of flotation equipment.

Standartenfurer
1 year ago
Standartenfurer 1 year ago

While I agree the rotor and stator must be kept in good order this trial had nothing to do with wear - it is all to do with improved design.

David Kano
1 year ago
David Kano 1 year ago

The improvement through your modification is very significant, 19% increase in recovery is huge. The versatility of the modification to different flotation cells makes it more interesting. I would like to have more detailed discussion about this your modification.

Ace Levy
1 year ago
Ace Levy 1 year ago

I think the change that I make is very important improvements can be made in the circuits of buoyancy in both the rougher, scavenger and cleaning with a machine flotation of a larger volume like OKS cells of different volumes works with a stator and rotor these have longer flotation recoveries so increases and improvements in the grades of concentrates with these mechanisms is the best control levels foams because they are controlled automated controllers. The liberation of the valuable particles, appropriate densities in the processes and also the different types of reagents and foaming and good management mainly Ph also recommend to achieves good recoveries.

Paul Morrow
1 year ago
Paul Morrow 1 year ago

You say you went from 50% to 69% with an engineering (hydrodynamic) solution. That's great, especially if you're recovering more fine values by increasing turbulence in the cell. 69% seems still low. Have you looked at surface chemistry and/or sufficient liberation from hydrophilic gangue?

Standartenfurer
1 year ago
Standartenfurer 1 year ago

69% certainly is not good when compared to many other installations. However, the improvement is considerable. For years, according to the mine personnel, the chemistry and liberation was investigated and had been optimised. I design and make machinery so I have not been involved in that aspect. I am pleased to say, though, that my designs (modifications) have given the biggest boost to the mine so far. Also, we are not increasing the turbulence in the cells but rather redirecting it. You are correct - there are many variables that influence the performance of the flotation process and my note to everyone is to explain how with some simple modifications to the machine itself you can get really big results - you just have to know what modifications to make!

OberstGruppen
1 year ago
OberstGruppen 1 year ago

Note that some mines determine that "lower" recoveries are better for their overall bottom line, as they produce much better concentrate characteristics; keep their Opex down, etc.

If your rotor and stator improvements have led to improvements in cell hydrodynamics such recovery has improved so markedly, and the net benefit to the mine is positive, then this is a great result.

Ace Levy
1 year ago
Ace Levy 1 year ago

For good buoyancy is to give more rpm for greater turbulence inside the flotation machine and have a good flow of air to form more compact pair and have a good foam flotation. Also would recommend making a full evaluation of the entire circuit flotation both mass, water and laws.

Standartenfurer
1 year ago
Standartenfurer 1 year ago

Just to clarify - we did not change the rpm, or any other variable other than our modifications to the mechanism itself.

Tony Verdeschi
1 year ago
Tony Verdeschi 1 year ago

We use Wemco Mechanical cells to float coal, based on metals industry concepts. i.e. 3 rougher cells feeding 2 cleaning cells. I am interested to understand if you made changes to the impeller or floor and draft tube design, we as fitted VVVF drives to our impeller drive for more flexibility, we removed a J Cell, and have seen improved yields and floating coals that were difficult in the past.

Oberstorm
1 year ago
Oberstorm 1 year ago

Did you establish what the process specification is? How did the original installation differ from the process specification before you decided on improvements? What parameters did you change to push the process towards similarity? If you did not follow this strategy then how do you know that you have optimised/maximised the process?

Standartenfurer
1 year ago
Standartenfurer 1 year ago

I don't think I claimed to have "optimised" the process - if you read my post you will see that we did some modifications to the flotation machine. The mine then reported the gains in recovery and is sufficiently convinced by their findings to convert the remaining flotation machines to our design.

Oberstorm
1 year ago
Oberstorm 1 year ago

OK, Then you must have improved the kinetic constant somehow. Meaning that you must have improved bubble surface area flux or floatability or forth recovery or all three parameters. Changing Sb you must have improved aeration, the bubble generation mechanism which is the rotor tip Reynolds number and rotor aspect ratio. Improving floatability you must have changed the particle size, reagent suite, conditioning time or conditioner tank turnaround time, circulation and Froude number. Changing froth recovery you must have improved froth depth, superficial gas velocity, rotor aspect ratio or you must have provided hydrodynamic or physical barriers to protect the collection zone. I have a dimensionless number called GIRR1=D^2/AR.h.H and GIRR2=D^2/P80.FD=200. These numbers completely define the position of the rotor in the tank and it also relates froth depth and P80. I have also found that the Rotor volume /tank volume ratio= d^2.e/D^2.H is a fixed number in many designs about 2%. So, can you give us an idea of what you have done and not "how".

Standartenfurer
1 year ago
Standartenfurer 1 year ago

You seem to have all the answers already! I'll reiterate - we made modifications to the rotor and stator to re-direct the flow pattern to improve air dispersion, solids suspension and in-tank mixing. Nothing else changed - reagent suite, power, rpm, and rotor position all the same.

Alan Carter
1 year ago
Alan Carter 1 year ago

I would be interested to know what process your team undertook to modify the rotor/stator system. Did you trial a range of alternatives, or was it by chance that you secured the alternative design. Was there any theoretical thought put into the new design by the mine or by the supplier of the mechanical improvements? What was the methodology used to form the basis of the initial investigation into the stator and rotor design; i.e. what made or who managed to view the problem differently to secure the successful approach?

Standartenfurer
1 year ago
Standartenfurer 1 year ago

Neither chance nor good luck had anything to do with it. It was from knowledge and experience that I designed the rotor and stator combination to address weaknesses that I saw in current designs. The mine had no input and I am not sure who you are referring to when you say "supplier" as Unit Process Consulting is the supplier. We made slight modifications once after initial lab test work. It has been very rewarding to see how well the design works and the big improvements that can be gained by flotation plants by retrofitting these components. I don't think this has been looked at in the past - so here is your opportunity!

Rahil Khan
1 year ago
Rahil Khan 1 year ago

Yes I am a plant operator. Operated flotation cells for 25 years. I know many things to improve grade and recovery and practically proved it. The only way to improve is to increase bubble surface area. It can be done by generating micro bubbles which we have done in column flotation. Same principle can be adopted in normal flotation too.

I remember Dr. Jameson Au, scientist who met me in Chennai INDIA, We discussed at length. He has good innovation of mixing air with slurry in most simple way. Trillion dollars saved in energy. Now I am interested to know more on your innovation.

Hauptsturm
1 year ago
Hauptsturm 1 year ago

I think that you will find that the concept is similar to what is used in the Pipsa Impeller design developed by Baker-Hughes in the 1970’s. This Pipsa Impeller design is currently used in the Agitair flotation machines at Mount Isa Mines.

Ace Levy
1 year ago
Ace Levy 1 year ago

The rotor and stator there is great agitation of similar to a pulp pump operation to promote bubble particle contact. From an average level of the cell has a less turbulent area where the mineral egregado hydrophobic bubbles rise less likely to break. As the bubbles move at the lip of the cell, are driven by the pressure of the bubbles that come after.

I think this principle helped improve their recoveries. 

Maya Rothman
1 year ago
Maya Rothman 1 year ago

Any new and innovative technology is certainly worth consideration. I certainly support what you are doing as often my Company is called upon to render over the cracks where lack of detail in the design of flotation cells is the real issue.

Any rotor that addresses the 'dead spots' that I believe exist with many of the modern cells can only present a potential opportunity for flotation operations to improve performance. For many years I have been critical of cells, or groups of cells where 'pulp surface area' has not been adequately addressed. I know the solution to these problems, and I know that fixing a physical issue with a chemical is wrong, but I also know that it can often take the movement of heaven and earth to convince an operation of the benefits of addressing the issue.

I have little doubt that with more efficient mixing in flotation cells that this too can only have a positive impact on an operations performance. As with the 'pulp surface area' issue, we know it can be difficult to prove without an operation taking a leap of faith. And as there is no mathematical calculation available you can understand the fear. I have seen some very poorly designed flotation cells in my time and many of these are still in use. I don't see why any operation would not want to at try your product in at least one of their cells. Really, it is pretty simple - what can be lost by giving your rotor a go, it can't be worse than what already exists, and then what has an operation got to lose? 

Hauptsturm
1 year ago
Hauptsturm 1 year ago

With regard to the operation and improvements of the Pipsa Impeller, below is a section of an article of the Pipsa Impeller development from June 1976.

LATEST DEVELOPMENT (from article in June 1976)

In an effort to improve pulp circulation without affecting the life of the wearing parts, a new impeller (see Fig. 1), the PIPSA, is at present undergoing trials. Generally, the design involves the standard AGITAIR Chile - X (16 large fingers on a disc 27 inches in diameter), with a shrouded vane type of pumper impeller mounted on top of the disc. The shroud is open at the shaft for entry of feed, and the circulating pulp discharges between the vanes at the perimeter of the impeller. The standard fingers (9 inches long) at the same time aerate and circulate in the usual pattern. Although this impeller is operated at a peripheral speed of 100 ft/min less than the conventional one, no signs of 'sanding out' have occurred to date, even with coarse feed having tramp oversize. Also, froth columns under these severe conditions are good. An added advantage of this impeller is that it cannot 'sand in' when operating in the reversed position and the cell can be started under full load conditions after a power failure without damage to the parts.

JOURNAL OF THE SOUTH AFRICAN INSTITUTE OF MINING AND METALLURGY – June 1976

MIMs R&D department spent a number of years comparing different impeller design in the parallel banks at Mount Isa Mines in the 1980s and 1990s and the Pipsa Impeller design was found to be the most robust and best performing design over the range of operating conditions in the Agitair flotation cells at the mine site. Though it does consume slightly more power than other designs, due to increased pumping action.

You need to be careful in your design of experiment to proper design the test work program to statistical measure any performance change over the range of operating conditions and variation in ore types. After proper measuring the baseline performance, then running parallel banks with different impeller designs with the same feed is one of the simplest ways to remove the day-to-day changes in operating conditions.

Also the OEMs have their own solutions that they have developed, e.g.: Outotec has a similar mechanism with their “Flow Booster” system for the OK Tank Cells for improved mixing, but for the effectiveness of design I prefer the Pipsa design, Agitair is now owned by FLS.

Possibly most of the reps of these OEM companies do not even know that these designs exist for options on their flotation cells for improvement, and you may need to refer to the OEMs flotation expert.

Victor Bergman
1 year ago
Victor Bergman 1 year ago

Would you rate the PIPSA Impeller superior to the Jameson Cell principle which XT also markets?

Hauptsturm
1 year ago
Hauptsturm 1 year ago

The Pipsa Impeller design was found, after significant test work, to be the best design for use in the Agitair float cells at Mount Isa Mines. I think you will find that the mixing intensity inside the Jameson Cell Downcomer is much higher than that occurring in conventional flotation cells, even after they have impellers designed to increase the mixing.

The bubble size in the Jameson Cell is smaller than conventional flotation cells giving high kinetics across all size fractions and larger carrying capacities and improved differential kinetics against slow floating gangue. Also the froth washing system allows for the minimisation of the entrainment of fine gangue into the concentrate producing higher grade concentrates.

All these factors give high upgrading ratios in one stage of Jameson Cell which is equal to three stages of conventional cleaning flotation banks. So there are many other benefits of the Jameson Cell technology, as have been discussed in many published papers.

During my career I have worked with a wide range of flotation technologies and conducted many test work and development/improvement programs with them, so am able to share my experiences with different methods of operation. In this discussion we were discussing the mixing intensity of conventional cell impellers.

Of course a question maybe whether the mixing intensity is the primary factor that is reducing the performance of the flotation cells/banks, or whether the main factor is not having enough air with fine bubble sizes causing low carrying capacities and low recoveries and causing poor selectivity or whether it is a froth recovery issue?

As stated above, good maintenance of the Rotor/Stators in the flotation banks is required to achieve the best performance from the banks. I have very often seen plants operating with some to many impellers not even turning in the banks, or missing stators or worn rotors, so you would not expect optimum performance from these circuits.

If mixing intensity in the conventional cells is determined as the major factor reducing performance in the banks, the first step would be to ensure the rotor/stators are maintained as recommended by the OEM. Once this is achieved then changing the impeller type or design may be a cheap upgrade, compared to adding more flotation cells.

But if you were looking at adding more flotation cells then I would be recommending Jameson Cells as there are many of other benefits that could further improve circuit performance.

Helena Russell
1 year ago
Helena Russell 1 year ago

Do you have some air dispersion data from the plant it went into as I’d be curious to see what Jg it is running at?

I can see why you made the PIPSA comment as it does have a fair bit of similarity with the PIPSA/Agitair rotor. Both seem to have a low profile and horizontally divorced pumping and air slots; albeit yours are at the bottom under a single ring. I think may have similar flooding problems at high air rates. See references below for some more details (to my mind this set of papers is some of the best testwork done on different rotors and stators and well worth a read if you haven’t seen it before).

Gorain, B.K., Franzidis, J-P. And Manlapig E. V. 1995. Studies on impellor type, impellor speed and airflow rate in an industrial scale flotation cell – Part 1: Effects of bubble size distribution. Min. Eng. Vol. 8, No. 6 pp 615-635.

Gorain, B.K., Franzidis, J-P. And Manlapig E. V. 1995. Studies on impellor type, impellor speed and airflow rate in an industrial scale flotation cell – Part 2: Effects of gas hold-up. Min. Eng. Vol. 8, No. 12 pp 1557-1570.

It will be interesting to see how it wears with the Ruston-turbine-esk blades and what happens to power/mixing/air dispersion as it wears. Do you have this yet or is it still too early? Still keen to some plant results > any idea when site will agree to publish some data?

I’m following your similarity comments with interest. I’m assuming you account for different impeller configuration via Reynolds, Froude numbers but how do you tackle air dispersion? Also can you please clarify the parameters in GIRR1 and GIRR2. AR=air rate?, FD=froth depth?, h=?, H=? etc.

Standartenfurer
1 year ago
Standartenfurer 1 year ago

You don't have to concern yourselves about wear or potential flooding of our rotor. Please rest assured, that while it is inevitable that power, air dispersion and mixing will all be negatively affected by wear of a rotor (that would apply to anyone's rotor), the performance was still better than that of their original rotors on change out. The flooding point was never reached at the highest air flow rates used by this particular mine. I can't tell you what the flooding point is of this rotor and the mine does not particularly care - they do care about the big improvement in performance though!

Bob Mathias
1 year ago
Bob Mathias 1 year ago

What you have mentioned is the key point in dispersing air in the pulp, redirecting the flow. Also, rotor/stator designs greatly affect the bubble size distribution in the pulp. I used to see in my CFD simulations of minerals froth flotation machines that air stream is above the water stream when exiting from the rotor. Redirecting the flow or creating more shear layers inside the rotor passages (in other words, sandwiching air between water jets) help to maximize the breakup of continuous air stream to an adequate bubble size distribution. And I believe that CFD is a cheap feasible alternative for physical experiments setup to study any design modifications. CFD requires much lower time and money to conduct some simulations. I believe that some minerals flotation companies are now going in the same direction to produce more efficient designs.

And as there is no mathematical calculation available you can understand the fear'. Yes, in physical experiments you measure the global effects of any design modifications by looking at the recovery rate without understanding where and why dead zones 'dead spots' inside rotor or in the region between rotor and stator where air mixing with water is essential. CFD simulation now provides us with more details about this and most companies are using to develop more efficient and competitive rotors. Now what are the impacts of the hydrodynamics and air dispersion in the pulp on the flotation rate constant or recovery? A CFD-based flotation model that rely on the spatial distribution of turbulent dissipation rate and air void fraction in rotor and pulp can convert these data to a spatial distribution for attachment and/or rate constant. This whole process has been described and presented in this PhD dissertation

http://is.gd/e7MX5B

Marshal Dienes
1 year ago
Marshal Dienes 1 year ago

It is inherent in the self-aerating rotor, like the Wemco, that it cannot flood. It only induces the air that it disperses. I'm assuming that you have done something along these lines or are in fact the same http://ultimateflotation.co.za/index.html

The problem with flotation cells is that use a rotor for both solids suspension and air dispersion (as fine bubbles) will always be in opposition. Any technology that addresses these will improve the kinetics of attachment that said, improved mixing through more agitation will increase the kinetics of detachment. This is where flotation technology needs to make its major step. There are thousands of flotation cells in the world looking for new modern internals what a great market!

Standartenfurer
1 year ago
Standartenfurer 1 year ago

I tend to favour forced air flotation machines and have rather focused on these and not Wemco or Ultimate type machines. And, yes, you are obviously correct in stating self-aerating rotors cannot be flooded.

Marshal Dienes
1 year ago
Marshal Dienes 1 year ago

Will be interesting to see what you have, I know of many Agitair installations that could use an upgrade and everyone loves a little more recovery and/or grade. Don't we?

Rahil Khan
1 year ago
Rahil Khan 1 year ago

CFD is a wonderful tool for analysing flow patterns, dispersion of air and solids and possible dead spots. One have to take cognisance of the assumptions made such as a single particle size, single bubble size, water viscosity instead of pulp, etc. It still is worthwhile doing it.

We applied the scaled down WEMCO to copper flotation which was part of the phosphate ore. We achieved an 80% recovery with a 30% concentrate grade with a 0.07% feed grade. The grind was P80=350 micron as it was optimised for phosphate flotation. The main plant was running at 35% recovery and we pushed it to 55% with the same feed and concentrate grade. We tried to push it towards similarity with the dimensionless process specification by fixing the eccentricity between rotor and draft tube We changed rotor engagement to 10% rotor diameter +10mm for high Sg material + 10mm for coarse grind. We also fixed the drive by replacing missing V-belds and fixing the tensioning mechanism. We then corrected the conditioner, level control and cleaned air intakes. We also inspected the pump floor to ensure no sumps were overflowing. By doing this we improved aeration, circulation, Reynolds number, Froude number. Froth depth and submerges. This lead to the improvement of bubble surface flux, floatability and froth recovery which improved kinetic constant. We were not allowed to spend any capital because the copper containing ore stockpiles were depleted and the plant was going to be refurbished for phosphate flotation. I would like to compare your improvements on this basis and see what happened in that plant. Especially what the dimensionless process specification looked like.

Zander Barcalow
1 year ago
Zander Barcalow 1 year ago

I think that he is talking about the froth phase (and to a lesser extent the pulp/froth interface); CFD struggles there. Fortunately with full scale tests you can easily see if the froth is moving or not. The challenge is to risk reducing performance without having any CFD or lab work to back you up. Also, any changes to the cell requires agitation energy and air addition to be re - optimized (assuming that work had been done in the first place).

In terms of the OP a sulphide float that had only 50% rougher recovery after optimized reagents and liberation (and a cell "upgrade") seems to me to be a rare case. Can anybody else share some sites with 50% recovery on a sulphide float rougher? Note these are only my personal views; I don't work with Outotec float cells.

Standartenfurer
1 year ago
Standartenfurer 1 year ago

Whether it is a rare case or not has nothing to with it. I mentioned that the recovery was a very low 50% as it would be difficult to expect a 19% increase when one's recoveries are already over 90%! What I have demonstrated is that regardless of your current recovery it can easily be improved by making your float cells work properly.

Bob Mathias
1 year ago
Bob Mathias 1 year ago

Yes, in CFD you may use single bubble size or single particles size to reduce the computational cost. This may have some uncertainty levels for air void fraction and hydrodynamic data. However, still you can obtain as much details as you need in the pulp phase to understand the flow structure in the pulp. Also, bubble size distribution is an available option in CFD. But you have to pay more for it and even not straight forward as in the case of single bubble size. I have done CFD of bubble size distribution in Wemco flotation machines and had to modify the breakup and coalescence models to get plausible results.

Thank you for your contribution. Yes, was talking about pulp/froth interface. But Rotor and Stator in any flotation cell is the main elements that control turbulent dissipation and air dispersion in the tank. Air distribution in the pulp greatly affects the pulp/froth interface. I did not simulate the froth phase. Although I had devised new boundary treatment that allow pulp interface to rise up until reaching steady-state. I did not use degassing boundary condition which seems to be unrealistic. So, let me assume that if the rotor does not disperse the air well in the tank what will happen in the pulp? Air will be concentrated at some regions in the pulp and air superficial velocity at the pulp/froth interface will be non-uniform. It will sound like burping! And we can obtain this from CFD if it happened without simulating froth phase. Froth phase is really important and hopefully we can simulate soon.

Helena Russell
1 year ago
Helena Russell 1 year ago

I think he is right that you are referring to the froth phase. Being someone who works with 'Outotec float cells', I can assure you that it is known how to fix the issue. I’ve seen it done it a number of times with great success, though we probably wouldn’t claim an 18% recovery increase at least without showing the data 😉 There are some pretty standard design figures that need to be adhered to. They work well least for base metal sulphides and the principles can be applied to non-sulphides as well (as its pretty much physics). Just because it is know how to fix it doesn’t always mean a site will implement the solution. Some people don’t believe this phenomenon is real which is evident in their float cell design but it is a very simple physical phenomena relating to froth stability. The fix is relatively easy to do in forced air machines and not so easy in induced air due to the rotor location. However if anyone is interested I’ve got a design ready to rock that we’d love to try.

Anyway back to SIMILARITY. The more I look, the more I’m intrigued as it seems to go further than previous applications of dimensional analysis I’ve seen in flotation. Can I suggest you start a new thread on this approach to continue the discussion? Have you ever published any of this, if so can I get a reference so I can chase down and read further? Anyway a few more questions/points:

What types of tanks / models / size of machines did you use to develop the dimensionless numbers and what applications where they in?

How do you account for liberation and chemical conditions (or are they considered to be the same as per phosphate example).

I think that perhaps GIRR2 could possibly be improved (as per my froth comment above) to maybe explain some more common phenomena and the similarity or lack thereof between the machines. Perhaps replace D with an equivalent diameter for froth area (or use the actual froth area in some other way in ratio to tank diameter)

I also like, but am not surprised, by the point you made on fixing up the WEMCO and getting improvements in performance. Ensuring the machines are maintained will lead to better performance. The challenge is getting a machine that requires minimum maintenance not one that requires so much TLC.

OberstGruppen
1 year ago
OberstGruppen 1 year ago

All, there are a number of different types of mines that run recoveries in the 40-60% range; a number of platinum mines run like this. Low-grade feeds with difficult to separate but high unit-value minerals are examples...

I'm sure your example was at a similar sort of site - if he's come up with a step-change improvement to conventional techniques that only yield in the order of 50% recoveries once reasonably optimised, then good on him and good for the mine.

However, it's incorrect for us to assert that because the initial recovery was so "low" that this necessarily takes credibility from the possible significance of his invention.

And remember, too, he runs a business, with various intellectual property considerations for his company and the site he is speaking of - again, therefore, demanding data is not exactly appropriate for, who are we to demand it?

He's not making "snake oil" type claims, so if we're really interested, why not just engage him in a way that will suit each as best as possible in a win-win commercial fashion? He's not obliged to "spill the beans" just because we are both only half-informed and cynical.

Engage the entrepreneur, or continue with the theorising - which has its place! - But won't necessarily answer questions!

John Koenig
1 year ago
John Koenig 1 year ago

Thanks for your thoughtful input. I have been amazed at some of the responses we have received. To those who have provided useful feedback and asked intelligent thought out questions, have asked about trials or provided positive feedback, Thank you!

I think that a number of people missed the first sentence of this Discussion 'If you are an innovative type of person you may be interested in this" What Unit Process Consulting have developed is the result of over 30 years of dedication to solving problems in the mineral processing industry. Innovation is not about doing the same thing over and over again, it's about change and continuous improvement. And I think that some of the incredulous remarks have been for the most part self serving. This is not a fly by night solution if it were I doubt a large Mining firm would be now replacing their whole flotation plant with our rotors. I also doubt that the firm who are about to lose that supply contract would fly in a high level exec for an Urgent meeting with the mine management!

The results and data will be published soon enough. A huge amount of time and effort has gone into this development.

Zander Barcalow
1 year ago
Zander Barcalow 1 year ago

I think that some of the incredulous remarks have been for the most part self-serving. I think the OP raised many questions with his post (surely the most self-serving of all of them - not that there is anything wrong with that). People are just trying to understand what work was done as this is a technical discussion forum. Personally I am curious how the original float cell compared to what was achieved at the bench top scale. But as he says we'll have to wait for the paper.

Thanks for reminding me that metal recoveries can be quite low even when the mineral recovery is high - life is much simpler in thickening (where we routinely achieve over 99% solids recovery).

Rahil Khan
1 year ago
Rahil Khan 1 year ago

BOILING FROTH: Also called burping.

My experience:

Collector:

If collector strength is more and flow rate is same it will cause forth to flocculate and become heavy, and become difficult to float. In such situations we added NaCN pellets in cleaners and found that froth started floating. Yes NaCN here acted as dispersant and particles became free to float. Even lime addition did not work. Dilution of pulp also did not work.

You try adding more NaCN and check.

Bill Rico
1 year ago
Bill Rico 1 year ago

Hopefully I won't get a head scrubbing for adding my 2 cent worth here, but I have been following this whole discussion with a keen eye. I have done some work with UPC on a mine where the mine is trialing their product and ours.

I have to agree that innovation is a very difficult thing, not only to prove that what you are suggesting works, but also the feedback and questions. I am just glad that forums like these exist, although from a point where it sometimes is viewed that sales people attempt to sell their products here, I do not fully agree.

I think from where you was coming initially, being innovative is a huge asset, and from a sales point of view, wait let me re phrase, a business owner with an innovative product and attempting to also assist the mining Industry with a passion, I feel this is an excellent forum to throw out the findings and have them discussed as this discussion has shown.

For those who did not even realize it, I have also learned an enormous amount from this discussion and from you guys.

Raje Singh
1 year ago
Raje Singh 1 year ago

Would you please suggest that what are the reliable laboratory test works which would provide the ultimate clean ability of a particular raw coal through fine coal beneficiation processes?

Suppose we are washing a raw coal in the flotation circuit and obtaining X yield at a particular ash level, we would like to know the ultimate cleaning possibility for that raw coal in the laboratory. What are the standard practices which would provide the result? This should be different from the normal lab scale flotation test normally done in the lab with a standard lab flotation cell.

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