Froth Flotation (Sulphide & Oxide)

Froth Flotation (Sulphide & Oxide) 2017-03-23T09:43:25+00:00
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Polymetallic sulfide flotation of gold ore (11 replies)

rokxter
7 months ago
rokxter 7 months ago

I have been involved in assaying a rock pit with sulfide ore for a couple of years.  We have done gravity concentration tests and the ore loses 75% of the gold and silver value when you gravity concentrate.  We did a down and dirty flotation test with biodiesel and successfully produced 33 opt gold concentrate.  I need direction in finding the correct sulfide flotation chemicals, and chemical suppliers that will sell to a small scale miner.  Can you help?

Bob Mathias
7 months ago
Bob Mathias 7 months ago

Do you want to just make 1 sulphide flotation concentrate? Pyrite or other base metals?

How did you do that down and dirty flotation test? What machine?

33 opt gold concentrate @ what %recovery?

rokxter
7 months ago
rokxter 7 months ago

Bob, we used biodiesel and a homemade column flotation unit about 10 feet tall and 8" in diameter. Basically a Jameson type cell.

The recovery was, as near as I can determine, based upon the weight of concentrate and the weight of the head ore sample and average assay for this ore was at best 50%.  

We know from multiple attempts to gravity concentrate this ore that the gold is primarily within the sulfide component.

Bob Mathias
7 months ago
Bob Mathias 7 months ago

OK, you know that column cells are not recovery and certainly not rougher recovery machines, but alright for your improve exercise. 

Are you looking for just enough chemicals for a lab test or small scale industrial? 

For homemade flotation machine ideas see https://www.911metallurgist.com/blog/homebase-flotation-tests-homemade-flotation-equipment

911metallurgist/David can help you with Pro testing.

rokxter
7 months ago
rokxter 7 months ago

I am looking for both, enough chemicals, (and hopefully the correct chemicals for this type of sulfide ore) to run on a denver sub a number 5 lab flotation cell for now, and eventually enough to run a pilot test of several tons.

 

 

David
7 months ago
David 7 months ago

Hi Rokxter,

Ok, for small quantities (under 1 Ton), your collector Flottec 2034 and your frother is MIBC.  I can get you as little a 5 gallons of each FOB Texas. 

Otherwise try https://www.alibaba.com/showroom/potassium-amyl-xanthate.html and https://www.alibaba.com/showroom/pine-oil.html or https://www.alibaba.com/showroom/mibc.html

Email me for details. 

max skinner
7 months ago
max skinner 7 months ago

Rokxter, How are you grinding and to what size? You need to grind to liberation so that you can float the sulfides away from the gangue minerals. There are a couple of people who sell reagents that I have dealt with and obtained reagents in 5 gallon cans. You can also ask people like Cytec and SNF Flomin for lab sized samples and they will send them to you for free. There are also some knowledgable people who will do this preliminary lab flotation test for in the $1,000.00 range and give you a report.   

rokxter
7 months ago
rokxter 7 months ago

We are grinding to 100 mesh and finer.  We are grinding to liberation for over 95% of the sulfides.

We are using a jaw crusher and a hammer mill, screening and rerunning the oversize

David
7 months ago
David 7 months ago

Hi rokxter

What makes you think you are grinding to liberation for over 95% of the sulfides with a hammer mill? Your hammermill supplier told you that?

Maybe some of the few <400 mesh sulfide grains contained in your float concentrate (those you looked at) were free and appeared 95% liberated but it is totally unlikely your sulfides are 95% liberated by a hammermill at 100 mesh, no.

Grinding to 100 mesh and finer: what % under 150um (100 mesh) are you hammering this to? Do you have a Particle-size distribution?

Have a read at https://www.911metallurgist.com/blog/size-microscopy-optical-mineralogy and try it if you have the equipment.

95% sulfide liberation seldom happens until you reach 40um of finer (sometimes 15 um).

You do not need to be this finely liberated to get recovery. Do do need 'energy' and you wont get that from a column cell. Do you have photos you can share?

The chemicals are really secondary. Frothers froth and sulfide collectors collect. It all starts with adequate liberation. If you are going at it without optimization, start with P80 100 micron and a mechanical float machine. Use a column if you must with extra time and recycle I suppose.

Do you have any assays at all other than your gold/silver? %Sulfur content in the ore? %Fe at least? 

Any arsenopyrite present? You need to know that to sell that conc. If you don't know, the buyer will tell you what it is. There are limits and penalties, am sure you know.

Your recovery would be extra low if your got a 33 Oz/t gold concentrate.

In your statement We have done gravity concentration tests and the ore loses 75% of the gold and silver value when you gravity concentrate. ->  It is not uncommon to have to grind to 75um to get full GRG https://www.911metallurgist.com/blog/gravity-recoverable-gold-grg-test

If you have GRG, you should still take if ahead of flotation.

https://youtu.be/sa3P1U3gJe0

rokxter
7 months ago
rokxter 7 months ago

Thank you for this response david.

I appreciate the input, and after viewing the pictures of the zinc sphalerite under the microscope I am inclined to agree with you, and our intent is to use our high speed rotary collider mill that produces 80% 200 to 400 minus mesh particle size for final grind.  I was basing my liberation estimates off of visual low power 10x hand held microscope and estimating volume of particles in ground head ore versus concentrate but that doesn't mean a lot!

Yes we have had 51 element scans done on the concentrate, and there is a small amount of arsenopyrite in the ore (less than 1% in the concentrate).

I do not have complete particle size distribution because I don't have all of the finer screens.  

The column was only for a quick test.  I have acquired 3 of the older Denver sub A number 5 lab flotation cells for additional test work.  

I will attempt to attach the ALS scan to an email to you but don't want it posted here.

Thank you again,

Rocky

David
7 months ago
David 7 months ago

Small amount of arsenopyrite in the ore (less than 1% in the concentrate)

That was at low sulphide recovery. Just beware that As concentrates often by factors of 10 to as much as 100X from feed assay to concentrate.  Here a 10:1 example I once had.

The more Enargite and Tennantite we mined and put in the mill feed, the more we got in the concentrate. If we put 0.07% arsenic in the mill feed, you get about 10X that or 0.7% in the copper conc for the Enargite and Tennantite can't be separated.

The parallel goes for a sulphide conc.

Anyway, assay that conc on a good float test to know.

 
https://www.911metallurgist.com/wp-content/uploads/2016/08/arsenic-in-gold-concentrate.png
max skinner
7 months ago
max skinner 7 months ago

Along with everything David is telling you, you should consider some screen analysis with assays to tell you   exactly where, size fraction, your gold is. You should do this on your heads and your tails. Most people do this as one of the first things you do. 

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