floatation question

[Wyndham]

I realize that all of the topic here have delt mainly with chemical extraction. I have a question that been nagging me for a bit.
I saw a video of a crude flotation setup in Mongolia where the ore is ground to extremely fine then mixed with water, agitated by large blender s in drums the oil is added. Paddles skim off the froth into a trough and later processed.
Because the oil is a hydrocarbon is it a possibility that the carbon acts like activated charcoal in helping attract the gold to the oil, as well as the stickyness of the oil.
If anyone knows, how efficient is this process and could this work in material that comes from fines from a river that is almost impossible to pan. The blk sands would have to be removed first then classified to below 200 mesh.
I have a bucket of silt from a washed gravel that has micro gold but I don't know how much and thought this might be a way to test a 5 gal bucket of silt.
Also would it make sense to then filter this through activated charcoal?
Have a happy 4th
Wyndham

 

[Anonymous]

Hi,
I just tried a little floatation test. 3ml gold chloride solution, added stannous, got a deep purple color. Wanted to see how long it would take to settle, but, I did not have enough patience to let it go all the way.

Added .25 ml vegetable oil and shook it for 1 minute.

Results purple layer at oil/water boundry and clump of black on the bottom.

seems oil sticks the gold together real good.

Jim

 

[aussco999]

Hey Wyndham:

The mineral flotation/extraction process has been around for over 100 years, and can be profitably used on low grade ores. The composition of the ore (mineral of value and type of gangue), will determine the types of chemicals needed for the flotation process. Various reagent chemicals can act as a promoter, frother, modifier and depressant to enhance recovery. There’s a lot of books and internet information available on different mineral flotation methods.

I think you are confusing two separate processes when asking about the attraction of gold to the carbon in oil. Petroleum and it’s byproducts are often referred to as long-chained hydrocarbons and are well bound together. As with most chemical combinations of elements they have created something total different when compared to the original characteristics of the single element. For example, both elementary sodium and chloride are dangerous, but when mixed together, become a simple table salt. The carbon in oil is bound and does not react with gold in the same manner as elemental carbon (charcoal) does.

The main reason the flotation process works so well on small to micro-fine gold is because it’s naturally hydrophobic, (doesn’t like water). The addition of an organic oil coating and an air source will greatly enhances this characteristic. In the early days of flotation, coal tar or pine oil (turpentine) were used in very small amounts per ton of ore to float gold. The finely ground ore was mixed in tanks with paddles designed to suck in air, or compressed air was piped into the bottom of the tank. The gold would attach itself to a rising air bubble and float. In today’s world, the chemistry has improved enough to better promote the coating of the gold with an oil, a stronger bubble froth, while depressing the gangue material.

You could probably process a 5 gallon bucket of fines in a cement mixer, with a few teaspoons of pine oil. As long as the solids were occasionally raised out of the water, the hydrophobic material will float. Mix the pine oil and water first, then add the solids. Pouring off the excess water and filtering should recover the values. Keep in mind that most of the larger visible gold should be recovered first by other methods. Screening to 100 mesh should be enough and I don’t think filtering either the float water or the silt through activated charcoal makes sense, because then you have to go through the extra process and expense of extracting the values back out of the charcoal. A paper filter is good enough and is much easier to burn (ash) than charcoal.

And, if any of this works for you, then here’s some more good news; the first flotation systems were made of wood. So building a few wooden float cells with air impellers (or an air compressor) isn’t beyond a handy carpenter’s skills. I’ve probably got photo drawings somewhere of the early wooden float cells if you want to progress beyond the cement mixer. Let me know if you need any more info on flotation.

Good luck, :mrgreen:

John

 

[Harold_V]

Very nice post, John. Thanks for sharing your knowledge.

Harold

 

[Platdigger]

Yes, very nice! Thanks

 

[Wyndham]

Yes That was a very good explanation and reasoned method of operation. I have all the parts, air compressor, buckets,screens etc.
The idea of a cement mixer is a good one, I'll have to see what Harbor Freight has and maybe on sale.
Question on the pine oil, would something like Murfey's oil Soap also work or mineral oil. I'm trying to think who has pine oil(would furniture polish work??)
Thanks Wyndham

 

[Palladium]

I'm not sure on this but i think i've heard of people using Pine Sol.

 

[qst42know]

Here is one modern chemical used for flotation.

http://worldwideresin.itrademarket.com/1998351/depramin-frothing-agent.htm

 

[aussco999]

Harold and Platdigger:

Thank you both for your kind words. Learning something new is one of life’s rewards and sharing the knowledge (within reason) is part of the repayment. My expertise is in the exploration, exploitation and the extraction (that’s a lot of X’s), of valuable minerals/metals from ore. So I pay attention to the good information provided by the forum’s knowledgeable members on the refining of my hard earned gains. And yes, I bought Hokes’ book a long time ago.

Wyndham:

I can’t give you a good answer on the use of Murfey’s Oil Soap, as I’m not familiar with the product. There are several different oils that can be used, but everyone knows of or has pine oil around in the form of turpentine. It’s the same stuff used to thin oil base paints and clean paint brushes when you’re done. (But, not the paint thinner or mineral spirits stuff, as they are both petroleum distillates). Pure gum turpentine is 100% distilled oil extracted from the gum of living pine trees. Another benefit of using pine oil is, because it comes from live pine trees, it’s a tougher argument for the greenie tree-huggers (pun intended) to accuse you of contaminating their world.

Because it’s immiscible in water, you’ll need to high speed mix it first with water to create an emulsion, before adding the solids. In the emulsion, the microscopic oil suspended in the water will easily attach to the hydrophobic mineral particles, while amazingly not have much effect on most of the gangue material. This is were your homework starts with empirical testing to determine the right amount of oil to water ratio for a better recovery. I suggest you start with several small measured ore samples and test until you get the desired results. With the exception of a some of the silica mineral, most of the black and blond sands will sink to the bottom. Adding some form of air bubble (either impellers or compressed air) will speed up the flotation process. If your results aren’t good, there’re a couple other tricks I’ll pass along to you.

Palladium:

The house cleaner/polisher Pine Sol may work. I looked around the house to see if the wife had any handy so as to check on the ingredients. No luck. Instead, I walked past the frig, found the beer and that search is now over. A concern I always have with using household products is that most of them contain some form of additive/preservative chemical that may or may not effect the process. In this case, probably not, but a gallon of gum turpentine is still probably cheaper than a liter of Pine Sol.

Gst42know:

There was a company called American Cyanamid that was a world leader in the manufacturing of flotation chemicals, and I’ve bought several 55 gal. drums from them in the past, but I don’t know if they’re still in business here in the states. I recently heard you could still buy their products in Mexico, and I’ll check on that as our project there gets closer to coming on line. For the time being, and due to the time and expense of getting special chemical permits, we will stay with the environmentally friendly pine oil for our flotation needs.

Good luck to all, :mrgreen:

John

 

[qst42know]

I checked the MSDS of Depramin. One ingredient listed, sodium methyl cellulose and no controlled substances. It's Cellulose gum. It should be a main ingredient in many soaps. It is used in food processing, eye drops, and a whole bunch of other stuff. I don't know how it compares performance wise to turpentine but it mixes easily with water and you would be far less likely to raise any eyebrows dumping it down a sewer or in your front yard for that matter.

You can get it pure and in bulk. Keep in mind I didn't price shop this.

http://www.chemistrystore.com/Chemicals_G_R-Methylcellulose.html

 

[Wyndham]

THis thread is getting more interesting all the time. I maybe wrong but I believe wall paper paste is a methyl cellulose
Also CMC gum that I use in my glazes as a suspending agent is listed as

Super Gum (CMC) - CMC Gum, also known as Sodium Carboxymethyl Cellulose Gum, or just Cellulose Gum is frequently used as a thickener and a texture ingredient in many applications throughout the food service industry. Food grade and industrial grade CMC Gum is also known as cellulose gum. It is derived from purified cellulose such as cotton linters. CMC Gum helps products retain moisture. CMC Gum is a man made gum.

Some interesting stuff once you get into it. Time to experiment
Wyndham

 

[aussco999]

Gst42know

You are confusing the purpose of two different flotation chemicals. Pine oil, in the form of turpentine is used as a frother, to float hydrophobic minerals. Depramin is used as a depressant to surface wet certain hydrophobic minerals, causing them to sink, instead of floating. A depressant permits selective flotation of different minerals, especially sulfides, in the same ore. For example, you can float galena (PbS), and sink sphalerite (ZnS) and pyrites (FeS) at the same time. In small quantities, Depramin cost about $15. to $19./lbs.

Wyndham:

In the early days of flotation (started as far back as 1860), there were several different types of flotation procedures developed. One procedure that may be more applicable to your situation was called Skin Flotation or Film Suspension. This simple process was patented in 1885 by Bradford (US Patent 345,951), and later by Nibelius in 1892 (US Patent 486,495). In 1907, de Bavay (US Patent 864,597) and Macquisten (US Patent 865,194 and 865,195) were actually used commercially at a rate of 5 tons/24 hour day. You’ll have to check to see if these patents numbers are still available on line. Maybe even some photos???

The Macquisten process used a revolving tube to mix the finely ground ore and oil together and then dumped down a slick plate in to a tank of water. The good stuff floated and the gangue sank. A weir discharge on the water tank allowed the float material to be skimmed off and collected. I’m thinking; a cement mixer, an old aluminum sluice box with the riffles/pad removed, a wash tub full of water with a weir slot cut in one side and a filtered collection overflow bucket, could be configured to work in a similar manner on a smaller scale.

All the info I have says that skin flotation worked best on slurry slimes, which sounded like your material. If you build a flotation recovery system, post some photos. I’m always interested in seeing improvements on 100+ year old systems.

Good luck with your project.

John

 

[qst42know]

Thanks for the explanation. :mrgreen:

 

[PGMAN]

Hey Wyndham:

The mineral flotation/extraction process has been around for over 100 years, and can be profitably used on low grade ores. The composition of the ore (mineral of value and type of gangue), will determine the types of chemicals needed for the flotation process. Various reagent chemicals can act as a promoter, frother, modifier and depressant to enhance recovery. There’s a lot of books and internet information available on different mineral flotation methods.

I think you are confusing two separate processes when asking about the attraction of gold to the carbon in oil. Petroleum and it’s byproducts are often referred to as long-chained hydrocarbons and are well bound together. As with most chemical combinations of elements they have created something total different when compared to the original characteristics of the single element. For example, both elementary sodium and chloride are dangerous, but when mixed together, become a simple table salt. The carbon in oil is bound and does not react with gold in the same manner as elemental carbon (charcoal) does.

The main reason the flotation process works so well on small to micro-fine gold is because it’s naturally hydrophobic, (doesn’t like water). The addition of an organic oil coating and an air source will greatly enhances this characteristic. In the early days of flotation, coal tar or pine oil (turpentine) were used in very small amounts per ton of ore to float gold. The finely ground ore was mixed in tanks with paddles designed to suck in air, or compressed air was piped into the bottom of the tank. The gold would attach itself to a rising air bubble and float. In today’s world, the chemistry has improved enough to better promote the coating of the gold with an oil, a stronger bubble froth, while depressing the gangue material.

You could probably process a 5 gallon bucket of fines in a cement mixer, with a few teaspoons of pine oil. As long as the solids were occasionally raised out of the water, the hydrophobic material will float. Mix the pine oil and water first, then add the solids. Pouring off the excess water and filtering should recover the values. Keep in mind that most of the larger visible gold should be recovered first by other methods. Screening to 100 mesh should be enough and I don’t think filtering either the float water or the silt through activated charcoal makes sense, because then you have to go through the extra process and expense of extracting the values back out of the charcoal. A paper filter is good enough and is much easier to burn (ash) than charcoal.

And, if any of this works for you, then here’s some more good news; the first flotation systems were made of wood. So building a few wooden float cells with air impellers (or an air compressor) isn’t beyond a handy carpenter’s skills. I’ve probably got photo drawings somewhere of the early wooden float cells if you want to progress beyond the cement mixer. Let me know if you need any more info on flotation.

Good luck, :mrgreen:

John

How to use the activators such as xenthates, what is the purpose of using activators.