Platinum...

[wohali]

I live near a mountain which has some silver colored ore (more than a ton of it). I took a sample of the ore, crushed it (it crushed easily) then sent it to a lab for a computer assay. The assay came back 99.3...% iron, .63...% platinum, followed by a very small percentage of silver, then a smaller percentage of vanadium. I have a 3 drum rod mill that can polverize the ore very rapidly. I just can't seem to extract the pt from the ore. There just seems to be too much iron in the way. I tried using hydrochoric acid to dissolve the iron but it just dissolves too slow. It seems like i am working backwards (like I should be trying to dissolve onlt the pt and leave the iron behind). I tried to use mercury by attempting to "charge" it: I used a glass jar, put about 1 1/2 kilos of mercury in the jar and filled the jar with water mixed with flakes of sodium hydroxide... then I partially stripped a solid copper wire and placed the stripped part in the bottom of the jar, connecting the other end to a 12 volt battery (negative post), ... then added the positive wire in the water/lye section ... fastening it to a washer with a nut and bolt. When I connected the wires and added the lye, the water got hot and turned dirty and blackish. I can tell the mercury is at least partially charged but it is still liquid and it just doesnt seem to collect the pt. I am sure I am doing something wrong. Any suggestions would be greatly appreciated.

 

[Functional]

I live near a mountain which has some silver colored ore (more than a ton of it). I took a sample of the ore, crushed it (it crushed easily) then sent it to a lab for a computer assay. The assay came back 99.3...% iron, .63...% platinum, followed by a very small percentage of silver, then a smaller percentage of vanadium. I have a 3 drum rod mill that can polverize the ore very rapidly. I just can't seem to extract the pt from the ore. There just seems to be too much iron in the way. I tried using hydrochoric acid to dissolve the iron but it just dissolves too slow. It seems like i am working backwards (like I should be trying to dissolve onlt the pt and leave the iron behind). I tried to use mercury by attempting to "charge" it: I used a glass jar, put about 1 1/2 kilos of mercury in the jar and filled the jar with water mixed with flakes of sodium hydroxide... then I partially stripped a solid copper wire and placed the stripped part in the bottom of the jar, connecting the other end to a 12 volt battery (negative post), ... then added the positive wire in the water/lye section ... fastening it to a washer with a nut and bolt. When I connected the wires and added the lye, the water got hot and turned dirty and blackish. I can tell the mercury is at least partially charged but it is still liquid and it just doesnt seem to collect the pt. I am sure I am doing something wrong. Any suggestions would be greatly appreciated.

Firstly, when it comes to hard rock mining, I'm not the person to give the most well informed advice, having only done placer mining and panning. Nor am I a chemist, but as a layman, I thought I would interject my opinion of what I would do in your situation.

As you know, there are several methods of separating platinum and palladium from an ore and I couldn't tell from your post, just how integrated the platinum is with the iron and whether, or not it would be possible to use a magnet to remove the iron without the platinum when in crushed form? If so, then I would take that material and vibrate it, (either wet or dry) to force the platinum down to the bottom of a "V" shaped hopper. Once a reasonable time had passed for the platinum to settle to the bottom of the hopper, I would start "lifting" off the iron with the magnet. If this is not possible due to the platinum being combined as an alloy, then obviously other alternatives would have to be considered.

I did a Google search that might have the information you need, but due to my limited bandwidth on dialup, I couldn't view all the pages, (pdf files are a pain on dialup).
http://www.google.ca/search?num=100...tinum+concentration+mercury&btnG=Search&meta=

There may also be some useful information in the following links:
http://www.goldandsilvermines.com/platinum.htm
http://www.istc.ru/istc/sc.nsf/html/projects.htm?open&id=1190

From what I've seen on the web about platinum separation from ore, flotation seems to be the most common but the method used likely varies with the minerals and metals that may be alloyed with it. This is one of the pages I'm referring to:
http://www.stillwaterpalladium.com/concentrating.html

I did find a definition of amalgam that has me wondering:
"an alloy of mercury with another metal (usually silver) used by dentists to fill cavities in teeth; except for iron and platinum all metals dissolve in mercury and chemists refer to the resulting mercury mixtures as amalgams"
(The above was quoted from: http://www.answers.com/topic/amalgam )

I've seen other pages that say the opposite, so I really don't know how true the above statement is and I haven't had to read up on assaying or concentrating platinum before, so I'm in the dark here. I'm obviously not chemist.

If your interested in more of a prospectors view of assaying and refining/smelting, you could check out this page:
http://www.prospectorsparadise.com/html/assaying.html

Most of the pages I've viewed relating to platinum and electrolysis, only use the platinum as a cathode which isn't of much use to you, so I left those out.

Sorry I couldn't find more info for you.

F.

 

[Real de Tayopa Tropical Tramp]

Woholi: you picked a good one. First have the assay rechecked by another lab, even better two others, since most assay labs in the us cannot give an accurate statement on the qualitive and quantitive on pt metals. The iron ores of cuba, as well as others in the world contain Pt. , It was used in the casting of iron canon but was considered of a poorer quality than other high grades of iron ore whch did not contain Pt..The presence of Pt weakened the bonds.

The process of separating Pt from Iron economically is complex. suggestions -----

http://www.platinummetalsreview.com/pdf/pmr-v37-i2-102-107.pdf

http://www.chm.bris.ac.uk/webprojects1997/JonathanT/Welcome.htm

http://www.platinum.matthey.com/production/africa.html (page 23 ---->)

This will keep you busy for a bit.

Don Jose de La Mancha

 

[privet12]

Well lets see now I think you said you had at least a ton of it and I just checked todays spot price is $1296.00 and lets see 2000 lb and you have .063 X 2000 = 126 lb X 12 = 1512 X $1296 = $1,959,552 . Are you sure it is worth it lol.

 

[djui5]

 

[aussco999]

Hey wohali:

The color of an unknown ore is seldom used as a means of identifying it’s mineral content. As iron almost never occurs as a natural metal except in meteorites, iron oxide ores will be dark black, brown or red in color. And iron is also found as sulfides and carbonates with color variations from brassy to a dull metallic gray, depending upon the contaminate.

I’ve never heard of a computer assay before (), unless you are talking about something like an AA or an ICP-MS analysis. If that is the case, did your assay also list any percentage of nickel or maybe cobalt. Nickel is an indicator element for platinum ores and basically means, no nickel, no platinum.

For now, you have to many unanswered questions to determining an economical extraction method of the platinum (i.e. verifying assays, liberation size, mineral combinations, pyro/chemical reactions, etc). Do you by chance know which iron mineral you are dealing with? That might help narrow down an extraction method if someone else has dealt with this type of ore in the past.

Also, platinum is only wetted by a sodium-mercury amalgam, which is a mixture of metallic sodium (<10%) added to heated mercury. Metallic sodium can be some bad stuff to handle as it’s explosive in water or free oxygen, and heating mercury has it’s own dangers. Just using sodium hydroxide will clean and charge the mercury, but it doesn’t add any metallic sodium to it, and that’s why that system doesn’t work as advertised. A common mistake.

I would have my doubts about chemically separating the platinum from the high iron content, due to the equipment/area/permits required, and a pyrometallurgy extraction would be a similar problem, but maybe a magnetic method might work. As most iron ores are magnetic or can be made so by roasting, use a regular magnet to separate the iron, and as platinferious minerals are only slightly (para) magnetic, you could use a RE (rare earth) magnet to recovery them. According to your assay () results, you are only looking for about 14 pounds per ton of non-ferrous material.

You might try running another test by pulverizing a few pounds of ore to <200 mesh, heating to >350 F to drive off the molecular moisture and use a regular magnet to separate the iron. If that doesn’t work, open-air roast it to a dull red and try the magnet again. If there is anything left over, send it out for analysis. If the assaying procedure is improperly performed, the high iron content can give you a false/positive result for platinum. A common mistake.

Just some thoughts to ponder. Let us know of your progress.

Good luck,

John

 

[Real de Tayopa Tropical Tramp]

HI JOHN, right on track.

Don Jose de La Mancha

 

[Nitro 54]

Well lets see now I think you said you had at least a ton of it and I just checked todays spot price is $1296.00 and lets see 2000 lb and you have .063 X 2000 = 126 lb X 12 = 1512 X $1296 = $1,959,552 . Are you sure it is worth it lol.

You forgot to put the decimal point in the right place. by my figures the total would be $19,595.52
Sorry, you won't be a millionaire.

 

[Functional]

Well lets see now I think you said you had at least a ton of it and I just checked todays spot price is $1296.00 and lets see 2000 lb and you have .063 X 2000 = 126 lb X 12 = 1512 X $1296 = $1,959,552 . Are you sure it is worth it lol.

You forgot to put the decimal point in the right place. by my figures the total would be $19,595.52
Sorry, you won't be a millionaire.

1 pound = 14.5833333 troy ounces
Based on spot price of $1329.00 from:
http://www.kitco.com/market/

0.63% = 0.0063
0.0063 X 2000 = 12.6 lbs.

lbs X # of troy oz per lb = total troy oz
12.6 X 14.5833333 = 183.74999958

total troy oz X spot price = Total $
183.74999958 X 1329 = 244203.74944182

Rounded off to roughly $240,000.00
Beats a kick in the behind with a wet boot.


F.

 

[aussco999]

While it’s still on my mind, allow me to point out a few questionable numbers I’ve noticed on this post, and I’m open for some clarification if anyone can provide the answers.

In my years of mining, I’ve never seen an assay report platinum in percentages. Maybe it’s that new computer assay I’m apparently not familiar with. Normally here in the states, an assay reports precious metals as ounces per short ton (2000 lbs.), and in most of the rest of the world, precious metals are reported as grams per metric ton (2205 lbs.). Help me out here, what I’m I missing?

Another questionable number example that caught my attention is according to my calculator .63% of a short ton (2000 lbs.) would be 12.6 lbs. of platinum per ton, which would probably be 1000 times richer than any other platinum mine in the known world. If the lab didn’t make a huge mistake, confusing iron for platinum, then everyone should be very interested in this project. Maybe that’s another reason why I question a lab reports that just don’t smell right. :P

And finally, for those precious metal math purist out there, the 12.6 number would be in avoirdupois pounds (as there was no conversion made to the troy weight system with that percentage number), of which there are 14.58 troy ounces per avoirdupois pound.

So IF the assay is real (and one could only hope), then the numbers would be;

12.6 lbs x 14.58 troy oz/lbs = 183.71 troy oz x $1296./oz = $238,085.56/ton.

YEP, in mining that is a good number, I could do this project, sign me up.

Anyway, let us know how it all works out.

Good luck,

John

 

[wohali]

Thanks for all of the replies. The type of assay used is called SEA. I live in the Philippines and have sent many ounces of Pt dust (that was sold to me here as a by-product of gold panning) to my partner in New York. He brought it to the market in Manhattan where they performed some type of computer assisted assay. On the top of the paper it says SEA. If I send this dust unprocessed, the assay reads usually about 64%pt, followed by iron, nickel, cr, and other base metals. I have been able to purify it using aqua regia and preciptiating the pt with zinc to about 98% purity. Whether their assays are correct or not, we have been selling the pt and receiving market value for several months there to the same assayer and other pt buyers as well. Now it comes to this ore... Some of the ore is silver and grey in color, some soft and damp, some hard and brittle. We sent a crushed ore sample to the same assayer that was analysing the dust we had been processing and selling. That is where the the .63% platinum was seen. Actually, the full report was as follows: Fe-99.29062%; Pt-.63155%; Ag-.07281%; Vn-.00502%. I don't have alot of heavy equipment for processing this besides a 3 drum mill that we can poulverize about 300 pounds per load (takes about 1 hour with this ore), and a few torches and pans. I have easy access to most chemicals as they are readily sold here. I have "charged mercury" that I make with a battery charger and sodium hydroxide. It causes the mercury to become more like a solid until it discharges in water. We used this mercury because i heard it will also amalgamate with platinum. Before we used the mercury, we soaked the ore for several days in concentrated HCl, then adjusted the pH and washed it in water. Ordinary mercury at this time had no effect at all on the ore. Finally we put the ore in a wooden pan, about 1 pound at a time, and the mercury became almost completely loaded. We gently rinsed the mercury (now discharged) in water, it still remained loaded. Then we retorted it in an iron retort. Large masses of black dust remained in the discharge chamber. We took that dust and washed it in 50% nitric acid. Very little reaction in the beginning (which I assumed was some copper and mercury remains), then no reaction so we washed it in water, dried it and sent about 10 ounces back to NewYork for assay and sale. This time, 2 assayers (using x-ray and SEA) said 99.9% iron, and 99.7584% iron, .0218% Vanadium, .2196% tungsten...!!! The thing that is bugging me now is how can mercury or "charged mercury" amalgamate with iron? If anybody can offer suggestions, it would be appreciated.

 

[wohali]

As stated, we used charged mercury to separate the precious metals from the iron ore, however, after the amalgam was retorted, the black dust that came out tested out to be over 99% iron. This doesn't make sense to me. I think there is an error but I could be wrong. Will charged mercury amalgamate with iron? Or can it be the pt or other metal jsut appears as iron in the element analysis test? We took again some of the blackish grey dust that we removed from the mercury amalgam and tried dissolving it in hot simmering aqua regia for over 2 hours. About 40% of the dust remained undissolved. I think that iron dust would have completely dissolved but i could be wrong.

 

[Functional]

As stated, we used charged mercury to separate the precious metals from the iron ore, however, after the amalgam was retorted, the black dust that came out tested out to be over 99% iron. This doesn't make sense to me. I think there is an error but I could be wrong. Will charged mercury amalgamate with iron? Or can it be the pt or other metal jsut appears as iron in the element analysis test? We took again some of the blackish grey dust that we removed from the mercury amalgam and tried dissolving it in hot simmering aqua regia for over 2 hours. About 40% of the dust remained undissolved. I think that iron dust would have completely dissolved but i could be wrong.

wohali, I'm being liberal with some quotes here, but the page links this information is copied from are lengthly and should be reviewed for further details.


The following statement is copied from:
HTML version:
http://72.14.253.104/search?q=cache...lgamation+with+iron&hl=en&ct=clnk&cd=10&gl=ca
PDF version is here:
http://www.chem.unep.ch/mercury/Sec...cs/070404SenegaTrainTrainers_First Report.pdf

"amalgamation can happen between mercury/copper and mercury/iron"


There is some information on the "sickening" of mercury that might be of interest here:
http://www.e-goldprospecting.com/html/gold_amalgamation.html

The following 4 paragraphs are copied from:
http://geology.com/publications/getting-gold/gold-extraction.shtml
(Bolding of text is my own.)

"It will be seen, then, that this water is nearly four times more salt that that of the sea. The effect of using a water of this character, as I have previously found, is to cause the amalgamation of considerable quantities of iron with the gold as in this case.

I received 10 oz. of amalgam, and having found what constituted its impurities proceeded to experiment as to its treatment. When retorted on the mine it was turned out in a black cake so impure as almost to make it impossible to smelt properly. I found the same result on first retorting, and after a number of experiments which need not be recapitulated though some were fairly effective, I hit on the following method, which was found to be most successful and will probably be so found in other localities where similarly unfavourable conditions prevail.

I took a small ball of amalgam, placed it in a double fold of new fine grained calico, and after soaking in hot water put it under a powerful press. The weight of the ball before pressing was 1583 gr. From this 383 gr. of mercury was expressed and five-eighths of a grain of gold was retorted from this expressed mercury. The residue, in the form of a dark, grey, and very friable cake, was powdered up between the fingers and retorted, when it became a brown powder; it was afterwards calcined on a flat sheet in the open air; result, 510 gr. of russet-coloured powder. Smelted with borax, the iron oxide readily separated with the slag; result, 311 gr. gold 871-1000 fine; a second smelting brought this up to 914-1000 fine. Proportion of smelted gold to amalgam, one-fifth.

The principal point about this mode of treatment is the squeezing out of the mercury, whereby the amalgam goes into the retort in the form of powder, thus preventing the slagging of the iron and enclosure of the gold. The second point of importance is thorough calcining before smelting. "


I'm wondering if you have considered small scale smelting as is used for black sand gold recovery? I know platinum has a much higher melting temperature, but some of the same techniques might work for your situation. There was a discussion on "black sand clean up" here:
http://forum.treasurenet.com/index.php/topic,86794.0.html

F.

 

[EDDE]

SEA=spectrum electron analysis

 

[nebraskadad]

Plats don't dissolve into solution readily. You make want to invest in Megan Rose's PMG recovery guides.

Or contact her http://members.aol.com/zeehansen/platinum.htm

If you purchase the book I think she works with people who buy the book to step through the process.

if the assay came back at 99% Ferrous, and 63/100s or 63/1000s Pt you've got a nice find.

The chemistry of PMG recovery is pretty nasty stuff. kind of the ol' (don't do this at home) stuff.
The classical procedure for separating the platinum metals begins with a mineral concentrate obtained as described above. This concentrate is leached with aqua regia, which dissolves the platinum and palladium and leaves the other metals as solids in the leach residue. The platinum is precipitated from solution with ammonium chloride, and the resulting crude platinum salt is recovered by filtration and then heated to decompose it to a powdered metallic form. The metal is redissolved in aqua regia, then reprecipitated with ammonium chloride and calcined to pure metal. The palladium, which remained in solution when the platinum was precipitated, is now precipitated by the addition of ammonia. After the palladium salts are recovered by filtration, they are redissolved and reprecipitated to form a pure salt, and this is converted to metallic form, usually by chemical reduction with formic acid.

The residue left over from leaching the original mineral concentrate contains rhodium, iridium, ruthenium, and osmium. This is treated with molten sodium bisulfate to convert the rhodium to rhodium sulfate. The rhodium is then solubilized by water leaching, separated from the insolubles, and precipitated from solution by reduction with zinc powder. The crude rhodium metal product is converted to a soluble salt by treatment with chlorine and sodium chloride at high temperature, dissolved in water, precipitated with sodium nitrite, filtered, redissolved, and reprecipitated with ammonium chloride. This final precipitate is reduced to a pure metal powder.

The residue from rhodium sulfate leaching is fused with alkali nitrate salts to convert ruthenium to soluble sodium ruthenate. After filtration, the solution of sodium ruthenate is treated with chlorine gas to distill off the ruthenium as the volatile compound ruthenium tetroxide. The ruthenium-bearing distillate is then treated with reducing agents to precipitate the ruthenium as a fine metal powder. Osmium is recovered in a similar fashion, although, unlike ruthenium, it can also be recovered by distillation from acidic solutions.

The final residue is treated with sodium peroxide to convert iridium to a form soluble in hydrochloric acid, from which it can be precipitated with ammonium chloride and calcined to metal powder.


maybe in the confines of a good mining mill. Consider the investment depending on how much high grade stock you have.

Maybe farm out the recovery might be more cost effective. (check dhfco.com)

 

[Twisted Fork]

I've heard of closely guarded secret system used to extract the precious metals from various forms of iron slag. An old timer I met years ago By the name of Rowan Williams (can't say If he's still around) inherited his father's work as a chemist and as the son reached his later years, he perfected a system that enabled him to freely collect slag from assayers and large labs, and with this system he was able to extract more gold ect. from their waste, than what was originally taken at the lab he collected the waste from. I know he received a substantial government grant in order to go into production somewhere in So. Utah, (Ceder City?) but this was 25 years ago so running this one down might be a real challenge. TF

 

[Twisted Fork]

I was told that some of the new approaches to converting crystals back into solids is gaining ground in confined gaseous atmospheres.

 

[AuExplorer]

I have never heard of a platinum ore containing only Pt and no other PGE's ie: rhodium or palladium.
They would have given you a name for the ore complex, do you remember what it was or could you check your plot sheet. PGE's must be be specificaly sought out in an assay and will almost never show in a fire assay and a ICP/MS, Inductively Coupled Plasma/ Mass Spectrometry assay must be done for each element.

Also, you will not know the extent of mineralization untill you core. We will save the conversation of complex refractory sulphide ores for another day.