# Platinum???



## amosfella (Mar 27, 2013)

I have a solution that I'm playing with as a test on black sands from a platinum placer mine. I'm trying to figure out what I have in the solution before I get an assay done. I put a small handful of the sands into a bucket that I had a fire going in while I was trimming dead branches off the trees. There was a fair amount of yellow smoke coming out of the bucket for a bit, and I kept the fire going till long after the yellow smoke stopped. Then I had the joy of panning the sand back out of the ash (elm wood leaves a lot of ash). After that I put a few pinches of the fine sand into a small bowl and put some hydrochloric on it. It did have some brown in it, but not much the next day, so I added a small amount of nitric to it and heated it for about 5 min. Then I let the solution sit for a day. I came back to an almost burnt orange color of solution. It has silvery metalic looking fines on the bottom of the glass that I couldn't dissolve with AR.
I mixed up some stannous chloride, and I poured a few drops of the burnt orange solution into a very small glass bowl. Then I added stannous, and the solution turned bright canary yellow, and then went clear a few seconds later. When I went back after leaving it for about an hour, the solution was brown. After a few more hours, the solution was almost the same color as the mother fluid.
Now, I'm trying to figure out what I have.
The solder I used was 97% tin/3% copper. Any ideas what I have there??




Untitled by wolverine00089, on Flickr




Untitled by wolverine00089, on Flickr

My stuff isn't the cleanest, I just grabbed somethings that looked like they would work from the top of the storage pile.


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## lazersteve (Mar 27, 2013)

The solution looks like iron to me, but I could be wrong.

You should *thoroughly clean your test dish* and place it against a white background so you can better see what the color change is, if any. When the stannous chloride is added the color should *change* to a bright red orange.

Steve


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## Lou (Mar 27, 2013)

Looks like iron to me too.


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## butcher (Mar 28, 2013)

You did good roasting a very important step, the yellow was most likely sulfur SO2 gas burning off of the sulfides.

Iron in solutions is funny it can fool you easily, it can look yellow very much like gold in solution, or be green or even brown, Hokes book page 100 gives the test for iron in solution.

Iron will leach from the ore before values if any, you should concentrate values before leaching this way you are not wasting tons of acids to leach iron , grinding the roasted material to fine powder, careful panning,or other gravity separation, also I would look into pre-leaching iron with an acid that will not attack gold, which can to help to further concentrate values, your goal should be to try to eliminate base metals as much as possible before putting your values into solution, removing as much of the non valuable material as possible with pretreatments like mechanical separation , roasting, grinding, pre-leaching...


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## amosfella (Mar 28, 2013)

The thing that puzzles me is that the solution went yellow (I was looking on a yellow/brown background at the time) immediately after adding stannous. According to hoke, there would be no reaction to iron with stannous if I read correctly on pg. 95. Very quickly after, the solution went clear, then brown, and then to a color somewhat brighter than the mother solution. Maybe I have to low a PH. I am sure that there's probably a lot of iron in the solution. However, the reaction makes me scratch my head. Some potassium iodide would settle this quickly if I read the quick testing of rocks and ore thread right.
Are there any common products that could be used as a second test for PGM metals in solution?? Or any common forms of potassium iodide??


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## amosfella (Mar 28, 2013)

Butcher, I did use HCl on some of the fines before I added the nitric to see what would happen. The HCl turned a greenish brown. Kinda an ugly color, really. As I said in the beginning, I was only running a test... Maybe I should get my furnace up and running again, and smelt it with some lead..... Or a crucible and my blacksmith's forge....


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## amosfella (Dec 26, 2013)

I had an assay done, and could use a little help interpreting the results, if someone here would be willing.

Au 10 ppb, Ag 7.5 ppm, Pt 130 ppb, Pd 5 ppb, Rh <5 ppb.

Is this worth perusing??


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## butcher (Dec 26, 2013)

10 PPB means 10 parts in a billion parts, for example 10 g Au/ 10^9 g rock. Unfortunately, your ton (assuming a metric ton) is 10^6 g of rock, so you have 10 milligrams of gold, the gold would be something like the size of a Horse fly's poop in a ton of rock.

1 ppm = one gram in one ton of sample (2200 pounds) or (1000 Kilograms), now this looks much better,
10 ppm,would be about 10 grams per ton. If you could get all of the silver out of the rock without costing you more than the silver is worth (not that easy to do).

This looks like maybe more silver in the ore, you do not mention all of the other metals in the ore that would complicate getting a little silver out of the rock, I doubt you would get much of anything out of this rock in your back yard. With the price of silver, and the price of labor (not counting scaling up with mining equipment), even covering labor of digging the rock at minimum wage may cost more than the rock is worth (just a guess).

P.S. I am not good at math, so I may be wrong here, but I still do not think I would sell the farm, to mine the ore.
There is gold in them there hills, many a man has gone broke trying to get it out, very few have ever made a profit...


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## nickvc (Dec 27, 2013)

As Butcher pointed out just because you have values in your ores doesn't mean they can be extracted profitably, you did the right thing gettIng an assay but you really need a full element assay to determine exactly what's there. Remember many ores contain potentially lethal elements when either heated or and acids are added and other elements can make extraction virtually impossible or vastly expensive. Black sands are a particular nightmare from the little I can understand and few seem to have managed to crack them or if they have they are very quiet about it and probably with good reason as I imagine many years of study and trial and error are involved to achieve even partial success but I wish you well but again as Butcher pointed out don't give up the day job just yet.


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## g_axelsson (Dec 27, 2013)

amosfella said:


> I had an assay done, and could use a little help interpreting the results, if someone here would be willing.
> 
> Au 10 ppb, Ag 7.5 ppm, Pt 130 ppb, Pd 5 ppb, Rh <5 ppb.
> 
> Is this worth perusing??


I can't see any way to mine an ore on these numbers, just calculate the value of the ore and then compare it with what it would cost you to extract the values.

I'm not up to speed with current mining costs, but usually any hard rock ore with less than 1 gram of gold per ton can't be mined profitably even with a large scale operation. That's close to $40 per ton. What the price is to mine a placer deposit I don't know.
Is your total value more or less than the extraction cost? If it's less then forget about it.

Göran


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## amosfella (Dec 29, 2013)

I told the guy who wanted me to refine it that he should probably try a lead smelter...


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## butcher (Dec 30, 2013)

Good Idea,
Let someone else get the headache over this problem. :lol:


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## amosfella (Jan 5, 2014)

Just for curiosity's sake, I'm going to see if my BIL will run it through the mass spec at his university. See what shakes loose.


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