# Recovering Silver from Crushed Ore?



## Ferrell (Jun 28, 2011)

We had an assay done on some ore and discovered both gold and silver in microscopic amts, but enough to pay to use a chemical process to recover the gold. Should we try to recover the silver before we do the gold recovery? Can anyone point me to a thread or instructions on what process to use to recover silver from crushed ore? We have approx 4 ounces per ton of raw material and would be processing ourselves as we have time. The gold will be our first consideration, but if we decide to go after the silver as well, we've heard it needs to come out first. Right or wrong, or does it matter? And any help in HOW to recover it would be so appreciated. Thanks!

Allen and Miralee


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## jimdoc (Jun 28, 2011)

Anything to do with ore you should post in the Prospecting, Mining, Ore Concentrates & Geochemical section to get the best answers.

A moderator can move this there for you when they get a chance.

Jim


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## Ferrell (Jun 28, 2011)

Oh, sorry. I saw that the thread I posted this in was anything to do with silver, so I assumed my question would be appropriate. Thank you for offering to move it.


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## jimdoc (Jun 28, 2011)

The people likely to be able to give you the best advice may only check this section. I think GSP moved it for you.

Jim


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## Ferrell (Jun 28, 2011)

Thanks, Jim and moderator!


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## Harold_V (Jun 29, 2011)

Without knowing a great deal about the ore in question, you're not likely to get much useful advice here. Extracting gold and silver from ores isn't a cut and dried process---there are many ways to achieve the end, each dependent on the type of ore. 

Frankly, unless your ore (fire) assays at least a few ounces of gold per ton, you can spin your wheels endlessly and never make a dime. Large corporations process ore that is as low as .10 ounce/ton and make a profit, but they also handle ore by huge volumes. 

Harold


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## Ferrell (Jun 29, 2011)

Thanks, Harold. We didn't just have it assayed, we took it to a company that actually extracts the gold from the ore, as that's the most accurate way to know how much you can get. An assay shows how much is there, but you might not be able to actually extract that much. They had two samples of several lbs each, and averaged 7 ounces per ton of gold per sample (actual extraction). 

We're not sure of the proper geological name, but we call it rotten rock. It's rock that can often be broken with your hands or easily smashed down to small pieces with a hammer. It's very easy and fast to break down to 100 mesh with a small rock crusher. A miner who looked at it believes it's a type of underground dunnite (sp?) tube from a nearby volcano, and we have watershed/springs in the area as well. We have been able to extract the gold, but don't know about the silver (there's about 4 ounces of silver per ton). We've been told it's a simple process to extract silver, and would like to know what the process consists of.


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## Richard36 (Jun 29, 2011)

Hello Ferrell,

That's some hot ore, wow.
Could you post some photos? 
I'd like to see what you're processing. 
It would help out as far as suggestions for processing too.

If you are actually working Dunite, 
Platinum would be on the list of metals to be looking, and testing for.

Just my thoughts on the subject.

Sincerely, Rick. "The Rock Man".


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## Ferrell (Jun 29, 2011)

Sure, I'll take some pics later today or tomorrow of the ore in it's natural state and the crushed product prior to cleaning. We won't be washing it, as it appears we're picking up part of the gold from the clay that surrounds the rock. We had tests run for Platinum and it was negligible, but it's possible it could be there, regardless. Would that be captured/extracted along with the gold when we're doing our SSN/Butyl/Oxalic extraction for the gold, or would we need to do something separate for platinum?


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## Richard36 (Jun 29, 2011)

I'm not sure what the abbreviation SSN stands for, at least at the moment, just waking up, 
so I do not know if that particular process would work for PT. 
My guess is that you would need a different precipitant to recover the PT, if in solution.


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## Ferrell (Jun 29, 2011)

Richard, SSN stands for saturated salt mixed with Nitric Acid. I don't know what PT stands for. :lol:


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## Richard36 (Jun 29, 2011)

Ferrell said:


> Richard, SSN stands for saturated salt mixed with Nitric Acid. I don't know what PT stands for. :lol:



Lol, funny.
Pt is the periodic table abbreviation for Platinum.

Does that salt and nitric trick actually work for you?
I tried that mix on some black sand with fine gold, and it didn't seem to do anything at all.
I ended up using Muriatic acid with Sodium Nitrate to make Poor Mans Aqua Regia to dissolve the gold from within the sand.


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## Ferrell (Jun 29, 2011)

Yes, the SSN does work on our ore, but it might depend on the type of ore, I'm not sure. I know it didn't work on a batch when the outside temp was in the 60's during the day and high 40's at night, so we had to put it in a warm room in a sealed bucket to get it up to temp. It's also a good idea to do 7-1 or 8-1 on the salt vs nitric. 
Can you tell me a bit more about the two chemicals you used and what kind of proportions and time/temp required? We're always open to checking other methods. 

Also, do you know what process to use to extract silver? I haven't gotten any feedback on that yet. 

Thnaks!
Miralee & Allen


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## Reno Chris (Jun 29, 2011)

As Harold said, it depends on the form your silver is in. If its sulfides you might need some sort of flotation method, if its an oxidized silver mineral, cyanide might work. Your SSN will not work for silver as silver chloride is insoluble, and that insoluble material will remain with the ore.


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## Macgiver (Aug 7, 2011)

Richard36 said:


> Ferrell said:
> 
> 
> > Richard, SSN stands for saturated salt mixed with Nitric Acid. I don't know what PT stands for. :lol:
> ...




The trick with SSN is making sure you have a super saturated solution of salt before you add the nitric. Once you add the nitric a lot of the salt will precip out. Then add iodine to make it more aggressive. :shock: My two point 6 cents.

CW


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## butcher (Aug 7, 2011)

most silver compounds can be roasted to oxides, Iron added helps to convert sulfides.


I have no expierience with it but thiosulfate ammonium solution comes to mind.

Most any leach it would be best to determine the chemical makeup of your ore, then look into chemically converting it (either in roast or with chemicals in solution) and then leaching dissolving silver or other metals from solutionleaving it richer in silver content,
I would roast any ore as a pretreatment, and then there is also smelting to recover your ore.

first you need to know what you have, then make the plan of attack.


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## Dirtdiggaler (Aug 14, 2011)

Try a 50-50 nitric acid water leach. Heat and when all reaction stops filter, then cement silver with pure copper and when you think your done add a drop of HCL if no white precip forms your finished cementing and smelt. To cement copper add tin then use wood ashes or sodium hydroxide to bring PH to 7 to dispose of acid properly.


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## Toddntucson7 (Apr 28, 2016)

My ore is CU, AG, PB, AU, MN, MO do I need to roast, crush then start? If it's a local oxidized in a carbonate limestone host? I added 50-50 nitric started leaching. What order do you pull elements? I don't want the worthless elements just AG and AU. It's a strong, hot, high grade consitrates at almost ^40 AG ton, grade of 684 g/mt with AG and PB being primary and gold a strong runner after @ 2.5 oz/ton. Do you leach, cement silver with copper, then PH with sodium hydroxide to a neutral 7 and pull your AU with stump out? Or is there an order? Do I have to cement the CU with tin then pull my AU? Do I do this at hot temps or cold? My rock has major AG with good PB and minor CU I would rather dump the low grade elements, pull the two if I can and smelt. Or send out in bars local then send to refinery to separate the AG/AU. Let me know thanks.


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## butcher (Apr 28, 2016)

My ore is CU, AG, PB, AU, MN, MO do I need to roast, crush then start?

Start what? You only have a small list of metals what the ore is composed of? What other elements (arsenic, sulfides, carbonates...), without knowing what you have it is difficult to come up with ideas of what pre-treatments may work the best to prepare the ore for concentration or prepare the ore for an extraction processes, or what you may have to experiment with, to see what may work best. Before experimenting with a recovery process, then experimenting with a refining process you really need to understand what your dealing with...



If it's a local oxidized in a carbonate limestone host? I added 50-50 nitric started leaching.
Carbonates neutralize acids. 
What order do you pull elements?

You have to concentrate and pre-treat before you can even worry about pulling elements.
But first you will have to find out what you are dealing with.


I don't want the worthless elements just AG and AU. It's a strong, hot, high grade consitrates at almost ^40 AG ton, grade of 684 g/mt with AG and PB being primary and gold a strong runner after @ 2.5 oz/ton. Do you leach, cement silver with copper, then PH with sodium hydroxide to a neutral 7 and pull your AU with stump out? Or is there an order? Do I have to cement the CU with tin then pull my AU? Do I do this at hot temps or cold? My rock has major AG with good PB and minor CU I would rather dump the low grade elements, pull the two if I can and smelt. Or send out in bars local then send to refinery to separate the AG/AU. Let me know thanks.

Your asking questions about refining when you have no clue about recovering the values from the ore.
Or even if you can mine it, and transport, or concentrate it or pre-treat it economically....

All you have at this point is gold fever, with no clue of what to do with the rock you found, or your gold fever.

Your gold fever is blinding you, and stopping up your ears from hearing reason, it is clouding your mind. 

You are trying to put your plow in front of your mule, and then trying to pull them both to get your field plowed. 

Lou has given you some very good advice to begin with, He has also made a thread to help you, and others with these types of questions.

Find a cure for that gold fever, and make your posts in that section, maybe we can be of help.


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## galenrog (Apr 28, 2016)

Putting your questions and comments about the same ore in several threads makes for a confusing conglomeration. Please keep all questions about your ore in a single thread. It keeps things simple. 

Moderators, could someone please review all of Todds' posts and put them in a single thread that allows this spread out mess to be more coherent? I, for one, have difficulty following the several threads that he has posted questions and comments concerning his ore. Thank you.

Time for more coffee.


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## solarsmith (May 1, 2016)

ok first of all look up a company called Hazen Research. they are located in golden Colorado and have a staff of about 200 people. they can answer your question about the best way to get the values out of your ore. It is what they do. you want all the values out of your ore and your interested in doing some sort of an acid leach.
it may work but if you do not concentrate first you will spend a lot more on acids than the values will pay for. your ore sounds hot and I hope you have lots of it .
if it is of a sulfide type hazen will probably recommend a froth flotation system as part of the concentration process. this will automatically recover most all of the silver and other values that might be in the ore. Hazen is very good at telling you what other values might be in it for you. Tell them what scale your able to dig 100lbs a day or 100 tons a day. they can and will recommend the best system for you. and if you like they will set up a small scale test plant for you. My thoughts are that if you have ore as rich as you say then it should be very easy to set up a concentration system to get it over 200 to 300 oz pgms per ton on your own. if this is even close to to what you can get then the next step is very easy smelt it or sell it to a smelter. have them send you a bar and then you can soak it in acid to your hearts content. and learn the chemistry to make your pregnant acid back into pt ag and au and cu . there are a 100 paths from ore to bar. Bryan in Denver CO 303x503x4799.


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## shrewdly (May 8, 2016)

First things first. You can take your raw ore and extract your gold & silver - anything is possible. Possible yes, profitable no. Although gold and silver can occur in native form (metallic) in most ores they locked into other minerals commonly the sulphide minerals. You should pre-concentrate your ore prior to trying to extract the precious metals, otherwise you're just wasting a lot of chemical. Concentrating your ore can reduce the volumes you treat by anywhere from 10:1 to 30:1. There are various techniques available to the small scale miner for producing a concentrate. Froth flotation is an excellent process that can obtain recoveries in excess of 90 percent of the contained minerals, however it is capital intensive usually requiring crushing , grinding and flotation as well as filtration. In your case I would suggest a gravity process. This would involve crushing your ore down to minus 80 mesh. You can find several types of equipment to do the separation - a sluice box, a shaker table, a jig, spirals etc... With gravity concentration techniques you're separating material by their differences in density (the lights from the heavies). The key parameter here is particle size you want them to be small (-80 mesh) and of the same size. A roller crusher produces the most uniform product and would be best for a gravity plant. The simplest and oldest gravity device is the sluice box, it can be made easily in various sizes, can handle large volumes and if set up properly can achieve high recoveries. The shaker table is another device that works quite effectively and I've seen tables do a very clean separation with distinct bands of the various minerals coming off the table. The major drawback to a table is it's limited throughput, a 3 ft. by 4 ft. table can process about 1000 - 1200 lbs. per hour. A jig can be effective but it requires a lot of water and a solid foundation. You should not discount the value of the base metals as their value could pay for your operating costs with the gold and silver as straight profit. It would probably be best if you produced a concentrate and just sold it to a smelter.
An excellent report on sluice box design and operation was written by Randy Clarkson P.Eng for the KPMA (Klondike Placer Miners Association). His design suggestions resulted in improvements in sluice box recoveries from 60 - 75 percent to 90 - 100 percent. If you go to the http://www.gpex.ca website you'll find an article by Gary Weisphaut on shaker table design and construction. There are various manufacturers and suppliers of small crushers out there. There is even one who manufactures a jaw/roller combination rated at a tonne per hour.

Good luck and may all your endeavours be golden


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