# First steps for this complex mix?



## Anonymous (Oct 7, 2010)

This is my first post here, although we've been gleaning info from this forum for a while now. You guys are GREAT! I sent an e-mail to lasersteve about this, but thought I'd throw this out to the rest of you to ponder.

We have been working on trying to process a placer ore from a clay bank that has always appeared to have an interesting mineral content. Have no money to throw at processing, but lots of will, we have been trying all kinds of "poor man" methods. We've learned a huge amount in the process, so we're not starting from scratch. We tried getting a couple of accurate assays, but kept getting conflicting reports because of a high iron content.

We finally found a lab tech who was intrigued by the powder and went the extra miles to give us an accurate readout. He was amazed at the number of minerals in the mix, thinks it would be worth our refining, but says it's too complex for any of the commercial refineries to want to mess with. So, we're now focused on refining it ourselves.

Here's the analysis, totaling 100% content from about 1 tsp of powdered ore (our desired minerals are in red):

Au 0.141 
Ag 3.40 
Pd 1.75
Rh 1.41 
Cu 0.282
Sn 2.53
In 2.09
Ir 0.062
Cd 2.48
Ru 0.455
Mo 0.248
Nb 0.171
Zn 0.188
Ni 0.888
Co 0.679
Fe 76.15
Mn 0.207
Cr 0.203
Ti 6.487

The main problem is the iron, which is alloyed with most, if not all, of the metals. *As a starting point*, what would you suggest we do to prepare this powder further before using AR, or possibly electrolysis, to precipitate the desired minerals?

The powder is currently at about 150 mesh, by the way.

We do have the Hoke book, and can follow her wet methods if that's the best approach.

All your ideas would be appreciated!


----------



## lazersteve (Oct 7, 2010)

I received your email while I was at work this morning and haven't had time to reply until now.

It's nice to have a detailed analysis of any ore before you work with it, especially for safety purposes and the peace of mind of knowing what you are dealing with. 

The lack of numbers for Silicon, Carbon, Hydrogen, and Oxygen makes me wonder about the analysis considering the material is from a natural source. It strikes me as odd that the clay is 100% metals without a trace of water, silicates, or carbon.

My biggest safety concern with processing the ore would be the more hazardous metals on your list: Cr, Co, Cd, and Ni (4.25% of the total) as well as how to properly remove and dispose of the left over waste. Not that the remaining metals do not pose any safety risk, just that these jumped out at me as especially toxic.

I feel that removing the iron and the bulk of the base metals should be easy enough simply with the proper flux. I would stay away from wet chemistry until the ore were reduced to a more concentrated form in the furnace using a collector metal for the precious metals. Mind you I'm not a metallurgist so I can't be certain of how easily the base metals will be separated using flux and a collector. I'm also unaware of how metals like Nb, In, Ti and Mo ( ~9% of the total) would affect the use of flux.

Since silver is already present in a fair quantity (3.4%) I would consider adding more silver as the collector metal.

I look forward to hearing other members perspective on the ore.

Steve


----------



## 4metals (Oct 7, 2010)

I agree with Steve that it is unusual to find a "natural" sample of ore that is 100% metals. However I would take advantage of the nobility of the precious metals and melt the material in a strong oxidizing flux to help separate the base metals from the values. 

Because the sample is a fine powder of approximately 150 mesh (105 microns) take advantage of the high surface area to make intimate contact between the oxidizable metals in the sample and the flux. A good flux to start with is 1 part sodium carbonate, 1 part anhydrous borax, 2.5 parts potassium nitrate, and 1 part silica. I would start with equal parts of flux and powder , mix it well and hold the mixture just below the metal melting point for a while, the flux will liquefy but there will be good contact between the molten flux and all of the oxidizable metals. 

Bring the mixture up to the hottest your furnace can get and if the flux is not fluid, add flourospar slowly to make the flux more liquid. Pour into a cone mold. 

If you cannot get the metals to pool you will need a collector, either silver or copper to help pool the metals. 

Assay the button to determine how much the percentage of values increased. Also crush up some slag to see how much of the values are left behind.


----------



## Lino1406 (Oct 8, 2010)

Did you try to exert a magnet on the powder? result?


----------



## Anonymous (Oct 8, 2010)

As I said, you guys are great. Thanks for the responses.

We wondered about the lack of silica, etc. in the readout. When we originally worked on smelting it with silica added to the flux, we were getting LOTS of glass. So, we stopped adding silica and still got plenty of glass, which indicated to us there there was ample silica in the ore. So, on this point, we'll give the lab tech a call and try to get clarification on why the readout didn't show these compounds.

We made a homemade gas furnace, which has been working to get our stuff molten if we add oxygen. We have been smelting at 8,000 feet, so O2 is skimpy in the air here. We will soon be moving to 1,200 feet, tho, which may help us with our temps. We do not have an accurate gauge, however by color we are estimating approx 2,300 F, maybe a little more (very bright yellow/slightly orange). 

Regardless, we are getting molten, however we are NOT getting good separation. We are getting a thin layer of molten silvery metals on the outside of the entire cone (at least 3 colors of silvery-gray), and a little thicker granular layer of dark silvery-gray at the bottom.

We are getting a variety of beads in the slag, including dark granular beads, silvery-gray molten beads, and gold-colored beads (which somewhat resemble pyrite in crystalline structure).

We started with a recipe for pt that we found somewhere else, which is quite different from the one you provided, 4metals. We have probably been using too much soda ash, which we increased from the original recipe to help reach molten temps. Our last version of flux was 6 p soda ash, 4 p borax, 3 p potassium nitrate, 0 p silica. We were using this mix 1.5 p flux to 1 p. ore, with the results described above (obviously not working). 

We will try 1: changing the flux to your suggestion, 2: changing the heating method to letting it "cook" for a while at a lower temp (How long would you suggest before increasing heat?). Once up to highest heat (very bright yellow- slightly orange), how long do you recommend we let it cook before pouring? We have been waiting until there are no more dark spots bubbling, and then keeping at high heat for another 5 minutes or so before pouring. We have been pouring into cone-shaped silica sand molds; do we need to get actual cone molds? If so, can you explain why?

So, it sounds like smelting is still in our future on this, huh? We are making our own clay crucibles from furnace cement w/ a 2700 degree limit. Each crucible is only good for 2-3 heats, and we can only do 1/3 cup of ore per heat. Any ideas on a better/cost effective crucible approach would also be appreciated. We tried fire clay, fire clay/silica blends, fire clay/silica/portland blends. All were too fragile in the high heats. The 2700 "Chimney Sweep" product is working and fairly inexpensive (about $1.50/crucible), but tedious to make. Considering that we currently have about 40# of powdered ore ready for smelting, that's a lot of crucibles!

Again, thanks for all your input. We'll be looking forward to your inputs.

Brad & Landa in Colorado (soon to be No. California)


----------



## Anonymous (Oct 8, 2010)

Regarding using a magnet...

Yes, we've done extensive magnet tests with strong magnets. Our powdered ore (which has been extensively washed and screened from its original clay clump form), assayed at 78% iron. However, while the magnet pulled some magnetic material, it was quite a small amount compared to the volume of ore. When we subjected the ore to HCl for approx 48 hours, stirred many times, then filtered, rinsed, and dried, the magnet pulled absolutely NO iron. This sample still assayed at 76% iron.

The assayer said the iron was alloyed with nearly everything in the ore. Our only thought is that the way it is alloyed must be impacting the magnetism.

Obviously the HCl soak did have SOME impact. We thought that, since we got nothing magnetic after the soak, the iron would have been greatly reduced. The before and after samples, however, only showed a drop in Fe of 2%.


----------



## Anonymous (Oct 8, 2010)

Regarding other organic compounds...

This material came from a clay bank. Our process for making it usable was as follows:

1. Soak in lye for 24 hours to break down clay platelets.

2. Wash through 60 mesh screen to get uniform initial size.

3. Wash off clays as much as possible through several washings.

4. Screen through 150 mesh.

5. Wash screened material several times to further remove clays.

6. Evaporate dry.

7. Smelt.

I would think that this process would have reduced some of the anticipated natural organic compounds, although I wouldn't think it would've gotten rid of all of them.

We did, by the way, keep all the solids above 150 mesh, as these have visual metallic ore as well. At some point we'll subject these to a mill.


----------



## Shecker (Oct 8, 2010)

Your analysis indicates the presence of ruthenium. Since ruthenium and osmium tend to occur together, it is reasonable to say that at some point you will encounter osmium.

Osmium and ruthenium are a deadly combination. In chloride media they both volatilize at approximately 136 degrees F. They both form volatile tetroxides. 
Ruthenium tetroxide produces a reddish fume. It is highly aggressive in attacking the lungs and mucous membranes. Osmium tetroxide is a green gase that attacks the eyes. At very low levels it is capable of causing blindness and death.

Lou would be the person to ask more about this.

I would recommend physical concentration by gravity separation and then have the concentrates analysis by Ledous and Sons. Depending on their analysis concentrates can be directly sold to smelters or chemical processing plants that are set up to handle the volatile nature of these two elements.

Randy


----------



## 4metals (Oct 8, 2010)

I usually do this before I respond to a post like this but better late than never. I figured out what this material is worth if the assay is correct. 

metal conc metal $/ton	
Au	0.141 $55,394.11
Ag	3.4 $3,371.59
Pd	1.75 $298,076.52
Rh	1.41 $908,841.73
Ir	0.062 $13,200.53
Ru	0.455 $19,242.27
total ---	$1,298,126.74

That works out to $649 per pound. 
That is a huge number, can you verify your assays?


----------



## Lou (Oct 8, 2010)

Assay seems weird.

How as the assay carried out again? It's easy to get such numbers with cherry-picking.


----------



## Platdigger (Oct 9, 2010)

This actually would make more sense if the iron was a percentage, and the rest were in ounces per ton.
With the balance being silicas, carbons, moisture and such.


----------



## HAuCl4 (Oct 9, 2010)

4metals said:


> I usually do this before I respond to a post like this but better late than never. I figured out what this material is worth if the assay is correct.
> 
> metal conc metal $/ton
> Au	0.141 $55,394.11
> ...



IMHO, for these type of heavily concentrated and valuable materials (if the assay is correct), the best plan is to mix with litharge and powdered charcoal 
and produce a lead button, then add some silver and slag the litharge.in a cupellation furnace, till a silvery button remains. Recycle the litharge and the sllags if these still contain values.

A cupellation furnace is the most useful item in smelting, but dealing with lead , litharge and their fumes is dangerous, and proper yet simple equipment and operator protection are essential. 

Smelting with lead and litharge has been used successfully for hundreds of years. I doubt anything I said above is new or complex, but it works..


----------



## Anonymous (Oct 9, 2010)

Thanks again, folks.

We will definitely be talking to the assayer again first of the week. He heads the lab at a large, reputable refinery, so I suspect he knows what he's doing, but that he communicated incompletely. Like many of you, we are speculating that the values given represent 100% of the metals present, not 100% of the material sampled. We know, for instance, that there is sulfur in the mix, because we've done some roasting of it and definitely got strong sulfur odor. His results were from ICP spectrometry, by the way.

Another large refiner did a quick check on a sample using X-ray fluorescence and basically told us it was 85% Fe, 3% Pd, 2% Ag, and .5% Au. The remaining 10% was not discussed, and was assumed to be the organic elements not listed in the assay currently under discussion. 

An assayer prior to that (private individual) also did XRF and told us it was "more than 10% Fe" and listed 4 other minerals in ppm: gold, silver, lead, and strontium (the last two haven't shown up on subsequent assays).

Both places that did XRF said the high iron readings make it impossible to get an accurate reading of the other contents, but that the fact that gold showed up at all in that much iron was a good sign.

So, our next step will be to talk again to the provider of these latest results (the ICP assay) to get clarification.

One of the big problems here is that we simply cannot afford at this time to keep paying for assays. The latest tech (from the large refiner who gave us the ICP results), is willing to work with us for very low cost.

Other than smelting (which is difficult for us currently), any suggestions on breaking the iron alloys and dissolving the iron using wet methods? If we could even get success with this on just enough of a sample to get an accurate assay, it would help.


----------



## Shadow-Savant (Oct 9, 2010)

HAuCl4 said:


> IMHO, for these type of heavily concentrated and valuable materials (if the assay is correct), the best plan is to mix with litharge and powdered charcoal
> and produce a lead button, then add some silver and slag the litharge.in a cupellation furnace, till a silvery button remains. Recycle the litharge and the sllags if these still contain values.
> 
> A cupellation furnace is the most useful item in smelting, but dealing with lead , litharge and their fumes is dangerous, and proper yet simple equipment and operator protection are essential.
> ...



Hello, first time posting here. I am one of blroon's sons and, as such, one of those working this material. I've no intention of hijacking the thread away from the material but one of our issues seems to be equipment. Therefore I'll be pursuing that line while my parents work on the process.

The cupellation furnaces you recommend are sadly unusable in our current location but we may eventually be able to get one after we move. (we're working off a less than 4000 watt generator for now) We are currently using a propane furnace with injected oxygen and the largest crucible we can use appears to be approximately the size of the A2 Crucible found on the table on the following page.

http://www.budgetcastingsupply.com/Crucibles.php

We have a possible lead on a 10kw induction furnace which appears to function very well and more than exceeds the requirement to levitate, much less melt, our material. It also supports up to a #4 Crucible, nearly tripling the volume according to the earlier link. The coil appears removable and thus able to be swapped out so we may be able to put a larger coil on if we don't require the full power in the normal coil. However, as none of us are *that* technically educated I'm seeking advice on where to go down the road. Electric furnaces seem far more viable where we're going, and we know induction would do our material if we could get the undesirables out of it. Is there a benefit to the heating from without method of gas or electric furnaces as opposed to the heat from within method of induction? I realize 4metals recommended we let the metal sit in the flux before getting it molten, so induction would more likely melt the metal sooner without proper attention and experience.

I've tried to find a price for comparison on cupellation furnaces vs. induction and since everyone hides the price of cupellation furnaces behind an email request it doesn't look good for cost. The one cupellation furnace I found on eBay was 8.5kw and over twice the price of the induction furnace we may be able to obtain after we can get some money coming in. Don't get me wrong, I'm not saying "oh crap it's expensive we should go induction" because I believe you get what you pay for. However, I do know from experience that sometimes you just get a shiny piece of crap that cost a lot. . . As I said earlier, my question is what makes which method better?

We value all the input we're not only receiving but also viewing in other threads. If you have a response on the method it'll be handled by my parents, but if it's regarding the technology I'll be following it up.

Thanks in advance,
Jeremy

{Edit} Regarding crucibles. Our experiences with the homemade crucibles seems to be an issue with the heat required to melt the material inside them. The crucibles fail on an average of the second smelt, sometimes lasting to a third and, once or twice, the fourth smelt. We tried fire clay crucibles as mentioned before but the issue with those was failure before reaching the temperature required, and it seems they were leaching the material into the walls which made recovery difficult. We've been told and have read that graphite crucibles will pollute PGMs but recently saw a coating that claims to prevent this. Were we able to purchase a graphite (or other high-temperature) crucible and use it enough times to make it cost effective this would be excellent. The two types of coating are described somewhat on the following links.

Metal coating = http://www.budgetcastingsupply.com/Marcote-7.php
Ceramic coating = http://www.budgetcastingsupply.com/ITC.php

Anyone have knowledge to impart about the use of graphite with PGMs? We've read many here using graphite crucibles for PGMs and, if it _is_ an issue we're curious about the possibility of coating one with the ITC coating(s). As far as I understand the temperature failure of our crucibles, heating the metal from within using induction could possibly eliminate this issue as they crucible itself wouldn't have to get as hot. Also, the force of the induction pushing metals toward the center should theoretically lessen the strain the crucibles are under from heavy material pushing down and out. Am I wrong? Looking forward to a response.


----------



## 4metals (Oct 9, 2010)

Shadow,

The size furnace, be it gas, induction or cupellation that you will require to smelt this stuff is cost prohibitive for a start up operation. I would focus on getting a consistent fire assay for this material from someone who knows ore. If this material can assay consistently and its value remains high, it is prime material for shipping to a copper smelter in Europe. There are ways of sampling the material here in the states while you watch so you don't have to travel. Then your money will be best spent on a ball mill and sifter to prepare the material into powder and drum it up. 

After you get your first ton processed and have some cash to work with, then you can decide to ship it or process it yourself. There is a member who has good feedback from others on the forum, he is a rock guy. check out this post. http://goldrefiningforum.com/phpBB3/viewtopic.php?f=84&t=5393 

His preliminary assay fees seem reasonable and if you can get multiple assays from different sections of the same deposit, consider raising cash by shipping it. I can point you in the right direction if you choose that option. I have no horses in this race just offering some assistance.


----------



## T3sl4 (Oct 10, 2010)

Shadow-Savant said:


> We have a possible lead on a 10kw induction furnace which appears to function very well and more than exceeds the requirement to levitate, much less melt, our material. It also supports up to a #4 Crucible, nearly tripling the volume according to the earlier link. The coil appears removable and thus able to be swapped out so we may be able to put a larger coil on if we don't require the full power in the normal coil. However, as none of us are *that* technically educated I'm seeking advice on where to go down the road.



That's very interesting. I've been building induction heaters _from scratch_, so I happen to know a bit about them!

I can tell you one thing: small materials do not heat efficiently at low frequencies. If you wish to start with powder, you'll need an RF unit (in the MHz). If you start with a "heel", something large enough to get things started, you can use a simple medium frequency unit (which is the range I have the most experience in).



> Electric furnaces seem far more viable where we're going, and we know induction would do our material if we could get the undesirables out of it.



An electric furnace, like a regular pottery kiln, would do a fine job of slagging the raw material. This gives you slow, even heat over a long time, which allows the mixture to melt, react and settle. You need a crucible large enough and corrosion-resistant enough, of course. Something with zirconia seems like a good idea (but probably pricey as hell).



> Is there a benefit to the heating from without method of gas or electric furnaces as opposed to the heat from within method of induction? I realize 4metals recommended we let the metal sit in the flux before getting it molten, so induction would more likely melt the metal sooner without proper attention and experience.



Once you have metal to heat, induction will gladly melt it underneath a still-frozen layer of slag. That may or may not be useful, I don't know. It would be fine for post processing, when you have a glob you want to play with (cupel / recast / etc.).

Induction will not melt slag or nonconductive powders alone; for that, you need a succeptor, which might be a graphite, carbide or molybdenum crucible. (Clay-graphite crucibles heat up very slightly, not enough to notice. Silicon carbide crucibles may work, understanding the PGM-carbon incompatibility mentioned.) Since this is external heat, it's fairly indifferent compared to an electric or gas furnace.

As cupellation goes, an electric furnace should be quite nice, as you get 100% clean air inside the thing, no shielding effect from burning fuel. I've not done cupellation personally, so I don't know how significant this is.



> Regarding crucibles. Our experiences with the homemade crucibles seems to be an issue with the heat required to melt the material inside them. The crucibles fail on an average of the second smelt, sometimes lasting to a third and, once or twice, the fourth smelt. We tried fire clay crucibles as mentioned before but the issue with those was failure before reaching the temperature required, and it seems they were leaching the material into the walls which made recovery difficult.



How high were these crucibles fired (cone ??) before use? Was this using lots of flux?

A lining of alumina and zirconia-rich chemicals may help. Offhand, I could suggest a combination of alumina, kyanite, zircopax, a little fire clay, and a dash of bentonite (<5%) to help it stick together. This mixture can be applied as a slip, either before firing, or after bisque firing. The final product should be fired as high as possible, cone 20 or so. The resulting product should be dense, and very brittle, so go very slowly with it. You may also want to add some alumina and kyanite to the crucible mix, to get the chemistry closer to mullite. Mullite crucibles are quite brittle too, but they are stronger and more resistant to flux than silica-rich mixes.



> Anyone have knowledge to impart about the use of graphite with PGMs? We've read many here using graphite crucibles for PGMs and, if it _is_ an issue we're curious about the possibility of coating one with the ITC coating(s). As far as I understand the temperature failure of our crucibles, heating the metal from within using induction could possibly eliminate this issue as they crucible itself wouldn't have to get as hot. Also, the force of the induction pushing metals toward the center should theoretically lessen the strain the crucibles are under from heavy material pushing down and out. Am I wrong? Looking forward to a response.



For the seperation of metal and slag, levitation isn't the best method: the biggest glob will be forced upwards, towards the middle, floating in a pool of slag, or up to the top. The fine metal particles will swim around in the slag, and settle to the bottom, because small particles aren't pushed up very much. As they settle, they will coalesce as usual. As the little globs become big globs, they will be pushed up into the main glob. I guess I would figure it would take slightly longer to seperate, since it doesn't simply fall to the bottom and that's that.

Tim


----------



## HAuCl4 (Oct 10, 2010)

If I were the OP, I'd heed the advice of 4metals: your edge is finding and accumulating good material with values.

I'd learn to fire assay, and setup a fire assay lab, to avoid relying on the costly results of others. You can probably setup a complete assay lab for less than 3 k$.

No use wasting your time and money in an industrial recovery and refining rig right now. Your edge is, I repeat for emphasis in accumulating good concentrates, assesing their value and selling for cash. Why worry about the crumbs if there is good meat?. Delegate the refining to the pros, learn to assay, and accumulate cash. KISS.


----------



## Shadow-Savant (Oct 11, 2010)

*4metals:*
Thank you for the feedback. I realize that attempting to process the materials as a startup wouldn't be economically feasible on a large scale. Some whom we have spoken to that have the capacity to process larger quantities have mentioned sending them buttons or beads. Being able to at least refine down to those was what inspired that line of thinking. Where we're going to next is pretty harsh on fires of any kind so that's why we were looking electric over gas.

Following this advice we will be focusing more on the process of fire assays and trying to get a more consistent series of assays for a confirmation of value.
-- For my own curiosity though, based on the % we received on the assay in the OP, what makes this a good potential material to ship to European copper smelters? I ask because the copper content seems pretty low compared to the other metals and one would think that a specifically copper smelter wouldn't reach the temperatures required for the more noble metals. Were you suggesting we find a way to separate the copper and ship just that? Also curious because of international shipping fees and the cut the government takes for income earned out of the country. (not certain if there's a minimum required before they take a cut, but it was an issue briefly addressed in my Management courses a couple years ago regarding sending management to outsourced companies and bringing their income back when they returned.)

With how much a pita this material is to work, we may opt to purchase the equipment required to process it ourselves when we have the funds.

*Tim (T3sl4):*
Thanks for the heads-up on material size. I believe my father read about that which is why we're happy to see the 10Kw unit has a frequency adjustment to meet different metal needs. I'm not certain what the range is, I'll have to find out. RF unit in the MHz, I'll see if that's what it is.

What I had meant by electric furnaces was induction or cupellation, powered by electricity instead of gases. If a well-made pottery kiln would work as well for less, for that purpose, we may add it to the list of possible methods. We were recommended, first step, to smelt. As fires and pollution are a big no-no in CA, that's why we're looking at going induction/cupellation/etc (electric). So long as we have adequate power we should be able to meet the smelting requirements without settling in one place. (pretty nomadic) I'll look into more crucible materials/linings such as those with zirconia as you recommend. Like I said in my last (first) post, I do believe you get what you pay for.

We've read that you can use a low melting point metal to assist in the melting/heating of other materials in the mix. On this note, could one add copper/silver or the like, set the frequency to melt that metal and through it the flux, then start changing frequency for other materials? I think someone was saying the reason you require more power (Kw) for iron and noble metals is that you need a different/higher frequency but as it's been nearly a month since I read that I can't be certain. On the point of it not melting nonconductive materials, is that a good selling point on spending the 3-4x more on an equally strong cupellation furnace? If we can Acid Peroxide or AR the mix and precipitate the precious we'll theoretically have (most of) the metals we want separated. At LEAST silver and gold to get a start on things. Would the induction then work to melt a single type of metal into a button? If we can at least get some income it'll help us prepare the material better.

Crucibles. . . ehh, not my deal. I didn't make or fire them. I know they were failing and I have a good idea of why but won't ever claim that "*this* is why" or the like. That's why I'm looking for advice on a good durable crucible or lining, so I both know how well they were made and what was done to keep them stable. As I said before, I'll be looking into the linings/materials you recommend.

Heh, the levitation was just an "ooh" thing my father was looking at for possible separation of the powder from organic compounds, not smelting. However, he did say that you require at least 50% more power, if not 100%+, to levitate the same material you're smelting. The induction coil it would come with is the crucible style so while it may mix the molten materials it won't levitate them. He was thinking if he could find a frequency to levitate the powder with metal in it, as opposed to that without, he could slowly pour the powder through a levitation coil into a bowl and let the silicates and clays fall free while his precious remained suspended. then swap the bowl for a crucible and turn it off, letting the metals fall into the crucible. Like I said, we don't know if it's possible but he was curious. If what he said was correct we could smelt iron with a 6Kw or 8Kw, I forgot exactly which, so theoretically we could attach a larger coil to the 10kw for smelting purposes. (not much, but maybe a #5 or #6 instead of #4).

*HAuCl4:*
It's good when people agree, it helps to give direction. As I said above we'll be looking more closely into fire assays so we can get a more consistent result. Unfortunately the 3k lab is far beyond our current capabilities. 3 years ago no, but the economy hit us very hard as our prior income stream was in the trades and they're still suffering greatly.

We do have the propane furnace and if that works to follow the instructions my parents have, they'll be able to at least come close to a rudimentary fire assay. Unfortunately getting multiple $50 assays is also out of our reach for the time being. We are as "backyard" as you can get and any advice to help get _out_ of that situation is appreciated. :lol: This is why we value the advice here so much.


----------



## HAuCl4 (Oct 11, 2010)

Try this for the "assay lab" without the lab:

http://www.butlerlab.com/

It will not be as accurate as a proper fire assay, but that's what I'd use if I were up a creek without a paddle, looking for gold or PGMs.

You'll need at least a torch. 3k$ is $3,000 just to clarify. If you are that short of money, I'm not sure what to recommend unless you already have a good find or claim to a mine. You could always sell a % right to the claim I guess.

Good luck. Tough times for many people. Been there done that!.


----------



## Shadow-Savant (Oct 11, 2010)

HAuCl4 said:


> Try this for the "assay lab" without the lab:
> 
> http://www.butlerlab.com/
> 
> ...



Thanks for the link. We'd heard of him through somewhere else months ago but I think that knowledge was temporarily misplaced. I'll be sending him an email after I respond here.

We could probably save up the $3k through the other work we can find but it might take us a year to do it. Been scraping by on the skin of our teeth since the collapse but it's improving a little now. If we have to put our focus elsewhere until we have the money to set up properly then we'll just have to do that. :roll: I'm flexible.

We'd go for nuggets to get us through but the places we know of are inaccessible this time of year. Have to wait for next year to try there.

As always, every little piece of advice helps. :mrgreen:


----------



## HAuCl4 (Oct 11, 2010)

Yeah. Go for that little manual and a used torch and tanks. No need to spend the $3k on the lab just yet. If you find a couple hundred Kg of the stuff you posted, you should be up in your feet in no time. The torch assay will not be fooled. You can probably be ready to go for $300 or so if you find a good deal on the tanks and torch. Maybe you already have a welder friend that you can borrow the torch from. Good luck. Tough times bring the best in good people. 8)


----------



## T3sl4 (Oct 11, 2010)

Shadow-Savant said:


> We've read that you can use a low melting point metal to assist in the melting/heating of other materials in the mix. On this note, could one add copper/silver or the like, set the frequency to melt that metal and through it the flux, then start changing frequency for other materials? I think someone was saying the reason you require more power (Kw) for iron and noble metals is that you need a different/higher frequency but as it's been nearly a month since I read that I can't be certain.


Frequency only matters for physical size. Small objects and small coils need high frequencies. Conversely, it would be hard to get 13.56MHz into a two-foot-wide induction furnace, it would look like an open circuit, no power would go into it.

My induction heaters cover the 10kHz-100kHz medium frequency band, and work well on stock about 1/4" and larger. For 1/40" grains (~40 mesh), you might need 500kHz, and for 400 mesh, maybe 5MHz. The particles need to be conductive, so it won't work well on ore grains (sulfides are semiconductors and may help; most oxides are insulators and won't do anything).



> On the point of it not melting nonconductive materials, is that a good selling point on spending the 3-4x more on an equally strong cupellation furnace? If we can Acid Peroxide or AR the mix and precipitate the precious we'll theoretically have (most of) the metals we want separated. At LEAST silver and gold to get a start on things. Would the induction then work to melt a single type of metal into a button? If we can at least get some income it'll help us prepare the material better.


I can't comment on the efficacy of a cupellation furnace. Just as a guess, it sounds like a glorified pottery kiln. It may be expensive purely because it's a niche market. Does it have a particular shape, is it made of robust materials? (One thing your average pottery kiln will NOT tolerate is flux, because they are usually made with lightweight refractory bricks, the kind that feel like styrofoam!)

Once you have a lump of metal, you can use induction to heat it further, melt more, cast into shapes, etc.



> Heh, the levitation was just an "ooh" thing my father was looking at for possible separation of the powder from organic compounds, not smelting. (snip)


Oh, you mean eddy current seperation -- yes, that's an excellent use of induction. If you hold a sheet of aluminum over the work coil, you'll feel a distict "bubble", exactly like holding two magnets pole-to-pole -- they repel with this bubble sort of shape!

If the frequency is right for the size (as listed above), the metal particles will be pushed out.

Iron particles may or may not fall through. At high frequencies, iron stops looking very magnetic (imagine it this way, the field is changing too quickly for the iron to respond), so it may repel. At low frequencies (including constant fields, i.e. permanent magnets!), the force is attractive. Only ferromagnetic elements (iron, nickel, cobalt, and some of their compounds) will be attracted, so this is a pretty specific seperation, and easy enough to do (magnets are cheap, eh!).



> However, he did say that you require at least 50% more power, if not 100%+, to levitate the same material you're smelting. The induction coil it would come with is the crucible style so while it may mix the molten materials it won't levitate them. He was thinking if he could find a frequency to levitate the powder with metal in it, as opposed to that without, he could slowly pour the powder through a levitation coil into a bowl and let the silicates and clays fall free while his precious remained suspended.


Ahh, so you're getting a coil, perhaps a whole furnace, with the machine? Yes, you can't do seperation very well with a straight solenoid coil. A levitation coil uses a conical bottom coil, so the force is mostly inward, but also upward, then above that, a small coil of a couple turns in the opposite direction, which keeps the work from shooting out the top.

You can imagine that, as you flatten out the coil, going from a straight cylinder, to a cone, to a pancake, you get more and more vertical push, and less inward "squish". This is indeed the case. Pancake coils are ideal for seperation.

Somewhere on your machine, you'll see where the coil connects. It might be plain old compression fittings or something. Personally, I use flare fittings. At this point, you can connect any coil you wish. It's very easy to make your own coils -- it's just a bunch of copper tubing, after all. The only thing you have to watch is to make sure the machine can handle the inductance. This should be in the manual, or maybe it can be calculated from other figures. If nothing else, you can make your coil have the same inductance as the original, in which case, the machine won't know the difference at all!

Tim


----------



## Shadow-Savant (Oct 12, 2010)

*HAuCl4:*
Thankfully where we're going next we'll be near my uncle who is a very highly trained mechanic/welder and does have tanks that he doesn't use TOO regularly. So mostly we'd need to get the system of Butler's to understand how to use them properly. This certainly sounds like a good first step so we'll see what we can do about the Butler course. Thanks again for the input, we'll certainly let you know how it works. :mrgreen: 

*Tim (T3sl4):*
lol, I wasn't expecting or intending on slapping a two-foot in diameter coil on the thing. :lol: According to what my mother said above, we're around 150 mesh. that would be what, 1.8MHz to 2MHz? As I said before we're not that technically educated on the induction so I'm not sure how the frequency ranges go on the machines. Most of the information we've found relates only the Kw usage and not the frequency ranges. Nailing that down would, definitely, be good to know.

If we can get the Butler torch assay method to work well enough to get started we may be able to start using the buttons from that in the induction coil instead of the powder. Would require selling quite a few off first though, to finally afford the equipment. :roll: 

The information about the field changes and the reaction of iron is really interesting to me at least. I love magnetic theory even if I don't know it too well yet. Always have. (loved the episode of The Universe dealing with solar storms). What do you think would happen to iron alloys in the mix? Seeing as the assayer reported iron being alloyed with nearly everything in there. . . Say the pure iron in this mix did not levitate, but the precious did. Would some of the predominantly iron alloys fall through or would the other material have enough grab to hold it weakly in the field? I realize that depends on what % of that alloy was the iron. 2% of a grain being gold wouldn't do squit. (sorry for the blip, just never got to talk to someone who understands it so well. Willing to take that conversation to PM though).

What we've been using for magnetic separation is a Magswitch 300 Amp Ground Clamp. We could have had the 600 Amp but it was out of stock and they wouldn't have had more in until after we had moved on at that time. (NAPA Auto Parts carries them sometimes, it's where we got ours). It's nice because we can turn it on to attract the ferromagnetic material, carry it over to a separate container, and turn off the magnetic field. Something in how they align a pair of (neodymium?) magnets inside the housing allows them to either negate or reinforce the magnetic field. Cool stuff. Magnetic field of a permanent magnet with the ability to turn it off like an electromagnet. Cost us about $35 for the 300 Amp, would have been $45 or $50 for the 600 Amp. Recently we picked up a http://www.soriaudio.com/zboard/data/sori_3/RADIO.JPG Bulk Tape Eraser for free and have been playing with it. We can pull off some dark grey/black(ish) material faster with the ground clamp and then pull almost pure black iron filings out of that with the tape eraser. Whatever doesn't get picked up from that pile by either magnet goes back in the source powder.

For now we're going to focus on the fire/torch assay method while we complete some personal projects/training for sustainable income. Once that's taken care of we should be able to start saving up for better equipment even if we can't immediately rely on this material. We'd like to get it worked out because everyone who's assayed it has told us that it's well worth refining, they just can't until we get it more manageable.

As always, the information we're getting has our focus less frayed and our future goals easier to timetable. Thanks to all of you whom are giving us this much needed advice.


----------

