# Urea is not KNO3, right?



## livinthedream (Apr 5, 2010)

I keep seeing people saying Urea is KNO3 (or saltpetre). This is not the case. Are people saying this becuse functionally they're the same? I'm wanting to drop my Au from solution. It's in pure AR. Just don't want to mess it up. I have several pounds of KNO3 from my pyrotechnic days, ans SMB from homebrewing. Man, I was meant for this hobby, ehh? I really trust Harold's published book, but he states using Urea, not KNO3. So again, I just want to be sure. It's looking like several thousand dollars of Au I've accumulated. This is fun. I'll see about some pics after done.

Thanks alot!


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## goldsilverpro (Apr 5, 2010)

Right. They are certainly not the same, functionally or chemically. The KNO3 will never be used at this point. 

The urea is typically used by many amateurs to eliminate the effects of any excess nitric acid in the AR solution, so that the SMB can then precipitate the gold without interference.

I doubt if Harold suggested using urea. Neither of us like using it. His method of eliminating excess nitric is to evaporate the AR solution. Mine is to not use any excess nitric to start with.

The best next step could be dependent on how contaminated (with base metals) your AR solution is. Questions I might ask are: How much weight of gold is in the AR solution? About how much weight of base metals is dissolved in the AR? How much AR solution do you have? What was the source of the gold? Karat gold? Electronics? Or, what? In other words, just give us more details of what you have and how you got to this point.


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## teabone (Apr 5, 2010)

Urea is used not only by "amateurs" but many professional gold recovery specialists use it to eliminate excess nitric. Sometimes its not feasible to boil down gallons of solution and can speed up your recovery time when you have to work against the clock.


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## Harold_V (Apr 6, 2010)

livinthedream said:


> I really trust Harold's published book, but he states using Urea, not KNO3.


Red flag time. 

I have no published book, nor do I endorse the use of urea. I do recommend reading Hoke, however, which, to my knowledge, does not recommend the use of urea. 

I refined for more than 20 years and never used it, nor did I care to. You are far better served to use Chris' method of dissolving the values, using only enough nitric to accomplish the task. That is generally beyond the ability of a newbie---they simply don't have the patience it takes, nor do they recognize the signs of total consumption, should it occur. By combining Chris' method of using just enough, with my method of adding a button of pure, to consume those traces that get left behind, you can eliminate the use of urea without evaporating totally. I heartily recommend you do that. 

Welcome to the forum. 

A tip. Be mindful of where you gather your information. There are people on this forum that are adept at passing along less then useful thoughts, although it's done with the best of intentions. We try to keep close watch over them, posting corrections as we deem appropriate. 

Harold


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## Palladium (Apr 6, 2010)

Wait until he finds out Hoke was a woman. lol


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## goldsilverpro (Apr 6, 2010)

I forget about Harold's method of adding a button of pure gold to use up the excess nitric. I like the method and, were I to refine again, I would definitely use it. I should add, however, that it would work only if there were an excess of HCl present. If there were too little HCl and an excess of HNO3, the AR would stop dissolving gold when the HCl ran out and there would still be an excess of HNO3. The same thing with my method of not using an excess of nitric to start with. There must be an excess of HCl to make it work. Since an excess of HCl causes no problems, it always pays to add a little extra when using either method.

Like Harold, I feel that, if things are done properly to start with, there will never be a need for urea. I refined many 10s of 1000s of oz of gold and never used urea once. I have experimented with it, however, and have found that it can effect the purity of the gold, especially if the metallic contaminants in the AR are above a certain level.

I suppose it could be of value as a quick-and-dirty first drop when there are tons of base metals in the AR or when one messes up and uses way too much nitric. A second AR, without urea, should be used in these cases.

I guess the term "amateur" depends on one's reference point.


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## livinthedream (Apr 6, 2010)

Thanks guys,

Harold, I appologize. I read alot, and must have confused you with someone else. There was a link to a reactions manual I came across. Thought it was written by Harold, but quite possibly not. 
Here's more info. The good news is I have not dissolved the values in the AR yet. acids are still separate. I unfortunately only have about 100ml of each, and the volume of scrap I have is like 400ml worth. (could I dilute with distilled to increase the volume so I don't have to use excess nitric/HCl? will this just slow down the reaction, or DELETED it up?) It's basically electronic scrap. probably very little base metals since these were Si wafers that were thrown out after deposiion of the Au layer. On most of them, it was the 1st layer of processing, so the only other metal I'll be coming into contact with is Cr (the adhesion layer for the Au) commonly 10nm of Cr is enough for adhesion. I do have a couple oz of 4 9's pure I can use to eat up the rest of the nitric if this is recommended. I'd rather use as little of this as possible since it's already good to go. worried about breaking a beaker, etc. Anyway, I have no good way to determine an accurate amount of Au present, so could I still use this method? 
Thanks again, very grateful for your eagerness to help. what a great forum.
Cheers!


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## livinthedream (Apr 7, 2010)

Sorry, didn't mean to offend. thought about it for a sec when typing and thought it would be OK. Wasn't necessary though. I guess when in doubt... 
Anyway, if anyone would like any further clarification on my process, let me know. As far as the process, I can come up with a weight of values plus or minus 30g, so I guess I should be able to use my pure Au to use up the nitric. I'll just be REALLY! careful. Hoping to get a pop-up for the family with the extra $!! I'll see if I can find a clear process for Harold's suggestion. If anyone can let me know about diluting with distilled to bring the volume up enough to cover all my scrap, that'd be great. Thanks again!


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## Harold_V (Apr 7, 2010)

livinthedream said:


> I have no good way to determine an accurate amount of Au present, so could I still use this method?


I hope I am addressing your concern. 
Using the right amount of acid requires that you have patience, and that you understand that too much HCl does no harm, and too much nitric does. I reflect on the patience because it's common knowledge that those unfamiliar with the way acid works on metals may not be something with which they are familiar. When they don't see violent action, it is often assumed that the reaction has ended, when that may not be the case. As the acid diminishes and the volume of remaining material does as well, the reaction becomes somewhat subdued. Adding more acid accelerates the reaction, so it is commonly wrongly assumed that the acid was exhausted. So then, in order for you to use the right amount, you must be patient and wait until you see NO further action, after having added some fresh HCl. 

How well this system works (using the proper amount of acid) is reliant on your ability to know that all of the values have been digested. That isn't always possible. I offer you, as an example, dissolving filings from the jeweler's bench. Because the filings are typically accompanied by bits of abrasive, it isn't always clear when everything has been put in solution. Therefore, it was always my intention to use just a little too much nitric. That way I could insure that I was NOT leaving behind any undissolved values. I then added a weighed button of pure gold to the solution, which consumed the traces of unused nitric. It was important for me to process in this manner, for I did NO assaying of customer materials. They were always processed as individual batches, flagged with the name of the owner attached to the vessel in which it was processed. By weighing the button of added gold, I could then determine how much gold was added to the lot, so the owner received a proper accounting of that which was recovered. 

I heartily endorse Chris' method----but it can get you in trouble if you lack experience. Play it safe and use a little excess nitric, then consume it in evaporation. The alternative is to intentionally use too little nitric, allowing the solution, which has an excess of HCl, to digest until all action ceases. You can then safely assume that the nitric acid you have added has been totally consumed, evidenced by the presence of yet undissolved values. Decant the pregnant solution, then start with a fresh batch of acid. That way, if you do happen to use too much nitric, the volume of solution that requires evaporation will be small, so evaporation will proceed quickly. You would, of course, still add a button of pure to the lot, which would consume the unused nitric acid. 

Don't be concerned about breakage. As long as you use vessels that are intended to be used in the lab, or are intended to be heated, breaking is not an issue. Use a thin asbestos pad between the heat source and the vessel. Be certain you work such that should you break a vessel, the solution can't readily escape. NEVER work in a sink, not unless the fluid runs to a catch barrel instead of a drain. Keep a supply of paper towels near. You can soak up a spill and achieve a respectable recovery that way. All that is required to recover the values is to incinerate the paper and to then reprocesses the ash. 

No apology is necessary. I am not the least bit concerned about your comments----I just want to insure that you have a clear understanding. Being misinformed is not in anyone's best interest. 

Harold


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## goldsilverpro (Apr 7, 2010)

Please note that I wrote this before seeing Harold's post.

Diluting it this much may or may not work well. I would guess that it might, but don't know for sure. You have plenty of nitric. You could buy a jug of muriatic acid (HCl) from the hardware store for less than $10?

You might divide the material into about 4 batches (or, more) and use the same aqua regia, over and over. After dissolving a batch, pour off the acid as much as possible. Rinse the chips well with as little water as possible and save the rinse water separately. Use the same strong acid on each batch. After you finish, the rinses can be added to the acid solution, the solution evaporated (as per Harold's method), and the gold dropped out (using the proper procedure).

Does the total amount of silicon wafers you have only occupy 400 ml of volume? Doesn't sound like much to me. Do you know the gold thickness? I used to run these reject wafers, from the Silicon Valley, by the drum load. The yields were good but I don't remember them being that good. Unless you know something I don't, I wouldn't expect much gold.

The wafers, when whole, tend to stick together and prevent the acid from getting in between them. You might break them up a bit and stir them carefully while dissolving the gold. Heat will help also.

The chrome is super thin and I don't think there's enough to cause any problem at all. After dissolving, you should end up with a pretty pure gold solution.


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## livinthedream (Apr 7, 2010)

Thanks guys. The wafers make up the bulk of the volume. The AU on the wafers is on the order of 1-3um. This is a research facility that designs probes, etc on Si. Alot of micromachining, etc. Typically in Si valley, they're depositing much thinner films (couple hundred nm typical). I also have some of the foil that lined the evaporator that deposited the metals, and was able to remove some of the Au form the wafers in sheets because it was stuck to a parylene layer, so this got rid of some of the volume of Si. Alot of the metal came off the Al foil, but it's layered with several layers Au between Pt, Pd, Al, Cr, etc. I don't have a ton of this stuff, but would it mess things up? Any idea if AR will dissolve parylene? THe problem with it is there doesn't seem to be much that will dissolve it. It's used as a biocompatable material because it's so inert, but I just don't know about AR. I'm worried some of the Au may not be able to contact the AR. I did crush the wafers that were still whole. I think I like the idea of multiple batches and decanting, etc. How long will the AR remain reactive however? I thought it degraded rapidly once mixed. It also sounds like I can add as much HCl as I want, the 1:3 and/or 1:4 ratio doesn't really matter? This could be the easiest way to make up for my volume problem. 
Man, thanks again. I love the free flow of information here. not always a real common thing. I'm into prospecting also, and have tons of black sand cons I'm looking forward to seeing what I can do with. I noticed another board along these lines. godspeed.


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## Harold_V (Apr 7, 2010)

About the proper ratio for AR-----the book is far from closed on that topic. A great deal depends on the two acids in question----their level of concentration. To play it safe, always use excess HCl. It is not only cheaper than nitric, but because it causes no problems when present in excess, it insures that you use all of the nitric, assuming there is enough metal present that requires dissolution. My policy, when I was actively refining, was to mix my AR at a ratio of 1:4. I then added more concentrating the solution by evaporation, at the same time I added the button of gold. That way it was obvious if the solution was free of nitric, or not. Well diluted solutions may be very slow to respond to an added button, so concentration can have value. 

Mixed emotions in that regard. Chris refined longer than I did, and enjoyed considerable success with his methods, as did I with mine. I'm not about to say which one was the better of the two, because I firmly believe that there are situations where both of us had the right idea, and where both of us could have improved what we did. That's the nature of refining. Lots of ways to achieve an end, but generally there's one that's better than all others. The problem is understanding the issues well enough, and to have enough experience, to know which is the best choice for any given circumstance. I expect I never achieved that level of performance, but I was more than pleased with the results I achieved. As long as you are not losing values, and you are comfortable with a given process, go with it. 

A closing note. I mentioned that excess HCl causes no problems. While that's true as far as the recovery of gold is concerned, it does present some problems when filtering. If you have an exceedingly high percentage of HCl, your filter will often fail. I always tried to achieve a delicate balance, because I filtered heavily concentrated solutions, regardless of the volume. Those that filter well diluted solutions shouldn't experience the problem. 

Harold


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## livinthedream (Apr 9, 2010)

I'm ready to go on this. Lastly can I get any advice on searching the forum. I don't seem to get the results I"m looking for when I do. For example, I'd like to find a link to Hoke's book, and to Harold's AR process. I guess since I'm on the subject, is uploading pics easy to do here? I can post some eye candy for any of my fellow sickos with the fever.

Thx!


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## Palladium (Apr 9, 2010)

Start with everything below.

http://www.goldrecovery.us

http://goldrefiningforum.com/phpBB3/viewtopic.php?p=6873#6873

1. Refining Precious Metal Wastes C[1].M Hoke http://tinyurl.com/mfnyhs
(REV) (Free Download)
2. Get the (FREE) Gold Refining Forum Handbook VOL 1 here >> http://tinyurl.com/nyutnp
3. Get the (FREE) Gold Refining Forum Handbook VOL 2 (Final) here >> http://tinyurl.com/y9w5y73
4. Chemistry Handbooks Here (FREE) >> http://tinyurl.com/n27pqu
ALL FREE-----ALL THE TIME


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## lazersteve (Apr 9, 2010)

livinthedream said:


> ... Lastly can I get any advice on searching the forum. I don't seem to get the results I"m looking for when I do. .... is uploading pics easy to do here?



Use the forum search page on my site, it work's much better than the forum search function:

http://goldrecovery.us/forum_search.php

There is a post in the 'Other Tutorials' section on uploading pictures.

Welcome to the forum, 

Steve


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## livinthedream (Apr 19, 2010)

Thanks alot guys, this is great stuff. I've been delayed in my project. Unbelievable amounts of good info here. I'll keep you posted.
Thanks again!


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## goldsilverpro (Apr 19, 2010)

Harold said:


> I'm not about to say which one was the better of the two, because I firmly believe that there are situations where both of us had the right idea, and where both of us could have improved what we did. That's the nature of refining. Lots of ways to achieve an end, but generally there's one that's better than all others. The problem is understanding the issues well enough, and to have enough experience, to know which is the best choice for any given circumstance.


I would like to make one final comment concerning the differences in the methods that Harold and I used. I've thought a lot about this, over the last couple of years, and feel that many of these differences stemmed from our different requirements of the accountability of the end results. 

Harold's way of dealing with his jeweler customers compelled him to take each separate job to completion and recover 100% of the gold in that job, as a separate entity. Only then could he properly settle with the customer. The best way (and, maybe, the only way) to do this is by inquaration.

I rarely dealt with jewelers on a recovery basis. When I did, I usually melted the lot, assayed it, and paid on assay. For this reason, and since most of the material I ran had already been paid for, I didn't care if I got 100% the first time. I knew I would always get the rest of it, eventually. In the case of karat gold, I rarely inquarted and, instead, dissolved the scrap directly in AR. There was always a little undissolved gold co-mingled with the resulting silver chloride/dirt. All this was accumulated and recovered at a later date, using one of several methods.

Harold's methods are more cut and dried than mine. If you follow his instructions, they always work, even the first time you try them. My methods are probably faster, but you often have to vary them, depending on what reactions happen to occur and the various materials that are involved. Therefore, you have to have more knowledge to use my methods. For this reason, I have always recommended (at least, for the last year, or so) that the members of this forum follow Harold's procedures to the tee.


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## Harold_V (Apr 20, 2010)

Very well stated, Chris. You covered the points that are relevant. Inquartation, properly applied, results in total recovery every time. Minimum losses to gold chloride absorbed by traces of silver chloride, but otherwise fully accountable. 

For a beginner to attempt to process without inquartation can lead to some serious frustration. My first experience certainly proved the point. 

Inquartation, from the perspective of the uninformed, looks like an overwhelming process. That is not true. It is routine, and happens quickly. It adds one step to the refining process, but permits the recovery of silver directly, and insures that the target metal, gold, is divided such that it can be readily dissolved. It has the benefit of cleaner gold in precipitation in that virtually all of the base metals are eliminated in the primary dissolution. 

I had options at my disposal through all of my years of refining---including processing without inquartation. My choice was to always inquart, which also was my way of processing silver that was received for refining. I was fortunate to keep a rather equal balance, almost always having silver on hand. YMMV.

Harold


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## nickvc (Apr 20, 2010)

The advice from GSP to follow Harold V methods is spot on for all the members of this forum,they work each and every time if followed correctly and remove many variables that can enter the refining process that dont need to be addressed unless your forced to.My methods were a combination of Harolds and GSPs mainly to due to ignorance as to the proper way to proceed, had this forum existed in the days i was refining commercially im sure i would have had better results and a lot less secondary recoveries to secure all the values.


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## livinthedream (Apr 20, 2010)

Excellent. think I'm gonna have to buy GSP's book based on the contents I read since this is fun as heck, and I have a limited supply of the current material I'm processing. Looks like there may be info on where the nonpro could inquire to obtain more material. (Hopefully?) I am in the semicon industry, but most stuff seems to be going to solar cell fab these days, other than Intel, AMD, etc. All the generic IC's are fab'd overseas anymmore. (China, etc,) "Political statement entered here" . 
Anyway, I must confess it appears I've not studied thoroughly enough and maybe gotten myself into the trap of the beginner. I've not done any inquartation if I'm understanding the meaning properly... mostly due to the idea that I thought AR would be a bit more selective to PGM's than it's appearing to be. As a side note, I do not care about purity in the end either. I will be taking the values I've dropped out to (someone like you guys?) to be assayed. They melt it, assay, while molten, then pay based on the weight and assay % Au. 
My values are currently in AR, and I may have been overly optimistic in thinkiing the other metals are insignificant. Turns out a couple of the substrates were alloys of Al, Ti, and Ni, and many may have used Pt as an adhesion layer. The sol'n is now a bubbling murky green (good news, the parylene doesn't seem to be reacting). Hopefully this is normal AgCl I'm thinking. It's going to be difficult to separate the AgCl from all the broken up wafer pieces I fear, but The Ag should be minimal, so if you all think there's 'not enough Au mixed in with the Ag, I may just sacrifice it to the chemical God's. Based on rough before and after weights, I've got roughly 3oz. dissolved metal in my sol'n based on before and after, but haven't tried to thoroughly rinse wafer pieces yet. 
OK, sorry for such a rediculously long post, but this potentially pays for my bride and I's camper expenses this year, so don't want to mess it up. It comes down to this. Can/should I use up the HNO3 with some pure Au, or with some scrap that's about 30% Au, and a mix of other metals? How long would it take one to evaporate 120ml HNO3 from the sol'n without heating it if they didn't?
Lastly, I'm all nervous I'll mess something up... Is there anything readily available I can get from a local that would act as Urea to eat up the nitric. remember, I don't care about final purity,
Thanks again!!


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## Barren Realms 007 (Apr 20, 2010)

livinthedream said:


> Excellent. think I'm gonna have to buy GSP's book based on the contents I read since this is fun as heck, and I have a limited supply of the current material I'm processing. Looks like there may be info on where the nonpro could inquire to obtain more material. (Hopefully?) I am in the semicon industry, but most stuff seems to be going to solar cell fab these days, other than Intel, AMD, etc. All the generic IC's are fab'd overseas anymmore. (China, etc,) "Political statement entered here" .
> Anyway, I must confess it appears I've not studied thoroughly enough and maybe gotten myself into the trap of the beginner. I've not done any inquartation if I'm understanding the meaning properly... mostly due to the idea that I thought AR would be a bit more selective to PGM's than it's appearing to be. As a side note, I do not care about purity in the end either. I will be taking the values I've dropped out to (someone like you guys?) to be assayed. They melt it, assay, while molten, then pay based on the weight and assay % Au.
> My values are currently in AR, and I may have been overly optimistic in thinkiing the other metals are insignificant. Turns out a couple of the substrates were alloys of Al, Ti, and Ni, and many may have used Pt as an adhesion layer. The sol'n is now a bubbling murky green (good news, the parylene doesn't seem to be reacting). Hopefully this is normal AgCl I'm thinking. It's going to be difficult to separate the AgCl from all the broken up wafer pieces I fear, but The Ag should be minimal, so if you all think there's 'not enough Au mixed in with the Ag, I may just sacrifice it to the chemical God's. Based on rough before and after weights, I've got roughly 3oz. dissolved metal in my sol'n based on before and after, but haven't tried to thoroughly rinse wafer pieces yet.
> OK, sorry for such a rediculously long post, but this potentially pays for my bride and I's camper expenses this year, so don't want to mess it up. It comes down to this. Can/should I use up the HNO3 with some pure Au, or with some scrap that's about 30% Au, and a mix of other metals? How long would it take one to evaporate 120ml HNO3 from the sol'n without heating it if they didn't?
> ...



You could find urea:
Local garden store
Hardware store
Farmers CO-OP
Wal-Mart
Home Depot

Found as:
Urea
Mixed fertalizer 13-13-13 pick out the white pellets and use them


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## lazersteve (Apr 20, 2010)

I have an inquarting video on my website.

http://goldrecovery.us

Steve


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## Harold_V (Apr 21, 2010)

Harold


livinthedream said:


> My values are currently in AR, and I may have been overly optimistic in thinkiing the other metals are insignificant. Turns out a couple of the substrates were alloys of Al, Ti, and Ni, and many may have used Pt as an adhesion layer. The sol'n is now a bubbling murky green (good news, the parylene doesn't seem to be reacting).


It's quite important for you to eliminate base metals before dissolving values. There are exceptions, of course, but if it's at all possible, you're well off to do so. In this case, the talk of Al being present is not good. Aluminum, in solution, presents much the same problems that are encountered with tin. Filtration becomes difficult, often impossible. There are pretreatments that can eliminate the aluminum, which would have proven quite valuable for you. 



> It's going to be difficult to separate the AgCl from all the broken up wafer pieces I fear, but The Ag should be minimal, so if you all think there's 'not enough Au mixed in with the Ag, I may just sacrifice it to the chemical God's.



All depends on how much you'd like to learn about processing, and if you'd like to know how to recover the silver in such an occasion. Assuming you get serious about processing, the mess can be processed in a furnace, where you'd eliminate the unwanted non-metallic substances in the slag. It would also recover traces of values that would otherwise be discarded. End result is a button of metal that can be processed easier than mixed garbage 



> Can/should I use up the HNO3 with some pure Au, or with some scrap that's about 30% Au, and a mix of other metals?


What other metals? Do not lose site of the fact that base metals precipitate values by cementation. If you add the wrong material to gold chloride, you'll create a mess that is better not created. If you intend to use gold to consume unused nitric, insure that the gold is of good quality, for two reasons. One of them is to avoid adding yet more garbage to the mix, the other being so you can determine the yield of the given lot of material. Any gold that is added will report in the final weighing, so it's nice to know how much was added. 



> How long would it take one to evaporate 120ml HNO3 from the sol'n without heating it if they didn't?


That's akin to asking how big is a rock?

Evaporation is not an exact science. Temperature and surface area will play a huge role in how long it takes, plus if you follow the idea that if you go through a give exercise a given number of times, success is assured, you open yourself to disappointment. Eliminating the excess acid isn't all that easy, contrary to the opinion of some folks. Even when consuming by added gold, you must allow the solution ample time at a low heat, to consume the acid, plus you must insure you have an excess of HCl. 

Do keep in mind, if you evaporate too quickly, you will lose values to the vapors coming off. That's especially true if you have added metal present and it is actively consuming acid. Two ways to determine if you are running to hot. One of them is to put a cold watch glass on the vessel, and note the color of the condensate. If you see anything but a solution free of color, you are evaporating too quickly. The other method is to examine the vapors coming off, again, looking for traces of color. If you see the slightest discoloration, you are losing values. 



> Lastly, I'm all nervous I'll mess something up... Is there anything readily available I can get from a local that would act as Urea to eat up the nitric. remember, I don't care about final purity,


I'm the wrong person to talk about urea, or anything similar, assuming there is such a critter. I never used urea in all my years of refining. Didn't care to---having worked out a refining process that was to my satisfaction, and turning out gold of exceptional quality. That was good enough for me, and my customers. 

Do not fear losing your values. As long as you don't evaporate too quickly, or so long as you don't discard anything without testing first, even if you can't recover the values by conventional means, they are not lost. When push turns to shove, you can always cement the values using base metals, and start the process anew. 

Read Hoke. 

Harold


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## livinthedream (Apr 21, 2010)

> All depends on how much you'd like to learn about processing, and if you'd like to know how to recover the silver in such an occasion. Assuming you get serious about processing, the mess can be processed in a furnace, where you'd eliminate the unwanted non-metallic substances in the slag. It would also recover traces of values that would otherwise be discarded. End result is a button of metal that can be processed easier than mixed garbage



I guess it depends on how/whether I'll be able to find sources of material going into the future. For now, I just want to cash this in asap. A furnace would be a failry large investment for myself I suspect, but that would be really cool. No idea how much one would be. All I have now is torch that uses O2.

The Au Ihave is 4 9's. I guess I'll go t his route. I just wanted to make sure I'm not going to end up loosing any of that also because I have some strange chemistry in my sol'n. I'll weigh it first, and just put in excess. Would overnight generally be sufficient time?



> That's akin to asking how big is a rock?


 that's funny. True I guess. Hopefully my last question isn't in the same realm. the 4 9's I have is not a solid button (lots of small pieces (couple mm in size ea), and I have somewhere between a 3:1 and 4:1 ratio of HCl to nitric. 

Remember, this go around, I'm not concerned in having pure precipitate. I just want to make sure all the Au is in it. The buyer will melt it all down, determine the % of Au while molten, and buy based on this. He'll finish refining or whatever he wants to do with it. I'll be happy to drop all the Al, and everything else out as long as all the Au comes with it. I won't have created some type of Au salt that won't drop out using SO2 having done this, correct? 
Thanks again everyone!!


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## Harold_V (Apr 22, 2010)

livinthedream said:


> I guess it depends on how/whether I'll be able to find sources of material going into the future. For now, I just want to cash this in asap. A furnace would be a failry large investment for myself I suspect, but that would be really cool. No idea how much one would be. All I have now is torch that uses O2.


While the reduction can be done by torch, it's not the recommended practice. The flux required is rather aggressive, and the material should have a sufficient soak time for all of the metals to agglomerate. 

The majority of us build our own furnaces. It' not a tough job, but one should have need before attempting the project. It does cost a little if you intend to build one that will endure. Commercial refractory, to me, is a must. 

Given your circumstances, unless you intend to pursue further refining, it stands to reason that a furnace is not for you. 



> The Au Ihave is 4 9's. I guess I'll go t his route. I just wanted to make sure I'm not going to end up loosing any of that also because I have some strange chemistry in my sol'n. I'll weigh it first, and just put in excess.


There's a couple things that might be helpful here. The gold I added was always in a button form, so it could be recovered easily. If you use small bits, there's a small chance you won't recover all of them easily, especially if you have an abundance of nitric in solution. An ounce of nitric has the potential to dissolve a troy ounce of gold, so it should be clear that you may end up with a multitude of tiny bits, or you may even dissolve them totally and still need more. 

It is relatively common for a beginner to use way too much acid. The ramifications of excess acid don't sink in until you are the one called upon to expel the excess, plus it's hard for one without experience to identify a solution that is free of nitric. As the level diminishes, reaction becomes quite slow. That would be particularly true if you didn't heat your solution. 



> Would overnight generally be sufficient time?


I am unable to answer that question unless you heat your solution. If you do, and you don't have too much water present, the solution will react relatively quickly with any added gold, assuming you have free nitric. The best way to address this issue is to insert the gold and continue to heat the solution, covered with a watch glass. If there is nitric present, assuming you have free HCl, you will see the familiar brown fumes forming in the beaker, and bubbles will emanate from the bits of added gold. Once the addition of HCl makes no difference to the performance, you can then remove the watch glass and allow the solution to evaporate. It changes color as it condenses, although with the garbage included with your lot, the color would be hard to predict. I would suggest it would be something like a dark green. It's much easier to work with relatively pure solutions, so you might keep that in mind for future operations. Rule of thumb is to always remove all base metals before dissolving the values. It's not always possible. 



> Remember, this go around, I'm not concerned in having pure precipitate. I just want to make sure all the Au is in it. The buyer will melt it all down, determine the % of Au while molten, and buy based on this. He'll finish refining or whatever he wants to do with it. I'll be happy to drop all the Al, and everything else out as long as all the Au comes with it. I won't have created some type of Au salt that won't drop out using SO2 having done this, correct?


Most likely, that's correct. The real problem is that when you combine various elements, some of them are very troublesome when in solution. Tin, for example, or aluminum, make filtration very difficult. There are some simple procedures you can follow to minimize, or even eliminate, the problems, however. The other problem is the credibility of the buyer. If you open the door to suggestion that your gold is not of high quality, you can safely assume that it will be far worse than it is. GSP has a favorite saying. The refiner is the last liar. My personal experiences with major refiners is that he is correct. They are, in general, notoriously dishonest in their dealings with low volume customers. 

It is for good reason that you should study Hoke, and it is also for good reason that you should begin processing in small increments. The concept remains unchanged when you go to larger volumes, but the processing time is much shorter for small batches. That allows you to make the proper observations and to improve your procedures instead of finding yourself in a huge mess, with a lot of values tied up in something that may require cementation and a start from scratch. That, too, is part of your learning experience, but you are far better served to have such experiences in small dosages, so you don't get discouraged. 

Refining is one of the simplest functions you can learn. It is not necessarily reliant on skill, but more so on following strict guidelines. If you pay attention to commonly accepted practice and don't get creative until you have a firm understanding of refining techniques, you should be able to turn out quality that rivals industry. 

I understand your position with this lot of values, but for future application, shoot for higher quality. It's not only in your best interest, but you will build a far more respectable reputation with those that matter. 

Harold


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## butcher (Apr 22, 2010)

I just love reading this stuff. we are so lucky to have these people spend their valueble time giving, we are blessed and I hope they will be too.


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## livinthedream (Apr 23, 2010)

> I just love reading this stuff. we are so lucky to have these people spend their valueble time giving, we are blessed and I hope they will be too.


 AMEN!!
Thanks so much again. With the smaller volumes I'll likely be dealing with in the future, it'll likely be more interesting also to get as pure as possible. I've already got this money spent in my mind, so... The buyer seems pretty reputable, but I was realizing the other day that I'm at his mercy. What am I going to say, "No, there was more Au weight in there than that." try to prove it. Even if I know I added more pure Au than the "assay" says the weight percent of Au is, what am I going to do, other than say that. Anyway, here's to hoping for decency. I guess I can always walk but then I eat the refining fee.
I'm going to go add my "buttons" and see how this goes. I'm giong to let it sit overnight and heat it tomorrow while I can watch for the brown vapor (gas). I'll keep ya'll posted. Last somewhat off subject question, I assume I can melt the sponge using my O2 torch, but will there be much loss? I hope I'm not pushing your patience. Hopefully I can give back someday also.
-dreamer


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## Harold_V (Apr 24, 2010)

livinthedream said:


> I assume I can melt the sponge using my O2 torch, but will there be much loss?


That, again, is a matter of how well you work, and how clean the gold is. Dirty gold tends to be somewhat reactive, often sending off tiny sparks. Those sparks are tiny bits of your gold. If you melt in a (very) clean area, after melting a substantial amount of gold with a torch, you'll find the area covered with minuscule gold spheres. The dirtier the gold, the more you'll find. 

Gold is easily melted with an oxy/acet torch, but you have to use wisdom. Start with a soft flame, so it doesn't blow the fine gold powder out of the melting vessel (which should _*NOT*_ be a crucible. Torch melting with a crucible is a sure recipe for losing some of your values). 

Melt your gold in a small melting dish, which has been properly seasoned. As the surface of the gold begins to fuse, you can move closer with the torch, or even sharpen the flame. You can allow it to solidify in the dish, but you must remove it from the flux coated dish while it's still red hot. If it cools enough for the flux to solidify, it won't release. You can clean the small amount of flux that remains on the gold by a boil in dilute sulfuric, which will also somewhat improve the appearance of your gold. 

Given the procedure you're suggesting, I expect it won't be pretty. A little pride in workmanship, along with a few more steps, will have your gold looking like it came from someone that knows how to refine. That builds confidence in your buyer, and lowers his ability to be crooked. Most of them are. Been there, done that, got the T shirt. 

Harold


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## livinthedream (Apr 24, 2010)

well, I'm heating my sol'n now. I think it's much more pure than I had originally feared. After the VERY fine pieces of non Au settled, there's very little of it at the bottom of the beaker, and the sol'n is clear yellow. The stuff in the bottom is very light, and moves with the slightest giggle. I also noted when removing all the substrate material that the Al Ni alloy substrates I was afraid of were still intact. They didn't look like they were attacked at all. I'm more optimistic now going forward. I'll post in a few hours and let ya'll know how it goes. Once any free nitric is used up, considering I may now have a quite pure sol'n, what color can I expect? Also, I wasn't sure how far to boil down before I add the SMB.
Cheers!


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## Harold_V (Apr 25, 2010)

livinthedream said:


> well, I'm heating my sol'n now. I think it's much more pure than I had originally feared. After the VERY fine pieces of non Au settled, there's very little of it at the bottom of the beaker, and the sol'n is clear yellow. The stuff in the bottom is very light, and moves with the slightest giggle. I also noted when removing all the substrate material that the Al Ni alloy substrates I was afraid of were still intact. They didn't look like they were attacked at all.


That doesn't make a lot of sense. Are you sure they're metallic?



> considering I may now have a quite pure sol'n, what color can I expect?


The color of the solution just deepens. If it is yellow now, it will move towards orange as it is more an more concentrated, eventually turning red and progressing through a dark brown, depending on how far you take the evaporation process. Do note, however, that if you have iron in solution, it, too, will react (and look) much the same way. 



> Also, I wasn't sure how far to boil down before I add the SMB.


To insure that you don't get the cart before the horse, here, let me make one thing perfectly clear. BEFORE you attempt to recover your values, the last operation should be filtration. The solution should be filtered until it is free of flocculence, or any solid substances. It will have color, but otherwise should be perfectly clear. Anything less is a sign of contamination that will report in your gold. 

As far as how far to boil it down, only you can answer that. By adding gold to consume the unused nitric, assuming you have evaporated until the volume has been reduced, and the color is deeper, and there is no action on the remaining added gold, even after adding a small amount of fresh HCl, you can safely assume the nitric has been consumed. 

None of this should be performed by the clock. If you make assumptions that a given time interval is all it takes to accomplish the expected end, you will be wrong more often than you are right. You must learn to make observations, following the guidelines I have provided. As you become familiar with the behavior of your solutions, it will all make sense. 

Harold


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## livinthedream (Apr 25, 2010)

> That doesn't make a lot of sense. Are you sure they're metallic


Yes, it's a new patented alloy they're using in biomedical applications now. It's called Nitinal (Ni, Sn, Al, and others I believe. the "others" may not be metallic however?). Interesting stuff. It has a fairly low temp memory, so it can be "wadded up", inserted into the body, then it will unfold to the shape that it was "set" to. 



> You must learn to make observations, following the guidelines I have provided. As you become familiar with the behavior of your solutions, it will all make sense.


yes, it was veryintersting to see the material that was giving it slight cloudiness floculate and clear the sol'n upon heating. The material is now heavier, black and sitting at the bottom with the remaining unreacted Au. I added 40g and am now going to filter the floculant and left over Au and either evaporate further, or just go ahead and drop the Au that's in sol'n. 
I've already learned alot. 
I did obtain some Urea, so I think I may add a bit of this after I filer the sol'n just to be sure the nitric is used. I did add HCl and didn't notice further reaction, but since it's my first time, and I solidly fall into the category of amateur, I just feel safer going this route before adding SMB. Again, I'll keep yoiu posted. Thank you sir so much!. I'm completely geeked right now.


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## butcher (Apr 25, 2010)

how easily did it filter? tin and aluminum are hard to filter.
just a few prills of urea to warmed solution can be an indicator of nitric in solution, if nitric they fizz, 

if added gold was used to rid nitric at evaporation and reaction on gold stopped even hot in concentrated solution, raising temperature will boil off any remaining NOx gas as any remaining nitric has already reached its maximum azeotropic mix in concentrated solution, and the gold in this hot solution reacted with nitric removing it, if any remaining Nitric it will not stay in solution at higher temperature with fresh HCL.

newbies seem to use way too much nitric, and acid to start with.


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## livinthedream (Apr 25, 2010)

OK. It is SLOOOOW to filter. Should I keep the filtrate and put it in with the material I'm taking to the buyer? Could it be AgCl? There's only a couple grams of it. I'll probably put it in with the mix since the buyer's melting down and assaying anyway. The black flake is still draining. I collected the sol'n that the filtrate was floating around in in a second beaker once it got low, so I'll process it separate from the large amount. 
Once I add the Urea, and it's no longer fizzing, the nitric is out, and all that's left is to drop the Au with SMB, correct? I put a couple little balls of it in the main sol'n and it did fizz, so there is some left. Just want to make sure there's nothing additional I should be weary of since I deviated from the original plan. 
The reason I used SO much nitric/acid was because the volume of pieces I needed to strip. I've learned from this process however watering it down to the level I'd have needed would have been sufficient since heating keeps the AR quite reactive. I was also under the impression and told from people who have used AR that it's only active for like 30min. That's FALSE!!! I guess it's exothermic reactivity is maybe about that, but heat that stuff up, and off it goes. I'd imagine it would dissolve Au indefinately if you heated it. Anyway. Interesting.
Almost there! It's kind of like cleaning out the dredge or getting to the bottom of a pan. exciting to see what you finally have! Au fever


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## livinthedream (Apr 25, 2010)

Oh yeah, thanks Barren Realms for the advice on finding Urea. (if you're still following this post) I found some that was 28% (instead of 13) Urea and picked it out from that. not that I'll need the extra. It was like a 20# bag! enough for a lifetime it would appear.


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## Barren Realms 007 (Apr 25, 2010)

livinthedream said:


> Oh yeah, thanks Barren Realms for the advice on finding Urea. (if you're still following this post) I found some that was 28% (instead of 13) Urea and picked it out from that. not that I'll need the extra. It was like a 20# bag! enough for a lifetime it would appear.



Very good. Keep it in a dry area. Prefeably in a sealed plastic container.


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## livinthedream (Apr 25, 2010)

nice, you're online. I'm curious about the Urea reaction. Got a good link of quick line? Is it just reacting with the Nitric? It's no neutralizing the sol'n, ehh? Any idea what gas is evolved?
THX again!


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## g_axelsson (Apr 25, 2010)

livinthedream said:


> The material is now heavier, *black* and sitting at the bottom with the remaining unreacted Au.



Am I the only one that is troubled by that statement? To me it sounds like cemented gold on the "Nitinal" parts. Have you tested the filtered liquid? Maybe your gold is in the filter with the nitinal parts.

/Göran


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## butcher (Apr 25, 2010)

The slow filtering makes me think tin (or aluminum) in solution these will precipitate your gold in the filter and collect some of it there.
usually if these are in solution other base metals are too.

Urea (NH2)2CO notice the two amines, amines once were distilled from seaweed for boiler water treatment (they smell of ammonia), and the carbonyl compound (CO)

here is a formula for nitric acid and urea
6H + 6NO3 + 5 (NH2)2CO ----> 8N2 (gas) + 5CO2 (gas) + 13H2O (liquid)

so from this our gas is carbon dioxide and nitrogen , but I would think different ratios may produce other forms of these nitrogen and carbon gases and possibly hydrogen gas also.

Also Urea as a fertilizer may have a mixture of other crap I would not want in a solution of pure gold.

Butcher


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## chemist (Apr 25, 2010)

There is something missing from that equation.
What about he red cloud? When you add urea to poor man's AR, you evolve nitrogen oxides that are visible. I don't see them in your formula.


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## butcher (Apr 25, 2010)

read that again

here is a formula for nitric acid and urea
6H + 6NO3 + 5 (NH2)2CO ----> 8N2 (gas) + 5CO2 (gas) + 13H2O (liquid)

so from this our gas is carbon dioxide and nitrogen , but I would think different ratios may produce other forms of these nitrogen and carbon gases and possibly hydrogen gas also.


NO2 and NOx are different forms of nitrogen gases.

there is no way I could write all of the formula someone may get from a batch of poormans somebody mixed with base metals and who knows what.
heck someone could have a highly concentrated nitric and add urea and make the explosive urea-nitrate in solution for all I know.

most likely the metals and nitric was where the red gas came from.


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## livinthedream (Apr 26, 2010)

One more quick question. Will the yellow solution (orange really) go clear once all the Au is dropped out. I haen't had time to absorb the last 2 posts. Will write again when I get home. The stuff in the filter only weighs a couple grams. I know for a fact there's at least 36g Au in sol'n. The stuff in the first filter with all the Si wafers and Nitinal never had contact with the 40g I put in the current sol'n that I filtered the black stuff off of. All chemicals are reagent grade. gotta split now. I'll write back soon. Thanks to everyone.


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## livinthedream (Apr 26, 2010)

OK. I'm back. I've decided to slow down with getting this gold out since I have alot, and it's becoming painfully more obvious that just as everyone warned, the new guy tends to use too much acid. Looks like I'm holding par for the course. 
chemist, I noticed the brown NOx's during the metal dissolution, but with the addition of Urea, not much at this point, the gases were most definately white vapor/clear. 
I've set aside a small amount in a different container (mostly my rinse, etc.) and am testing on this first since I know I stand to mess up what to me is alot of $$ (6 kids and counting baby!! choo choo). I was more nervous last night since this sample amount took a goodly amount of Urea to stop reacting (by the way butcher, the Urea can be separated from the other stuff. you have to make sure you're getting the right fertilizer. It's certainly not reagent grade. I was hoping just a safety net) not only that, after it stopped fizzing, the sol'n seemed to be "carbonated" when I'd shake it (it'd fizz up again). normal? ehh. proceeded with SMB, again poor man's version (campden tablets) It takes alot more of these than I'd have thunk also. I wasn't happy with the cloudiness of the sol'n, and lack of dark precip. I noticed this am however the smaller bottle I was doing this in has essentially become "Au plated" up to the level of the sol'n (not like the sponge I've seem come out of different sol'n's I've worked with). I wish I had a way to know if I've precip'd all the Au (I don't have SnCl, can save the sol'n till I can obtain some I guess though). As stated earlier, I know I have to get at least 36g since that much dissolved using up excess nitric. Doesn't appear it was enough either. Arghh There it is. I"m not doing much more except separating Urea from sol'n till I know for sure what to do. Not sure I have enough pure Au to finish with original plan, and a little nervous to do so honestly. I totally trust the advice I've been getting, just don't trust myself.
Thanks!


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## butcher (Apr 27, 2010)

go to hardware store get solder 95% tin 5% antimony with HCl you can make stannous chloride to test for gold in solution.


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## Harold_V (Apr 27, 2010)

I'm having more than just a little trouble with not only you, but anyone that thinks they can refine without knowing where they are in the process. 

With all due respect to you, your situation, your family, and anything else that may be relevant, you should have never even thought of dissolving your values until you had a means of testing. 

My only advice, now, is for you to stop all this foolishness and get some stannous chloride, so you can make some determinations. 

Damn it, would any of us think of putting on blinders and then driving our cars? It's no different from refining blindly, although the consequences may not be as severe. 

If you can't afford to lose this batch of gold, it's all the more important for you to be able to test. Until you can, and do, you'll never know if you have all of your gold out of solution, or if it's safe to discard an unknown solution. 

Take a break, read Hoke, and get on the stannous chloride bandwagon. Only then can you be assured of what you're doing. You might also investigate the use of ferrous sulfate instead of SMB. It does an adequate (read that "good") job, and isn't expensive. It's all in Hoke. 

Harold


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## livinthedream (Apr 27, 2010)

hmmmm. Thanks butcher! I'll definately do this. 
Harold, I have nothing invested in this. It's pure profit. (with the exception of the pure Au (which I paid very little for long ago so it's not budget affecting)). I did say this is alot of $ to me, but I suspect it's alot of $ to all of us. I could afford to pay someone else to do this (which I still will in fact) but I find it interesting and exciting like prospecting. Let's not take this personal now. I'll try to not include personal sentiments in my posts I guess. I'm very appreciative for all the input you've provided. I've discarded nothing, so I'm not in a bad situation. 
I'm testing on a very small amount and it seems to be going fine. I'm always unsure the first time I do something (I would think most are). Ever get excited about something and just jump in? Sorry if I"m going on, but I have alot of respect and appreciation for you, so I'm hoping you'll see my side. I had decided last night before reading your post to just slow it down and find the time to read the material I need. really I think once I've concocted some SnCl, I'll be doing quite well. Well, off to the hardware store. I'll post after I test my test sol'n unless something goes wrong with the SnCl fabrication.
Thanks again!!


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## livinthedream (Apr 27, 2010)

I'm getting more and more turned on to the idea of SO2 for precipiration now. I've seen some info on creating a generator, but don't quite have the complete mental picture yet. I have plenty of S left over from the pyrotechnic days, so good there. a fouintain pump and a bucket, so I think I'm close. 
I tested my small test batch with the SnCl2 I made today, and got a black indication. gotta find more info about that. Read Chumbawumba and laser steve's threads so far. SnCl2 seems fine.


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## Noxx (Apr 27, 2010)

Trust me, SO2 precipitation is pure joy.


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## Harold_V (Apr 28, 2010)

Noxx said:


> Trust me, SO2 precipitation is pure joy.


It served me perfectly well for almost my entire refining career. As long as one can obtain it in a cylinder, I recommend it highly. Don't know how I'd feel about making my own, however. If you haven't lived in an environment where you are subjected to SO2 (I was---I was raised in a smelter town, long before it was not acceptable to discharge SO2 to the atmosphere), you may not understand what you're asking for. 

I used ferrous sulfate in the beginning, but preferred the convenience of simply turning a valve. I had my SO2 plumbed directly to my fume hood, so I was never exposed. Wouldn't have it any other way, not after having lived with the damned stuff for years, as a child. 

I would still recommend ferrous sulfate for the guy that has an irregular need. It's quite convenient, and easy to use. 

Harold


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## Harold_V (Apr 28, 2010)

livinthedream said:


> Harold, I have nothing invested in this. It's pure profit. (with the exception of the pure Au (which I paid very little for long ago so it's not budget affecting)). I did say this is alot of $ to me, but I suspect it's alot of $ to all of us. I could afford to pay someone else to do this (which I still will in fact) but I find it interesting and exciting like prospecting. Let's not take this personal now. snip balance of good stuff


I fully understand being excited over the prospects of recovering, and even refining the values. I, too, started without knowledge at some point in time, and was every bit as excited as you appear to be. That I understand. Not testing I do not. 

The point I'm trying to stress is that unless you know where you are with the operation, you have no idea what is required. Testing answers those questions. Further, in order for anyone to give you viable guidance, they, too, must know what your tests reveal. 

We have a reader on the board that sees absolutely nothing wrong with running without testing. She has openly said so. She does not consider that running blindly. I know it does. She is also the person that has a huge inventory of solutions, about which she knows exactly nothing. She has no clue if they should be processed for disposal, or if they contain further values. No clue, and apparently is content to operate that way. All I can conclude is that it's different strokes. That would not suit me under any condition. 

No testing capability? No problem, so long as you don't rely on input from someone that may know how to proceed. You expect help? Then you must be willing to meet, half way, those of us that offer assistance. You do that by learning how to test. 

I can't stress testing enough. No one should even think about dissolving values until they have the necessary testing capability. Thing is---it's not expensive, nor difficult. There's no excuse for not having the ability. 

Read Hoke. 

Harold


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## lazersteve (Apr 28, 2010)

livinthedream said:


> I'm getting more and more turned on to the idea of SO2 for precipiration now. I've seen some info on creating a generator, but don't quite have the complete mental picture yet.



The sulfurous acid document on my website demonstrates making SO2 with SMB powder and a few pieces of glassware.

Steve


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## livinthedream (Apr 28, 2010)

Great thanks. I'll check it out. I had a little lecture bottle of SO2 at one point we were going to use for testing different solutions effectiveness of capturing stable sulfur isotopes. We were isolating the sulfur isotopes from rocks and obtain signatures using MS. These were then used to help interpret the paleoclimate during rock/mineral formation. Throw in some stable C and O isotopes, and it was pretty amazing the amount of information you could get from some rocks. continental drift, precipitation amounts, type of ecosystem/vegetation, etc. Anyway, where was I going with that. wish I still had that lecture bottle. never got around to that project. may still be sitting in the fumehood. Oh yes, I do remember bubbling it through some of the sol'n's and preciping Barite, PbS, ZnS, etc. If the Au comes out like that stuff did, I totally understand the pure joy comment. First time I ever saw how reactive a gas actually is with a liquid. We weren't even using an aerator, just bubbling it out of the end of a tube, and man did it go. 
I hear you Harold, and see your point. I respect that. I'm learning first hand about testing right now. (maybe a little late, but better then than never) 
I did test my little bottle I have that I put a bit or urea in (about 30ml or mostly rinse). I thought I put in excess SMB (campden tablets actually. much rather know I'm working with pure. package doesn't say). Au definately dropped, and the sol'n left over is a bit milky I assumed from excess SMB. I tested with SnCl2, but didn't see any comparable color to steve's posts. It was black (I mixed a couple drops of the sol'n with a couple drops SnCl2. then diluted to see if it was just REALLY dark purple). I see purple is the indicator, but couldn't find in any threads what color it should be if negative. I've been assuming there'd be no color change if negative. Hopefully having some base metals in my sol'n isn't going to make SnCl2 testing impossible. So, going back, I know what the maximum thickness of could have been for these films of Au on my stock material, and based on the average etch rate at said temp, I'm confident I got all the values off the stock. Since I did the AR etch "cold", this could be the reason also the nitinal substrates were still intact. It is a strange alloy, but I remember Harold thinking it odd a metal substrate was still there. I guess this could be a method for minimizing base metal dissolution of you know how thick your film of values is. (assuming your substrates are all open to the AR (not stacked, etc.))
well, this post is getting too darn long. I'm going to check out what Hoke says about SnCL2 in the meantime and Steve's site about SO2.
Cheers!


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## Harold_V (Apr 29, 2010)

livinthedream said:


> Oh yes, I do remember bubbling it through some of the sol'n's and preciping Barite, PbS, ZnS, etc. If the Au comes out like that stuff did, I totally understand the pure joy comment. First time I ever saw how reactive a gas actually is with a liquid. We weren't even using an aerator, just bubbling it out of the end of a tube, and man did it go.


I used SO2 for years, exactly as you suggested. Not so much as a pressure regulator. A valve to regulate flow, and a 3/8" pyrex tube, fire polished on the ends. I'd place the tube within a half inch of the bottom of the cylinder or beaker, and turn on the SO2. Regulated properly, the flow comes as individual bubbles which are totally absorbed by the solution before they rise to the top. It wasn't uncommon for the solution to absorb the gas with little action, then for the entire volume to flash, looking very much like bronze paint. 

In all my years of refining, I never got tired of watching gold precipitate. It is, truly, the magic moment of refining. 

Harold


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## livinthedream (Apr 29, 2010)

> In all my years of refining, I never got tired of watching gold precipitate. It is, truly, the magic moment of refining


.
NICE!!
OK. I checked out Steve's site and was wondering if anyone's ever done this. My question is whether one could just bubble directly into the AR. The idea for using the train is to catch an acid that may make it through as vapor, but would a little H2SO4 in your AR solution mess it up? 
On a second note, after testing my little batch with SnCl2 and getting the instant black result, I was took it as a positive and dumped a bunch of SMB in. I noticed last night that the sol'n wasn't cloudy anymore, and there was a very significant amount of precipitate in the boottom. The precip was black, with some gold coloration mixed in becaue the precip when I swirled the bottle pulled off the "plating" on the inside of the bottle I had mentioned earlier. Curious what people think. I didn't have time to test last night, so I will tonight to see if I get a negative in the remaining sol'n. I'm going to Hoke now, if she doesn't mention what a negative shoiuld look like, I'd appreciate it if someone can let me know. I suspect she will. no big deal. I'm just messing around with this little amount of rinse while I learn cause I gotta do something ;-)


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## Harold_V (Apr 30, 2010)

livinthedream said:


> > In all my years of refining, I never got tired of watching gold precipitate. It is, truly, the magic moment of refining
> 
> 
> .
> ...


Depending on what you may have in solution, it's hard to say what you'd expect, but if you have nothing present but gold, and all of it has been precipitated, the reaction will be nothing. Nothing at all. The solution being tested doesn't respond, aside from being diluted by the stannous chloride. Any color change is generally an indication of values present. Which ones can be difficult to determine until you are very familiar with the reactions. You do that by making standard solutions and testing them until you are familiar with their appearances. 

When you introduce stannous chloride to gold chloride, I believe the reaction you see is colloidal gold being precipitated. With platinum, the reaction can be anywhere from a light orange color though dark brown. Some here say they don't see the brown reaction, but that is, in my opinion, because they have little platinum in solution. When you have a few ounces dissolved, it behaves differently, just as gold does. 

I am not familiar with anything else aside from palladium. It is the chameleon in the lab. It can manifest itself in several ways, likely due to the strength and age of the stannous chloride, to say nothing of the level of concentration of the solution. I have experienced palladium tests that were easily confused with gold, although only gold will leave behind a purple stain in the spot plate cavity. You can expect reactions from brown through blue and green with palladium, with reactions made even more confusing when you have a mixture of platinum, palladium and gold. Common for refining wastes from the jeweler's bench, or when processing dental alloys. Best scenario in such a case is to test multiple ways, including using a crystal of ferrous sulfate, to eliminate gold, then to test the remaining solution with stannous chloride. You can also use DMG (dimethylglyoxime) to test for palladium. It responds with a deep canary yellow precipitate, and is also useful in testing for the presence of nickel. It's all in Hoke.

Harold


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## livinthedream (May 1, 2010)

great. Yep, I"ve been reading alot of HOke lately. good stuff. I've been successful at dropping my gold. The ScCl2 tested negative just as you described. I think the original test was such a dark purple it looked black. I just put a ton of SMB in after I saw that, and in the morning, I had ALOT of dark precip at the bottom. I tested the sol'n and not really a reaction. tHERE was a very slight orange which settled relatively quickly. Not unlikely it's seeing Pt or Pd since both are not uncommon adhesion layers under the Au. I filtered, dried and weighed the beautiful bronze precip from the Sol'n (had some flakes of gold also since the "plating" from earlier was rubbed off the sides of the bottle when I swirled the precip still in sol'n). It's pretty rich. I've got over 2g in that 15-20ml. Over a liter left to process!!!! This has been really fun for me. Unfortunately, I've been accumulating these choice wafers that were just being thrown out for years now, so it'll be a while before I can accumulate enough to bother with again. I've enjoyed it so much however, I''m going to see what I can do about finding other sources. I'd actually love to be able to do this for a living. I have alot of black sand cons I may try to process. There's no visible Au left in it, but I read somewhere there can still be Au present in combination with the black minerals. May just be something else fun to experiment with anyway. Any tips on finding sources of material would be great. There's a local dentist in the little town I'm in I thought I'd talk to at least to begin with. You guys have been great. 
Harold, I especially appreciate yourhelp. If there's anything I can do to help you out, let me know. I've got a propane O2 torch, and Hoke gives me the impression I can melt the Au with it, so I'll be sure to get a pic for everyone at least. More to come. You guys and this site are amazing!!
Cheers!!


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## livinthedream (May 1, 2010)

forgot to ask, does Hoke discuss the use of SMB to drop the gold. I've only read about her using copperas, which I'd rather now. Ideally, I'll use SO2, but since the SMB worked on my small rinse test, "if it ain't broke...." I know, not a very good phrase since I do want to learn more methods, but for now a good reference on SMB (maybe particularly even campden tablets) would be great.
I guess specifically, Hoke mentions if the excess nitric hasn't been removed, the copperas will do this, you just have to add more. Will SMB tablets do the same thing?


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## Harold_V (May 1, 2010)

livinthedream said:


> I filtered, dried and weighed the beautiful bronze precip from the Sol'n


That's good for the moment, but your precipitated gold should be washed. That's true even if the resulting barren solution is colorless. Amazing things are removed by the (proper) washing process. 



> I'd actually love to be able to do this for a living.


My hobby evolved to just that. It was so successful that I had to close the doors on my commercial machine shop. It can be done, but it happens on it's own schedule. 
I might also add, my success came at a time when there was little control on chemicals. I could purchase my needs through my machine shop, with prices that were very reasonable. A 55 gallon drum of HCl cost but $57 back then, and a 55 gallon drum of nitric cost $207. It is much more difficult, today, to make something like this work. That's not to discourage you, but to keep your thinking on an even plane. 

The best advice I can offer anyone where refining is concerned is to get established with manufacturing jewelers. They have a constant need for refining, and produce the second best possible scrap on the market, the dental trade being the best. 

By making connections with jewelers, you not only create sources of material to refine, but an outlet for pure gold. These people generally pay over spot for pure, so you can offer your refined goods for spot, or even slightly higher, which will be to their, and your, advantage. You will come to understand that selling gold for spot is not easy, but is made much easier when you become recognized as a competent refiner. 



> I have alot of black sand cons I may try to process. There's no visible Au left in it, but I read somewhere there can still be Au present in combination with the black minerals. May just be something else fun to experiment with anyway.


If nothing else, it will help you understand why black sands are not generally accepted for processing. I expect you'll be wasting your time, but you will gain knowledge, and that comes with a price, so it's worth your time to investigate. 



> There's a local dentist in the little town I'm in I thought I'd talk to at least to begin with.


The advantage of dental wastes is that they are (or used to be) of much higher quality. They also contain platinum and palladium, so the overall value is much greater than typical jewelry. The problem is, gold is no longer used as it once was, so it is likely not a great source. Still, old dental work is replaced as it wears out, so the old material is still out there. It comprised a small percentage of the refining I did when I was active, often provided by jewelry manufacturers (bench men) who took it in in trade. 



> Harold, I especially appreciate yourhelp.


Welcome. I hope I have been of some assistance. As you discovered, I have little patience for those that don't pursue refining with some structure. There are no shortcuts, and if you gloss over the operations, it is unreasonable to expect acceptable results. I have all the patience in the world for someone that is trying, following acceptable procedures, but run short in a hurry with those that ignore proper procedures and look for instant gratification. Refining can be very rewarding, but you must do your part in order to achieve success. I believe you see that now. 



> I've got a propane O2 torch, and Hoke gives me the impression I can melt the Au with it, so I'll be sure to get a pic for everyone at least.


With O2, it will work. It's a tough call without, however. 



> More to come.


Good! I'll be looking forward to your posts and pictures of your success.

Luck!

Harold


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## Platinum (May 2, 2010)

Harold_V said:


> It has everything to do with how you're refining.
> 
> There are NO shortcuts. If you want pure gold, you MUST follow accepted practice. Remember, those that went before us have gone through this time and again----and have perfected a process that will yield good quality------so if you're interested in achieving that level, follow instructions that are at your disposal. Don't experiment-----leave that for others with time on their hands that are content to re-invent the wheel. This is particularly important for you, considering you're trying to establish a refining service.
> 
> ...


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## livinthedream (May 2, 2010)

WOW, more. working on the HCL wash right now. I found some yellow bits in my filtrate that tested positive for Au. I may not have rinsed the little bit I had REALLY well, but it was VERY positive. Any ideas what this might be? It looks just like S that's been melted. There's not a lot of it, but... Seems to either be H2O soluble or really easy to break up into small enough particles to seem dissolved in the H2O.


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