# Proper mixture of various precipitants



## eaglewings35 (Sep 5, 2013)

Guys, I have been on this forum for a couple of years now, and I have probably made the same mistakes that MANY of yall have.
Most notable was my first "Crockpot Brick". I never did get that thing to break back down. It was as solid as a Brick.
Anyway, after that experience I decided to Stop wasting time and money on acids, and take my time and read-and re-read the posts on this forum, and Hokes book. I will say that, yes Hokes book was an easy read, but as far as my understanding it, not so much. I have been told that I have a "Thick skull", 
and now I DO agree. All that being said......
The information contained in this forum is so much help, except for some of us you really have to help with instructions and ratios because the answers are scattered through out this site, and it takes a month of Sundays to find it all.

For instance......
I want to use SMB as a precipitant to drop my gold on the first round.

I want to use Oxalic on the second drop, to get any impurities out that may have gotten by the SMB.
But, I don't find anywhere on this forum where it is told, how much to mix with water or acid?

I have read that Oxalic does really well at purifying if used as the 2nd drop, not the first.

So if any of yall alchemist, chemistry teacher, or scientist can way in on this and post the proper mixing instructions, we lay persons would surely appreciate the help.


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## rusty (Sep 6, 2013)

Use SMB sparingly, test with stannous after each addition. Dry and weigh up your precipitated gold powder to calculate the amount of oxalic acid required.


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## yar (Sep 6, 2013)

When using SMB what I have read and learned is that it should be 1 gram of SMB per 1 gram of gold you have in solution. I have not mixed it in H2O prior to using and have not had any problems. Have not used Oxalic yet but plan to give it a try in the future. All this is information is right here. If I, a person that is horrible on a computer can find it, so can you.


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## bswartzwelder (Sep 6, 2013)

Was going to post on SMB, but was beaten to it. It was a really quick search. It is my understanding that it takes from 1.1 to 1.2 grams of SMB for every gram of metal in your solution (not just the gold). As I recall, it take even more Oxalic acid per gram of gold to precipitate your gold. These questions have been answered before and that's why you get so many hits when you use the search function. 

Sit back with your favorite snack and/or beverage and prepare to do some reading. It's all there. 

Also, when using SMB, you can use it dry, or mix it with water. It seems to be a matter of preference. One thing to think about, if SMB is premixed with water, it could add a considerable amount of volume to the solution you're precipitating from. To be a respected and responsible refiner, your solutions will need to be treated before disposal. While adding a little water may not sound like much, in the end, it may need to be evaporated down, or at the least, treated to remove toxic chemicals and heavy metals. Always test solutions before discarding. Remember, at one time, they held your PM's.


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## yar (Sep 6, 2013)

I use SMB dry because I expand, hope this is correct terminology, my AuCl to 3 times it volume with distilled water before dropping. So not having to add more water will mean less waste to properly dispose of later after testing with stannous.


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## eaglewings35 (Sep 6, 2013)

Thanks folks for the info. Yes, I have used SMB before, but NOT Oxalic Acid.
I was wanting other people to add to the list of precipitants and share how they mixed it up.
I was hoping that this would be a good place for simple people like myself to come and see the process, and decide which method they wanted to use.
But, I guess I figured wrong.


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## yar (Sep 6, 2013)

I can assure you that all you need to find is here on the forum. Videos, pictures, measurements..etc. I am surprised that since you have been here since 2010 you don't know that by now. No one is going to give you what you are looking for without you showing you have done some work on your own. 

There is a thread here that was posted by Harold V recentley concerning people that think they are entitled to have their questions answered without doing any work on their own. It sounds like you fall into that category and if you read the responses above you should be able to figure out how and where to find the answer to your question.


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## Geo (Sep 6, 2013)

oxalic acid is cheap in my opinion (cheaper than SMB) and trying to estimate to the fraction of a gram is a waste of time. the question should be "is there way to add TOO much oxalic acid for X amount of gold" . many processes will react the same way with an excess of certain chemicals than it would with just the right amount. keeping good notes is important and some people have to have a reference every time they perform a process even if they have done it before and i understand that. i just think that unless its absolutely necessary, measuring to a fraction of a gram complicates an already complicated process.


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## eaglewings35 (Sep 6, 2013)

Geo said:


> oxalic acid is cheap in my opinion (cheaper than SMB) and trying to estimate to the fraction of a gram is a waste of time. the question should be "is there way to add TOO much oxalic acid for X amount of gold" . many processes will react the same way with an excess of certain chemicals than it would with just the right amount. keeping good notes is important and some people have to have a reference every time they perform a process even if they have done it before and i understand that. i just think that unless its absolutely necessary, measuring to a fraction of a gram complicates an already complicated process.



Thanks Geo, I appreciate the KIND words. I don't like to put anyone down, but it is obvious that others were not raised that way.
Any yes, others experiences can give you a greater understanding of the process. I have had a stroke, and therefore my mind now is unable
to stay focused, especially when "searching for a needle in a haystack". The info here, and most of the people here, are really great and would lend
a helping hand, while other love to say "Search for it" The information contained in this forum is sooooo spread out, and interrupted by idle chatter
that it makes it hard sometimes to know when you are in the right place.
Please don't get me wrong, I understand that is how you get to know people, and that is the way everyone (including me) does it.
Just saying it is hard to focus when you are reading on a subject and suddenly the topic shifts to something wwwaaaaayyyy of topic.
And more times than I can count, the topic ends with the subject incomplete.

That is why I posted what I did. Because I want to know the correct way to use Oxalic Acid, before I kill my self by suffocation or blast !!!!


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## butcher (Sep 6, 2013)

I have not had a stroke Yet, but the same thing happens to me, I begin looking for an answer to a question and I end up with ten other questions, and about five other things to study, many times my search leads me to all kinds of new information, and in several different directions of study, and many times I forgot what my original question was...

Some of your problem can be from not being good at using the search function (practice make you better), I know there has been a lot of discussion on using the oxalic acid / ammonia to adjust pH, I believe it was Kadriver that had a very good topic and thread on this topic, although my memory is bad it could have been another member. anyway searching for their posts can give you better details than I can.

Oxalic acid (formulas I have seen for it) COOH2 or CO(OH)2 
A toxic white powder, sold as wood bleach, radiator cleaner, or rust remover, (supply one hardware store paint dept).

Usually used for high purity gold, as in a second refining.

Use about the same weight as the weight of gold, (slight excess of reagent).

Aqua regia needs de-noxxed.

In one vessel the oxalic acid dissolved in water, and ammonia added (adjust pH to about 5) no smell of ammonia, this solution is brought to a boil.

The de -noxxed and filtered gold chloride solution is also brought to just below a boil in a separate vessel. 

The gold chloride solution is poured into the oxalic acid solution.

The precipitating of gold should occur fairly quickly.

The solution tested for values.

The gold washed per Harold's instructions (getting your gold pure and shiny found in the help needed section.

3COOH2 (aq) + 2HAuCl4 (aq) --> 2Au (s) + 6CO2 (g) + 8HCl (aq).

Again other members may have much better details, so searching for their answers can only help you when you do try this.


eaglewings35, 
Writing your question down in a note book, and then making notes of the answers you find to your question, can help to keep track of the questions and the answers, my memory is so bad I have to keep notes on most everything.


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## eaglewings35 (Sep 6, 2013)

Thanks Butcher, You have been a BIG help. And No, I will not give up the searching of the forum. It sounds like you and I have pretty much the same problem memory wise, CRS disease (Cant Remember S**t)
Yes, that is the most frustrating thing as to be searching for something specific, then find the answers to something else, and by now you cant remember
what you were looking for to start with. And, I do make notes, but even in my notes I cant find things. (Never was a good note taker in school).
But, this time I am doing things differently...... When I find something that I am needing to know, I print it off and write on my paper
what it is about. Then my search resumes.

Thank you for the kind words, and help !!!


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## yar (Sep 7, 2013)

Congratulations you got what you asked for without doing any work. Amazing the double standard that goes on around here sometimes. I read everyday, put in the work, follow the advice given to study, study, study and read some more. Use the search bar, as confusing as that is most times, try to avoid asking questions that have been asked hundreds of times and yet your question which is easy to find the answer to gets answered quickly. 

I sit here and worry about getting taken apart for asking something stupid and waste time looking for answers, maybe if I stay on for a year or so, pretend that I have studied and read and understand Hoke then I can ask what I want.
Sorry for the rant but you have to admit anyone new reading this has got to be saying the same thing I am.

I am a grown man and take responsibility for what I write and do so if this gets me in trouble so be it, but the way the above was handled was wrong and a slap in the face to everyone else that tries to follow the way to do things here.


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## Geo (Sep 7, 2013)

no one should be afraid to ask questions. this is after all a forum. most questions do get an answer, its just sometimes the answer is not what we expect. there cant be a blanket policy to not answer questions because if it were, this wouldn't be much of a forum. keep in mind that no one here is required to give answers of any kind and any answer you get to a question should be considered a gift and treated as such even if its an admonition to study on the subject. the gift of receiving an answer to a question should always be given a thank you even if its something you dont want to hear. answers are given by members of their own free will and if no one wants to answer your question, then so be it. that doesnt mean to become hardened by the experience but to try a different approach or a different angle or to phrase the question in a way that people will want to answer.


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## yar (Sep 7, 2013)

To the OP...I was raised just fine thank you. It is you who feels you are entitled to something because of a physical ailment. I have an 11 year old daughter who did not walk till she was 4 and is severely handicapped to this day. She has not once used her disability to gain sympathy or favor with anyone, unlike yourself.


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## niteliteone (Sep 7, 2013)

Looks like someone is having trouble understanding the difference between a worthy question and the stupid questions of a newbie.
The OP asked a worthy question that the answers would have benefited ALL who find this thread, but jealousy seems to be a problem being suffered by the detractors of this knowledge. :shock:


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## butcher (Sep 7, 2013)

How many threads like this one do we have to read to find an answer?
Instead of asking so many questions.
Instead of just harping on members to study.
...
We could all be sharing information, and writing threads that can help us and others learn.

I will help anyone, even new members where I can, sometimes, the best advice I can give them is to begin by reading Hokes, other times providing a little of what I have learned and try to point them in a better direction to learn more.

This thread started out as a topic of " Proper mixture of various precipitants" I would like to see members discuss various precipitants, in this thread, so when we search for answers, and come upon this thread it will actually contain something of content and helpful information, not just another thread just full of yada yada we have to read through to find our answer, or even something meaningful...

Yar, I ask you to help us to make this thread and forum what it was intended a place to learn, and share information, can you help to discuss a precipitant for precious metals.

A few chemical or metal precipitants we could discuss:
SO2 gas and how to make it.
Copperas and how to make it.
Ammonium chloride How to make it.
Oxalic acid and how to use it.
Sodium metabisulfite.
Sulfurous acid.
Sodium bisulfite
Hydrazine
Ammonium hydroxide
Copper I chloride
Formic acid
HCl or NaCl
Sodium chlorate
Butyl diglyme
Dibutyl carbitol
Dimethyl gloxime DMG
Copper, zinc, iron, aluminum.
Any others you can think of or wish to discuss.




eaglewings35, I also expect that you will further your study on using Oxalic acid, and other precipitants, Taking notes, and doing the best you can, I know the more you work the better you will recover from the stroke.


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## pgms4me (Sep 7, 2013)

niteliteone said:


> Looks like someone is having trouble understanding the difference between a worthy question and the stupid questions of a newbie.
> The OP asked a worthy question that the answers would have benefited ALL who find this thread, but jealousy seems to be a problem being suffered by the detractors of this knowledge. :shock:



Thanks Butcher for taking the time to post on this query, your simplified list on using oxalic acid is straightforward and helpful. a couple of things you mentioned confirmed what i needed to know. I Couldnt find the answers before when I looked, and it wasn't on my urgency to do list, so I had it in my notes to complete the search at a future time. Now I am all set. Thanks also to the OP for your question.


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## butcher (Sep 7, 2013)

How we can make sodium metabisulfite

we can generate SO2 gas (sulfur dioxide gas), well if we done this we would probably just use it to precipitate our gold and forget the SMB :lol: 



sodium metabisulfite Na2S2O5 can be made by bubbling SO2 gas into a solution of sodium bisulfite Na2SO3, while evaporating solution.


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## moose7802 (Sep 7, 2013)

I am new to this forum as well as the whole gold refining process and I have to say that i agree with yar though I'm not upset that the OP got the answer to your question. I am afraid to ask any question on here, thankfully I saw one of Geo's videos on youtube before I joined this forum and he answered a few of my questions on there. Since joining this forum i have spent 90% of my time reading on here. The one thing I do not understand is why I can type in the search bar "how to precipitate gold" and get nothing yet read on here that theres 558 posts on it. Why is this? I will post a picture of my first button from a few small batches of 100 grams of trimmed fingers, 50 grams of cpu pins, 26 MMX black fibers, 5 ceramic pentiums, and 6 AMD k6's. So far everything has gone well, I do feel as though I have probably lost a little bit in my filtering process. I have a lot of filters with multiple types of trash filtered out and some with fine gold flakes. I will definitely read up more on what to do with all of my filters before trying to process them!! Thanks for all the great info on here.its been a huge help. I have a nice little batch of powder i am collecting to wash once Im done with all of my First ever processes. A special thanks to Geo for taking the time to answer my questions! Cant wait to post the picture of my first button!!!


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## niteliteone (Sep 7, 2013)

butcher said:


> How we can make sodium metabisulfite
> 
> we can generate SO2 gas (sulfur dioxide gas), well if we done this we would probably just use it to precipitate our gold and forget the SMB :lol:
> 
> ...


If I made SO2 gas I wouldn't waste it making SMB, I would bubble it through my Auric Chloride directly to precipitate my gold. 8)


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## Geo (Sep 7, 2013)

moose7802 said:


> I am new to this forum as well as the whole gold refining process and I have to say that i agree with yar though I'm not upset that the OP got the answer to your question. I am afraid to ask any question on here, thankfully I saw one of Geo's videos on youtube before I joined this forum and he answered a few of my questions on there. Since joining this forum i have spent 90% of my time reading on here. The one thing I do not understand is why I can type in the search bar "how to precipitate gold" and get nothing yet read on here that theres 558 posts on it. Why is this?



actually, its more like 4,520. :lol: use the search bar at the top of the page. the one that goes all the way across and has Google™ custom search. i copied and pasted (how to precipitate gold) and it pulled up that many topics.


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## Harold_V (Sep 8, 2013)

moose7802 said:


> I am afraid to ask any question on here,


For that you can thank the countless number of individuals who come here with the thought in mind of becoming a refiner of precious metals in fifteen easy minutes, without lifting a hand. These individuals don't seem to understand that this isn't something you learn quickly, nor do they understand that the information is here for the taking---_*if they'll do their part.*_ Some of them refuse. They want to be spoon fed. That's not going to happen. I've put my foot down and will now just ban these guys instead of plead with them to start by reading Hoke's book and the forum, so they become familiar with terminology and processes that are commonly accepted as useful. 

Having said that, if you've doing what is expected, and you have questions, post them. We're more than willing to talk with folks who are trying, but do that *only after you have a basic understanding, so the replies will have meaning to you,* not simply answer the questions you'd have because you've done nothing. 

We are about refiners helping refiners. We are NOT about refiners helping deadbeats. 

In regards to "how to precipitate gold"---Hoke discusses that issue at great length. Perhaps you can see why I keep telling readers to* read Hoke*?

Harold


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## eaglewings35 (Sep 8, 2013)

butcher said:


> How many threads like this one do we have to read to find an answer?
> Instead of asking so many questions.
> Instead of just harping on members to study.
> ...
> ...


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## yar (Sep 8, 2013)

Try typing Oxalic acid precipitation in the search box. Its all right there. I will step aside Eagle and watch what pearls of wisdom you bestow on the rest of us. I am content to read and learn and use the search box properly. Any questions I have i am willing to search for the answers myself. 
Goodbye
One more thing for those that are interested go back and read some of the op's old posts. All questions and how do I do this and mix that. And the sympathy card was played once before my friend. If I remember correctly it was around oct 9 2010 when you were trying to get someone to buy some computers. And how did the "blue clay" work out for you? Bet you couldn't get anyone here to buy that either!


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## Geo (Sep 8, 2013)

yar, im going to give you some advice, drop this now before it comes to the attention of the moderators. personal attacks are not permitted on the board. if you have a problem with the way things works here, you should take it up with a moderator and not on the public board. in my time here, ive seen more than one charity drive on the forum for members that was having a hard time so that is nothing new. if one member receives more than you (in your opinion), should be angry with that member? i would think that most members would be happy that another member is receiving extra help or attention instead of taking it personally. 

in my opinion, you are coming very close to breaking one of our most important rules by personally attacking another member.


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## rusty (Sep 8, 2013)

yar said:


> Try typing Oxalic acid precipitation in the search box. Its all right there. I will step aside Eagle and watch what pearls of wisdom you bestow on the rest of us. I am content to read and learn and use the search box properly. Any questions I have i am willing to search for the answers myself.
> Goodbye
> One more thing for those that are interested go back and read some of the op's old posts. All questions and how do I do this and mix that. And the sympathy card was played once before my friend. If I remember correctly it was around oct 9 2010 when you were trying to get someone to buy some computers. And how did the "blue clay" work out for you? Bet you couldn't get anyone here to buy that either!



I did just that, out of curiosity went and read some of the OP's previous posts, rings the same bell.

In my humble opinion it would be well advised that this member use the search button more often plus re-read Hokes book until it starts to make sense. I spent a lot of my own personal time making that book available to our members and find it very discouraging that most will not take the time to crack open the pages.


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## butcher (Sep 8, 2013)

I agree with all sides in this discussion :lol: 

Read more and ask less stupid questions.

Seek and search and ye shall find.

You cannot learn by asking a few thousand questions, it only leads to more questions and answers you would not understand anyway.

Help your fellow member.

Read Hoke's.

I do search, and spend my free time studying; I also try and spend time contributing to the forum and helping others, from what I learn from my study, and from others.
Many times that help comes by telling the person asking the question to study.


Well let’s see if I can add a little more to this topic.

Here I will do a couple of search’s for information on oxalic acid, I will not spend much time looking for the information, and will use tools available like the forum search, and my computer search engine like goggle.

Several of our members have made some very nice videos

These are also good tools, to go along with your study, seeing it action can also help to understand better what You have been reading about, or what people have discussed although the video will not replace study, because without study you would not understand many of the very important minor details which the video most likely will not go into, or discuss, so without spending your time studying, you most likely would not be able to produce the results seen in the video, and without study the video although very interesting would be of little help.

Goggle search of video:
http://www.youtube.com/results?search_query=Oxalic+acid+gold&oq=Oxalic+acid+gold&gs_l=youtube.3...0.0.0.16982.0.0.0.0.0.0.0.0..0.0...0.0...1ac..11.youtube.

The forum has links to many very good video’s made by our members, reading their threads, and checking out their web sites you can learn from these fine members, who have spent time studying and sharing with others what they have learned.

Just asking these members to repeat information they have shared, will most likely not help you get started, you would not understand what you needed in the discussion, they would most likely just tell you to go and read Hokes book and study the forum, and the safety section and study other safety information. Because there is no way they could explain everything you would need to know or understand unless you spent time understanding the basic principles, this is where studying Hokes, and the forum will help you understand the basic principles.

If you are working hard and studying and ran into something you do not understand, or run into a road block and need pointed into a direction to help you in finding information, and you have studied and wish to learn a few more details, or need help in a process you have been studying and run into trouble or just wish to discuss the topic to learn more these members are more than willing to help where they can.

Forum search oxalic acid, notice how the recent thread (we
Are in now) is in the results of the search, hopefully we can make this thread useful for members who later search the key word oxalic acid or precipitants.

Notice also 617 hits with this word in my search, my guess is that the task of finding how to use Oxalic acid here is going to be very time consuming I will bet most of these posts only mention oxalic acid in the topic, or may help someone with a detail of the subject, it may be very hard for us to find a process or detailed explanation here.

Forum search Oxalic acid:
http://goldrefiningforum.com/phpBB3/search.php?keywords=Oxalic+acid+&terms=all&author=&sv=0&sc=1&sf=all&sk=t&sd=d&sr=posts&st=0&ch=300&t=0&submit=Search

The search above was too daunting of a task to read through all of those posts to find information, here is were reading the forum helps, you begin to learn a little about the members, and can use this in your search to possibly help you find more information and to limit or narrow the search results.

Forum search Oxalic acid / Kadriver (author):
http://goldrefiningforum.com/phpBB3/search.php?keywords=oxalic+acid+&terms=all&author=kadriver&sv=0&sc=1&sf=all&sk=t&sd=d&sr=posts&st=0&ch=300&t=0&submit=Search

Another way I may look for information on this topic, is to search through the subjects on the forum like Chemical processes, other processes, techniques…, and looking for a title of the topic which may lead me to more interesting information on the subject.
This also is time consuming but sometimes will lead to good results (and normally many others interesting things to learn about).

Search / Board index / techniques:
http://goldrefiningforum.com/phpBB3/viewforum.php?f=39&start=550

A look into the thread with topic of oxalic method as title.
http://goldrefiningforum.com/phpBB3/viewtopic.php?f=39&t=601


Okay I have searched and searched, read until my old eyes are sore, and still have not found enough information what shall I do?, Ask a question on the forum? And get the answer to read Hoke’s, and read Harold’s Ranting?

After reading Harold’s post I decide to look into Hoke’s index, and I see that on pages 59, and 173 there she discusses Oxalic acid.

From Hoke’s book page 173 we read:

The Use of Oxalic Acid
This method was mentioned briefly in Chapter VI as being especially
suitable for the recovery of gold from solutions that contain
relatively few impurities. Its disadvantage is that it will work only
when all the solutions are hot preferably boiling which means
that the precipitation must be carried out in vessels that will with
stand considerable heat. It costs more than copperas or sulphur
dioxide, about the same as sodium nitrite. Under most conditions
the gold recovered is of high purity.
For each Troy ounce of gold you will need at least a Troy ounce
of oxalic acid crystals. If you failed to expel all the excess nitric
acid, you will need more.
Dissolve the oxalic acid in hot water. Add a little ammonia, say
a teaspoonful or less to an ounce of oxalic acid; add slowly to avoid
spattering.
If you have litmus paper,
use it here, and let the mixture show a slight acid reaction. Have
the mixture in a big beaker or jar that will withstand heat.
Next, heat your aqua regia solution to boiling. Also have the
oxalic solution hot boiling if possible. Pour the gold solution
slowly into the oxalic acid solution. Gold comes down at once with
hot oxalic acid, but takes hours or even days if it is cold.
Some people pour the oxalic into the gold; we think it is better
to pour the gold into the oxalic.
There will be bubbles and fumes, so work slowly or the liquids
may boil over when they come together. If you failed to expel all
the excess nitric acid, brown fumes will appear here; if this happens
you may have to add much more oxalic acid in order to kill all the
nitric acid.
Let the mixture stand for some time, keeping it hot if possible.
The gold comes down as bright clean crystals, often very beautiful,
which usually settle promptly.
Finally pour or filter off the liquid, after testing some of it with
the stannous chloride testing solution to be sure you used enough
oxalic acid. If worthless throw it away at once. In rare cases it
may show enough palladium or platinum to be put in the Stock Pot.
The brown powder of gold should now be washed well with much
hot water, to remove all traces of hydrochloric acid, then boiled with
a little nitric acid, to remove traces of palladium or base metals.
Finally wash with plenty of hot water again, and dry and melt as
usual. This normally gives gold of high quality.

Dang I should have listened to Harold and read Hoke's book first.

Now I can ask the question:

When precipitating gold in the second refining process, Hokes mentions to adding ammonia (she states a teaspoon or less), but gives no details of how much oxalic acid in a water solution she has mixed up, (besides about the same amount as gold ounce for ounce or a little excess), when adding ammonia to the oxalic acid she does not say how much oxalic acid was used or how much gold she is wanting to precipitate, but she states "Do not use too much ammonia the mixture should not smell of ammonia after being stirred. If it does, add enough additional
oxalic acid to kill the ammonia smell.

Is there an ideal pH for the ammonia in the oxalic acid solution? or is smell the best way to tell the proper amount used.
I have seen it mentioned as pH 5, in other information I have studied is this the ideal pH.


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## bswartzwelder (Sep 9, 2013)

I started a thread on July 5, titled "Precipitants in General". I listed SMB, ferrous sulfate and oxalic acid. Others graciously chimed in mentioning sulfur dioxide. Lasersteve even had a chart (I don't know how old it was) that was packed with valuable information. There have been many hours devoted to precipitation, because without precipitation, you can have tons of gold tied up in thousand of gallons of solutions. If you don't precipitate, the gold is just sitting there in an almost worthless state. (You can't take a beaker of solution into any store that I know of and walk out with merchandise.) 

There are any number of methods used for recovering gold. Dissolution, electrolytic gold cell, pyrolysis/incineration, and inquartation just to name a few. They all have their pros and cons. They all take different equipment and all have their strong points and weak points. Without precipitation in some form, the processes for recovery and refining don't get you to your end point. Therefore, the different precipitation methods should all be tools in your Recovery and Refining process toolbox.

I have two little neighbor children (about 5 years old) living next door. As I was working in my driveway starting to build a pyrolysis/incineration unit, they appeared on their deck. I have repeatedly warned them not to watch while I'm welding, but it does little good. As a result, I have to physically stand between what I'm welding and them. The conversation usually starts out with them yelling over "Hi Mr. Bert", to which I reply "Hi boys". Then it starts. "What are you doing?" Let me just say, I don't answer their questions as they would like. I refuse to try to tell some 5 year old kids about the nuances of pyrolyzing and incineration. Likewise, if I am working with chemicals, I will not try to explain how or why SMB reacts with gold chloride to precipitate gold. I have tried wearing my shooting headphones which seems to help me not hear them. Asking them not to bother me, no matter how diplomatic I try to be, just doesn't work.

I was using a hot sand bath to remove components from cell phone circuit boards when they showed up on their deck and asked for an explanation of my activities. That time, I told them: "I'm depopulating circuit boards." Funny, all I heard was "Oh", like they knew what I was saying. Truth is, they didn't know what I was saying, but couldn't formulate more questions based on my answers.

I recently started dismantling an unused home-made trailer to make some much needed parking space in my driveway. The questions started again. I have finally found what I think is the perfect answer. I tell them "I'm just minding my own business." I'm almost to the point of telling them to read Hoke.

They once saw me evaporating my poorman's AR. While watching it, I pulled out my copy of Hoke and started re-reading it. Again, the questions. "What are you doing?" "I'm reading a book." "What's it about?" "It's about a lady who took a journey through a land of magic filled with all kinds of interesting things." Since this was about to be an extended session of Q & A, I shut everything down, put it away, then went into my home. As fate would have it, their mom came out within a half hour and loaded them into the car. Didn't see them for the rest of the day. 

Any diplomatic responses which will help keep them quiet would be welcome. I will not resort to using foul language with them, but I will tell them to mind their own business.


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## niteliteone (Sep 9, 2013)

I've always believed that Tall Fences make for good neighbors.


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## bswartzwelder (Sep 9, 2013)

I wish I could. But their house is slightly uphill from ours and the fence would, by necessity have to be about 10 to 12 feet high. Fences also make it difficult when cutting grass.


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## lazersteve (Sep 28, 2013)

I'm seeing a lot of threads and posts lately on precipitating gold with Oxalic Acid. I'm at a loss to understand why so many people are pursuing this precipitant as you can get just as pure gold using SMB with the proper filtration, washing, and melting techniques. The advantage to using SMB is that it is much safer, easier to use, cheaper, and faster. 

I use SMB exclusively in my refining ( both first and second refining stages) and my gold is as pure as I can possibly get it (99.9%+) every time. Is anyone using Oxalic acid getting paid more money for the added expense and labor of using it? Even if you get an extra fraction of a percent purity as an end result, it makes no sense unless you are getting paid more for the extra effort.

Why is everyone so interested in oxalic acid lately? To me it is much wiser simply to use SMB.

Steve


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## niteliteone (Sep 29, 2013)

lazersteve said:


> (snip)
> Why is everyone so interested in oxalic acid lately? To me it is much wiser simply to use SMB.
> 
> Steve


I don't know about others, but for myself I am learning / experimenting with other variables to refine my gold. I purchased a pound of Oxalic acid after reading here that SMB might be removed from our use and will try it later this year when I finish building my work shop for gold processing.
I do remember reading in many posts, that we should use different precipitants on "re-refining" to help reduce incidental drag down associated with using only one precipitant.


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## lazersteve (Sep 29, 2013)

I'm not sure if SMB will be removed from the shelf of common stores like Lowes, Home Depot, or wine making shops, but I'm fairly certain it will not be removed from chemical suppliers where I buy my SMB in bulk. I guess that arguments validity comes down to where you get your reagents and if they really remove it from the shelves. If it was removed from shelves, you would be better served using Ferrous Sulphate instead of Oxalic acid in my opinion. For me economy is the name of the game when recovering and refining, so oxalic acid ranks very low on my list for several of the above reasons I already mentioned. When working on the narrow margins that I do, my choice of reagents makes a big difference in my profit margin.

Drag down is not related to the precipitant nearly as much as it is related to the concentration of the gold with respect to other contaminates (base metals and other PMs) in the solution. Switching precipitants after the first refining may have very subtle effects on your gold purity due to precipitation of unwanted contaminates, but these affects are negligible in the grand scheme of the small percentage change in the resulting gold purity verses the effort and cost to get the extra 0.005% to 0.01% purity increase. Palladium contamination may be one exception to this, but trace Pd can easily be removed with much less expensive and easier to use DMG used as a scavenger for Pd. It's much easier to add a few drops of DMG to solutions of gold containing trace Pd followed by filtration, than to go through the fuss of handling expensive carcinogenic compounds, and spending lots of time performing the precipitation process. It takes a fraction of a gram of DMG to precipitate trace Pd impurities.

The precipitant used in the first in second refining phases is not nearly as important to your gold purity as the proper recovery, filtration, washing, and melting of the refined gold. For example if you precipitate gold with SO2 (or SMB) in a dirty copper CuCl2 solution, you will have some CuCl that will co-precipitate. This is easily removed with proper wash procedures after the first refining. Traces of Palladium are removed as stated above. 

On the topic of the novelty of using Oxalic acid, I completely understand that mentality, as that is what lead me to try oxalic acid many years ago. After a few experiments with it, I quickly wised up and went back exclusively to SMB. I have several pounds of oxalic acid that I purchase several years ago, and to this day I've only used a few grams of it in my gold refining. My over reaching point in this discussion is when it comes to final purity, time required in labor, safety, economy, and ease of use, SMB beats oxalic acid hands down. If your lab has a specific reason to use Oxalic acid, you can not obtain SMB, or you get paid handsomely for the few extra hundredths of a percent purity increase, these may be a valid points to use it, but using it simply to be using it, is a bad business decision in my humble opinion.

Steve


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## kadriver (Nov 27, 2013)

butcher said:


> Is there an ideal pH for the ammonia in the oxalic acid solution? or is smell the best way to tell the proper amount used.
> I have seen it mentioned as pH 5, in other information I have studied is this the ideal pH.



I was wondering the same thing. And I would also like to know the reason for raising the pH.

I can't remember where pH of 5 came from - maybe it was Lou.

But I would really like to know the reason as to why it is important to add the ammonia to increase pH.

Hoke does not explain why it has to be done in her book, only that it should be done before we use it to precipitate the gold.

This evening I was trying to precipitate 4.5 Troy ounces of pure gold using Hoke's process for oxalic acid precipitation located in chapter XV "Repurification".

I dissolved 6.5 regular ounces of oxalic acid in 600ml hot distilled water, did a hot filtration, then set to boil.

I added strong ammonia (28% ammonium hydroxide) to the boiling oxalic acid and checked with pH papers.

I ended up adding over 60ml of strong ammonia and got the pH to 2.

I added the boiling oxalic acid to the boiling chloroauric acid - all 600ml of it.

After adding all the oxalic acid solution, I boiled the mixture for over an hour and some gold precipitated nicely, but there is still much gold left in solution.

It was late so I turned it all off and went home.

Hoke says to use about 1oz of oxalic acid for each Troy ounce of gold.

I used about 1.5oz for each Troy ounce of gold and it still did not "bring down" all the gold.

Tomorrow I'll boil again and add another couple of ounces of oxalic to get all the gold out of solution.

My main question here: why is it essential to get the pH up on the oxalic before it is combined with the chloroauric acid (gold dissolved in AR)?

kadriver


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## butcher (Nov 27, 2013)

Why is it essential to get the pH up on the oxalic before it is combined with the chloroauric acid?

This is just a wild guess of mine, from another topic we have been discussing earlier (reduction of silver chloride with the glucose [karo syrup] and sodium hydroxide method).

From that discussion we seen where the NaOH was used to convert silver to an oxide, but then we needed an excess of NaOH which was also needed to open the glucose ring of the aldehyde in the hydrolyzed carbon chain of the glucose (sugar), I am no organic chemist but I suspect that oxalic acid also being an organic carbon compound with the formula H2C2O4, that the adjustment of the pH in our process to precipitate gold from AuCl3 with H2C2O4 oxalic acid also serves a similar purpose with the reduction process of gold when using this oxidized sugar compound of oxalic acid.

The process or reductions of metals in these two different processes, of silver chloride and the karo syrup method, and the gold and oxalic acid seem to me to have a lot in common.


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## kadriver (Nov 27, 2013)

Thanks Butcher.

With respect to what you have postulated above, what would happen if I added the oxalic acid full strength with no ammonia to adjust the pH value up?

I think I am agreeing with Lazersteve - oxalic acid is a troublesome way to go, and SMB can probably get the job done with much less hassle and in much less time that it takes using oxalic acid. 

I only did this batch to maintain a certain level of proficiency. Pouring those two boiling liquids together is a little frightening.

kadriver


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## butcher (Nov 27, 2013)

kadriver,

I am not the best one to answer this, but the way I understand it for the oxalic acid to be able to precipitate gold there can be no free acid (this means HNO3 or HCl), and only the solution of gold chloride salts. So here were we basically neutralize the acid (changing it into salts with the base solution of NaOH a base of ammonia) we are eliminating acids from solution, so that oxalic acid can work to precipitate the gold, which in turn produces CO2 gas and makes our remaining solution acidic again of HCl.

Hydrogen from the carbon chain combining with the chlorides from the gold, leaving the gold free to precipitate.

2AuCl3 + 3H2C2O4 --> 2Au + 6CO2 + 6HCl

It is funny to me to look at this, it looks kind of like they took sugar glucose and oxidized it in nitric acid to make oxalic acid and we basically burnt that sugar compound with our gold :lol: to form carbon dioxide of that carbon compound.


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## sharkhook (Nov 30, 2013)

Not to disrupt the conversation, but after reading the entire post I took away a very clear understanding of the reason for multiply washes. Thanks for the information on that. As I am new to this, and have only removed foils from various boards, I am just starting to look into the refining part and was having questions form in my mind about the wash processes.


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## kadriver (Dec 2, 2013)

lazersteve said:


> I'm seeing a lot of threads and posts lately on precipitating gold with Oxalic Acid. I'm at a loss to understand why so many people are pursuing this precipitant as you can get just as pure gold using SMB with the proper filtration, washing, and melting techniques. The advantage to using SMB is that it is much safer, easier to use, cheaper, and faster.
> 
> I use SMB exclusively in my refining ( both first and second refining stages) and my gold is as pure as I can possibly get it (99.9%+) every time. Is anyone using Oxalic acid getting paid more money for the added expense and labor of using it? Even if you get an extra fraction of a percent purity as an end result, it makes no sense unless you are getting paid more for the extra effort.
> 
> ...



Steve, if the gold is to be sold to a refiner then there is really no reason to dissolve in AR and precipitate with SMB. If the gold is inquarted right (I calculate the amount of silver needed to get the gold to 6k then multiply the silver by 1.1).

I then treat the inquarted gold in four treatments of BOILING 50/50 nitric/distilled water. The final boil is usually crystal clear and completely free of color. I then rinse until neutral pH with hot tap water, dry and melt.

I get any where from 99.6% to 99.9% on assay. There is always little to no loss, but when I dissolve and precipitate, there is always some loss. The more it is handled, the greater opportunity of losses.

One draw-back: I found that my proficiency suffers, when I do decide to refine a batch all the way, I start to forget steps that used to come automatically when I was dissolving and precipitating all the time.

I can go from karat scrap to a 1 Troy ounce button in about 3 hours, ready for delivery to the refiner with hardly any chemicals used and the gold very pure.

Of course if the gold is for a trusting client things would be different. All my gold is sold to a refiner.

kadriver


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## lazersteve (Tuesday at 7:31 AM)

I found this old thread and wanted to reply to it despite its age.

Kevin,
The majority of the scrap I run is from cpus and turbine jet engines. I do get the occasional karat batch which I typically return the customers portion as fine gold. Gold filled is another primary feedstock in my lab.

In all of the above mentioned instances complete refining to an acceptable 99%+ purity is my goal for two primary reasons:
Customer expectations of yields and customer satisfaction.
In other words, I want to provide a high quality product to my customers that reflects the best possible yields from thier scrap that is repeatable given the same feedstock. As an added benefit I have a very accurate idea of what my share is worth when batches arrive and selling my share. You are correct that inquart and several post cleanup stages can accomplish this with true karat scrap.

You make a good point about processing losses, but it's a necessary evil in my opinion to give the customer a clean product so they can resell their share at a know value whenever they choose. It also helps them when buying future lots to send me.
If the customer is interested in quick turnaround times or fast cash on karat, then why bother to inquart (aside from knowing exactly how much Au is present), just melt and sell. 
That also brings up a whole separate can of worms and that's "fake" or "mismarked" and even unmarked "karat" items. Over the years I've encountered lots of these pieces, even entire batches. It's never a good feeling to have to give your customer that kind of news especially on sizeable batches. I've seen karat that was passed from generation to generation that turned out to be plated copper with karat hallmarks. Turns out grandmas jeweler was a crook. The specific batch that I am referring to here was acquired and processed by a good friend of mine and it was his own grandma's karat so there was no question where the bad egg was. I can cite other examples, but I'm already running long winded here.
By processing everything to fine Au along with photographing your work, the customer is less likely to think you are to blame for the loss.
We touched on the topic of the dishonest buyers as well in other topics so I won't repeat my feelings on that except to say even reputable companies have untrustworthy employees and the lure of gold has a way of corrupting people in general. There are even the instances where the employee may make an honest mistake in measuring or analyzing the batch depending on their level of knowledge.

Steve


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