What would cause my AR solution to only drop part of the gold powder?

[Shark]

Real nitric avoids many of the quirks of using a nitrate salt. Once you try it, it is hard to go back. Knowing the peculiarities of each helps a lot when using them. Seems in my case using sodium or potassium nitrate causes more colloidal gold to form, especially potassium nitrate. In the case of a friend of mine, he has more problems with sodium nitrate. With care it can be avoided, but it changes how you process some. I think it is good to know how to use each of them, the more we know the fewer problems we run into. And while I prefer to let Kurt explain it better, I use aquarium pumps. the more solution that comes into contact with the copper, the sooner it is done. Another way of saying it, the more solution that contacts the copper the more you recover.

 

[Mountain Man]

Kurt,

You were right, copper has done the job. All of my solution bottles show no gold at all. This is the first time that has actually happened. I have drums of solution I got frustrated with not getting all the gold from the solution. I said before I had a 55 and a 35 gal drums but I actually have 2 55's and a 35 for a total of 145 gallons of solution that I know have gold in them. Some are 3 years old or more. I am curious. Do you think there is any chance the gold will have settled to the bottom by now? I ask because it is quite a cocktail of solution and smb and who knows what may have taken place. Just wondering.

Thanks for all the help from everyone. I am going to re-read all of your posts and make sure I have not missed anyone's comments. They are all appreciated and I don't want anyone to feel ignored or that I didn't appreciate your input and sharing your vast knowledge of how to become an expert at this. Final question. Is nitric worth the cost and potential danger to use in my AR solution instead of a substitute like sodium nitrate?

I have nitric already but have only used it in the purifying stage, however if it reduces potential problems that exist with the substitutes then I would lean more to using the actual nitric instead regardless of the cost.

Thanks again.

 

[FrugalRefiner]

Final question. Is nitric worth the cost and potential danger to use in my AR solution instead of a substitute like sodium nitrate?

I have nitric already but have only used it in the purifying stage, however if it reduces potential problems that exist with the substitutes then I would lean more to using the actual nitric instead regardless of the cost.

It depends on what you have to pay for nitric. If you can get it at a decent price, it's definitely the way to go. If you have to pay $50 to $70 per liter, the workarounds are worth consideration.

Dave

 

[Shark]

I use both depending on the situation. I started out with only sodium nitrate, then found some potassium nitrate. From there I learned to make my own nitric, then managed to get hold of some real nitric. I am reasonably comfortable with either of them in the majority of situations, but prefer certain ones for specific materials at times. Since you have the chemicals, try a few small scale runs and see if you find one easier than the other. I have produced some very nice gold, even using "poorman's AR".

This was made from gold filled materials using poor mans nitric and poor mans AR. Xrf read it at .9999 on both sides, twice.

 

[kurtak]

Kurt,

You were right, copper has done the job. All of my solution bottles show no gold at all. This is the first time that has actually happened. I have drums of solution I got frustrated with not getting all the gold from the solution. I said before I had a 55 and a 35 gal drums but I actually have 2 55's and a 35 for a total of 145 gallons of solution that I know have gold in them. Some are 3 years old or more. I am curious. Do you think there is any chance the gold will have settled to the bottom by now? I ask because it is quite a cocktail of solution and smb and who knows what may have taken place. Just wondering.

Yes - it is "possible" that "some" more (but not all) gold has precipitated out over time (considering the chemical "soups" you have made) &/or "ultra" fine gold that has settled out over time

Concerning nitric acid - yes it is always "preferred" over using nitrate salts

However - cost of the nitric plays into what to use

it takes "about" 4 times more nitric acid to dissolve base metals then it takes to dissolve gold or silver

Example; - one gallon of 67% - 70% nitric will dissolve "about" 8 pounds of silver/gold but one gallon of nitric will only dissolve "about 2 pounds of base metals

so if you are processing say ceramic CPUs with AR - besides dissolving the gold you are dissolving the base metals (copper lids, kovar lids & kovar pins) the base metals being the greater amount of metals - therefore needing more nitric to dissolve those base metals

therefore if you are having to pay a high price - like $50 - $70 or more per liter for nitric - the cost of the nitric may well be more then the value of the gold you recover

On the other hand if you can find a source of nitric that only cost $2.50 - $12/$15 per gallon it is well worth using real nitric

in other words - IF - you are paying a high price for your nitric (acid) save it for you final refining - you can still use nitrate "salts" for the "recovery" process where you need to dissolve a lot of base metal

That said - concerning using nitrate salts - you want to use clean/pure forms of the salts

Question - for your sodium nitrate --- are you using a sodium nitrate fertilizer - like the Hi-Yield nitrate of soda fertilizer

If so I would suggest changing from using that to using "Spectracide" (brand name) stump "remover" (stump remover not to be confused with stump "out")

stump "out" is SMB --- stump "remover" is potassium nitrate

Hi-Yield nitrate of soda is only 16% nitrate & 26% sodium (the sodium nitrate) so 42% of the active salt that makes your Poor mans" AR --- the other 58% of the fertilizer is buffers &/or fillers - the buffers/fillers are put in the fertilizer so that the sodium nitrate brakes down "over time" to feed plants "over time" - its being dissolved by water - not (HCl) acid - so the buffers allow time delay feeding of the plants other wise the fertilizer would burn the plants

In other words - more of a chemical "soup" in your poor mans AR - & as I said before - the more of a soup you make - the greater "potential" with problems you "may" have dropping your gold

Spectracide stump remover is a clean/pure form of potassium nitrate - no buffers/fillers - so a more clean/pure source of nitrate salt then a fertilizer with crap (buffers/fillers) other then the nitrate salt wanted to make your poor mans AR

Though I have never used poor mans AR (because I have always had "cheap" nitric acid) logic tells me if I was going to use a nitrate salt I would want a clean pure form of the salt & not the salt plus other crap

Therefore IF I was going to use a nitrate salt to make poor mans AR I would most certainly use the potassium nitrate stump remover & not the sodium nitrate "fertilizer"

And - for what is worth - I do use potassium nitrate as a flux ingredient when melting "dirty" gold powders - but that's another story for another day

Kurt

 

[Mountain Man]

Kurt,

Thank You again for sharing your hard earned knowledge and wisdom. I completely understand the what and why of the products you are using and the benefits. I will make the switch and adjustments. Is the use of the sodium nitrate the reason why I get so much salt in my batches? I have been so frustrated with the salts for a long time. I have not understood why I have had salts until now. I do not have a reasonable priced source for nitric but I do keep it on hand. I am going to go to try and find a cheaper source of the nitric and then switch to the potassium nitrate and give that a go also.

I started a batch last night and it is now ready for dropping the gold. I bought copper powder and do have it on hand. It is the straight copper powder and I am hoping that was the right one to purchase. I divided the batch into 2 separate jars so I can try the copper powder on one and copper plate again on the other. I am really happy with the amount of gold powder I recovered using the copper. I am going to rely on it from here on.

I will let you know how it turns out on this batch. It is 4 pounds of ceramic cpu's. I am going to reread your comments on how to with the copper powder. I want to say thank you again for taking your time and helping me understand and isolate my errors in the process.

You have been a great help and I truly do appreciated your help.

Kirk

 

[kurtak]

Kurt,

Is the use of the sodium nitrate the reason why I get so much salt in my batches?

Kirk

To clarify my last post - I really can not speak to using nitrate salts for making "poor mans AR" as I have always had actual nitric acid to use when refining

So what I was saying is that - IF (big if) you are using a product like the Hi-Yield (brand) nitrate of soda fertilizer then you are using a very low grade of sodium nitrate because it is only 16% nitrate plus 26% sodium which = only 42% sodium nitrate - the rest of the (Hi-Yield brand fertilizer) is 58% buffers &/or fillers (so 58% "other" crap)

its that 58% other crap I am concerned about that is ether not going to dissolve thereby leaving you with some kind of crap in the form of solids that then need to be filtered out - or - if it dissolves its more crap in you solution that "may" cause a problem dropping your gold

Therefore (if you are using the Hi-Yield fertilizer) I was suggesting using a more pure form of nitrate salt - such as the Stump "Remover" which is a pure 99% potassium nitrate

You can also get sodium nitrate in a pure 99% grade of sodium nitrate (instead of the Hi-Yield fertilizer)

If you do a search for - "where to buy sodium nitrate" you will find that DUDA ENERGY sells it for about $24 for a 5 pound bag & it is 99% pure sodium nitrate - be sure you get the nitrate & not the nitrite

Now then - what I don't know - is that even with higher grade nitrate salts (sodium or potassium) is if the sodium &/or potassium in these nitrate salts ether (1) do not dissolve thereby leaving solids that need to be filtered out - or (2) if they dissolve & then precipitate back out as the salts of sodium or potassium - or (3) if they dissolve & stay in solution

What I do know is that the nitrate in the sodium &/or potassium nitrate will serve the same purpose as nitric acid for dissolving metals as a "poor mans" method for refining --- which is why its called poor mans AR instead of just AR (where nitric acid is used instead of nitrate salts) because nitrate salts are easier to get then nitric acid AND most people have to pay a VERY high price for nitric acid - but can get nitrate salt "cheap"

So the bottom line is that others (like Shark, Geo, butcher, etc., etc.) will have to answer your question as to a problem of salts (sodium/potassium) that form (or not) when using the salts to make poor mans AR

Years ago I did try an experiment using the Hi-Yield fertilizer & I did get A LOT salt that ether did not dissolved &/or that precipitated --- I "assumed" it was because of the 58% crap in the Hi-Yield fertilizer so never tried using a nitrate salt again because I have always had cheap nitric acid

Glad to hear the copper is getting your gold back from all you old solutions :G :mrgreen:

Kurt

 

[Shark]

I wish I could explain it better, I just do not have the ability to do so.

When using nitrate salts to make AR if you add to much you will get left over salts. The way I think of it is to make AR you use a specific amount of Hydrochloric acid then add a set % amount of nitric acid. Example to make a 4:1 AR you would use 40ml of HCl and 10ml of nitric acid. When using poormans AR you need to figure out how much of your nitrate salt is the equivalent of 10ml of nitric acid. Sodium nitrate will give a lower yield of nitric acid than potassium nitrate in a given weight. That is why many prefer potassium nitrate over sodium nitrate as well. I prefer to add the hydrochloric and only use small amounts of nitric or nitrate salt, the same as using nitric acid rather than a set ratio. If you excessively add either salt it will settle and can be filtered or is soluble in water especially hot water. For a given amount of hydrochloric if you add the excess nitrate salts the excess is wasted in that only so much nitric can be produced by the given hydrochloric. It can be increased to a small extent with the addition of small quantities of sulfuric acid which aids in the conversion of the salt to nitric acid. Between the process of filtering your auric chloride and the repeated wash cycles for the gold powders the left overs must be fairly thoroughly removed (by my thinking) as both sodium nitrate and potassium nitrate are capable of producing some very nice gold. If you add sulfuric acid you run the risk of some of the left over salts producing sulfate salts which often are not water soluble but can be filtered out fairly easy, so long as you don't produce large amounts. They can easily stop filters up and cause nightmares when filtering. Another point of using the nitrate salts is they almost always require heat. They will not work well with out it. I am not sure of the exact range of heat but a coffee maker hot plate will work for a coffee pot, but it is still a bit slow. If they were 20 or 25 degrees hotter they would work very well. Something to keep in mind if processing larger batch's.

I am not sure of how potassium nitrate is produced so that would be a point for further research. Sodium nitrate is a mine product and, as with Hi-yield fertilizer and other brands, the amount of trash can vary quiet a lot. Some of the reasons I keep going to Hi-Yield is because it is a known source, easy availability and has a proven track record in my notes, for my methods. It will have beads of dirt because it is a fertilizer, and not produced for quality. I tried a generic brand of sodium nitrate fertilizer and it was so dirty I gave up on it for refining, but it worked great on my shrubs. Duda Diesel, does sell a high quality product that I have not tried (I have used their nitric acid) and the advantage would be they sell it in large quantities. Hi-Yield comes in 4lb bags. I have dealt with Duda Diesel before and never had a problem.

I really hope that makes some sense.

 

[Mountain Man]

Kurt and Shark,

Thank you both very much. Both of your comments make perfect sense. You both have explained clearly what my next questions about the salts I keep having to deal with would have been.

I first want to say that I am never going to use anything but copper to recover my gold. No more precipitants for me.

My next question was about the cause of the salts and how to get rid of them when they occur. The best solution all though it is more costly is the pure nitric and I do have it on hand. When I calculate the time required to remove the salts it becomes a trade off, unless like you said I go to a high grade product. I am becoming more convinced that I will be farther ahead to simply stick to nitric and avoid all the other problems associated with the nitrate family.

When I consider the time lost in removing the salts to get to my gold it becomes a lost cause. Time is money and the more of it I can save produces more gold on a faster pace.

I can't thank you both enough for you willingness to share your wealth of knowledge and your time. Your expertise in this has opened my eyes and the door to actually move towards not only making some money but also becoming more knowledgeable in the venture I have been working at for a while now. It is your willingness to share your knowledge that makes this worth not giving up. If it were not for your help I would have done so long ago. I am just to stubborn to ever admit defeat.

Thank you all so very much.

 

[Mountain Man]

Kurt,

I am going to switch over to nitric until I can get some high grade sodium nitrate.
I am not sure of the ration using nitric. I no some say 4 to 1. HCL 4 parts to 1 nitric. What are your thoughts on that? I have a 5 lb batch of ceramic cpu's I am ready to start.

Thanks again.
Kirk.

 

[Mountain Man]

Hey Shark,
I was re-reading your comments on sodium nitrate and the salts they can produce. I have been plaque'd by the salts in virtually every batch I have ever done. All the things that you mentioned that the salts could do to my batches are exactly what they do. When you said that heat needed to be involved for some reason I thought you meant when I was trying to recover the gold but I just realized you meant in the beginning stages of the batch and that heat would help reduce or eliminate the salts from the S.N.. I have never been able to solve the mystery of the salts and the loss of significant amounts of gold do to not being able to separate the salts from the gold. I live in N. Id. and it gets dang cold here and in the dissolving stage of my batches, it is sitting outside in a cold wood shed. It is not until I take it back to my gold processing room that it gets warm again. I have been plagued with this problem since I started doing this over 4 years ago.

Have I understood what you were saying?

Kirk.

 

[Shark]

In my experience when you heat a solution more salts will dissolve into it. The heat will also aid in the dissolving of your metals. When it cools the excess salts will drop back out. Example, when making nitric acid, you add your chemicals and heat it up. This will make a form of nitric which is contaminated with sulfate salts which become noticeable as it cools to ambient temperatures. To clean those sulfates even more you can sit the whole solution in a cold atmosphere, somewhere around 32*F or around freezing. The salts will now form even more while leaving a cleaner nitric acid. The same often happens with poormans AR due to over use of the nitrate salts. Even a pure form of of salts will do this if you add to much, but you do have less filtering problems the purer the salts are.

When using salts for your nitrates it easy to over add the nitrates. Keep in mind most left over salts are still a nitrate that lacked the other necessary ingredients to become nitric acid. Most often a lack of water. Heat will allow them into solution and work to some extent, but they will fall back out once cool.

NOT preferred but works
To aid in the separation you can filter while it is still hot the first time. This removes solids and allows your gold and most salts to pass through. Once it cools you can filter again and trap the salts and rinse with very cold water which will take some of the salts with it but leave the majority.

Preferred
Or you can filter, then drop your gold while hot, so as to keep the salts in solution. Being very careful as it will boil over easily when adding the precipitate (which I like hot as well). Once your stannous test is negative, use hot water for your first wash cycle to remove the vast majority of the salts. If you used a large amount of nitrate salts you may want to do the hot water a few times (I always do several), depending on how clean you want your gold. This also helps remove any acids from your gold and stops some losses when melting.

Keep in mind:
The vast amount of left over salts are water soluble, especially in hot water.

I have noticed as well if there is copper in your material, at times it will aid in the production of nitric acid, and cause an over use of nitrate salts. This makes killing any excess nitric produced harder. Heat and sulfamic acid works, but makes it harder to identify when the nitric is actually killed off as sulfamic has the ability to reproduce the needed sulfuric to make salts into acids. When it does work it is a noticeable change in the reactions. Hot solutions and adding sulfamic can be very violent, add it slowly.

Hope that helps

 

[Mountain Man]

Kurt,

I have a 5 lb. batch of ceramic cpu's all dissolved and filtered. Buckner filter. The gold content shows very high. I have also have on hand pure copper powder and the copper plate I used before. But before I drop the gold I would like to know which way you prefer? Powder or Plate?

Kirk

 

[anachronism]

I'll bet Kurt's answer is powder.

That given I would go with Ferrous Sulphate 8) 8)

 

[Mountain Man]

I don't have any Ferrous Sulfate. I do have smb, copper powder, or copper plate. Your choice would F.S. and I am not opposed to getting it. I am curious why that is your choice? I am not doubting your reasons I just don't know them.

Kirk

 

[Shark]

Ferrous sulfate is pretty good at dropping gold from dirty solutions with minimal drag down of non gold metals. In other words, the gold drops cleaner from dirty solutions. If your doing a second refine, it can help to use ferrous sulfate as a first drop, then another precipitant such as SMB for the second. This allows you to perform two refines, in the same basic methods, producing different results of cleanliness. Cleaning your gold at the end of each refine, with good washing habits, will produce some very nice quality gold.

As for the copper, I think Kurt will go with powder as well, but that is only based on some recent study of cementing with copper. This thread has me looking at some new things to try. I am waiting to see what Kurt replies as well.

 

[Mountain Man]

Hello Shark and Kurt,

I have been hard at work in my g. room and have made some changes. 1. I no longer use nitrates. I look back and read thru notes from the past and have decided the losses compared to using nitric is well worth the cost of nitric. 2. I am using the copper powder and I like it best over the copper plate. Reason being is that some white powder accumulates on the plating and I don't know from what. Also, the process of recleaning the plate of copper is a hassle. I like the power but have used to much in the early batches and have an excess of copper powder mixed with the gold powder. The gold powder is a very nice clean brown but I am wondering how to separate the gold from the powder. I have a question, will Nitric alone dissolve the copper powder? I know it won't dissolve gold by itself but I do not know about the copper. I like the clean gold powder I get from using the copper powder instead of the copper plate as well. What are your thoughts on Nitric dissolving the copper?

MtnMan.

 

[Shark]

Make sure there are no acid residues left in your copper/gold precipitate before doing any of the following. PH test wash waters to be sure. Remaining residues of acid could cause some of your gold to go back into solution.

Once your sure there is no acid left, add some hydrochloric acid to the powders and heat to a low boil, being sure to use a catch pan (pyrocyram) and a watch glass. It should turn a shade of green if copper is the primary contaminant as in copper chloride. (I use hydrochloric so as to save some on the cost of nitric and it works very well) Blue would indicate the possibility of left over nitric (copper nitrate) Repeat this until the hydrochloric shows no signs of coloring, while rinsing with water in between the hydrochloric wash's. If done until there is no discoloring of the hydrochloric and boiling in water shows no cloudiness you will have some very clean gold. Done right it will push three nines or very close.

I hope Kurt weighs in here, I would appreciate his input as well.

 

[Mountain Man]

Thank You Shark,

As always I am extremely grateful for your help and your willingness to share your knowledge and wisdom. I truly do appreciate it more than words can provide.

I will let you know how it goes.

I too would like to hear from Kurt.

Kirk.

 

[Alliedft]

Mountain man am I reading it right that you are processing everything and instead of dropping the gold your just putting in drums with copper to deal with later?

As for these guys on here they are awesome, I'm sure some of the questions we ask makes them roll their eyes a few times but they are always willing to help. Great goup