# Dropping gold problems with SMB



## PARKER113 (Jul 3, 2020)

Hello forum members, 
Thanks again for a wonderful form. I joined a few years ago and have had two decent refining seasons thanks to all of the information on the forum. 
Well it's gold refining 2020 for me and I have a decent amount to work with. 
I am doing chips, pins and some fingers. 

My problem started last year with slow dropping gold, or gold just not dropping out of solution. I use AP for everything and hcl and water for washes and hcl and bleach to dissolve gold. 

I saved a solution that wouldn't drop last year before my time ran out. It was gold plated pins from servers and computers. This year I decided to evaporate it down, add hcl and attempt to drop it again with smb that was dissolved in water. I ended up evaporating it down too long and it turned into dry crystals. Maybe some from smb and maybe some from the bleach I used for dissolving the gold foils in the first place. 

I added hcl, dissolved the crystals, filtered tried to drop it, failed, and ended up cementing it out with copper bars. 
I washed the fine reside with hcl a few times to get rid of any green color and washed with water. 
I decided I want a decent button so I added a bit of gold powder that took to long to settle from dip chips, and some other clean black powder from cementing a gold solution last year. 
I added those three together and washed with hcl twice and did not notice any color change so I water washed it with water, added HCL and started to add new all purpose bleach. I believe I used around 100ml in total squirting it in and stirring with a pipette
I was surprised by the bright red color. I tested with stannous and it was a yellow orange color. I let it sit over night with my other beaker of 1030 grams of 2 sided ram chips that I also used bleach to dissolve. It turned a nice deep yellow. 
The next day I figured (after searching the forum for what might be the red color) to drop the gold out of the solution with smb since the chlorine would of left the solution. And deal with the pgms if there are any later. But I noticed a bit of gold at the bottom of the flask so I decanted it, added a bit of hcl and bleach to dissolve the bit of gold. Then added the two together, filtered, waited 15 min. Then added two tea spoons of smb to a small amount of water and added it to the solution and it turned a golden color. Nothing dropped. 

I've been looking this up for a while now as I suspect that my problems dropping are due to ph but I can't find ph test strips or just to lazy to drive around.. Either too much water or too much hcl is what I've concluded. 

So My other solution of chips also didn't drop anything. With that one i added double the amount of hcl before adding smb thinking maybe it needs to be more acidic. 
It turned almost clear after adding the smb. Nothing dropped but a grain or two.

So now the orange solution was heated up and is sitting uncovered to possibly evaporate the leftover chlorine (if that's the problem) 
And the other solution was heated up and is left alone to possibly drop the gold over the next few hours. 

When I first started out using hcl and bleach, dropping with SMB worked like a charm. I got nice fast light brown drops. Now it's like everytime I try it is always a huge struggle. Either not dropping or dropping very fine useless powders that take forever to settle. 

Could anyone point out what I might be doing wrong?
It should be extremely simple with the same results everytime if I add the right amount of hcl and let the chlorine evaporate off. Right? 

Thanks guys!


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## FrugalRefiner (Jul 3, 2020)

What is the source of your SMB, and is it fresh or what you had left from last year?

Dave


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## PARKER113 (Jul 3, 2020)

Hey there Dave! 
It's a new solution. I used fresh HCL, 3 smal chucks of new solder wire and 1/4 of a gram of TIN II stannous chloride. I didn't heat it up.


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## FrugalRefiner (Jul 3, 2020)

Not the source of your stannous, but the source of your SMB; the stuff you're using to try to drop your gold.

Dave


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## PARKER113 (Jul 3, 2020)

Oh ha, sorry Dave. I bought the SMB in 2018 pure sodium metabisolphate. I bought 4 sealed bags then. I tried this year with the old one. And it didn't work the best so i opened a new bag. As i read on the forum that it can get old and lumpy. And the old stuff was a bit lumpy although it powdered up nicely. 
The new package was less lumpy, but still not all completely granulated. But easily broken up.


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## PARKER113 (Jul 3, 2020)

I should also add after problems dropping with my first batch ( Dip chips large and small 645 g ) this year I researched on here for a few days and realized the SMB may be bad. I tested the old stuff on fresh HCL and it sizzles and bubbles when dropped in. But I decided to get the new bag opened anyways.


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## FrugalRefiner (Jul 3, 2020)

I could easily be wrong, as there can be so many variables, but I would try some fresh SMB.

Dave


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## PARKER113 (Jul 3, 2020)

Ok, I will get some new smb and try to drop it again. 
Thanks for the advice Dave!


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## goldenchild (Jul 3, 2020)

From my experience old smb shouldn't be a problem. I've on many occasions used ancient SMB to drop gold. As long as it can produce sulfur it should work. If it's old you may just have to use more than usual. When you used the SMB did it produce a pungent nose punching smell? If so the SMB is fine.


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## PARKER113 (Jul 3, 2020)

Honestly I don't recall a smell as I usually wear a respirator. I can take a small waft next time I add some of the older stuff and see. Neither solutions fizzed when I added a small amount of dry SMB which gets me wondering if it's acidic enough. But since I doubled the HCL in the one batch and didn't drop or fizz that idea seems shot down.


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## PARKER113 (Jul 3, 2020)

So I retested the solutions with stannous after giving it about 5 hours. Some gold has dropped. But the tests still show a positive for I believe gold in the clear solution and PGMS and/gold in the once red but now yellow solution. 
After adding a bit more dry SMB I didn't get any major sulfur smell. I will get more SMB tomorrow.


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## Shark (Jul 3, 2020)

Did you use heat while doing the AR step? If yes, how much?

It is possible that your acid is used up and a bit of hydrochloric is needed to get the SMB to work properly. That sulfur smell is a sure way to know that the SMB is working. It is also the reason I started using copperas more often. I hate the smell and my wife is allergic to sulfur. 

Also, I recently emptied a bottle of SMB that was opened four years ago and it worked fine.


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## PARKER113 (Jul 4, 2020)

Hi Shark, I warmed them up but did not get them hot before I tried dropping. As it would release the chlorine too fast to do a good job dissolving. And I have a hard enough time dissolving half a gram of powder with HCL+CL Haha. It takes about 75 millimeters and I have been adding a bit more HCL after 50 millimeters as I think maybe it's getting too basic with the water from the bleach, as it's taking awhile to dissolve. 
It starts as a small solution and ends up with almost a full beaker after the HCL, bleach and water from washing the filter.. It could be that the chlorine takes more than a few minutes to dissolve the gold and stays in the solution longer than I thought. It usually takes me 15-20 sitting there putting in a few dashes of bleach, stirring it lots. Wait a min or two, then continue to add bleach and do it again until it's all dissolved. Around 20 min and sometimes a bit less than double the starting solution. 

Sorry if I'm leaving large replys. I'm just trying to get out all of the information so you guys may have a better idea of what is going on. Hopefully it's useful information


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## ZiegenSauger (Jul 4, 2020)

A better explained version of my problems. When I say you guys are great!!

I use lab/industrial level chemicals (from Science Company mostly), so I am not concerned with them.

For me is a matter of process and the moment to precipitate.

Let's see what we get here, for certain will be another great lesson for me.

Cheers


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## PARKER113 (Jul 4, 2020)

Yes quite the annoyance! I'll get some new SMB today and give it a try. Hopefully that's my problem. I would be very happy to finally have nice, fast drops. 
On a side note, last night, after leaving the stannous tests for about 15 minutes from the originally red solution, the test turned clear. 
The clear solution stannous test remained purple.


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## kurtak (Jul 4, 2020)

PARKER113 said:


> I bought the SMB in 2018 pure sodium metabisolphate.



Per the underlined - are you using the right product to drop your gold :?:

You want to use bisulf(I)te NOT bisulf(A)te 

Bisulfate (spelled with an A instead of spelled with an I) will not drop your gold

Kurt


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## PARKER113 (Jul 4, 2020)

My apologies Kurtak, it's metabisulfite. Silly me.


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## kurtak (Jul 4, 2020)

PARKER113 said:


> Neither solutions fizzed when I added a small amount of dry SMB



Again - this tells me you are using the wrong product

You want bisu - fite (spelled with an i)

not bisul - fate (spelled with an a)

The SMB (spelled with an i) I have is 12 years old & still drops gold (so how old it is should not be a problem)

Kurt


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## kurtak (Jul 4, 2020)

PARKER113 said:


> My apologies Kurtak, it's metabisulfite. Silly me.



opps - didn't see that before my last post

Kurt


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## goldenchild (Jul 4, 2020)

This is where I got my SMB. They used to sell a nice litte 3 gallon bucket at one point. But you can buy it in a five pound bag for cheap. I'd recommend putting it in a bucket to keep it dry. With a large amount you'll never have to worry about SMB again. If you go through a five pound bag or even a... *gulp* 50 lbs bag you're doing well! 8) 

https://www.dudadiesel.com/search.php?query=sodium+metabisulfite


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## kurtak (Jul 4, 2020)

Ok - just went & looked at the last pictures you posted (showing stannous test) - (first time around I didn't really look at the pics - just read the post)

From what I see (stannous test) MOST of the gold has dropped with only a "trace" of gold left in the solution - likely due to a "small" amount of chlorine still in solution

This is based on the "last" pic that shows a clear beaker/solution - with a "very" slight purple "trace'" indicator for gold (stannous) test

I would put it on a hot plate to try to drive off any "trace" of remaining chlorine - which (once remaining chlorine is gone) should drop the remaining "trace of gold --- test with stannous every so often (while on heat) should tell you when the chlorine has been driven off & the remaining "trace" of gold has dropped

Again (according to the last pic) MOST of your gold has dropped with only a "trace" remaining in solution - there just wasn't as much gold in "that" solution as you thought

When all else fails - cement with copper

Kurt


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## PARKER113 (Jul 4, 2020)

Thanks Kurt! When I checked on it 30 minutes ago there was no color change after testing it with stannous! So the very acidic solution dropped all of the gold after about 24 hours. I gander due to the leftover chlorine.

What I did next is I decanted all but 100ml of solution added 50ml of HCL and dissolved the gold again with 50ml of bleach. I then filtered the solution, heated it up on the hotplate and took it off to gas off the chlorine. 

I did buy new SMB today as suggested so I figured I would see if I can get a much better drop. 

I was hoping after heating it and leaving it uncovered for 15 minutes it would give it adequate time to remove the chlorine. But after seeing the gold taking so long to drop due to excess chlorine in solution the last time maybe it's best to give it until tonight to drop. 

I tested the once red solution and it still shows orange. Last night after giving the test a an hour the orange went away to colorless.


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## PARKER113 (Jul 4, 2020)

Here's the new SMB and also a picture of a test I took of the once red solution a minute before uploading. Also beside it is the solution the test came from, also the smaller jar which I took from that solution which I doubled it with HCL and added a sprinkle of new SMB. I did see a very small amount of droppings. But that solution still showed an orange test.


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## PARKER113 (Jul 4, 2020)

I noticed the color change to purple and got me thinking to test again using a clean glass rod instead of the pipette which I used for the other batch and still small gold particles around the edge.. No purple showed up.


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## PARKER113 (Jul 4, 2020)

goldenchild said:


> This is where I got my SMB. They used to sell a nice litte 3 gallon bucket at one point. But you can buy it in a five pound bag for cheap. I'd recommend putting it in a bucket to keep it dry. With a large amount you'll never have to worry about SMB again. If you go through a five pound bag or even a... *gulp* 50 lbs bag you're doing well! 8)
> 
> https://www.dudadiesel.com/search.php?query=sodium+metabisulfite



Thanks Kurt! There are lots of brewery stores near me so it's not too tough to find  In 2018 I bought four one pound bags thinking I might need that much Ha! Way too much. I don't know if it's bad or not. But let's see if this new stuff solves the dropping problem.


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## PARKER113 (Jul 4, 2020)

Good news, I successfully dropped all of the gold out of solution after 45 minutes. I added a few ml of water to half a teaspoon of SMB stirred it so there was no crystals, then added it to the solution. It took a few minutes to get clearer. But it didn't drop anything.. So I figured maybe it still has chlorine.. I put it on the hotplate as suggested, stirred, added a quarter teaspoon of dry SMB (It sizzled this time, possibly because I dashed more in at a time than before)
and what do you know, some darn chunky gold started precipitating. 
I continued heating and periodicity stirring and after about 25 minutes of that the stannous tested negative for gold. I will let sit for an hour and melt it tonight!

Conclusion? Not quite sure yet. But either it could be the newer SMB helped or the chlorine has been lingering in the solutions longer than I've thought. Which makes sense.. I have a hard time with patience at times and I may of been either heating it up to much, too long, killing the acid. Or attempting to drop it to soon before the chlorine leaves the solution.
Thoughts?

I took the red solution and added heat and stirred hoping maybe I have leftover chlorine in that solution. But it's been sitting loosely covered for a few days now.. 
I will update on that soon.


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## PARKER113 (Jul 5, 2020)

I washed the gold from the 1030 grams of 2 sided ram chips using Harold's method and then melted it. I'm pretty sure my torch blew gold off the crucible.. I did sprinkle borax on the top before going down with the torch but I noticed some of the borax blew out as I may of went down to close to fast. 
I weighed it and only got .36 grams. Disappointing to say the least. 

I still have N/S bridge tops 1691.98 grams, 
Ram bga 885.6 grams and Various bga chips 1072 grams. Saved the best for last.
I sure hope I can get some good results!


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## butcher (Jul 5, 2020)

Nice thread, nice pictures, and yes, nice gold, well done. I do not see anything to be disappointed about, the gold is worth the journey to gain the education, and with that comes the understanding to get that gold...


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## PARKER113 (Jul 6, 2020)

Thanks butcher! Learning is priceless that's for sure. And lots of fun along the way. I've enjoy reading your posts throughout the years! Time sure flies.


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## PARKER113 (Jul 6, 2020)

So I still have this orange solution that tests orange with stannous. It dropped some gold in the first few days of adding SMB. I've decanted it and saved what dropped.

Now I'm not sure what to do with the solution. It came from two batches of cemented gold. And some fine gold power from a previous batch of chips. 

I've added so about 4 teaspoons of SMB in total and I'm expecting 1 to 3 grams of gold. 

The PGM may have come from a batch I had last year of about 5 seemingly gold plated things that came from a few older servers. Under the CPU there were these pads that were easily removed. I was able to pull golden hair like fluff from where the CPU pins would go in the pads. I found them interesting so I saved 5 and attempted to poke them all out with a pin. But after 1 I decided to soak them in HCL. A week later I was able brush them all off with a toothbrush. 
Then I washed the powder and tried dissolving it with bleach. I can't seem to remember but I think I wasn't able to dissolve everything so I filtered it, washed it and tried dropping with SMB. I forget if some gold dropped but it still tested positive for gold after and I couldn't drop anymore. I ran out of time to experiment further. 
So this year (last month) I cemented everything and cleaned the powders until there was no color change in the solution. 
I've added all three powders together, dissolved with bleach and the solution turned red. After adding a few grams of SMB the solution turned yellow orange and dropped maybe .2 of a gram of powder after heating. 

I don't know how to deal with silver, or PGMS with the chemicals I have yet. 

If you guys care to voice your thoughts, what should the next step be?


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## PARKER113 (Jul 6, 2020)

Last night washed the precipitate in a separate beaker and let settle. 
I added the two test solutions I made from it to the main orange solution.
One with double HCL (nothing dropped) and the other test, double water (some dropped and solution turned clear but tested a faint orange) 
Also added another teaspoon of SMB to the orange solution last night. 
Just a few minutes ago I checked on everything and some dark powders dropped. But the test is still orange with a faint purple. I may decant it to get the powders again.


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## DylanDownright84 (Jul 7, 2020)

goldenchild said:


> This is where I got my SMB. They used to sell a nice litte 3 gallon bucket at one point. But you can buy it in a five pound bag for cheap. I'd recommend putting it in a bucket to keep it dry. With a large amount you'll never have to worry about SMB again. If you go through a five pound bag or even a... *gulp* 50 lbs bag you're doing well! 8)
> 
> https://www.dudadiesel.com/search.php?query=sodium+metabisulfite



I order the same 5lbs bag and when it goes into my dedicated SMB jar I add a few of these to help keep moisture out. Pretty sure I add a few packets to anything that I keep in a bag or jar that needs to stay dry.


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## PARKER113 (Jul 7, 2020)

That's a good idea! I didn't add any to my plastic container. But I think it will help it keep better.


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## kurtak (Jul 7, 2020)

PARKER113 said:


> Last night washed the precipitate in a separate beaker and let settle.
> I added the two test solutions I made from it to the main orange solution.
> One with double HCL (nothing dropped) and the other test, double water (some dropped and solution turned clear but tested a faint orange)
> Also added another teaspoon of SMB to the orange solution last night.
> Just a few minutes ago I checked on everything and some dark powders dropped. But the test is still orange with a faint purple.



per the underlined - I don't see a "faint purple" in the test --- what I do see is the orange/brown known as a FALSE positive which is the result of using excess/more SMB then needed for dropping the gold - which is no big problem just shows you are using more SMB then needed

It can also be confused for as a positive for PGMs but is really just showing you used to much SMB

Kurt


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## PARKER113 (Jul 7, 2020)

Thanks for the insight Kurt! Couple questions, why is the solution still orange, why did it turn purple in the first place, and what should I do with the solution now? 
Thanks alot! My family thinks I'm a pro refiner/ scientist. Im just a noob mining for gold! You guys are the real deal


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## FrugalRefiner (Jul 7, 2020)

When in doubt, cement it out. I should probably add that to my signature line, as it addresses so many situations like this. Put some chunky pieces of copper in your solution, add some circulation (an aquarium bubbler, or at least some periodic stirring), and it will cement out any precious metals. Any thing that cements out can be dissolved and re-refined.

Don't get caught up in the color of the solution. Many elements can give many different colors.

Dave


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## Shark (Jul 7, 2020)

You have recovered a fair bit of gold, if not all of it. If your doubting that, process your left overs (waste). The first step is usually to add copper to it to drop any remaining or missed values. 

In case that is not clear, the first step of treating your waste is to remove left over values by using copper. You get any remaining valuable metals AND start treating your waste for proper disposal. Dave's advice is spot on, I think.


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## PARKER113 (Jul 8, 2020)

Thank you Dave and Shark. I will cement out any remaining values if there are any left. 

Right now I'm letting the dropped precipitate settle and tonight I will decant and wash a few times with HCL and water and then dissolve with bleach. I'll heat it up and let it cool off until the next afternoon. Then I'll add SMB. 

For my next batch to dissolve of 1586 grams of Square flatpacks I've noticed there are grayish shells of pins floating around. I would assume they are silver. When I dissolve them together with the gold will they drop as white crystals at some point before I drop the gold? 
I've tried searching for a while but all posts deal with nitric acid. I would be thrilled to learn how to drop silver or PMS from a HCL-CL solution. 

Best regards!


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## FrugalRefiner (Jul 8, 2020)

PARKER113 said:


> Right now I'm letting the dropped precipitate settle and tonight I will decant and wash a few times with HCL and water and then dissolve with bleach. I'll heat it up and let it cool off until the next afternoon. ___ Then I'll add SMB.



You left out a step. TEST with stannous. It will not only tell you if there are any values in this batch, but it will build your experience for future batches.



> For my next batch to dissolve of 1586 grams of Square flatpacks I've noticed there are grayish shells of pins floating around. I would assume they are silver. When I dissolve them together with the gold will they drop as white crystals at some point before I drop the gold?
> I've tried searching for a while but all posts deal with nitric acid. I would be thrilled to learn how to drop silver or PMS from a HCL-CL solution.



Assumptions can often lead you in the wrong direction. I've never heard much about silver pins. I've often heard of pins being coated with metals that have dissolved, then cemented out.

Silver is only marginally soluble in chloride solutions. If the Cl- concentration is high, a bit of silver can remain in solution. Diluting the solution prior to filtering and dropping the gold will cause it to drop as insoluble AgCl.

I'm not sure what you're referring to as "PMS".

Dave


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## PARKER113 (Jul 9, 2020)

Thanks for the reminder to test! Usually I don't test solutions after I dissolve. But it is good practice and I'll be able to spot other noble metals too. 

Sorry, that's what I meant by PMS except it was supposed to be PGMS. I missed the G. 

The thing is I'm expecting to run into at least one of them when I use HCL-CL for the silicone wafers and when I get around to the magnetic and non magnetic wires from the dip chips and flatpacks. I read there could be some on the wires. I will probably AP them or if i have time do as recommended and use salt water to rust them out.


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## PARKER113 (Jul 9, 2020)

And thanks for the tip about getting silver to drop by diluting with HCL Dave!
My apologies, when I said silver pins I meant silvery wires from chips. Also possibly coated with PGM if I'm not mistaken.


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## nickvc (Jul 9, 2020)

I wouldn’t get to excited about finding PGMs in e scrap they are not that common, Soviet manufactured material used them extensively but much rarer in the west except in old telephone exchanges newer telecom boards that look rubbish and some military applications. There may be others but as I said not commonly found.


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## PARKER113 (Jul 9, 2020)

Thanks for the reply nickvc, I think you are right. But I have read on here repeatedly though that there may be some on the braze of the silicone wafers and also some on the wires from the chips. Maybe it's best to address that in detail for the members hehe.


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