# Reuse Your SMB?



## joekbit (Dec 17, 2014)

Hello all

I know I'm new around here but I finally got things going, and took on one of the hardest jobs. Pins from socketed CPUs' . among other small items that I have been practicing with for about 5 months.

So here's the deal. I had 3 batches of AR. I dropped the first batch and it went like a charm. I used a plastic syringe with a tube attached to recover the powder from the bottom. At that time I was tying to decide what to do with the fluid, put it in the waste or just let it sit and see if anymore gold would drop. Instead I took my 2nd AR batch and poured it in to the fluid from the first and wow it dropped as fast as it hit. So since there was more than enough room in the beaker I took the third batch and poured it in and the same result. :lol: 

Going to give it a day or so, test with stannous, use the syringe to suck up the powder and just keep the fluid sealed to see if it can handle a fourth batch of AR. 

One last thing, the syringe works great. Leave it inverted a few minutes for the powder to settle and just drip it into a storage container. I'm using a 10 ml jar for now. Once its full of the lovely black mud, "very concentrated" I will then use the same procedure to extract it for final washes and melting.


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## yar (Dec 17, 2014)

I have to ask why are you not decanting or siphoning after precipitating? That way you can do your washes in the same vessel. I would think that you may be losing some values, the powder is going to stick to the inside of the tube and the syringe.


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## MarcoP (Dec 17, 2014)

As above, I was about to say that with my little experience PMs powders loves to stick in plastic and may get stuck to it.
In any case don't put the liquor in the waste, but in a stock pot.


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## joekbit (Dec 17, 2014)

Thanks, stock pot it is. As far as what sticks, I thump the syringe and I can see the powder slide down. When I am done I rinse with water back into the drop jar.


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## Shark (Dec 17, 2014)

The powders will get stuck between the wall of the syringe and the rubber plunger. After a few times you will notice it getting harder to move the plunger in an out. If the plunger is actual rubber, eventually it will also become hard and loose it's ability to suck in the liquids effectively. I think that is due to the nitric attacking the rubber, but I am not sure. I use a cheap turkey syringe here, but I switch to a new one pretty often, before I start having problems with them. The best cure would be true pipettes and avoid the plunger all together. Since I do this as a hobby, I haven't moved to using some of the true tools needed yet.


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## MarcoP (Dec 17, 2014)

Syringes have found a good rule in my lab as I'm able to suck fluids out without disturbing what's settled. But that's about it, a 20ml syring is way faster then a 3ml pipette, and is washable too.


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## joekbit (Dec 17, 2014)

Sorry , I did decant down about 80% then used the syringe. The fluid I decanted was what I poured the other 2 batches of AR into. Photo's, first batch AR followed by the drop from it. The last photo is the last drop done in the decanted fluid from the first 2 drops. Photos are in wrong order, top should be bottom and bottom should be top.


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## FrugalRefiner (Dec 17, 2014)

Shark said:


> The best cure would be true pipettes and avoid the plunger all together. Since I do this as a hobby, I haven't moved to using some of the true tools needed yet.


The best practice is to leave the gold in the vessel in which it was precipitated. Decant / syphon / suction the liquid from the vessel. Then dry the gold in the same vessel. Every time you use another vessel, syringe, pipette, etc., you risk losing your values.

Dave


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## joekbit (Dec 17, 2014)

FrugalRefiner said:


> Shark said:
> 
> 
> > The best cure would be true pipettes and avoid the plunger all together. Since I do this as a hobby, I haven't moved to using some of the true tools needed yet.
> ...



Understood, thanks, I have been looking for pipets. Any links for suppliers would be great. The syringes I prefer to use for my acids, accurate measurements and no spills. After use I put them in water. Been using the same syringes for about 4 months, plungers are in great condition.


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## FrugalRefiner (Dec 17, 2014)

joekbit said:


> I have been looking for pipets. Any links for suppliers would be great.


On things like bulb syringes, pipettes, etc., I check Amazon prices against FeePayPal prices and usually find something that's a pretty good value.

Dave


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## joekbit (Dec 17, 2014)

Thanks Dave

I really want some center spouted syringes. The ones I have are side spouted. In other words the spout is right at the edge. With the centered ones the convex shape is dead center to the spout.


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## Shark (Dec 17, 2014)

FrugalRefiner is right. I was just considering the removal of the solution not the powders. Each unnecessary step avoided improves the odds for a better recovery rate. I found that one out the hard way,


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## necromancer (Dec 18, 2014)

i use my old e-juice bottles.

sample shown here:
http://www.ebay.ca/itm/30Pcs-30ml-E...658?pt=LH_DefaultDomain_0&hash=item3a9e2056c2

you can get 10ml to 100ml with a long dropper spout. i also use them for my Stannous Chloride.

much better then a syringe. in my opinion. you can control the flow with 2 fingers, not 2 hands.


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## rickbb (Dec 18, 2014)

I believe that I have read that using too much SMB can lower the quality of gold by dragging down base metals. 

The rule of thumb I've read is to use no more than 10% over the expected yield of gold, by weight. If you think your going to get 1 gram of gold then you use a maximum 1.1 gram of SMB.

And as others have said, decanting after letting it settle, usually overnight, then leaving the powder in the original beaker to wash is best. At least in my experience.


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## yar (Dec 18, 2014)

A tip I recentley read from G_Axelson is to dissolve SMB in warm to hot distilled water and pour about 3/4 of it in your gold solution. After the initial drop then pour the rest in. Your gold should drop completley within an hour or two. Tried it for the first time the other day and it worked like a charm. 

Next time I am going to not add water to my gold solution before adding SMB. What I will do it add enough water to my SMB that will equate to how much water I would have added to my solution prior to adding SMB. So if I have 50 ml of Au chloride i will dissolve SMB in 100 ml of water and then add to my gold solution. This way I am not adding an excess of water and will not have an excess of waste to deal with after decanting the used SMB.


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## FrugalRefiner (Dec 18, 2014)

yar said:


> Next time I am going to not add water to my gold solution before adding SMB. What I will do it add enough water to my SMB that will equate to how much water I would have added to my solution prior to adding SMB. So if I have 50 ml of Au chloride i will dissolve SMB in 100 ml of water and then add to my gold solution. This way I am not adding an excess of water and will not have an excess of waste to deal with after decanting the used SMB.


Ray,

One of the reasons for adding water to your concentrated gold solution prior to precipitation is to cause any silver that may be in solution to precipitate out before you reduce your gold. A small amount of silver can go into solution in a strong aqua regia solution, but it drops out when the solution is diluted. This is why most people recommend diluting and cooling the solution, and adding a bit of sulfuric acid before reducing the gold. The sulfuric will cause any lead to precipitate. Diluting and cooling the solution will cause both the lead and any silver chloride to precipitate. Then filter the solution before adding the reducing agent of your choice.

Dave


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## MarcoP (Dec 18, 2014)

yar said:


> After the initial drop then pour the rest in.


I think it should read


> After the initial drop, test with stannous chloride and then pour the rest in if necessary.


Off course the OP is able to reuse SMB simply because he over used, say 3x time over what's needed, otherwise he would'nt be able to.


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## yar (Dec 18, 2014)

MarcoP said:


> yar said:
> 
> 
> > After the initial drop then pour the rest in.
> ...


 I try to use an equal amount of smb to gold in solution. So adding 3/4 and then adding the rest after the drop seems to be ok. Then after all smb has been added and when gold is no longer dropping I test with stannous. If it is positive then I add a bit more, if it tests negative I know that I have not used an excess of smb and should not have a problem with base metals being dragged down with my powders. 

@ Dave, you are absolutely correct sir, after typing I realized my mistake. Thank you for the correction. Have to chill solution after adding water, allow any silver to drop and then add sulfuric to drop any lead. Filter and then drop with precipitant of choice.


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## goldenchild (Dec 18, 2014)

If you're dead set on using a syringe instead of the usual decanting by pouring use something larger like this

http://www.ebay.com/itm/Fork-Oil-Syringe-Motorcycle-Shock-Gauge-Level-Easy-Professional-Adjuster-Tools-/331318463470?pt=Motorcycles_Parts_Accessories&hash=item4d241e8bee&vxp=mtr

or even this!

http://www.ebay.com/itm/VS405-SEALEY-OIL-INSPECTION-SYRINGE-1-5LTR-OIL-SUCTION-SYRINGE-NEW-TOOL-/400729851228?pt=LH_DefaultDomain_3&hash=item5d4d5c455c

This will make the process go much faster than with a little itty bitty syringe. But then why not just start a siphon? I'm just not understanding why you want to capture the gold and leave the solution behind.


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## kurtak (Dec 18, 2014)

it looks to me like you used "WAY" To Much SMB to start with which is most likely why it is continuing to precipitate gold over & over & over again

the tell tail sign is also in how dirty you gold powders look - they should be a nice golden orange brown in color (when wet) & should shift to a nice orange blond color when dry - so you got "A Lot" of base metal co-deposit due to using To Much SMB

OK - now you have your gold powders in this little bottle - how you going to get them out when it comes time to wash, dry & melt :?: (not saying it cant be done - just that you are making more work of it with potential loosing gold the way you are going about it)

Do what others are telling you --- decant the solution from the beaker you precipitated in - then do your washing in that beaker (do you even know what we are talking about here?) then dry it in the same beaker

Make sure you use a watch glass on your beaker when doing the washing - or it likely going to sputter out the top especially being that dirty

Kurt


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