# Metabisulfite



## Anonymous (Nov 13, 2010)

Hi all, I have a question,(precipitant Gold)) the sodium metabisulfite = sodium bisulfite?


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## qst42know (Nov 13, 2010)

Two different chemicals but both precipitate gold.


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## Anonymous (Nov 13, 2010)

thank you very much


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## Anonymous (Nov 13, 2010)

There are other "sulfites" that will precipitate also.A few years ago I couldn't get sodium metabisulfite fast enough for a process,so I used an off the shelf product that contained sodium pyrosulfite.The resultant powder was dirtier than usual due to the other contaminents in the product,but none-the-less it worked.


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## butcher (Nov 13, 2010)

sodium pyrosulfite is just another name for SMB.
http://www.google.com/#hl=en&expIds=17259,23756,24472,24692,24878,24879,27023,27404,27584,27601&sugexp=ldymls&xhr=t&q=sodium+pyrosulfite&cp=0&pf=p&sclient=psy&site=&source=hp&aq=0&aqi=&aql=&oq=&gs_rfai=&pbx=1&fp=c258727765a73be7


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## Anonymous (Nov 15, 2010)

The gold not precipitate, it gets dark and after turn to his yellow color. To add urea, I do not precipitate. To boil and to add cloridric ultimately, I do not precipitate ¿?


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## butcher (Nov 18, 2010)

Aros, I suspect we have a language difference making this a bit more difficult to help with your questions.
Aqua regia can be hard to learn. Is this your process? What materials are you processing, tell us steps you have done so far.

Are you reading HOKE'S. It is very important to your success in this work.

It sounds like maybe oxidizer's nitric acid (or bleach depending on process) keeping gold in solution?
Urea is the NOT best way in my opinion, try driving out nitric with careful slow evaporation to thick solution, adding HCl to rewet do this 3 times. Then dilute solution with water.

Or is there too much base metals also dissolved in solution?
These can also hold gold in solutions.

Gold can also be cemented out with copper buss bar and then reprocessed, if you cannot get it out by driving off nitric.

Do not forget to use your stannous chloride test of these solutions.

More detail of your process can give us clue's to something we may see to help with your trouble.


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## Anonymous (Nov 19, 2010)

I sorry for my English. I am reading hook's book. The process is with aqua regia. I Buy today bisulfite sodium new, I went back to boil and I added new bisulfite this time aftertaste a white sediment, it put turbid yellow itself but black no. Theoretically only there was gold, do the cleaning before with nitric


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## Anonymous (Nov 19, 2010)

Is the white residue gold in this process?


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## butcher (Nov 20, 2010)

Aros, white residue can be several things, depending on process and what you have done so far.
some possibilitys are NaCL table salt, very water soluble even cold, silver chloride will usually darken in light if not too acidic not very soluble in water even hot, lead chloride, slightly soluble in very hot water, copper I chloride this will dissolve in HCl, many other things may give white powders did you use Urea?

also are you having trouble with precipitating the gold? did you evaporate off nitric before adding the sulfite?

if you can explain the steps you have done so far it will help with our ability to answer your questions.


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## Anonymous (Nov 21, 2010)

Thank you for answering . I am going to reinitiate the proof.( the child tries ) I Have problems to precipitate. I carry many proofs
1- Dissolving in nitric to eliminate another metals
2- I will filter 
3- Doing the cleaning with water
4- Dissolving in aqua régia the gold
5- I will reduce three times the nitric boiling . ( bad that did I crystallize?)
6- Adding hydrochloric 
7- Adding 0,5g bisulfite
That do you hold an opinion? Correct steps?


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## butcher (Nov 21, 2010)

sounds like you are getting it good job. 
maybe I suggest., other members may have better suggestions?

2. let settle decant (remove liquid from powder), if small lots, I usually do not want my powders stuck in paper.
3. washing here may not be needed
5. remember not boiling just evaporate, too hot is not good, notice in Hokes they use steam for heat (unless the steam was under pressure) , this would make the aqua regia below the boiling point of water less than 100 degrees C, we just want the vapors to remove the more volitile gases, not be boiling in the pot.
5. if lead a few drops of sulfuric acid last evaporation.
5. you will need to dilute if silver chloride, some HCl may push out more silver chloride if it is involved.
5.let powders settle, decant and filter solution
7. is this how much gold you expect in solution? 0,5g

steps 8, read more in Hokes, your doing a good job, I may be forgeting something.
steps 9, do not forget stannous chloride testing.


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## Palladium (Nov 22, 2010)

What type of material is this your processing?
How much gold did you start with after you removed the other metals with the nitric?

You know if it we me i would just throw some copper in there and recover your values and start the process over again. At this point it would be fairly easy for us to walk you thru it step by step after you recovered your values.


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## Palladium (Nov 22, 2010)

butcher said:


> 5. remember not boiling just evaporate, too hot is not good, notice in Hokes they use steam for heat (unless the steam was under pressure) , this would make the aqua regia below the boiling point of water less than 100 degrees C, we just want the vapors to remove the more volitile gases, not be boiling in the pot.



Butcher makes a good point. Though the experienced members of the board know what this means most students who come here to learn get this term confused. Literally !!!!

I would like to see if we all can't start correcting this terminology and using the simplified term so as not to confuse the ones who don't understand the meaning. What do you think guys?


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## Anonymous (Nov 22, 2010)

I am with the following proof, now filtering the nitric. The cl sn do not work, the gold was, did it with sn electronic solder sn 60 pb 40. I added water being necessary to it happened, immediately they precipitated wits. Apply blowtorch, you went back to metal leave. Now I dissolve sn plumber sn 97 ag 3. I am going to try. I make them out the proofs of electronic trash with restrooms, I do not lose very much, only you are to learn the technique. I have a doubt on the acidity of the acid, once I boiled to eliminate the nitric and I added cl, if I add bisulfite it boils, is that good? Or must I dilute in water staff of the flag that not boil 

Thank you for the information, I have much to read


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## butcher (Nov 24, 2010)

This is hard 
I cannot understand the question.

Are you trying to test for gold in solution with stannous chloride SnCl2 (tin and HCl)?
If you used 60/40 solder you have introduced lead, this will form lead chloride white salts. 
We need more information and the language barrier is hard for us to communicate as we need to be able to help.
Do you have lead in gold solution now?
Does solution contain gold?
Is solution full of other metals besides gold?
What color is this solution?
We need to test for gold, with good SnCl2 solution, if shows gold.

Evaporate solution to thick syrup but not to salts, add small amount HCL, evaporate to thick add some HCl, evaporate thick add 10 drops H2So4 sulfuric acid,
Add 10 times water, let settle, If white powder (silver or lead if any), can add a little HCL, if white milk form's silver still in jar let settle, 24 hr, decant (remove liquid from powder, try not to move powder) filter liquid is it yellow? 
If liquid is yellow, and gold in solution (stannous chloride test), try sodium bi sulfite, should smell SO2 gas (rotten eggs), liquid may turn brown, and gold will make brown salt let settle, remove liquid without moving powder.

If all everything fails, and gold is in acid water, use piece of copper to cement replace gold, brush off copper, let gold powder settle, decant (remove liquid from powder), test solution for gold.

Did you get HOKE'S book? You do need to get it and read, gold cost too much! We are not going to be able to tell you how to get gold, there is so much you need to learn, and the language difference slows us down too much, read that book, it has the answers better than we can give, 

Hoke’s book will make small hill from this mountain,


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## Anonymous (Nov 24, 2010)

Sorry, short sentences
I have now the yellow syrup, Now like do I prepare it to add bisulfite? 
Do I add water, acid cl, both, proportion? 

I added copper in the previous proof, it turn black. Is it black the gold?
Thank you for patience


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## butcher (Nov 24, 2010)

What is previous proof? Please explain meaning of word proof.
Is this other solution from this yellow syrup?

If copper in acid and gold dissolved, the gold goes to the copper and Gold falls to bottom, powder black gold, some black gold can stay on copper. (Black = gold)

Test drop of yellow syrup (no nitric) add drop stannous chloride (tin dissolved in HCL), what color? Purple (violet = Gold) (no change = No Gold).

If yellow syrup has gold dilute (1 part yellow syrup: 4 part water), add bisulfite, change brown color, smell like bad egg, (brown powder = Gold).

Short sentence good.


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## butcher (Nov 24, 2010)

Aros, Juan speak spanish, maybe he be big help?


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## Anonymous (Nov 25, 2010)

Today or morning to try on it. Does the black gold melt down or initiating cycle?

A curiosity for the members, sorry it this in Spanish

http://nostrabola.blogspot.com/2008/09/refinacin-de-oro-por-agua-regia.html


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## butcher (Nov 25, 2010)

when you get the powdered gold, if light brown wash it using Harolds instruction's.

if powdered gold is black I would dissolve it again and re-refine it, them wash.

after brown powdered gold is washed and dried it can be melted.


thanks for the spanish version (cpu in aqua regia), I have seen an english version of that same process.


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