# General Reaction List



## lazersteve

All,

There seems to be a lot of confusion on the various acid mixtures used in the different reactions. I've put together this quick list of reaction mixes. I know it's incomplete so I'll be adding to this list soon.

Here's a quick reaction list:






 AR= Aqua Regia = 1 part 70% Nitric Acid (added in small increments), 3 parts Muriatic Acid (some guys use 4 parts muriatic). Used to dissolve high karat gold, gold powder, gold foils, dissolves Platinum when hot. Excess nitric must be evaporated off or neutralized with Urea to pH 1 +/- 0.4, then drop gold with SMB.
Hoke states 4 fluid ounces HCl + 1 fluid ounce HNO3 dissolves 1 troy ounce gold. This is equivalent to 3.8 mL HCl + .95 mL HNO3 per gram of gold.






 AR Recipe 2= Poor Man's AR = 8 oz Sodium Nitrate (added in small increments),(aka Subzero), 480 ml water, 960 ml Muriatic Acid plus heat. Used to dissolve high karat gold, gold powder, gold foils, dissolves Platinum when hot. Excess nitric must be evaporated off neutralized with Urea to pH 1 +/- 0.4, then drop gold with SMB. In lieu of urea, I prefer Sulfamic Acid used in the dry crystals form. Add the crystals until the solution no longer fizzes when stirred. When using dry sulfamic acid you will have a small amount of undissolved crystals in the bottom of the solution once all of the fizzing stops. These left over crystals can be dissolved by adding a little warm water. Many thanks to 4Metals for the sulfamic acid tip!
The above mentioned recipe makes enough AR to dissolve 160 gm Pins or 32 oz of ceramic cpus.







 HCl-Cl= Clorox Method = 4 Parts Muriatic, 1 Part Clorox (added in small increments). Used to dissolve gold foils and powder. Drop gold with SMB, NO urea needed.






 AP= Acid Peroxide = 2 Parts Muriatic Acid, 1 Part 3% Hydrogen Peroxide. Dissolves base metals, slowly dissolves gold when heated. If gold is present drop with SMB, NO urea needed. An even better method of precipitating dissolved gold is too continue using the solution until it becomes saturated with copper, then the gold precipitates as fine black powder.






Acid Peroxide Must Read



 Dilute HNO3=Dilute Nitric Acid= 1 part water, 1 part 70% Nitric Acid. Used to inquart, dissolve base metals, dissolves palladium, and dissolves silver. Silver nitrate will stain skin blue which turns black in sunlight. Skin remains black for nearly 1 week.
Hoke states 4-6 pounds of concentrated nitric acid dissolves 1 pound of base metals. 5 pounds of 70% nitric, 1.41 sp.gr. is 1610 mL =~ 0.425 gallons. This equates to 1610 mL / 454 gm =~ 3.55 mL per gram.



Lazersteve said:


> *Nitric with Copper*
> The key equation for copper from wiki is:
> Equation (1) :
> Cu + 4 HNO3 → Cu(NO3)2 + 2 H2O + 2 NO2
> 
> Copper (Cu) has an atomic mass of 63.55 grams per mole
> 
> 70% Nitric acid has 15.8 moles per liter of nitric acid (HNO3).
> 
> Using the ratios from the equation above:
> 15.8 / 4 = 3.95
> 
> Therefore 1 liter of 70% HNO3 is enough HNO3 to dissolve 3.95 times the mass of copper in equation(1):
> 
> 3.95 x 63.55g =~ 251 g ( 3.98 mL of 70% HNO3 per gram of copper)
> 
> *Nitric with Silver*The key equation for silver from wiki (Wiki Silver Nitrate) is:
> 
> Equation (2):
> Ag + 2 HNO3 → AgNO3 + NO2 + H2O
> 
> Silver (Ag) has an atomic mass of 107.9 grams per mole
> 
> 70% Nitric acid has 15.8 moles per liter of nitric acid (HNO3).
> 
> Using the ratios from the equation above:
> 15.8 / 2 = 7.9
> 
> Therefore 1 liter of 70% HNO3 is enough HNO3 to dissolve 7.9 times the mass of silver in equation(2):
> 
> 7.9 x 107.9g =~ 852.4 g (1.17 mL of 70% HNO3 per gram of silver)
> 
> The above numbers are the theoretical figures, in practice you will find that you can get more life out of your nitric by :
> 
> a. Adding water to the reaction.
> b. Covering the reaction vessel with condenser or watch glass (reflux).
> c. Capturing the NOx (mixed nitrogen oxides) off gases.
> d. Recycling the nitrate by products of the reaction.
> 
> 
> You can use the examples above to determine the amount of nitric required to dissolve any metal by substituting the appropriate equation and molar mass of the metal into the formulas given. Please note that nitric will not attack all base metals, and even passivates some and their alloys (wiki nitric acid).



 Cold Nitric Acid Recipe
 Dry Nitric Acid Recipe
 Distilled Nitric Acid Recipe

 H2SO4= Sulfuric Acid = 1 cup 96%+ Sulfuric, 1/8 tsp glycerin (optional). Used as electrolyte in electrolytic cell along with a small amount of glycerin. Effective on medium to large gold plated items. With specially designed anodes and cathodes large batches of smaller plated items can be processed. Not used for Gold filled or karat jewelry. 
Use until acid is saturated with black powder typically 12-24 hours of operation. Sink any floating black powder, let settle overnight, pour off bulk of acid for reuse, and dilute remaining acid with 4 parts water.










Cell Information

Black Powder from the Cell

 HCl= Muriatic Acid = 31.45% Hydrochloric Acid. Used in the crockpot method and for general cleanup of gold foils and powders. Dissolves base metals. Also used in making stannous chloride gold testing solution.

 SMB= Sodium Meta Bisulfite (aka Storm Precipitant) plus water=28.3 Grams Sodium Meta Bisulfite, 240 ml H2O. Used to drop gold from gold bearing solutions.
Add 65 grams to 100 ml water for saturated solution. Add to pregnant solution until stannous chloride test on solution is negative for gold.






*Here's a procedure that can be used to clean and dry the resulting gold powder:*

Cleaning and drying Gold Powder

Colors of Borax in Dish

Details of Gold Drying process



 AuCl3= Auric Chloride= Term used to describe gold dissolved into solution. Typically imparts a golden yellow color to solutions. Stains skin and other organics purple. 






 SnCl2= Stannous Chloride= Used to test solutions for precious metals. Made by dissolving metallic tin in hot muriatic acid. Loses strength when stored. Made by adding 1-2 grams of powdered tin to 30 mL of HCl. Heat until fizzing starts. A little extra undissolved tin powder helps the solution keep for longer. Keep air out of container when stored to extend life.
Positive color test as follows: 

Purple/Black color is Gold in solution, the darker the spot the more Gold.

Yellow/Brown that turns to Blue-Green after 30 seconds indicates Palladium in solution, the darker the spot the more Palladium. 

Orange/Brown color is Platinum in solution, the darker the spot the more Platinum. 






Stannous can be used to test for Rhodium in solution as described here:

Rhodium Test

Stannous Chloride False Positives

 (NH2)2CO= Urea= 8 oz Urea, 480 mL Water. Used to neutralize excess nitric acid in AR process before dropping gold with SMB. Add until solution doesn't fizz and pH reaches 1 +/- 0.4.

 H3NSO3= Sulfamic acid: Add dry crystals to pregnant solution with constant stirring to remove excess nitric acid via nitrous oxide. Once fizzing is no longer visible excess nitric acid is gone. Add enough warm water to dissolve any left over crystals in the bottom of the solution, filter 100% transparent, and precipitate your gold, platinum, or palladium. When large excess of nitric acid is present solution will foam vigorously and expand to 3 to 4 times it's original volume. Make sure your reaction vessel has enough head room for this rapid expansion. Sulfamic acid can also be used to test for excess nitric in solution: Add a pinch of sulfamic acid to the pregnant solution and observe the surface of the solution. If you see vigorous fizzing and foam around the area where the crystals entered the solution, you have excess nitric acid. Add sulfamic to pregnant solutions *before* any filtration to eliminate toxic NOx fumes when filtering. If you do not observe a vigorous fizzing and foam, your solution is free of nitric acid.

 AgCl= Silver Chloride= White precipitate that forms when silver is exposed to chlorine in solution. Turns purple in light, darkens further in sunlight. Solid by product of using AR on lower karat jewelry. Hazardous to melt due to fumes. Production of silver chloride should be avoided if possible. Can be converted to silver metal with lye and karo syrup or HCl and Al foil. Also can be converted using very dilute (10%) H2SO4 and an iron stirring rod. Do not let it dry out before conversion to silver metal.

For 1 tr.oz. of silver metal, about 41.5 grams of silver chloride, it takes about 20 grams of sodium hydroxide, 13.3 mL of light Karo syrup, and 133 mL of water. (Thanks GSP!)







 Precious Metals Precipitants Chart

 Inquartation= 3 parts base metal (Silver preferred) , 1 part Gold, Dissolved in hot dilute nitric acid. Powder/Honeycomb that remains is Gold and higher PGM's if present in source material. Left over liquid contains Silver, base metals, and Palladium if present in original alloy. Detailed Inquarting Process.


Hoke states 4-6 pounds of concentrated nitric acid dissolves 1 pound of base metals. 5 pounds of 70% nitric, 1.41 sp.gr. is 1610 mL =~ 0.425 gallons. 1 gram of material requires 1610 / 454 =~ 3.55 mL HNO3 + 3.55 mL H2O.



*Inquarted gold before acid processing:*











Properly inquarted gold after acid treatment.
 C12H26O3 =BDG or DBC= Butyl DiGlyme or DiButyl Carbitol = Organic solvent that combines with Auric Chloride and is insoluble in water based solutions. Separates from water based solutions as an upper phase (layer). After washing with dilute HCl gold is dropped as flakes using Oxalic Acid. Can be used on AR solution without neutralizing excess nitric acid.






 CH3C(NOH)C(NOH)CH3 =DMG or DimethylGlyoxime = Organic solid that combines with Palladium to form canary yellow crystals. Dissolve 1 gram in 25 mL of alcohol and add to 75 mL of hot water. Test with a single drop of DMG solution in a test tube sample of suspected palladium acid solution. In a minute or less you will see a yellow suspension of crystals if palladium is present.






 Conversion of Colored PGM salts to Sponge with Zinc Turnings

Separating Mixed PGM Blacks

 Purifying Colored Palladium Salts

Common Chemical Cross Reference

 HNO3 + K2Cr2O7 =Schwerter's Silver Test Solution = Add 20 grains of potassium dichromate to 30 mL of 35% nitric acid. Test by applying a single drop to clean silver surface. 

Here is a test on sterling silver:






and A test of Pure silver:





Here's an alternate method for making the silver test solution:

Dissolve Potassium Dichromate salt in 8mL of distilled water in a glass container. Add crystals until no more salt will dissolve in the liquid. 
Add 25mL of 70% Nitric Acid
Store in a small bottle.


*Testing with Schwerter's Solution*

Apply a drop of Schwerter's Solution to the test piece.

The color reaction of the solution with the metal will be as follows: 
Brass - Dark Brown 
Copper - Brown 
Nickel - Blue 
Palladium - None 
Gold - None 
Silver Pure - Bright Red 
Silver .925 - Dark Red 
Silver .800 - Brown 
Silver .500 - Green 
Lead - Yellow 
Tin - Yellow 






You can smelt to instructions

This list is *not* all inclusive. There are many more methods to dissolve gold and base metals.

Steve


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## aflacglobal

This i like. 8) 

Thanks Steve.


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## firedan525

Great post Steve


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## catfish

Hey Steve:

You did it again. This post is great.

Thanks for your many contributions to this forum.

Catfish


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## lazersteve

Catfish,

This post is a good example of the power of the community. Your formulas are part of the post, don't you recognize them? I have just began to summarize what we all have contributed. The idea actually came to me today when Destroyer repeatedly criss crossed several reaction ingredients in his posts. After the second time, the idea just hit me like a ton of bricks. Ralph has been prompting me via PM to do some Chemistry posts as well. For these reasons, and many others, I have to share the credit with many people here. I'll be expanding this post in due time so keep checking back for more updates.

The thanks should go to all the members for doing their parts in this forum.

Steve


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## aflacglobal

Yes, we do contribute.

But it takes people of your drive to keep it alive.
I don't see how you can do it and still find time for all the other things.
Trust me i know.

Thanks for the effort Steve.

Ralph


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## Destroyer

Yes that was awesome, I had been skipping thru some posts and next thing I knew I was all messed up. This will go in my Garage on the wall where I can see it plainly. 
I now understand there is reverse Plating.
I also see that AR can be made in different ways.


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## AuMINIMayhem

WOW!.. Kudos, Steve! That's exactly what I've been looking for as I often get confused to the different methods and the reason for making say AR over AuCl , etc.. Thanks .. once again you have proven, you are the man! 8)


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## Ky.Sam

lazersteve What color does the HCl-Cl solution turn? Should I heat it to get it to work better?

I put some material in a small amount today. Set it out in the sun to help heat it up. Seems like some salt fell out of the solution. Is that possible?

Maybe I did something wrong. Thanks


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## lazersteve

Ky,

The solution turns deep golden yellow when the gold dissolves.

Sunshine and heat will destroy the active chlorine. Chlorine is what dissolves the gold.

The salt is normal, add just enough water to dissolve the salt. If it does not dissolve in water it may be silver chloride and will remain in the bottom of the reaction vessel when it's all said and done. Just rinse the remaining salt very well with water when you complete the dissolution process. 

Steve


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## Ky.Sam

What is the ratio of acid and tin to make Stannous Chloride?


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## Noxx

I put about 1 inch of tin solder in about 50 ml of Muriatic Acid. I don't know if it the good ratio but works pretty well for me.


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## Anonymous

Hey all, my first post, got on the forums a couple days ago, first chance to sit down and start reading through the post. at first it was all intimidating, I'm not a chemist and refining these metals is just something I was starting to take interest in with no clue how it works. I'm still not understand NEAR enough, but Steve, your post alone explained so much that it removed an enourmous amount of the intimidation. Just wanted to drop a line here and say thanks for the work, I'll make another post elsewhere more appropriate as a more formal introduction and to ask my questions and explain what I'm looking at trying to do.


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## lazersteve

Doomsday,

Take your time to soak it all in before asking questions.

Welcome to the forum!

Steve


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## 61 silverman

Steve; Thank You Very Much this is the closest too the a-z''s of it all in a nut shell as I have read yet,I'm printing a copy of this post so at breaks and at lunch when working I will have plenty to read up on and memorize the what's and when's and hows of this refining..I talked with MIKE at Ation Mining the other day, It is a two (2) minute detour on my way home from work, tempting too stop in every day, just too be in the inviroment "LOL", Got a little bit of advise that I had not yet learned. Anyway great post STEVE thanks alot MARK.


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## lazersteve

Mark,

This list represents my early attempts at summarizing the reactions used in refining. It's in dire need of many additions. It pretty much focuses on gold refining and should be expanded to include the PGMs.

It's nice to know that despite it's age this post is still helping forum members.

Steve


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## Bernie Foley

Hi Steve,and members,
This has saved me rereading alot of the posts.It keeps me straight!
Very good job Steve!!!..Old information that is good information never loses it's value!!!!!....Bernie


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## phoenix_phx_

Great work! Thank you very much! You are very helpful


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## arthurcorbit

I'm new to this group and that puts me in a better position to see the true value of information like this. Some on here are used to seeing this kind of information and take it for granted. To me it is like turning on a good light in a dark room. I have been stumbling around in the dark for a lot of years but thanks to this forum and the people that have shared the information I don't have to do that any more. If I could have found this information 20 years ago my life just may have been different now. Please keep up the good work and you can bet this is one old coot that will be dloing a lot of reading on the fourm and paying close attention to anything new that's posted. Thanks Guys.

Art


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## Kbow

Thanks for the useful charts...
Hey Steve
When you coming to Decatur Alabama?
We got the lazer ready and waiting on you.

Thanks again for all that you do.

I got a batch of fingers in Acid Peroxide now.

Keith
(son of the man with lazer Bill)


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## lazersteve

Keith,

I was going to come up there last weekend, but the storm that wasn't (Fay) stopped me. Maybe this weekend (depending on the current storms track) or next (my Birthday weekend ). 

I'm taking off of work the entire second week of September so that looks like a prime time for me to travel.

Email me and we will set an exact date.

Steve


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## 61 silverman

STEVE, a question about # 5 in the list ( dilute nitric ) you state it can be used to **inquart** is this too mean that melting a combined amount of base metal and gold to make 6kt, is not necessary.. that adding the proper amounts to make 6kt gold content, then chemically disolve all the base metals leaving only the gold.. disolving using dilute nitric..
Is this so? I have been thinking for a long time this should be possible..
THANKS MARK :idea:


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## Noxx

Yes Mark you are right,
It's what it means.


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## Harold_V

Clarification is in order due to your post, which tends to repeat itself. 

If your question is can gold be inquarted, then parted in order to eliminate the dissolution of the gold and then precipitating--------no------it can not. You'll improve the quality of gold considerably, but you'd struggle to achieve even 98% purity, if that. In order to get gold fine, you must dissolve it and follow accepted practice, or part it in a gold cell. Regardless of how hard and long you boil inquarted gold, you're going to have inclusions that are not desired. 

Gold that has been dissolved and precipitated is rarely of great quality----unless the gold was already quite fine. Even precipitation doesn't purify perfectly. That's why you wash well afterwards. 

Read Hoke and achieve a better understanding, assuming you have any questions. 

Harold


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## wop1969

This list is not all inclusive. There are many more methods to dissolve gold and base metals. 
Steve

Steve, What method would you recomend is the safest with easy to abtain chems?. I have been reading for some time now. I have to give this a go but I am going to be very carfull as the more I read the more worried I feel  but I got to try, its in my nature to do things like this.


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## goldsilverpro

There are many methods, but only a few are practical. This is not usually an all-inclusive chemical forum. It tries to be a practical refining forum.

What exact type materials do you want to process?


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## Harold_V

goldsilverpro said:


> There are many methods, but only a few are practical. This is not usually an all-inclusive chemical forum. It tries to be a practical refining forum.


Yep! So much so that I am not much help here. All of my experience revolves around refining with commercially available reagents, using well known and accepted processes. It doesn't help that I have no chemical background. I have learned far more than I have taught others.

Harold


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## wop1969

goldsilverpro said:


> There are many methods, but only a few are practical. This is not usually an all-inclusive chemical forum. It tries to be a practical refining forum.
> 
> Wop. What exact type materials do you want to process?




gold and maybe plat, I have a freind that owns an auto salvage yard an he knows allot of salvage yad owners so if i choose I can get allot of cat cons.


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## goldsilverpro

C'mon Harold. You're the most practical man on the forum. That's good. We need someone to keep us on the straight and narrow.


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## butcher

And help us get the to get our gold pure, thanks Harold.


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## HAuCl4

What is the exact chemical reaction when dropping gold with SMB?. 

What is left in the liquid exactly asides of extra HCL?.


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## lazersteve

I've posted this before, but can't seem to locate it now.

Chemical formula of reaction between gold and sodium meta bisulfite:

Sodium Meta Bisulfite + Water = sodium bisulfite

Na2S2O5 + H20 --> 2NaHSO3

then we precipitate gold:

sodium bisulfite + auric chloride + water = sodium bisulfate + hydrochloric acid + gold

3 NaHSO3 + 2 AuCl3 + 3 H2O --> 3 NaHSO4 + 6 HCl + 2 Au

Steve


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## HAuCl4

Thanks Steve.

I guess the HCL can be recycled. Is there any recycling use for the sodium bisulfate or how to re-constitute it into bisulfite?


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## lazersteve

HAuCl4 said:


> Thanks Steve.
> 
> I guess the HCL can be recycled. Is there any recycling use for the sodium bisulfate or how to re-constitute it into bisulfite?



The equations involve only theoretically 'pure' reactants and products. In real life this is not the case. Most folks will have varying degrees of contamination in the mix too, so it's impossible to give on method that affords the complete recycling of all left over solutions aside from the standard removal of base metals and subsequent neutralization before proper disposal of the wastes.

Now that the disclaimer is out of the way, yes HCl can be distilled from the solution. Sodium bisulfate (NaHSO4) can be used to as a substitute for sulfuric acid to make nitric acid, hydrochloric acid, and is also useful in dissolving Rh in a melt. I'm not advocating that this is a practical or even economic method of utilizing the by products, just that it is theoretically possible.

There are many posts on the forum for utilizing the purified versions of the by products.

Steve


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## hfywc

Chemical formula of reaction between gold and sodium meta bisulfite:

Sodium Meta Bisulfite + Water = sodium bisulfite

steve,

from the equation, i assume that sodium bisulfite could be used in place of smb diluted in water. 

thanks alan.


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## lazersteve

hfywc said:


> Chemical formula of reaction between gold and sodium meta bisulfite:
> 
> Sodium Meta Bisulfite + Water = sodium bisulfite
> 
> steve,
> 
> from the equation, i assume that sodium bisulfite could be used in place of smb diluted in water.
> 
> thanks alan.



Yes.


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## butcher

Just thought I would kick up the dust on this for the new guy's.


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## NoIdea

lazersteve said:


> Dissolve Potassium Dichromate salt in 8mL of distilled water in a glass container. Add crystals until no more salt will dissolve in the liquid.
> Add 25mL of 70% Nitric Acid
> Store in a small bottle.
> [/list]
> 
> *Testing with Schwerter's Solution*
> 
> Apply a drop of Schwerter's Solution to the test piece.
> 
> The color reaction of the solution with the metal will be as follows:
> Brass - Dark Brown
> Copper - Brown
> Nickel - Blue
> Palladium - None
> Gold - None
> Silver Pure - Bright Red
> Silver .925 - Dark Red
> Silver .800 - Brown
> Silver .500 - Green
> Lead - Yellow
> Tin - Yellow
> 
> 
> 
> 
> 
> 
> 
> This list is *not* all inclusive. There are many more methods to dissolve gold and base metals.
> 
> Steve



Thanks Butcher, I was looking through my chem. stocks and was wondering what I was going to do with these.



The little piece of paper that came with it states: 1ml contains 0.004904g of K2Cr2O7 or 0.4904g/100ml.

Solubility is 15g/100ml at STP (ISI handbook). 

Do you think this will do or is it too weak?


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## butcher

I am not the one to ask. but looks to me like the ampules are fairly concentrated solution. I see no reason why they would not work.

just don't add as much water as the formula above stated, that is how I would approach it. and test your solution to see if it reacted on known metals as the post above states.


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## NoIdea

Thanks Butcher, Ill wait and see if anyone else cares to comment, don't really want to open it unless i have to.

Cheers

deano


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## lala14

Potassium dichromate, K2Cr2O7, is a common inorganic chemical reagent, most commonly used as an oxidizing agent in various laboratory and industrial applications. As with all hexavalent chromium compounds, it is potentially harmful to health and must be handled and disposed of appropriately. It is a crystalline ionic solid with a very bright, red-orange color. It is also known as potassium bichromate; bichromate of potash; dipotassium dichromate; dichromic acid, dipotassium salt; chromic acid, dipotassium salt; and lopezite.

Potassium dichromate (oxidizing agent). The reduction half-equation can be seen:

Cr2O72−(aq) + 14H+ + 6e− → 2Cr3+(aq) + 7H2O (E = +1.23 V)

compared with potassium permanganate. It is used to oxidize alcohols. It converts primary alcohols into aldehydes, or into carboxylic acids if heated under reflux. In contrast, with permanganate, carboxylic acids are the sole products. Secondary alcohols are converted into ketones — no further oxidation is possible. For example, menthone may be prepared by oxidation of menthol with acidified dichromate. Tertiary alcohols are not oxidized by potassium dichromate. 

its not to strong to use as it is but if want to reduce its value i would reduce to 80ml of distilled water \not 100mml 500ml of course you can make it but i heard its good stuff to dissolve gold an drop with smb or sb or magnesium but drops all the metals dissolved then you have a mess but good luck 


d[-_-]b jesse


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## steyr223

Excellent post Steve.
You put together a cheat sheet that I have.been working
On for almostt 4 months

Thanks


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## kj13

my aqua regia turned red, and wont precipitate...help


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## Oz

Well no one can help you without more detail. How much of what were you trying to digest would be a good start. What have you added besides hydrochloric acid and nitric?


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## kj13

I would like to know if anyone knows why some reasons on why my aqua Regia has turned red and everytime I add precipatant I get a red foam instead of a nice blue. Please replay, I need to get the Gold Chloride to solidify
:|


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## kj13

kj13 said:


> I would like to know if anyone knows why some reasons on why my aqua Regia has turned red and everytime I add precipatant I get a red foam instead of a nice blue. Please replay, I need to get the Gold Chloride to solidify
> :|


I was try to digest 187 grams of a mix of scrap 14 and 10 k I still have gold chloride that is still testing positive, I dont want to add to much precipatant, I added urea and it appears that a cycle of precipatate and digestion is occuring.


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## Oz

Aqua regia usually turns red when you have a decent concentration of gold or platinum. I have never seen blue foam on aqua regia when I precipitate gold.

You still have free nitric in your solution. It is a common mistake using too much.


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## AndyWilliams

lazersteve said:


> I've posted this before, but can't seem to locate it now.
> 
> Chemical formula of reaction between gold and sodium meta bisulfite:
> 
> Sodium Meta Bisulfite + Water = sodium bisulfite
> 
> Na2S2O5 + H20 --> 2NaHSO3
> 
> then we precipitate gold:
> 
> sodium bisulfite + auric chloride + water = sodium bisulfate + hydrochloric acid + gold
> 
> 3 NaHSO3 + 2 AuCl3 + 3 H2O --> 3 NaHSO4 + 6 HCl + 2 Au
> 
> Steve



Uh oh, I think I just understood my first chemical reaction! Maybe. . .


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## Harold_V

kj13 said:


> I would like to know if anyone knows why some reasons on why my aqua Regia has turned red and everytime I add precipatant I get a red foam instead of a nice blue. Please replay, I need to get the Gold Chloride to solidify
> :|


You have made a request two times, each time providing absolutely no information that might help someone provide some guidance. Why is that?

Harold


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## butcher

Lately we have many questions from new members wanting to learn the processes we use.

I have not read the general reaction list for several years.

But I have been referring new members to read it.

Today I spent a little time scrolling through the general reaction list and the organized links to other information that Laser Steve has so well put together.

I have read most all of this over the years and understand it, I am amazed at the work and thinking that Steve has put into doing this.

Any new member should spend some time reading and following this thread and links, it would help them in understanding the process.

New Members Go back to page one of this thread and read through it, also follow the links in the general reaction list by clicking your mouse on them, these links lead you to more information with even more links, so by using the back button, to get back to where you were in the general reaction list, Steve has done an excellent job of linking together this very helpful information. 

Here is a link to more:
http://goldrecovery.us/forum_search.asp

Thank you Laser Steve, you have done a lot of work to help all of us here on the forum.


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## lazersteve

Butcher,

Thank you for the compliment. What many old and new members alike don't understand is that the posts in the Guided Tour where carefully choosen to help everyone navigate the ever increasing size of the forum as it grows. It never ceases to amaze me how many times noobs are asking questions that have been answered over and over again. I know Ralph made a few versions of the 'GRF Handbook', but I have made many changes to the original posts of mine that he has included in that book. Everyone wants a 'drive thru' answers booth without putting in the real hard work required to learn not just how to do the reactions, but why they are happening the way they do, and what variables affect the outcome. Once they learn the basics, they forget to look back to where they learned the information from to refresh and renew what they have studied in the past.

It seems the forum has turned into a new group of 'instructors' who are merely teaching from the same old material that has been here since the early years. I personally have tried to continually refer members with questions back to the original content when possible, as opposed to repeating the same information over and over again. This serves several purposes, mainly to keep the size of the forum down and to give the proper credit to those who posted the original answers in the beginning. I would venture to say that over two thirds of the answers to common recovery and refining questions were answered in the first year the forum was open to the public. 

I owe a big debt of gratitude to Harold and Chris (Goldsilverpro) for the helping hands they have extended to me over the first year of my membership here. I want to thank Lou for trading me for lab quality samples of the PGMs to hone my PGM skills. I also want to make special mention of all of the members who have taken the time to put in the hard work required to grow to the point of being able to contribute real content to the forum. It seems that the forum these days is full of so much 'chatter' that it is hard to find the wheat in all the chaff. I only hope I have succeeded in returning the favor to everyone for what I have gained here. Lastly, I strive to never forget my roots when it comes to learning. 

Steve


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## Lou

Thank you very much, Steve. 

I am very glad that you have been able to bring as much accessible knowledge about extractive PGM hydrometallurgy to the forum and the general public at large, and done so in a way that is both technically correct and easier to chew for those without extensive chemical backgrounds. 


Likewise, I also owe Steve, and all of the other moderators as well as the forum at large quite a bit of gratitude for the things I've learned from them, the business that some of us have conducted, and, most important, the friends I have made.


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## malfeces

I am speechless. Rereading over and over... This is phenomonal info...
Thanks LS!


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## goldsilverpro

Thanks, Steve. I really appreciate what you said.

This is a game of knowledge and experience and no one on the planet knows it all. I did it professionally for most of my life but, if the truth were known, I have probably learned at least as much during my 5+ years on the forum. Not only from the moderators but from many, many of the regular members. Not a day goes by when I don't learn something new.


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## Anonymous

lazersteve said:


> 6. H2SO4= Sulfuric Acid = 1 cup 96%+ Sulfuric, 1/8 tsp glycerin (optional). Used as electrolyte in electrolytic cell along with a small amount of glycerin. Effective on medium to large gold plated items. With specially designed anodes and cathodes large batches of smaller plated items can be processed. Not used for Gold filled or karat jewelry.
> 
> Use until acid is saturated with black powder typically 12-24 hours of operation. Sink any floating black powder, let settle overnight, pour off bulk of acid for reuse, and dilute remaining acid with 4 parts water


I have my cell setup and ready to start stripping gold plated pins. But I have a few questions I'd like to ask you Steve.

*No# 1.* I see that the glycerin is optional, but what is the reason for adding it to the Sulfuric Acid?
*No# 2.* Do the Sulfuric Acid have to be 96%+? or will a lower strength just take longer to deplate the pins?
*No# 3.* Is the forming of the thick sludge/mud the indication that the solution has been used to its capacity?
*No# 4.* How many batches should I run after a single batch batch has started, as to not over-heat the charger and the pyrex? Let's say one batch of 100 grams take only 20 minutes to complete.

The pins that I'm going to be working with do not have any solder or any other visible signs of other materials on them. They're 100% gold plated. 

Thanks again for your videos and all the information that I've been learning since being a member here.

Kevin


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## Geo

testerman said:


> lazersteve said:
> 
> 
> 
> 6. H2SO4= Sulfuric Acid = 1 cup 96%+ Sulfuric, 1/8 tsp glycerin (optional). Used as electrolyte in electrolytic cell along with a small amount of glycerin. Effective on medium to large gold plated items. With specially designed anodes and cathodes large batches of smaller plated items can be processed. Not used for Gold filled or karat jewelry.
> 
> Use until acid is saturated with black powder typically 12-24 hours of operation. Sink any floating black powder, let settle overnight, pour off bulk of acid for reuse, and dilute remaining acid with 4 parts water
> 
> 
> 
> I have my cell setup and ready to start stripping gold plated pins. But I have a few questions I'd like to ask you Steve.
> 
> *No# 1.* I see that the glycerin is optional, but what is the reason for adding it to the Sulfuric Acid?
> *No# 2.* Do the Sulfuric Acid have to be 96%+? or will a lower strength just take longer to deplate the pins?
> *No# 3.* Is the forming of the thick sludge/mud the indication that the solution has been used to its capacity?
> *No# 4.* How many batches should I run after a single batch batch has started, as to not over-heat the charger and the pyrex? Let's say one batch of 100 grams take only 20 minutes to complete.
> 
> The pins that I'm going to be working with do not have any solder or any other visible signs of other materials on them. They're 100% gold plated.
> 
> Thanks again for your videos and all the information that I've been learning since being a member here.
> 
> Kevin
Click to expand...


Kevin, i can answer a couple of those for you.glycerin is not needed. it was believed the the glycerin helped precipitate the gold out of solution. this was later found to be a false assumption and that the gold would precipitate out on its own. the sulfuric acid has to be concentrated or it will dissolve base metal which will contaminate your gold. also,dilute sulfuric acid will attack your anode basket.the sulfuric will continue to be effective until it absorbs too much base metal (copper, nickle, and what ever else it will attack).diluting the acid and then evaporating will cause the base metal to precipitate out as sulfides of those metals and then it will be ready to use again.normally, you can use the same solution until it resembles thick brown molasses. the charger should not overheat unless it has a malfunction. keep the amps below 8 amps with a 1 L cell for about a half hour if you are using a basket and then shut down and let the cell cool completely. doing small pieces 1,2,3 pieces at a time should need no shut down or cool down.


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## Anonymous

Thanks *Geo*, you've answered my questions, and thanks for the quick reply too. 

This forum is awesome.

Kevin


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## g_axelsson

Geo said:


> ...diluting the acid and then evaporating will cause the base metal to precipitate out as sulfides of those metals and then it will be ready to use again.



Are you sure it is sulfides and not sulfates?

/Göran


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## Geo

im not a chemist and most of what ive learned of it has been mostly in the last couple of years. this is what ive learned about sulfides and sulfates.most sulfides are not water soluble while most sulfates are water soluble. the precipitate that occurs when i evaporate my used sulfuric acid from my stripping cell does not seem to dissolve in water. since ive never tested for either and didnt weigh the powder for weight changes, i suppose there could be a combination of both sulfides and sulfates. i cant really argue about it one way or the other but just state what ive seen happen with my material. i am assuming that is what is going on there and its just my opinion.


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## burningsuntech

Eureka, Steve. All this in one place. Great job. Thanks! - RA :idea:


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## sharkhook

Newbie here, and WOW! Answered all my basic questions right off the bat. Thanks, I know that took some work.


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## Ollie1016

I have found this post really informative. I will definitely make my own silver testing solution now! Thank you.


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## lazersteve

This post was created with the noob in mind; however, reading the links in the Guided Tour will bring new refiners and pros up to speed on the vernacular used here on the forum as well as educate them on the common processes.

Steve


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## Toddntucson7

Good info thanks, I was looking for solutions today and was hopping around. Thanks for the work put into that.


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## jonrms

A+ very helpful as a guide


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## Sleepydann

lazersteve said:


> Mark,
> 
> 
> It's nice to know that despite it's age this post is still helping forum members.
> 
> Steve



It's now 2019 and it is helping me quite a bit!, 
Thanks to everyone!


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## Gorillatactics28

Myself being a noob I would like to express my appreciation of the work it took to compile all this information as well as gratitude for the wealth of knowledge available at no cost. Thank you!!!! 
To the new members if you want to succeed and learn these skills then my suggestions are
1. Read C.M. Hokes (until you comprehend the information)
2. Search for your answer in the forum (alot of hard work went into posts don't be disrespectful and lazy)
3. Do not start using chemicals until you understand how to safely!!!! 
4. Hard work pays off!!!! Do not try to rush or skip steps. You will lose gold, time, and risk your life and those around you.
5. READ HOKES. 

Don't expect to be coddled on this forum they take their valuable time to help us out. If you don't put the effort into learning and are searching for "drive thru" service this is not the correct forum to join.


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## Rust6

Thanks simplifies some processes


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## DarkspARCS

You're the BOMB Steve =)


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