# THE SALT AFTER NITRIC ACID BATH , NEED HELP



## Adrian2 (Jun 28, 2021)

HI all,

i'm probably new on the forum ,

I'm wondering guys , is there any effective solution ( or chemicals or anything...) to not have any salts after nitric acid bath? how can i avoid salts??

for years i did it and for years i always found salts after the acid bath,

cause for a big quantity of electronics scrap i always spend time to remove the salts '' properly '' , for me to get a clean AR solution,,,,

need help please,

kind regards to all of you.


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## butcher (Jun 28, 2021)

Acid + metal = salt of that metal and the acid that dissolved it...

Nitric +acid metal produces a metal nitrate salts.
Hydrochloric acid (HCl) + metal gives metal chloride salts.
Sulfuric acid + metal makes a metal sulfate salts.

A mixture of acids and a mixture of metals will make a mixture of metal salts either insoluble or dissolved in solution,and any other acids that can attack a metal will produce salts of that metal, Now whether these salts are soluble or not , or can over saturate the solution to the point of crystallization ( which can be redissolved in more solution),for clues on the solubility we can refer to the solubility rules for metal salts...

letting the solution sit still overnight can allow many of the insoluble salts to settle so you can decant the solution filtering can also remove larger particles, soluble salts can be redissolved in the same solution or with water...

many times we may add another acid, to create an insoluble salt of a metal dissolved in solution for example adding a little sulfuric acid to aqua regia to make or convert the more water soluble lead chloride salts into a less soluble lead sulfate salt so we can remove lead from the solution, temperature can also play a role in solubility, most or many of the salts are less soluble in cold solution and more soluble in hot solution...


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## Adrian2 (Jun 30, 2021)

thanks for your answer butcher


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## butcher (Jun 30, 2021)

Note: 
An acid (even if the acid is fairly safe and nontoxic like citric or vinegar)and a metal ,or a base, caustic , or alkali solution and a metal will produce toxic salts or chemical compounds of that metal and acid , or alkali, along with toxic or dangerous fumes and other byproducts (some of which can become hazardous such as explosives or shock sensitive, or even make other substances catch fire very easily or flash into flames on there own 9sometimes becoming a catalyst for some other chemical reaction) under certain conditions.

Learn the dangers and how to safely deal with toxic waste waste, and the many different dangers involved in this type of work...

The dangers are many, if you wish to succeed in recovery or refining, or to survive and keep yourself your family and your neighbor safe, you should understand the dangers of the chemistry you are working with.

If not you might as well put a gold bullet in a six chamber revolver and put the gun to your head and pull the trigger, because either way you would waste the gold and put yourself and others at risk.


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## Adrian2 (Jul 27, 2021)

one more thanks mate,

cheers


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## Orlus (Oct 29, 2021)

butcher said:


> Acid + metal = salt of that metal and the acid that dissolved it...
> 
> Nitric +acid metal produces a metal nitrate salts.
> Hydrochloric acid (HCl) + metal gives metal chloride salts.
> ...


Thank you, lesson received!


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## au-artifax (Oct 31, 2021)

Orlus said:


> Thank you, lesson received!


There is one very big concern here..... the formation of hydroxides, which can really make filtration difficult. If a lot of your, "salts" as you call them, may form when you dilute your solution with water, (this is the hydroxides of your metal salts forming). So you cannot help metal salts forming as that is what you are trying to do. Most of the precious metal salts stay in soulution (unless you add a halogen like chlorine, which reacts with silver to form a solid metal salt). It is the lot of a refiner to know which chemicals will precipitate the solid salts selectively..... like when we precipitate gold, PGMs, or silver. Remember, precipitation occurs best with concentrated solutions, and addition of water goes against that principle... and complicates things when the hydroxides form.


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