Creating Nitric Acid

[Toadstool]

Other than the creation of a large amount of salt, is there anything wrong with creating nitric acid by combining potassium nitrate and sulfuric acid for recovery purposes? Here is a video about the subject: https://www.youtube.com/watch?v=lxj-8bBRQoI

If there is nothing particularly wrong with the method, what is the best way to separate the acid from the salt?

 

[NobleMetalWorks]

There are very few situations where separating Nitric Acid from it's salts would be cost effective. Is it really easier for you, or less expensive for you to obtain Sulfuric acid than it is Nitric acid?

Why wouldn't you just simply purchase Nitric Acid instead?

Scott

 

[Toadstool]

There are very few situations where separating Nitric Acid from it's salts would be cost effective. Is it really easier for you, or less expensive for you to obtain Sulfuric acid than it is Nitric acid? Why wouldn't you just simply purchase Nitric Acid instead?

Scott

500 mL of 70% nitric acid cost me $43 with shipping. I found half a gallon of 93% sulfuric acid at ACE for $14 and a one pound bottle of potassium nitrate for $6. So it is cheaper, yes, but is it safe enough to try/use? Pretty sure the resulting salt is potassium sulfate which according to wikipedia is "a non-flammable white crystalline salt which is soluble in water. The chemical is commonly used in fertilizers, providing both potassium and sulfur."

 

[NobleMetalWorks]

There are very few situations where separating Nitric Acid from it's salts would be cost effective. Is it really easier for you, or less expensive for you to obtain Sulfuric acid than it is Nitric acid? Why wouldn't you just simply purchase Nitric Acid instead?

Scott

500 mL of 70% nitric acid cost me $43 with shipping. I found half a gallon of 93% sulfuric acid at ACE for $14 and a one pound bottle of potassium nitrate for $6. So it is cheaper, yes, but is it safe enough to try/use? Pretty sure the resulting salt is potassium sulfate which according to wikipedia is "a non-flammable white crystalline salt which is soluble in water. The chemical is commonly used in fertilizers, providing both potassium and sulfur."

Anytime you are using acids or chemicals it's more than likely dangerous in some way. In what we do, recover and refining precious metals, we utilize many processes that are extremely dangerous. However, we also take every precaution, or at least I feel most of us do. It's all about minimizing the risks as much as is humanly possible.

If you are using a known, proven process to create Nitric Acid, it should be safe. The video that you provided shows the basic way to create Nitric Acid using the acid and chemicals suggested. Know that this will not be a pure form of Nitric Acid and will contain pollutants that might alter how your Nitric Acid actually performs when using it to create Aqua Regia.

This is a more complex, but better way to produce a more pure Nitric Acid. I wouldn't use the first method in the video, but instead I would use the second method.

https://www.youtube.com/watch?v=2yE7v4wkuZU

Using HCl to produce Nitric Acid is probably better as it is much less expensive, HCl is sold at places like hardware stores, or Home Depot, etc and is fairly inexpensive. Generally it's called either Hydrochloric or Muaritic acid.

Scott

 

[g_axelsson]

Just do a search of "cold nitric acid recipe" and you get 151 hits. I'm sure you will find something worthwhile there.

Nitric acid made from sulfuric acid will contain sulfates and that will create problem when working with silver.

Nitric acid made from hydrochloric acid will be more or less aqua regia and is usually called "Poor mans AR" and I get 137 hits on google : https://www.google.com/search?q=site%3Agoldrefiningforum.com+%22Poor+mans+AR%22
It will dissolve gold and it might not matter much or it might, depending on what you are going to do.

Göran

 

[rickbb]

Several ways to safely make nitric, the purity varies by method and your skill.

Which one you use depends on what you need the nitric to do.

Dissolve gold? Use poor mans AR and skip the nitric in the first place.

Purify silver? You'd be better off buying a known good, quality nitric. IMHO.