Nitric issues Please help

[Harkey1]

I followed Lasersteves recipe and instructions for Nitric acid. I have made this before with no issues. This time I had to run an errand in the middle. The boiled Sodium Nitrate cooled to room temp. I did not even think about this before i put the sulfuric in. I put it in the freezer for aabout three hours. it did not clear up. It is still a cloudy orange to yellow color. I have read around and have found no one with this same problem. Should I heat the final product that I have to get it right?
Glenn
Thank you

 

[lazersteve]

Glenn,

The nitrate should not cool to below around 90C before you add the acid.

Try slowly heating the mixture up again, then let cool to room temperature, then freeze.

Steve

 

[Harkey1]

Thank you Steve
I did that and it did not clear up much. I did, however, drop more salt crystals. Should I do it again? Is it too weak to use in this state?

 

[lazersteve]

Cool until no more crystals form.

Test by adding a small pinch of silver powder to 5 mL of the solution and heat. The silver powder should fizz and dissolve. If not, you may need to check your sulfuric acid to be certain it is 95% or better concentration using a specific gravity check. You may also have a problem with your nitrate source.

You mention you have done this before, what is different this time aside from the cooling of the nitrate solution?

Odd colors could be a result of contamination from the acid or nitrate reagents.

Steve

 

[Harkey1]

The difference this time is the supplier. I purchased the Nitrate from a supplier that I could also get the SMB from. I needed both. Most of the suppliers had one and not the other. Some had both but at a much greater price. I got Mr. Hollywood's number from a string here on the forum. All that to say this. The only difference is the supplier. All of the packages that I ordered were labeled. the Sodium Nitrate looked exactly like it did the first time I used it.

I did a little test last night. I put a pinch of the pins that I ran through the nitric the first time in a small container with the 15ml of Nitric+ 60ml of distilled water. the next test was a pinch if pins from the same supply and 15ml of straight nitric. (this is the nitric that I am having trouble with).
Both fizzed and started disolving. the straight nitrric stopped reacting and it now has a lot of blue crusty junk in the bottom with the blue liquid on top. Is the crusty stuff copper?
The dilluted Nitric disolved most of the pins over night and now has no more reaction. Is this the expected reaction.

 

[Harkey1]

The latest on my tests...
The test with the dilluted nitric has disolved all of the metals and left the gold plated shells.....Success!!!
Nitric may be yellow but it still works as expected.
Thank you
Glenn

 

[glorycloud]

A little heat and the blue crystals should dissolve back into solution
so you can filter the gold foils from your pins. 8)

 

[Harkey1]

Ok guys,
I have had about enough of the Nitric. I have tried the crockpot method and love it. It works very well and in an short amount of time. It takes too much Nitric to get the total amount of base metals dissolved. The nitric process stops mid stream and starts depositing the greenish crystals in the bottom. I got tired of it and went to the crockpot method while the nitric sat. The nitric eventually dried and is now hard. My question is this. Would it hurt anything to take the pins et al that were started in the nitric and move to the crockpot method?

 

[Barren Realms 007]

Ok guys,
I have had about enough of the Nitric. I have tried the crockpot method and love it. It works very well and in an short amount of time. It takes too much Nitric to get the total amount of base metals dissolved. The nitric process stops mid stream and starts depositing the greenish crystals in the bottom. I got tired of it and went to the crockpot method while the nitric sat. The nitric eventually dried and is now hard. My question is this. Would it hurt anything to take the pins et al that were started in the nitric and move to the crockpot method?

There will be enough traces of nitric that you gold will be disolved into the solution. Wash and continue with the nitric.

 

[Harkey1]

Thanks Barren,
Should I wash with water or HCL?
I have read through many threads and cannot locate the one that tells how to keep the nitric working for a longer period of time. I know that Hokes says to put the material in new nitric when the reactions stop. I am using a 4:1 ratio of nitric to distilled. Should I be using a smaller ratio to get it to react fast? Or is there a way to re-activate it when it stops?

 

[lazersteve]

Thanks Barren,
Should I wash with water or HCL?
I have read through many threads and cannot locate the one that tells how to keep the nitric working for a longer period of time. I know that Hokes says to put the material in new nitric when the reactions stop. I am using a 4:1 ratio of nitric to distilled. Should I be using a smaller ratio to get it to react fast? Or is there a way to re-activate it when it stops?

Sounds like you are driving all the water out. I've posted numerous times about the importance of water in the nitric reaction, as have others. Anytime you get crystallization you can assume you don't have enough of the solvent required to dissolve the crystalline product. In your case it's likely copper nitrate which is soluble in water.

Another factor of any reaction is the saturation level of a given volume of solution. Once it's saturated you must pour off the solution and add some fresh solution to get things going again.

Steve

 

[Harkey1]

Thanks Steve,
Adding water "wakes up" the nitric? It is time to change the solution when the water no longer "wakes up" the nitric. Meaning that when it gets too concentrated with base metals, water will free up acid to disolve and obsorb more. We do this until we eventually have diluted the acid to a point that it will no longer work.
Am I understanding this correctly?

 

[Barren Realms 007]

Thanks Steve,
Adding water "wakes up" the nitric? It is time to change the solution when the water no longer "wakes up" the nitric. Meaning that when it gets too concentrated with base metals, water will free up acid to disolve and obsorb more. We do this until we eventually have diluted the acid to a point that it will no longer work.
Am I understanding this correctly?

If you have quite a bit of solution and you have to add nitric to get any activity, let the last adddition stand till action stops then remove existing fluid and continue the process with an addition of nitric. That is if it already staurated with base metals as well. More than one thing to look at in that question.

 

[Harkey1]

Many things to consider in this process. Thus my question...Keep adding water and a little Nitric? Or is it time to change fluid. At what point is the solution so saturated that it needs to be changed?

 

[Barren Realms 007]

Many things to consider in this process. Thus my question...Keep adding water and a little Nitric? Or is it time to change fluid. At what point is the solution so saturated that it needs to be changed?

Question's HMMM..... :!:


How much fluid did you start with?

How much nitric have you added and aprox what time intervals?

How much water have you added and at what intervals?

How much fluid do you have?

What color is your solution?

Have you added heat to this to help the reaction?

If so for how long and aproximately what temperature?

What have you put in the solution?

How much material have you put in your solution to be processed?

How much of your material is left that needs to be processed that is in your solution?



A picture is worth a thousand words. :idea:

 

[lazersteve]

Many things to consider in this process. Thus my question...Keep adding water and a little Nitric? Or is it time to change fluid. At what point is the solution so saturated that it needs to be changed?

For dilute nitric reactions the amount of water in the reaction must be kept relatively constant. Water will evaporate off quickly if a watch glass is not used on the reaction beaker. Saturation is obvious when crystals form in a hot solution.

Adding water won't 'wake up' the nitric, it will only mobilize nitric that has not reacted. Once the nitric has given up hydrogen for a metal ion, there is no getting it back without water. The by product of reacting nitric with metal is NOx gas. These gases combine with oxygen and water to form more nitric. When all the brown gas escapes the reaction or combines with base metal, the nitric is all spent. You can extend the life of your nitric by capturing the brown gas and refluxing it back into the reaction in the presence of excess water.

The NOx attached to the metal can be 'woke up' with the addition of sulfuric acid. The sulfuric acid provides hydrogen to the NOx attached to the metal and forms fresh nitric with enough water. You can use sodium hydrogen sulfate to provide one additional hydrogen, but at the expense of adding sodium sulfate salt to the mix. Eventually all of the NOx goes up in smoke and the solution saturates with a sulfate salt of the base metal.

If you study the balanced chemical reactions this will all be evident.

Steve

 

[Harkey1]

Many things to consider in this process. Thus my question...Keep adding water and a little Nitric? Or is it time to change fluid. At what point is the solution so saturated that it needs to be changed?

Question's HMMM..... :!:


How much fluid did you start with?

I started with 150 mls of Nitric and 4 times that in water (distilled).

How much nitric have you added and aprox what time intervals?

I added about 30 mls of nitric and 120 mls of water once a day. for a couple of days.

How much water have you added and at what intervals?

How much fluid do you have?

Now I have none, I let it dry while I worked on something else and tried to figure out what to do with this mess.
What color is your solution?

Solution is a blue green when I quit. Now the crystals on the bottom are as I stated the same color.
Have you added heat to this to help the reaction?

If so for how long and aproximately what temperature?

I have not gone to the heat yet. I was waiting to see if I could stop the nitric and go to the AP. Now I know that I cant.
What have you put in the solution? Pins and other plated parts of components.

How much material have you put in your solution to be processed?
about 1 lb.

How much of your material is left that needs to be processed that is in your solution?
Most of it. looks to be about 3/4ths of it.



A picture is worth a thousand words. :idea:

 

[Barren Realms 007]

I think the figure I remember is 1 liter of nitric will disolve 1 lb of copper. I think you are a little short of the amount of nitric you will need to finish this.

 

[goldsilverpro]

I think the figure I remember is 1 liter of nitric will disolve 1 lb of copper. I think you are a little short of the amount of nitric you will need to finish this.

If you're not using H2O2 along with it, one gallon of concentrated 70% nitric, diluted to 2 gallons with water, will dissolve about 2 pounds of copper (or 7 pounds of silver). That's about 2 liters of concentrated nitric per pound of copper. If you properly use H2O2 with it, this could theoretically cut the nitric usage as much as 50%. Maybe that's what you had in mind. I have not used the H2O2 for this purpose but some on the forum have.

 

[Harkey1]

Thank you guys. I need to spend a night reading studying this proceedure. I know that I have read the thread about this process and about the amount of nitric that it takes for copper. I did not anticipate that I had that much copper at all. Live and learn. I will get back to you later and let you know if I have other questions.
Soooooo much to learn.
Thanks again