65% Nitric acid
- Thread starter Dude4ever
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Sure. You could use 50%. I always liked a little splash of water in my aqua regia, anyway.Dude4ever said:Does 65% technical grade nitric acid, bought from pharmacy cut it in making AR?
This is really the highest (and only) concentration I can buy, if I don't want to buy 25L minimum of nitric though, and I really don't
maynman1751
Well-known member
I like mine on the rocks, neat! :mrgreen:
65% is fine
Hi
I am
In Massachusetts (western) and cannot find a supplier of Nitric Acid anywhere.
Are you able to get yours as you stated at a pharmacy chain and if so which one?
I am trying to save and get it as local as I can .... Shipping is a killer!
Thanks
I am
In Massachusetts (western) and cannot find a supplier of Nitric Acid anywhere.
Are you able to get yours as you stated at a pharmacy chain and if so which one?
I am trying to save and get it as local as I can .... Shipping is a killer!
Thanks
Geo
Well-known member
Dude4ever lives in Norway, thats a long way from Mass.
sourcing nitric acid is a big problem here in the U.S. because it is so dangerous.
sourcing nitric acid is a big problem here in the U.S. because it is so dangerous.
If you are heating a metal in Aqua Regia the water will assist in keeping the acids in solution reacting with your metals instead of evaporating off in gasses, so I also will use a little water in my reactions, especially if heating the solution for long periods of time as the solutions also will loose water in the process and concentrate the acids as the solution evaporates while dissolving the metals in solution.
Geo
Well-known member
:lol: :lol: http://www.grainger.com/Grainger/LABCHEM-CHEM-GOLD-CHLRD-1PCT-WV-125ML-8G299?Pid=search
i wish i could get that much for it.
i wish i could get that much for it.
Your nitric acid will be fine for AR, but you will need to adjust the amount used to dissolve the gold. The normal recipie is 4ml:1ml; 31% HCl: 70% Nitric Acid per gram of gold to be dissolved.
Your nitric is 15% :
70%/15% = 4.67
So you will need roughly 4.67 mL of 15% nitric acid to 4 ml of 31% HCl per gram of gold to be dissolved. I rounded up so you could easily get by with 4.5mL:4mL of your nitric to hardware store muriatic acid.
Steve
Your nitric is 15% :
70%/15% = 4.67
So you will need roughly 4.67 mL of 15% nitric acid to 4 ml of 31% HCl per gram of gold to be dissolved. I rounded up so you could easily get by with 4.5mL:4mL of your nitric to hardware store muriatic acid.
Steve
Mathematically, using the specific gravities of 70% and 15% nitric, at 20C, I came up with a ratio of 6.08 to 1, in strength. Therefore, if you want to end up with a comparable ratio of 4 to 1, 32% HCl/70% HNO3, you would use a ratio of about 6ml of 15% HNO3 and 4ml of 32% HCl. If anyone wants to know the math on this, let me know.
When you do this, however, you end up with very close to 50/50 aqua regia, due to all the extra water in the 15% nitric. It would be like making up a 4/1, 32% HCl/70% HNO3, AR, and then adding an equal volume of water.
This would work fine (but, slower) in most cases, such as in dissolving gold foils or the gold powder left from inquartation. A guy I knew used a 50/50 diluted aqua regia to dissolve all gold ceramic CPU packages, in about 50 pound lots. I'm thinking he heated it somewhat but am not sure about that. He used the dilute AR because it cut down on the fumes and eliminated boilovers. It worked fairly well but it took about 3 days and, even then, I don't think he got all the gold braze under the silicon chip. If he had had the patience (and the money) to leave it for a few more days, he might have gotten it all. He then dropped the gold with SO2. All of the gold dropped but it was only about 97% pure.
About the only other item I can see any problems with would be if you were trying to directly dissolve karat gold jewelry. It might still work but it would certainly be much slower.
When you do this, however, you end up with very close to 50/50 aqua regia, due to all the extra water in the 15% nitric. It would be like making up a 4/1, 32% HCl/70% HNO3, AR, and then adding an equal volume of water.
This would work fine (but, slower) in most cases, such as in dissolving gold foils or the gold powder left from inquartation. A guy I knew used a 50/50 diluted aqua regia to dissolve all gold ceramic CPU packages, in about 50 pound lots. I'm thinking he heated it somewhat but am not sure about that. He used the dilute AR because it cut down on the fumes and eliminated boilovers. It worked fairly well but it took about 3 days and, even then, I don't think he got all the gold braze under the silicon chip. If he had had the patience (and the money) to leave it for a few more days, he might have gotten it all. He then dropped the gold with SO2. All of the gold dropped but it was only about 97% pure.
About the only other item I can see any problems with would be if you were trying to directly dissolve karat gold jewelry. It might still work but it would certainly be much slower.
Chris,
I'm not quite understanding how you derived your answer.
Here's was my thinking:
It would require 2x the amount of 35% HNO3 as 70% HNO3;
or 4x the amount of 17.5% HNO3,
or 6x the amount of 8.75% HNO3.
From the chart you posted here the density slope is nearly linear at STP.
Nitric Acid Specific Gravity Chart
15% HNO3 has a sp gr of approximately 1.09 g/cc
70% HNO3 has a sp of approximately 1.42 g/cc
Steve
I'm not quite understanding how you derived your answer.
Here's was my thinking:
It would require 2x the amount of 35% HNO3 as 70% HNO3;
or 4x the amount of 17.5% HNO3,
or 6x the amount of 8.75% HNO3.
From the chart you posted here the density slope is nearly linear at STP.
Nitric Acid Specific Gravity Chart
15% HNO3 has a sp gr of approximately 1.09 g/cc
70% HNO3 has a sp of approximately 1.42 g/cc
Steve
I used this S.G. chart. On the link you gave, I think the guy made the graph from this chart.
http://www.handymath.com/cgi-bin/nitrictble2.cgi?submit=Entry
According to this chart:
At 20C, the S.G. of 15% nitric = 1.0842g/ml. Therefore, 1 ml would contain 1.0842 X .15 = .1626g HNO3
At 20C, the S.G. of 70% nitric = 1.4134g/ml. Therefore, 1 ml would contain 1.4134 X .70 = .9894g HNO3
Therefore, the strength ratio is .9894/.1626 = 6.08
Using similar logic, when you dilute 1 ml of 70% nitric with 1 ml of water, you end up with 2 ml of 41% nitric. Here's the math:
1 ml of 70% nitric weighs 1.4134g and contains 1.4134 X .70 = .9894g of HNO3. 1 ml of water weighs 1g (or close enough to not really affect the results). Added together, the 2 ml weighs 2.4134g. The percentage by weight of HNO3 is .9894/2.4134 = .41 or 41%
I know it doesn't seem to make much sense. Before I did the math, I thought the same as you did - that 50/50 70% nitric was 35% by weight. The problems are that these weight percentages aren't exactly linear and that weight percentages and volume percentages are like apples and oranges. I have come to the conclusion that, if you want accuracy in these type calculations, you MUST use the S.G. charts. I started the thread that you gave the link for. Check the first post on the first page of the thread. Better still, re-read the whole thread.
http://www.handymath.com/cgi-bin/nitrictble2.cgi?submit=Entry
According to this chart:
At 20C, the S.G. of 15% nitric = 1.0842g/ml. Therefore, 1 ml would contain 1.0842 X .15 = .1626g HNO3
At 20C, the S.G. of 70% nitric = 1.4134g/ml. Therefore, 1 ml would contain 1.4134 X .70 = .9894g HNO3
Therefore, the strength ratio is .9894/.1626 = 6.08
Using similar logic, when you dilute 1 ml of 70% nitric with 1 ml of water, you end up with 2 ml of 41% nitric. Here's the math:
1 ml of 70% nitric weighs 1.4134g and contains 1.4134 X .70 = .9894g of HNO3. 1 ml of water weighs 1g (or close enough to not really affect the results). Added together, the 2 ml weighs 2.4134g. The percentage by weight of HNO3 is .9894/2.4134 = .41 or 41%
I know it doesn't seem to make much sense. Before I did the math, I thought the same as you did - that 50/50 70% nitric was 35% by weight. The problems are that these weight percentages aren't exactly linear and that weight percentages and volume percentages are like apples and oranges. I have come to the conclusion that, if you want accuracy in these type calculations, you MUST use the S.G. charts. I started the thread that you gave the link for. Check the first post on the first page of the thread. Better still, re-read the whole thread.
I was formulating another reply to your previous post and while running the numbers the light went off about the percentage being non-linear as well.
I did the math and it worked out to ~40% for 50/50 also by my numbers.
All this time I was assuming 50/50 was 35% also.
Steve
I did the math and it worked out to ~40% for 50/50 also by my numbers.
All this time I was assuming 50/50 was 35% also.
Steve
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That isn't true because you're not dealing with 100% with the 70% solution. The ratios do not remain as a constant.lazersteve said:
It works the same way as discounts. Buy something with a 40% discount isn't the same as buying with a 30% discount, then an additional 10% discount. Get my drift?
Harold
jeneje
Well-known member
Don't know if this will help you but try Greenwaychemical.comgsfnbc said:
Ken
If using the dilute nitric to dissolve gold, silver or another metal, I would consider several options.
Add HCl, then add the dilute nitric acid in increments, as the solution concentrated the water in solution would evaporate off, (in the reaction the water evaporates first, then nitric then HCl, they do not come off in vapors pure , but mostly these solutions as gases in that order), as long as you do not heat too strongly the acids would attack the metals, dissolving them as salts in solution, as the acids concentrate the metals would react more, (also the water in solution can help keep the nitric from going off in Nox gas before reacting with the metal as solution concentrates as long as you did not have the heat too high, it would take a little longer because you would be diluting the solution some with each addition of the dilute nitric acid, you would also have to not let the heat reacting on this solution get too high, because it would take a little while to remove the water and as the nitric solution concentrated the acid would begin to react much more vigorously (if the temperature was too high at this stage you would have a boil-over, as the nitric would be beginning to react seemingly all at once), (this same thing can happen when using more concentrated acids).
Silver could also be dissolved in the dilute nitric acid using heat to drive off water, as in the reaction described above.
Or you can concentrate your dilute nitric acid, (then use it as concentrated 68%, or just concentrate it up to what percentage you wish to use like approximately 40% or silver), using heat to drive off water until the azeotope of 68% nitric acid was reached, paying attention to the temperature of the reaction and controlling the temperature can be used in this process, (nitric acid has differing boiling points depending on concentration of the acid).
Add HCl, then add the dilute nitric acid in increments, as the solution concentrated the water in solution would evaporate off, (in the reaction the water evaporates first, then nitric then HCl, they do not come off in vapors pure , but mostly these solutions as gases in that order), as long as you do not heat too strongly the acids would attack the metals, dissolving them as salts in solution, as the acids concentrate the metals would react more, (also the water in solution can help keep the nitric from going off in Nox gas before reacting with the metal as solution concentrates as long as you did not have the heat too high, it would take a little longer because you would be diluting the solution some with each addition of the dilute nitric acid, you would also have to not let the heat reacting on this solution get too high, because it would take a little while to remove the water and as the nitric solution concentrated the acid would begin to react much more vigorously (if the temperature was too high at this stage you would have a boil-over, as the nitric would be beginning to react seemingly all at once), (this same thing can happen when using more concentrated acids).
Silver could also be dissolved in the dilute nitric acid using heat to drive off water, as in the reaction described above.
Or you can concentrate your dilute nitric acid, (then use it as concentrated 68%, or just concentrate it up to what percentage you wish to use like approximately 40% or silver), using heat to drive off water until the azeotope of 68% nitric acid was reached, paying attention to the temperature of the reaction and controlling the temperature can be used in this process, (nitric acid has differing boiling points depending on concentration of the acid).
