what is ration of 68% Nitirc Acid?

[talalstuvs]

I have 68% Nitirc acid for sample testing .What ration i should use for Frist and Second Acid ?

Thank for Advance
waiting for reply.

 

[HAuCl4]

I have 68% Nitirc acid for sample testing .What ration i should use for Frist and Second Acid ?

Thank for Advance
waiting for reply.

The answer is in this thread, along with many other answers to other many questions. 25% and 50% worked for me many years ago for fire assays of bullion.

http://www.goldrefiningforum.com/phpBB3/viewtopic.php?f=41&t=4789

 

[talalstuvs]

18. Add the beads to numbered beakers and add 40ml of a mixture of 1 part ntric acid and 2 parts distilled water.
19. When mixing the acids, always add acid to water, never add water to acid!!
20. Heat the beakers for ab
out 15 minutes in the first acid. The silver will dissolve and leave behind gold particles
which look like coffee grounds. When the reaction stops you can change the acid. The particles are heavy and
behave well. (meaning they rinse well and with reasonable care will not pour off when rinsing) Gently pour off the
acid leaving the gold at the bottom, squirt with a stream of distilled water from a squeeze bottle. After a few
seconds the gold settles and can be decanted as well.
21. All of the used acids and rinses contain silver, collect them in a glass bottle for future recovery, you can recycle
this silver and re use it over and over.
22. Now add a mixture of 1 part Nirtic acid and 1 part distilled water to the beakers. Again about 40ml per beaker,
continue heating on the hot plate for 15 to 30 minutes.

There no any mention of Nitric % i don't know which percent acid they are using by there mixing could you tell me which % Nitric acid they are using ?and is this ration also good for 68% not break up gold?

 

[HAuCl4]

18. Add the beads to numbered beakers and add 40ml of a mixture of 1 part ntric acid and 2 parts distilled water.
19. When mixing the acids, always add acid to water, never add water to acid!!
20. Heat the beakers for ab
out 15 minutes in the first acid. The silver will dissolve and leave behind gold particles
which look like coffee grounds. When the reaction stops you can change the acid. The particles are heavy and
behave well. (meaning they rinse well and with reasonable care will not pour off when rinsing) Gently pour off the
acid leaving the gold at the bottom, squirt with a stream of distilled water from a squeeze bottle. After a few
seconds the gold settles and can be decanted as well.
21. All of the used acids and rinses contain silver, collect them in a glass bottle for future recovery, you can recycle
this silver and re use it over and over.
22. Now add a mixture of 1 part Nirtic acid and 1 part distilled water to the beakers. Again about 40ml per beaker,
continue heating on the hot plate for 15 to 30 minutes.

There no any mention of Nitric % i don't know which percent acid they are using by there mixing could you tell me which % Nitric acid they are using ?and is this ration also good for 68% not break up gold?

If you take your 68% lab grade nitric and dilute it with distilled water, 2 parts water, 1 part nitric, you get: 68/300 = 22.67% nitric. This is fine for first boil. If you take your 1 part 68% nitric and dilute it with 1 part distilled water, you get 68/200 = 34% nitric. That'll probably work for the second boil, but I'd prefer at least 50% nitric.

Other people like to use grams and densities instead of volumes, etc. I guess you could use the 68% acid directly for the second boil too without much problems. The idea is to boil in a weak enough acid so first so that the cornet will not disintegrate, and then use the stronger acid to make sure all the silver is gone.

 

[talalstuvs]

18. Add the beads to numbered beakers and add 40ml of a mixture of 1 part ntric acid and 2 parts distilled water.
19. When mixing the acids, always add acid to water, never add water to acid!!
20. Heat the beakers for ab
out 15 minutes in the first acid. The silver will dissolve and leave behind gold particles
which look like coffee grounds. When the reaction stops you can change the acid. The particles are heavy and
behave well. (meaning they rinse well and with reasonable care will not pour off when rinsing) Gently pour off the
acid leaving the gold at the bottom, squirt with a stream of distilled water from a squeeze bottle. After a few
seconds the gold settles and can be decanted as well.
21. All of the used acids and rinses contain silver, collect them in a glass bottle for future recovery, you can recycle
this silver and re use it over and over.
22. Now add a mixture of 1 part Nirtic acid and 1 part distilled water to the beakers. Again about 40ml per beaker,
continue heating on the hot plate for 15 to 30 minutes.

There no any mention of Nitric % i don't know which percent acid they are using by there mixing could you tell me which % Nitric acid they are using ?and is this ration also good for 68% not break up gold?

If you take your 68% lab grade nitric and dilute it with distilled water, 2 parts water, 1 part nitric, you get: 68/300 = 22.67% nitric. This is fine for first boil. If you take your 1 part 68% nitric and dilute it with 1 part distilled water, you get 68/200 = 34% nitric. That'll probably work for the second boil, but I'd prefer at least 50% nitric.

Other people like to use grams and densities instead of volumes, etc. I guess you could use the 68% acid directly for the second boil too without much problems. The idea is to boil in a weak enough acid so first so that the cornet will not disintegrate, and then use the stronger acid to make sure all the silver is gone.

I will try it if i got any difficulity then i wll contact you.
Anther problem is about my scal. I use 6 digit scall which is very sensative. Its on a simple table. when i weight sample first time it's give me an other weight and when i want to check it again same time its gave an other weight. what is it main problem could be ? i also calebrate it but it's gave same result .

 

[HAuCl4]

Air drafts, unlevel table, vibrations, big noise, etc, etc can affect a sensitive scale. The scale could be damaged too and be unstable. 5 digit precision is more than enough if you use 1 gram or 0.5 gram samples.

 

[talalstuvs]

Air drafts, unlevel table, vibrations, big noise, etc, etc can affect a sensitive scale. The scale could be damaged too and be unstable. 5 digit precision is more than enough if you use 1 gram or 0.5 gram samples.

Yes your right if i use 5 digit scal there some diffrence in my result and other lab.Diffrence is about 3 or 4 point but when i use 6 digit now the diffrence is 2 or 3 point.
I take 0.075 to 0.100 Mile gram sample for 750 to 916 and 0.120 to 0.150 silver. For pure gold I take 0.060 to 0.065 Mile gram for 958 to 999 and .120 to 0.125 mile gram silver. I don't know what to do to get diffrence out of my work.
I use fire Assay. I boil the sample in Test Tube on fire.Is this procedure good ?
Is there someway to get out vibration, unlevel or big noise that effect my scal ?
I have to take 2 sample from 0.5 gram or not ?
Thank in Advance
waiting for your reply.

 

[jimdoc]

I used to see little marble tables at auction,and I was told they were for precision scales.
Don't know if that was true or not,but they were cool little tables,and very heavy.

Jim

 

[nickvc]

May I suggest that you run some samples of known and trusted assayed metals so that you can have standards,and run them every now and again so you can verify your accuracy on your assays. It would pay to run them from low grade to 999+ as this will allow you to assay most Au & Ag samples that come your way.

 

[goldsilverpro]

Even with a 4 place balance, the table must be sturdy and fairly heavy to prevent vibration. With a 6 place, the problem is magnified.

There are several types of anti-vibration tables available for balances. They are all heavy and expensive.
http://www.google.com/search?num=100&hl=en&safe=off&rlz=1B3GGLL_enUS395US396&q=scale+anti-vibration+table&btnG=Search&aq=f&aqi=&aql=&oq=&gs_rfai=

 

[HAuCl4]

Air drafts, unlevel table, vibrations, big noise, etc, etc can affect a sensitive scale. The scale could be damaged too and be unstable. 5 digit precision is more than enough if you use 1 gram or 0.5 gram samples.

Yes your right if i use 5 digit scal there some diffrence in my result and other lab.Diffrence is about 3 or 4 point but when i use 6 digit now the diffrence is 2 or 3 point.
I take 0.075 to 0.100 Mile gram sample for 750 to 916 and 0.120 to 0.150 silver. For pure gold I take 0.060 to 0.065 Mile gram for 958 to 999 and .120 to 0.125 mile gram silver. I don't know what to do to get diffrence out of my work.
I use fire Assay. I boil the sample in Test Tube on fire.Is this procedure good ?
Is there someway to get out vibration, unlevel or big noise that effect my scal ?
I have to take 2 sample from 0.5 gram or not ?
Thank in Advance
waiting for your reply.

The obvious answer is to use a bigger sample. I routinely used 1 gram, often 0.5 gram and never less than 0.25 gram. I have used 2, 5, and 10 grams as well, but it gets cumbersome and tedious and expensive with 5 and 10 grams.

You must have squirrel hands to use the size of samples that you mention.

I ran proofs to begin with, but after I settled on a routine procedure, I stopped running proofs and double assays, etc. I ran one assay per bar most of the time. If the assay started "spitting" for any reason, then I had to repeat the assay, that's all. I really, really never found the actual, real, repeatable reason for "spitting". I wonder if anyone, really, really, knows to the point of making an assay spit or stop spitting. Granted one can take measures to minimize the risk of spitting, but some assays will spit randomly no matter how many precautions you take, or at least that was my experience. I only made some 1,000 assays though. There are people here with tens of thousands of assays and more experience that may comment with more knowledge.

If you stick to the procedures in the thread I pointed out, step by step, you will likely find success in your attempts, and with time and experience, perhaps mastery one day.

 

[talalstuvs]

Even with a 4 place balance, the table must be sturdy and fairly heavy to prevent vibration. With a 6 place, the problem is magnified.

There are several types of anti-vibration tables available for balances. They are all heavy and expensive.
http://www.google.com/search?num=100&hl=en&safe=off&rlz=1B3GGLL_enUS395US396&q=scale+anti-vibration+table&btnG=Search&aq=f&aqi=&aql=&oq=&gs_rfai=

someone advice me to get vibration out of scal i should
"You can build you a box out of plexiglass to put your scales in and then put the box on top of a rubber antivibration dampening pad"
Is this method work ?

 

[qst42know]

I don't know what is available in Iran.

Machinists use granite surface plates in many sizes. Granite kitchen counter tops are popular and expensive here, a sink cut out might be affordable. Pastry chefs use marble slabs for rolling dough.

Any flat polished stone slab should help. What can you find in your country?

 

[talalstuvs]

I don't know what is available in Iran.

Machinists use granite surface plates in many sizes. Granite kitchen counter tops are popular and expensive here, a sink cut out might be affordable. Pastry chefs use marble slabs for rolling dough.

Any flat polished stone slab should help. What can you find in your country?

I can find marble slab here in iran . what should be it's weigt and size to control vibration ? some speical marble or not and i cover surface of marble with any kind of rubber or something eles ?

 

[goldsilverpro]

I have heard of people putting a marble slab on top of a sturdy container (say, a 30 gal steel drum) filled with sand. The drum could be put on a rubber pad.

 

[talalstuvs]

I have heard of people putting a marble slab on top of a sturdy container (say, a 30 gal steel drum) filled with sand. The drum could be put on a rubber pad.

I don't understand your mean of drum fill with sand and put on a rubber ?
could you explain it plz ?

 

[goldsilverpro]

I've never done this or seen it but I've heard of someone doing it a long time ago. They put a drum filled completely with sand on a rubber pad and put a marble slab on top of the drum. I think I remember that they used a 30 gal steel drum.

 

[talalstuvs]

I've never done this or seen it but I've heard of someone doing it a long time ago. They put a drum filled completely with sand on a rubber pad and put a marble slab on top of the drum. I think I remember that they used a 30 gal steel drum.

Could anyone tell me the procedure of getting the karat of silver please ?
waiting for replay.

 

[goldsilverpro]

I've never done this or seen it but I've heard of someone doing it a long time ago. They put a drum filled completely with sand on a rubber pad and put a marble slab on top of the drum. I think I remember that they used a 30 gal steel drum.

Could anyone tell me the procedure of getting the karat of silver please ?
waiting for replay.

I replied to your same exact question on another thread. No duplicate posts, please.