talalstuvs
Well-known member
- Joined
- Sep 5, 2010
- Messages
- 52
I have 68% Nitirc acid for sample testing .What ration i should use for Frist and Second Acid ?
Thank for Advance
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Thank for Advance
waiting for reply.
talalstuvs said:I have 68% Nitirc acid for sample testing .What ration i should use for Frist and Second Acid ?
Thank for Advance
waiting for reply.
talalstuvs said: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 said:talalstuvs said: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.
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.HAuCl4 said: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 said: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.HAuCl4 said: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.
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.
someone advice me to get vibration out of scal i shouldgoldsilverpro said: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=
qst42know said: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 don't understand your mean of drum fill with sand and put on a rubber ?goldsilverpro said: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.
goldsilverpro said: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 said:goldsilverpro said: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 ?
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