Marcel, it seems you have the naming of anode and cathode backwards in your discription, although you do have the correct polarity.
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kadriver
Well-known member
Edited twice for content to clarify part of the process and to add a picture
I do remember being confused when it was time to harvest the gold (black gold powder) from my sulfuric acid stripping cell.
The acid had turned a dark color and it was hard to see when the gold powder had settled.
Also, being new to refining, I was very impatient and tended to rush. Resist the urge to push ahead when your material is still settling.
The idea is to get the black powder into a filter paper so it can be incinerated - sulfuric acid will dissolve filter paper so it must be washed out before filtering.
1) first let the cell sit for several days to allow the black gold powder to settle as much as possible. Shine a bright light through the acid in the cell to check that the powder has settled. The acid is viscous and it takes a long time for the gold powder to settle completely.
2) once settled, carefully decant the acid off by siphoning - don't attemp to pour it off because the black powder will get disturbed and be poured off with the acid - I used 3/16 inch ID plastic tubing from the hardware store. Get as much of the acid out as possible without disturbing the black gold powder. Don't suck on the tube to get the flow started, use a syringe to start the flow available on Ebay. Slightly elevate one side by placing a folded up paper towel under one side to get the acid to drain to the side with your siphon tube.
3) fill a large container (I used a 3 liter jar from the thrift store) about 3/4 full of distilled water (you can use tap water instead if no DH2O is available).
4) using an old flexible kitchen spatula, carefully scrape out the black gold powder and remaining acid from the stripping cell container into the large container of distilled water. Rinse the spatula in this same water to get all the gold powder off of it as well.
5) once you have all the black gold powder and remaining sulfuric acid in the water, stir it up real good to wash the acid from the powder and let it settle completely - over night is best.
6) next day when the powder has settled completely, siphon off the rinse water to a waste container. Don't try to pour it off becasue the black gold powder will get disturbed and get poured off with the rinse water. Get as much of the water as possible by slightly tilting the container, but be careful not to let any of the black powder get sucked up the siphon tube.
7) repeat this several times, and if you have them, test the pH of the rinse water with pH test strips until you get close to neutral. This lets you know that the acid has been removed. I would guess that at least 5 or 6 washings would do it.
8) after the last siphoning of wash water, pour the black gold powder into a filter paper to filter out the black gold powder. This powder is so fine that some of it will probably go through the filter paper and end up in the filtrate under the funnel. If this happens, just run the filtrate back through the same filter paper with all the black gold powder in it until the filtrate runs clear.
9) treat the resulting black powder as if it were full of lead, tin, and other base metals just like gold filled scrap from this point:
10) remove the filter with the black powder in it and place it in a pyroceram dish (a corningware casserole dish) DON'T ATTEMPT TO USE A PYREX DISH BECAUSE IT WILL EXPLODE IF HEATED WITH A DIRECT FLAME OR ON TOP OF A BURNER. You MUST use a corningware dish like the ones shown in the picture below. Pyrex glass (even though it is heat resistant) will not stand up to this type of useage.
11) using a propane torch with only about a 1/2 inch flame, incinerate the black powder and filter so that the filter burns completely to ash and all the powder has been turned red hot by the small flame. Avoid melting the black gold powder. If you use a larger flame then it will blow your gold out of the dish and cause loss of your hard earned gold powder!
12) once the filter and black powder has been incinerated, then let the corningware dish cool and add some full strength hydrochloric acid right in the corningware dish - about 100 to 200ml depending on how much black powder you have. This will loosen any bits that tend to adhere to the bottom of the corningware dish (like deglazing a frying pan with white wine) and you can use some fresh HCL, to rinse the gold powder into your beaker with a pipette. The amount of HCl you add is not critical. This acid addition will remove metal salts and any other base metals that may still be present that will dissolve in concentrated hydrochloric acid. It will then need to be removed by siphoning or being drawn off with a pipette and put in a waste container.
13) transfer everything to a heat resistance 600ml beaker being carefull that the HCl with the black gold powder in it does not run down the side of the corningware dish as you pour it into the beaker and end up on your work surface (instead of in your beaker). the reason you transfer everything to the beaker is so you can allow everything to settle completely (overnight is best) and then siphon off, or draw off this waste acid and get rid of it - don't try to pour it off becuase the settled powders will bloom into a cloud before you get it all poured out of the beaker - SIPHON OR DRAW THIS WASTE ACID OFF WITH A PIPETTE.
14) allow the black gold powder to settle completely then decant the acid with a transfer pipette (I like to use the 7ml plastic disposable kind) and get rid of the acid to a waste container. Get as much of the acid as possible being careful not to let any of the black gold powder get in the pipette, then throw it away into a waste container because it contains impurities that you dont want mixed in with your gold powders.
15) next add some fresh hydrochloric acid to the beaker and place it on low heat with a watch glass (or saucer) cover to keep the fumes in the beaker.
16) begin adding small amounts of nitric acid to form aqua regia. The black powder will dissolve very quickly as it is in a finely divided state. Add the nitric acid 1/2 ml at a time with low heat until all the black powder has dissolved. Some dirt may be present that will not dissolve, add the nitric slowly to avoid overshooting. If you overshoot with nitric additions, then you will have to get rid of the excess nitric acid by adding some urea or by evaporating down to a syrup and adding HCl to drive off the excess nitric acid.
17) once all the gold powder has dissolved, add 10 drops of sulfuric acid to precipitate out any lead as lead sulfate - it will get trapped in the filter and removed later on.
18) now filter the gold chloride solution to remove solids and any lead that precipitated. Rinse the filter clean with distilled water so that no traces of color are left in the filter paper.
19) if the gold chloride solution is cloudy, then you may have to pour it back through the same filter paper until the resulting liquid is crystal clear.
20) next precipitate the pure gold powder by adding sodium metabisulfite to the gold chloride solution. Add it a teaspoon at a time and stir. When the foam from stirring begins to turn white (from yellow) then the gold precipitation is almost complete. Test the solution with stannous chloride to make certain that all the gold has precipitated. If the test indicates that there is still gold in solution then add some more sodium metabisulfite and restest with stannous chloride.
21) once the pure gold powder has settled completely (overnight is best), decant the liquid to a waste container and begin washing the pure gold powder with boiling distilled water - takes about 5 or 6 washings with boiling distilled water (about 300ml distilled water per wash) to get all the chemicals out of the powder.
22) with the powder washed free of chemicals, add some strong ammonia (10% industrial strenght from the hardware store is OK, but 29% ammonium hydroxide is better) and boil the gold powder for several minutes in the ammonia.
23) decant the ammonia to a waste container and rinse the pure gold powder with boiling distilled water 5 or 6 times or until the smell of ammonia is gone from the gold powder.
24) add some 50/50 dilute nitric acid (50% concentrated nitric acid and 50% distilled water) about 50ml to 100ml of each to the pure gold powder - this will dissolve out any base metals that made it this far in the process. Cover with a watch glass or saucer and boil for about five minutes. Keep a cover on at all times because this mixture will pop and spit hot acid and gold out of the container - don't walk away from it as it boils. If it starts to pop, then remove from the heat with beaker tongs until it calms dowm, then continue boiling.
25) decant the dilute nitric acid and save it because although it may contain impurities, it can be used to dissolve silver or inquarted karat gold scrap. Make sure and label the container "used dilute nitric acid".
26) rinse with boiling distilled water 5 or 6 times and transfer the now clean and pure gold powder to a drying dish - I like to use corningware casserole on low heat.
27) once the pure gold powder is dry, transfer to a melting dish and melt the pure gold powder into a buttom. Remove the buttom from the melt dish with CLEAN metal tweezers before it glues to the bottom of the melt dish, and then dunk it in cold water.
28) if some flux adhered to the gold button, you can dissolve it off with a 5% solution of sulfuric acid (10ml concentrated sulfuric acid added to 200ml clean water). Heating the acid on low heat will hasten the flux removal.
I do remember being confused when it was time to harvest the gold (black gold powder) from my sulfuric acid stripping cell.
The acid had turned a dark color and it was hard to see when the gold powder had settled.
Also, being new to refining, I was very impatient and tended to rush. Resist the urge to push ahead when your material is still settling.
The idea is to get the black powder into a filter paper so it can be incinerated - sulfuric acid will dissolve filter paper so it must be washed out before filtering.
1) first let the cell sit for several days to allow the black gold powder to settle as much as possible. Shine a bright light through the acid in the cell to check that the powder has settled. The acid is viscous and it takes a long time for the gold powder to settle completely.
2) once settled, carefully decant the acid off by siphoning - don't attemp to pour it off because the black powder will get disturbed and be poured off with the acid - I used 3/16 inch ID plastic tubing from the hardware store. Get as much of the acid out as possible without disturbing the black gold powder. Don't suck on the tube to get the flow started, use a syringe to start the flow available on Ebay. Slightly elevate one side by placing a folded up paper towel under one side to get the acid to drain to the side with your siphon tube.
3) fill a large container (I used a 3 liter jar from the thrift store) about 3/4 full of distilled water (you can use tap water instead if no DH2O is available).
4) using an old flexible kitchen spatula, carefully scrape out the black gold powder and remaining acid from the stripping cell container into the large container of distilled water. Rinse the spatula in this same water to get all the gold powder off of it as well.
5) once you have all the black gold powder and remaining sulfuric acid in the water, stir it up real good to wash the acid from the powder and let it settle completely - over night is best.
6) next day when the powder has settled completely, siphon off the rinse water to a waste container. Don't try to pour it off becasue the black gold powder will get disturbed and get poured off with the rinse water. Get as much of the water as possible by slightly tilting the container, but be careful not to let any of the black powder get sucked up the siphon tube.
7) repeat this several times, and if you have them, test the pH of the rinse water with pH test strips until you get close to neutral. This lets you know that the acid has been removed. I would guess that at least 5 or 6 washings would do it.
8) after the last siphoning of wash water, pour the black gold powder into a filter paper to filter out the black gold powder. This powder is so fine that some of it will probably go through the filter paper and end up in the filtrate under the funnel. If this happens, just run the filtrate back through the same filter paper with all the black gold powder in it until the filtrate runs clear.
9) treat the resulting black powder as if it were full of lead, tin, and other base metals just like gold filled scrap from this point:
10) remove the filter with the black powder in it and place it in a pyroceram dish (a corningware casserole dish) DON'T ATTEMPT TO USE A PYREX DISH BECAUSE IT WILL EXPLODE IF HEATED WITH A DIRECT FLAME OR ON TOP OF A BURNER. You MUST use a corningware dish like the ones shown in the picture below. Pyrex glass (even though it is heat resistant) will not stand up to this type of useage.
11) using a propane torch with only about a 1/2 inch flame, incinerate the black powder and filter so that the filter burns completely to ash and all the powder has been turned red hot by the small flame. Avoid melting the black gold powder. If you use a larger flame then it will blow your gold out of the dish and cause loss of your hard earned gold powder!
12) once the filter and black powder has been incinerated, then let the corningware dish cool and add some full strength hydrochloric acid right in the corningware dish - about 100 to 200ml depending on how much black powder you have. This will loosen any bits that tend to adhere to the bottom of the corningware dish (like deglazing a frying pan with white wine) and you can use some fresh HCL, to rinse the gold powder into your beaker with a pipette. The amount of HCl you add is not critical. This acid addition will remove metal salts and any other base metals that may still be present that will dissolve in concentrated hydrochloric acid. It will then need to be removed by siphoning or being drawn off with a pipette and put in a waste container.
13) transfer everything to a heat resistance 600ml beaker being carefull that the HCl with the black gold powder in it does not run down the side of the corningware dish as you pour it into the beaker and end up on your work surface (instead of in your beaker). the reason you transfer everything to the beaker is so you can allow everything to settle completely (overnight is best) and then siphon off, or draw off this waste acid and get rid of it - don't try to pour it off becuase the settled powders will bloom into a cloud before you get it all poured out of the beaker - SIPHON OR DRAW THIS WASTE ACID OFF WITH A PIPETTE.
14) allow the black gold powder to settle completely then decant the acid with a transfer pipette (I like to use the 7ml plastic disposable kind) and get rid of the acid to a waste container. Get as much of the acid as possible being careful not to let any of the black gold powder get in the pipette, then throw it away into a waste container because it contains impurities that you dont want mixed in with your gold powders.
15) next add some fresh hydrochloric acid to the beaker and place it on low heat with a watch glass (or saucer) cover to keep the fumes in the beaker.
16) begin adding small amounts of nitric acid to form aqua regia. The black powder will dissolve very quickly as it is in a finely divided state. Add the nitric acid 1/2 ml at a time with low heat until all the black powder has dissolved. Some dirt may be present that will not dissolve, add the nitric slowly to avoid overshooting. If you overshoot with nitric additions, then you will have to get rid of the excess nitric acid by adding some urea or by evaporating down to a syrup and adding HCl to drive off the excess nitric acid.
17) once all the gold powder has dissolved, add 10 drops of sulfuric acid to precipitate out any lead as lead sulfate - it will get trapped in the filter and removed later on.
18) now filter the gold chloride solution to remove solids and any lead that precipitated. Rinse the filter clean with distilled water so that no traces of color are left in the filter paper.
19) if the gold chloride solution is cloudy, then you may have to pour it back through the same filter paper until the resulting liquid is crystal clear.
20) next precipitate the pure gold powder by adding sodium metabisulfite to the gold chloride solution. Add it a teaspoon at a time and stir. When the foam from stirring begins to turn white (from yellow) then the gold precipitation is almost complete. Test the solution with stannous chloride to make certain that all the gold has precipitated. If the test indicates that there is still gold in solution then add some more sodium metabisulfite and restest with stannous chloride.
21) once the pure gold powder has settled completely (overnight is best), decant the liquid to a waste container and begin washing the pure gold powder with boiling distilled water - takes about 5 or 6 washings with boiling distilled water (about 300ml distilled water per wash) to get all the chemicals out of the powder.
22) with the powder washed free of chemicals, add some strong ammonia (10% industrial strenght from the hardware store is OK, but 29% ammonium hydroxide is better) and boil the gold powder for several minutes in the ammonia.
23) decant the ammonia to a waste container and rinse the pure gold powder with boiling distilled water 5 or 6 times or until the smell of ammonia is gone from the gold powder.
24) add some 50/50 dilute nitric acid (50% concentrated nitric acid and 50% distilled water) about 50ml to 100ml of each to the pure gold powder - this will dissolve out any base metals that made it this far in the process. Cover with a watch glass or saucer and boil for about five minutes. Keep a cover on at all times because this mixture will pop and spit hot acid and gold out of the container - don't walk away from it as it boils. If it starts to pop, then remove from the heat with beaker tongs until it calms dowm, then continue boiling.
25) decant the dilute nitric acid and save it because although it may contain impurities, it can be used to dissolve silver or inquarted karat gold scrap. Make sure and label the container "used dilute nitric acid".
26) rinse with boiling distilled water 5 or 6 times and transfer the now clean and pure gold powder to a drying dish - I like to use corningware casserole on low heat.
27) once the pure gold powder is dry, transfer to a melting dish and melt the pure gold powder into a buttom. Remove the buttom from the melt dish with CLEAN metal tweezers before it glues to the bottom of the melt dish, and then dunk it in cold water.
28) if some flux adhered to the gold button, you can dissolve it off with a 5% solution of sulfuric acid (10ml concentrated sulfuric acid added to 200ml clean water). Heating the acid on low heat will hasten the flux removal.
Attachments
Great post Kevin,
I merged your post with the existing thread on the same topic.
Steve
I merged your post with the existing thread on the same topic.
Steve
A
Anonymous
Guest
From the time I've been a member here and reading so much, to me, by far, this is one of the best threads I've read. One reason is because I've already done some refining of keyboard mylars with great success, been reading and learning the vocabulary and terminology of the words of this field and kept on reading.
Since I've done my initial batch of refining for silver, I'm ready to do my sulfuric cell. I have everything needed and I have plenty of gold plated material.
Everyone of you like lasersteve, Barren Realms 007, philddreamer, goldsilverpro, and special thanks to kadriver for the post on page 5, gave me more of an understanding and confidence to do this. I'm ready, but, unfortunately it's raining outside and it's going to do it for a few days as of now.
Reading this thread helped me understand what is to be done all because I've been reading and looking up the words and understanding their meanings. I kid you not, I wish I had a fume hood right now. The instructions and replies were great because I followed this from the first page to the last and I reread it too, just to pick up on more that I may not have understood. I can do this.. safely too.
I do have a few questions though.
Q1. After all the gold have been stripped in the cell, could I let it cool down, then pour everything into a beaker, then after that settles overnight, siphon the solution out, back into the cell to reuse?.. leaving the black mud in the beaker and process from there?
Q2. When kadriver talks about step no# 23, do each time have to settle overnight?
Once again, this thread and forum has opened up my mind and my eyes even more, because I understand more, because I'm reading more.
Kevin
Since I've done my initial batch of refining for silver, I'm ready to do my sulfuric cell. I have everything needed and I have plenty of gold plated material.
Everyone of you like lasersteve, Barren Realms 007, philddreamer, goldsilverpro, and special thanks to kadriver for the post on page 5, gave me more of an understanding and confidence to do this. I'm ready, but, unfortunately it's raining outside and it's going to do it for a few days as of now.
Reading this thread helped me understand what is to be done all because I've been reading and looking up the words and understanding their meanings. I kid you not, I wish I had a fume hood right now. The instructions and replies were great because I followed this from the first page to the last and I reread it too, just to pick up on more that I may not have understood. I can do this.. safely too.
I do have a few questions though.
Q1. After all the gold have been stripped in the cell, could I let it cool down, then pour everything into a beaker, then after that settles overnight, siphon the solution out, back into the cell to reuse?.. leaving the black mud in the beaker and process from there?
Q2. When kadriver talks about step no# 23, do each time have to settle overnight?
Once again, this thread and forum has opened up my mind and my eyes even more, because I understand more, because I'm reading more.
Kevin
Yes you can transfer the liquid and black powder to a separate container. A few notes of caution:
1. Transferring concentrated sulfuric acid is a very dangerous operation, so suit up properly and have a spill catch just in case.
2. Do not add water to the concentrated acid. Diluted acid cannot be used for the cell. This is why I simply recommend letting settle over night and pouring off the transparent portion of the acid as you will have to have some means of rinsing the gold powder from the bottom of the cell.
3. It is possible to vacuum filter the concentrated acid to recover the black powder with proper filters ( Teflon or polypropylene). This is the best way in my opinion if you don't mind waiting for the vacuum to finish as the filter easily clogs.
4. It is possible to gravity filter using a fiberglass 'charmin plug', search for phildreamer's posts on fiberglass plugs.
I used to do all the rinses on my black powder, but I have since realized it is much easier to rinse once and dissolve directly in AR. It's much faster to refine twice with proper filtering between each step and obtain high purity gold. When working will larger batches the law of diminishing returns takes over and it is counter productive to perform all of the in between rinses which consume lots of time for the same end result.
Be safe and good luck!
Steve
1. Transferring concentrated sulfuric acid is a very dangerous operation, so suit up properly and have a spill catch just in case.
2. Do not add water to the concentrated acid. Diluted acid cannot be used for the cell. This is why I simply recommend letting settle over night and pouring off the transparent portion of the acid as you will have to have some means of rinsing the gold powder from the bottom of the cell.
3. It is possible to vacuum filter the concentrated acid to recover the black powder with proper filters ( Teflon or polypropylene). This is the best way in my opinion if you don't mind waiting for the vacuum to finish as the filter easily clogs.
4. It is possible to gravity filter using a fiberglass 'charmin plug', search for phildreamer's posts on fiberglass plugs.
I used to do all the rinses on my black powder, but I have since realized it is much easier to rinse once and dissolve directly in AR. It's much faster to refine twice with proper filtering between each step and obtain high purity gold. When working will larger batches the law of diminishing returns takes over and it is counter productive to perform all of the in between rinses which consume lots of time for the same end result.
Be safe and good luck!
Steve
Hello all,
I am trying to find out which metals will precipitate out of an hcl/cl to make aucl3 then dropping with msb?
I have a batch of pins that produced foils that i filtered, dissolved in hcl/cl, and precipitated with smb as per lazersteve's acid peroxide video. I have a nice brown powder as expected.
Ok, Im fine on all of that. My question has to do with the black powder that has accumulated as the reaction continues. This is my first run and I had already started the pins before I read that ap is not the preferred process for these. What all is in the black powder from acid peroxide process?
I assumed that continuing to rinse with warm hcl on the black powder until it clears up and stops turning green is what im supposed to do. Then I read that you process your black powder from the cell through ar twice after a rinse.
I havent graduated to auqaregia yet..... so can I dissolve the black powder in hcl/cl? What comes along with the gold in the precipitate of aucl3 using smb to drop?
Not that im lazy, but the rinse and settle then decant process is going on and on and on. And what could be eliminated if you did a second hcl/cl dissolution and drop the gold with smb again?
Im getting excited to see my first gold button, I just dont want to get in too big of a hurry and mess something up or end up with an inferior product.
I thank all of you gurus for your great wisdom and experience. I dont want to waste your time, I just wanted to let you know that I have searched and searched the forum before posting.
I am trying to find out which metals will precipitate out of an hcl/cl to make aucl3 then dropping with msb?
I have a batch of pins that produced foils that i filtered, dissolved in hcl/cl, and precipitated with smb as per lazersteve's acid peroxide video. I have a nice brown powder as expected.
Ok, Im fine on all of that. My question has to do with the black powder that has accumulated as the reaction continues. This is my first run and I had already started the pins before I read that ap is not the preferred process for these. What all is in the black powder from acid peroxide process?
I assumed that continuing to rinse with warm hcl on the black powder until it clears up and stops turning green is what im supposed to do. Then I read that you process your black powder from the cell through ar twice after a rinse.
I havent graduated to auqaregia yet..... so can I dissolve the black powder in hcl/cl? What comes along with the gold in the precipitate of aucl3 using smb to drop?
Not that im lazy, but the rinse and settle then decant process is going on and on and on. And what could be eliminated if you did a second hcl/cl dissolution and drop the gold with smb again?
Im getting excited to see my first gold button, I just dont want to get in too big of a hurry and mess something up or end up with an inferior product.
I thank all of you gurus for your great wisdom and experience. I dont want to waste your time, I just wanted to let you know that I have searched and searched the forum before posting.
You can refine the dirty black powder from Acid Peroxide reaction and copper cemetation using HCl/Cl as long as it is wet and finely divided. HCl/Cl has a hard time with dried chunks of material. You'll likely have to perform two refining passes on the black powder to get the purity up to par.
Steve
Steve
A
Anonymous
Guest
On step 12 above, wouldn't it be easier to let the Corningware dish cool first, then transfer everything to the 600 ml heat resistant beaker, then add the HCL? It seems that if it's all done in the dish first, then transferred, it'll leave much room for spills.
Also, do the HCL need to be just above the powder, or how much are we suppose to use? Do we weigh the powder first?
Kevin
Also, do the HCL need to be just above the powder, or how much are we suppose to use? Do we weigh the powder first?
Kevin
kadriver
Well-known member
lazersteve said:
I wondered what happened to it, Thanks Steve.
testerman; yes let the dish cool before adding the HCl. I just did a batch of gold filled and forgot to let the dish cool. As soon as I started to add the acid, the hot dish began to spatter my hard earned gold foils all over the place!
kadriver
kane333
Well-known member
- Joined
- Aug 5, 2012
- Messages
- 140
Hey all. I have read this and http://goldrefiningforum.com/phpBB3/viewtopic.php?f=53&t=17058&hilit=black+powder&start=20 multiple times to see if I was missing what I'm looking for. The steps are to add H2SO4 to AR to precipitate lead sulfate out of solution. My problem is, I don't have HNO3. I was going to use the HCL/CL route to dissolve the black powder. I've washed the black powder 8 times in bottled drinking water (better than our well water I hope) to get rid of the bluish green tint (copper?).
One thing I've used to my advantage over all these washes is to heat the solution slightly, just turning my burner up to warm. I've found that it helps the powder settle quicker since solids cool quicker than liquids. The black powder will almost completely settle within 1-2 hours using a little bit of heat, then allowing the solution to cool to room temp, I've found. I'm using a 500ml boro beaker in a sand bath which is inside of a pyroceram dish on my burner. After warming slightly, I remove from the sand bath to help the solution cool quicker. Without this slight warming technique, I've had to wait overnight for the powder to settle completely and could only get in one wash per day.
I've also washed the powder 3 times in straight HCL and it's sitting in my beaker at the moment in 100ml of HCL with about 20ml of H2O2, which is now yellowish green, using no heat. This yellowish green solution, I've tested with stannous and it comes back negative. My question is, when do I add the H2SO4 to drop any lead sulfate which I presume may be present since we do use a lead cathode? Any suggestions would be appreciated.
One thing I've used to my advantage over all these washes is to heat the solution slightly, just turning my burner up to warm. I've found that it helps the powder settle quicker since solids cool quicker than liquids. The black powder will almost completely settle within 1-2 hours using a little bit of heat, then allowing the solution to cool to room temp, I've found. I'm using a 500ml boro beaker in a sand bath which is inside of a pyroceram dish on my burner. After warming slightly, I remove from the sand bath to help the solution cool quicker. Without this slight warming technique, I've had to wait overnight for the powder to settle completely and could only get in one wash per day.
I've also washed the powder 3 times in straight HCL and it's sitting in my beaker at the moment in 100ml of HCL with about 20ml of H2O2, which is now yellowish green, using no heat. This yellowish green solution, I've tested with stannous and it comes back negative. My question is, when do I add the H2SO4 to drop any lead sulfate which I presume may be present since we do use a lead cathode? Any suggestions would be appreciated.
jeneje
Well-known member
kane333 said:
kane333, if I understand this right you add 10 drops of H2S04 when you process the black powder in AR. I don't know if it will work in the HCL/Cl maybe someone else can answer that for you.
Ken
Tub Buster
Well-known member
- Joined
- Sep 5, 2013
- Messages
- 53
This only happens if the basket is at a higher elevation than the cathode. Wouldn't it make more sense to keep the cathode higher?lazersteve said:
In a short Pyrex dish like I used in the videos, the height of the cathode is limited to a few inches or less. It is much easier to lower the front edge of the copper mesh basket than it is to raise and properly support the cathode while keeping the cathode submerged in the acid.
Steve
Steve
I talked to a guy last week ( who has a large e-scrap yard and has been into recovery for long) and he said that he would add in a copper bar to the remaining solution, which would make more black gold powder precipitate.
I told him that I do not understand this, because as far as I see it no gold goes into solution using the cell. (he used concentrated sulfuric acid and the setup that is being described in this thread here)
He leaves the copper bar in until the solution gets water-clear.
Btw: He uses the same process - in another cell - for silver plated cuttlery.
So, any thoughts? Can this really be gold that precipitates? Is there gold being dissolved in the cell process?
I told him that I do not understand this, because as far as I see it no gold goes into solution using the cell. (he used concentrated sulfuric acid and the setup that is being described in this thread here)
He leaves the copper bar in until the solution gets water-clear.
Btw: He uses the same process - in another cell - for silver plated cuttlery.
So, any thoughts? Can this really be gold that precipitates? Is there gold being dissolved in the cell process?
solar_plasma
Well-known member
Did I understand this right: He puts copper, which does not dissolve in cold, conc. sulfuric, into the same in order to cement gold, which also does not dissolve in sulfuric, by reduction of the gold and oxidation of the copper and then he gets a non-coloured waterlike sulfuric? Sounds strange to me.
Could it be traces of rhodium instead?
Could it be traces of rhodium instead?
necromancer
Well-known member
its stated here that rhodium is dissolved in hot concentrated sulfuric acid and it is attacked by molten alkalis.
http://www.lenntech.com/periodic/elements/rh.htm
i never thought gold could be dissolved in sulfuric acid.
http://www.lenntech.com/periodic/elements/rh.htm
i never thought gold could be dissolved in sulfuric acid.
wrightytighty
New member
- Joined
- Sep 24, 2014
- Messages
- 1
This is my first post.
I am going the "poor mans" route on the gold refining and had a few questions about kadivers list, which is awesome btw.
I am deplating jewlery from a sulphuric cell. I am doing the HCL/CL method to refine.
I have no nitric acid.
I was wondering if step 17 on kadivers list would work with the HCL/CL method.
"16) begin adding small amounts of nitric acid to form aqua regia. The black powder will dissolve very quickly as it is in a finely divided state. Add the nitric acid 1/2 ml at a time with low heat until all the black powder has dissolved. Some dirt may be present that will not dissolve, add the nitric slowly to avoid overshooting. If you overshoot with nitric additions, then you will have to get rid of the excess nitric acid by adding some urea or by evaporating down to a syrup and adding HCl to drive off the excess nitric acid.
17) once all the gold powder has dissolved, add 10 drops of sulfuric acid to precipitate out any lead as lead sulfate - it will get trapped in the filter and removed later on."
Also, I'm pretty sure I have silver in my powder, what would be the best way to deal with that if I avoid step 24
Is there anyway to remove silver from my powder so I can obtain a higher purity?
"24) add some 50/50 dilute nitric acid (50% concentrated nitric acid and 50% distilled water) about 50ml to 100ml of each to the pure gold powder - this will dissolve out any base metals that made it this far in the process. Cover with a watch glass or saucer and boil for about five minutes. Keep a cover on at all times because this mixture will pop and spit hot acid and gold out of the container - don't walk away from it as it boils. If it starts to pop, then remove from the heat with beaker tongs until it calms dowm, then continue boiling."
would my powder turn out okay if I skipped the above steps?
I appreciate this fourm and all the wisdom it has.
I am going the "poor mans" route on the gold refining and had a few questions about kadivers list, which is awesome btw.
I am deplating jewlery from a sulphuric cell. I am doing the HCL/CL method to refine.
I have no nitric acid.
I was wondering if step 17 on kadivers list would work with the HCL/CL method.
"16) begin adding small amounts of nitric acid to form aqua regia. The black powder will dissolve very quickly as it is in a finely divided state. Add the nitric acid 1/2 ml at a time with low heat until all the black powder has dissolved. Some dirt may be present that will not dissolve, add the nitric slowly to avoid overshooting. If you overshoot with nitric additions, then you will have to get rid of the excess nitric acid by adding some urea or by evaporating down to a syrup and adding HCl to drive off the excess nitric acid.
17) once all the gold powder has dissolved, add 10 drops of sulfuric acid to precipitate out any lead as lead sulfate - it will get trapped in the filter and removed later on."
Also, I'm pretty sure I have silver in my powder, what would be the best way to deal with that if I avoid step 24
Is there anyway to remove silver from my powder so I can obtain a higher purity?
"24) add some 50/50 dilute nitric acid (50% concentrated nitric acid and 50% distilled water) about 50ml to 100ml of each to the pure gold powder - this will dissolve out any base metals that made it this far in the process. Cover with a watch glass or saucer and boil for about five minutes. Keep a cover on at all times because this mixture will pop and spit hot acid and gold out of the container - don't walk away from it as it boils. If it starts to pop, then remove from the heat with beaker tongs until it calms dowm, then continue boiling."
would my powder turn out okay if I skipped the above steps?
I appreciate this fourm and all the wisdom it has.
When you strip gold plating using the sulphuric cell the powders are rarely pure gold but contain a mixture of various metals so it really doesn't matter which way you decide to refine them. Doing acid rinses at the start will help to remove more base metals as would incineration and a hot hydrochloric soak but the chances are you are going to have to refine your powder twice to get decent purity.
Keep up your studying and find a method that you have access to the necessary chemicals and equipment to be successful with, remember your gold is safe unless you throw it away.
Keep up your studying and find a method that you have access to the necessary chemicals and equipment to be successful with, remember your gold is safe unless you throw it away.
MarcoP
Well-known member
By using HCl/Cl the silver with change into silver chloride which is pretty much insoluble in cold solutions.
wrightytighty, if I've understood your questions, yes, adding a bit of sulfuric acid to an HCl/Cl solution will work the same as it will in AR. Any lead that is in the solution as a chloride will be precipitated as insoluble lead sulfate.
As far as silver goes, as Marco said, it becomes insoluble silver chloride (AgCl) when you're dissolving your powder. However, while AgCl is quite insoluble in water or dilute chloride solutions, it is somewhat soluble in strong chloride solutions. Once your gold is dissolved, we usually recommend diluting your solution with two or three times as much ice. The ice both dilutes the solution and cools it, both of which reduce the solubility of both AgCl and lead sulfate. Once the ice melts, filter the solution to remove any remaining solids and precipitate the gold from a crystal clear solution.
Despite your best efforts, there will still likely be some contamination in the precipitated gold. That's where the final washing procedures come in. Harold_V wrote up his washing procedures, and his procedure works very well.
Dave
As far as silver goes, as Marco said, it becomes insoluble silver chloride (AgCl) when you're dissolving your powder. However, while AgCl is quite insoluble in water or dilute chloride solutions, it is somewhat soluble in strong chloride solutions. Once your gold is dissolved, we usually recommend diluting your solution with two or three times as much ice. The ice both dilutes the solution and cools it, both of which reduce the solubility of both AgCl and lead sulfate. Once the ice melts, filter the solution to remove any remaining solids and precipitate the gold from a crystal clear solution.
Despite your best efforts, there will still likely be some contamination in the precipitated gold. That's where the final washing procedures come in. Harold_V wrote up his washing procedures, and his procedure works very well.
Dave
