# When In Doubt, Cement It Out



## FrugalRefiner

*When In Doubt, Cement It Out*

This is advice I often give to new members who find they've created a bit of a mess, and they're wondering how to recover their values (gold, silver, PGMs, etc.).

Perhaps they've followed a process they've seen on YouTube that left out some important details. Perhaps they've used too much oxidizer. Perhaps they've dissolve a bunch of ewaste into a toxic mix of predominantly base metals with a small amount of values. Whatever the cause, "cementation" is a way to recover.

But cementation is not just for recovering from a mess. It is also the principle used in the stock pot. Solutions that have traces of values remaining in them are best treated in the stock pot to recover whatever may remain after the bulk of the values have been recovered through other methods.

It is also a good method for precipitating PGMs. PGM salts, particularly platinum(IV) salts, are very hazardous. While PGMs can be precipitated as relatively insoluble salts, they are still hazardous and must be further processed to recover them as metals, and some of the metal salts will still remain in solution. Cementing them out of solution recovers them as metals, and does so completely.

In simple terms, a solid piece of metal is put into a solution that already has a metal dissolved in it. The solid metal goes into solution and the dissolved metal precipitates, or "cements", out. This is also known as a "replacement reaction", as the solid metal replaces the metal that was in solution. The precipitate often looks like wet cement due to its color and texture as it settles to the bottom of the container. That simple reaction is the subject of this post.

*Testing*
The first question to ask is whether there are values in the solution.

As an example, someone may have put a bunch of gold plated circuit boards into some acids, watched their gold disappear, and so they "know" they have gold in their solution. But, although their gold may have dissolved into the acids, it may have already "cemented" back out onto base metals in and on the circuit boards. Or it may never have dissolved, but been coated by other metals as the various, more reactive, metals went into and out of solution on metals that remained on the circuit boards.

The first thing to do is to test the solution. If you're pursuing gold or PGMs, stannous chloride is most often used. To test for palladium, use dimethylglyoxime (DMG). If your target is silver, salt or HCl can be used to detect its presence. All these tests are discussed in the book in my signature line below, as well as extensive posts on the forum that can be found using the search function.

*Cementation*
Cementation is a process where a solid, elemental metal is used to replace a dissolved, ionic metal that is in a solution. The metals we pursue are usually known as noble metals. The name comes from the resistance of these metals to being oxidized and dissolved. This is all based on the number of electrons in their various orbits, and their locations in the various "shells", but that is far beyond the scope of this post. It is sufficient to understand that various metals are more or less resistant to oxidation, and we can use these properties to our advantage.

These varying resistances to oxidation are summarized in the reactivity series of metals. The list below is my own compilation of the many charts I've reviewed. For this post, it contains only the more common metals.

Aluminum
Zinc
Chromium
Iron
Cadmium
Nickel
Tin
Lead
Copper
Silver
Mercury
Palladium
Platinum
Gold

You may see charts that vary slightly from the list above. Many metals can exist in more than one oxidation state, and those varying oxidation states can move a metal up or down the list. Mine is a "generalized" list that serves the purpose of this post.

When viewing a reactivity chart, the more reactive elements (primarily metals) are usually at the top of the chart, indicating they are more reactive (higher reactivity), and the less reactive metals are usually toward the bottom of the chart (lower reactivity). _In general_, a more reactive metal can be used to "replace" a metal that is lower on the chart (see notes below in "Things To Keep In Mind").

It can occur unintentionally during a process as described in the example above where a bunch of circuit boards have been put into acid and metals have dissolved, then cemented back out of solution in an uncontrolled manner. It can also be used intentionally to recover values that have been dissolved.

*A Cementation Tank*
The simplest way to cement values out of a solution is to simply put a piece of solid metal into the solution. But the reaction will be slow and may not recover all the values. The solution needs to circulate so the dissolved values come into close proximity to the solid metal. Circulation also helps prevent the solid metal from just developing a plated surface that will stop further reaction, leaving values in solution.

4metals was kind enough to share his design for a simple, but very effective cementation rig in a post in the Fuzz Button Interconnects, need some advice thread. I've reproduced his diagram below, but it's worth reading the complete, original thread.




My setup is slightly different. I'm sure whatever 4metals used was many times larger than my little system. My modifications suit my much smaller needs.

My PVC pipe is the full height of my container, while 4metals' is shorter and the top sits below the liquid level. My pipe for this build is 2" diameter PVC. I drill large holes in both the bottom and the top of my pipe to allow the solution to flow in at the bottom and out at the top, where his solution simply flows out of the top of the pipe.

The holes at the bottom are a bit above the bottom of the pipe so it doesn't tend to draw in any cement as the solution flows in. The holes at the top are at various levels a little higher than where I put the copper. This allows the solution to flow out regardless of how full the container is, as long as it is at least as high as the lowest holes.

I put a small hole near the bottom of the pipe that I can put my air hose through. It's just big enough for the hose to make a snug fit that keeps it in place.




I also put a piece of perforated plastic just above the lower set of holes. I use a short piece of the same 2" diameter PVC with a section cut out. I can squeeze it together and push it into the bottom of the main pipe, then push it up the pipe so it is just above the lower holes. The tension of this "retainer" holds it in place, but allows it to be removed for cleaning. The round disk of perforated plastic then sits on top of the PVC retainer. The perforated plastic is sold in craft stores as "plastic canvas". It is easily cut with a pair of scissors. This keeps me from having to drill holes in the chunks of copper to hang them inside the pipe. I can just drop a couple of chunks into the pipe and I'm ready to go. *Note:* I use these chunks of copper because I have many pounds of them. Using pieces of copper pipe that have been cut open and flattened will work faster due to the increased surface area.






I use a lid on my small container to contain the spray. *Note:* While the lid is silver and might look like metal in the pictures, it is plastic. I glue a short piece of a smaller diameter, 1-1/2" PVC pipe to the center of the lid of my container. It fits inside my main pipe and helps keep the main pipe centered in the container. I put small, matching holes through both pieces of pipe so I can assemble the cap and pipe, and put a small strip of PVC through both of them to hold them together, so I can put it all together before screwing the cap on when I run the rig. I cut the strip along the length of a piece of pipe. I round the edges a bit and heat the ends a bit so I can bend them down a bit to make assembly easier. This is a little fancier than it needs to be, but I enjoy the build. 

I drill a small hole in the lid for the air hose. I drill another larger hole and glue a short piece of small diameter CPVC pipe to it to act similar to a reflux condenser. Any spray that tries to escape the container settles onto the inside of the pipe and drips back into the container while allowing the air from the pump to escape.







Here are all the parts laid out before it's put together.




And this is the full rig put together.




That's it! To put it together, fit the retainer ring into the main pipe and push it up till it's just above the lower set of holes. Put the air hose through the lid and then through the bottom of the pipe. I cut a taper on the end of the hose so it will fit into the pipe a little easier. Drop in the perforated disk and add some copper, or hang it inside if you haven't built a perforated disk like mine. Align the main pipe with the smaller section of pipe glued to the lid and put the strip of PVC through the holes to hold them together. Lower the lid and PVC pipe into the jar, screw the lid on, and turn on the air pump.

4metals was kind enough to provide a picture of a 50 gallon cementation tank used by one of his customers.




For you video fans, here's a quick video showing me putting it all together.



You can watch a larger view of the video on YouTube by clicking on the title of the video above.

The air bubbles rise through the pipe, carrying a constant, fresh flow of solution and helping to dislodge the cemented values from the copper. Let it run. Test a sample of the solution from time to time. When the solution tests negative, turn off the pump and remove the lid, pipe, and any remaining copper. Allow the cement to settle and decant or syphon off the barren solution. You can wash the cement in the container, or pour it off to an appropriately sized container for washing.

*Why Copper?*
Many people talk about using iron, zinc, aluminum, or other metals for cementing. While they will certainly work, and they have their place in certain situations, they will also cement everything below them on the reactivity series. The advantage of using copper is that it will only cement silver, gold, PGMs, and mercury if it happens to be in your solution. Any other metals can be cemented out with iron when you treat the solution for waste. This is discussed fully in the book in my signature line and on the forum. Search for "stock pot".

*Things To Keep In Mind*
For cementation to work, the metal being used to cement out the values must be soluble in the solution. Looking at the reactivity list, it might be tempting to try to use silver to cement out gold or PGMs. But silver is not soluble in a chloride solution, so it won't work for gold. Copper will work in both nitrate and chloride solutions, so it can be used to recover all of our target metals from either type of solution.

There also needs to be a significant difference in the reactivities of the metals. Silver and the other precious metals are far less reactive than copper, so it works well. Tin is only slightly more reactive than lead, so it won't work well to cement lead out of a solution.

Keep all of the copper under the surface of the solution. If it extends above the solution, it can react with the oxygen in the air, and bits of copper oxides can flake off and join the cement, contaminating it. While cementation is generally considered a recovery process, so the cement will probably be refined further, it's better to keep out as much contamination as possible.

Circulation is necessary. As mentioned above, the solution must be kept in motion. It brings fresh solution into proximity with the copper, and the air bubbles help to dislodge the cement, preventing the copper from being plated/coated over stopping the reaction.

Some people report difficulties when their solutions are highly concentrated. They can be prone to forming an adherent coating on the copper, slowing or stopping the cementing process. In these cases, diluting the solution can help stop this problem, allowing the cemented metal to fall more easily from the copper.

Keep your air pump ABOVE the tank. Electricity can go out. The pump can fail. The hose can burst or come off the pump. If any of those happen, and the pump isn't above the container, the liquid can rush up the air hose and over the top creating a syphon that can cause your solution to flow out and possibly be lost.

I haven't been able to refine much since we moved, so I may have forgotten some important points. Please feel free to add to this thread as needed.

Dave


----------



## GREENER

FrugalRefiner,

Thank you for this elaborate explanation in combination with the pictures and drawings.

I am perhaps the newest member on this forum.
Although I have watched a huge lot of videos ( Geo, Sreetips, 999 Dusan, etc...) about refining,
and that I have accumulated a real lot of PCB`s, I still dont feel ready to start with the real refining.

To try and see if I would get the same colours or reactions as seen in numerous videos, I have done some really tiny tests,
which have given very encouraging results sofar.

At this stage I`m still busy on accumulating and sorting and expanding my already large stack ( I`d say; 5-6 cubic metres) of boards and components, mostly consumer elektronics, but also defense, industrial, telecom and medical grade stuff.
I`m also preparing in the sense of dismanteling cable plugs, switches and what not.

The reason for me posting this reply is threefold;

1st; To say hello to the community, I will not mention any specifics about myself, because in my home country, I`m not allowed to recover/refine.

2nd; In one of the last videos from Geo on youtube, he mentioned on trying to come up with a way (if I`m correct in understanding) to,
"rid the boards of magnetics and aluminum, then use HCL to remove tin, and then burn to a crisp and start recovery/refinement.

Could you please tell me if Geo has progressed in finding such a method?
Because my accumulation is so great by now, and I will continue accumulating for at least the next two years, by then I will have close to 10 cubic metres of closely stacked boards.
Let alone the cables and plugs.

3rd reason; On this forum I read a lot about chlorides already. Is it not so that PVC inherently contains a chloride already?
There is a good possibility that I will be making a cementation device similar to yours.
I own a large diameter perspex pipe (the transparent one).
In my train of thought, I think that it might be wise to use this instead of PVC?

Not my intension to be smug here, I only wish the best start for me for whatever refining steps I will start with in the near future.

Thanks in advance to who-ever might reply.

I have a lot to learn still.

Sincerely,
Chris


----------



## MicheleM

Thanks @FrugalRefiner , can I ask you if there is a method to recover/cement metallic aluminium from a aluminium-chloride liquid solution ? I know Iron is the way to treat liquid waste but when I started as a beginner I followed the AP flowchart.pdf using Al. I read the thread on filtration problems too late when I was raising the PH with baking soda after the recovery of copper and other base metals.


----------



## FrugalRefiner

GREENER, I'm afraid I don't know what progress he may have made on any of his projects. Perhaps he'll see this thread and respond.

MicheleM, I've never tried to recover aluminum from solution. I generally avoid it in my refining.

Dave


----------



## Jado

MicheleM said:


> Thanks @FrugalRefiner , can I ask you if there is a method to recover/cement metallic aluminium from a aluminium-chloride liquid solution ? I know Iron is the way to treat liquid waste but when I started as a beginner I followed the AP flowchart.pdf using Al. I read the thread on filtration problems too late when I was raising the PH with baking soda after the recovery of copper and other base metals.


Short answer is no.

Long answer is to boil dry, process to aluminum oxide, heat to 1000 degrees under some expensive, otherwise useless slag and electrolyze it out. It’s not cost effective, safe, eco friendly, or easy.


----------



## MicheleM

Thank you!


----------



## orvi

dont bother with aluminium "recovery". look at the chart above and you will see aluminium right on top of the reactivity series (part of it). truth is, theoretically, you can "cement" aluminium with a more reactive metal, but this metal will be something like sodium, potassium or lithium. and not to mention, you cannot obviously precipitate it from aqueous solution, because for metals like aluminium or sodium, water is enough acidic to act like acid and react with these metals.
reason why regular aluminium metal (bulk) dont react with water is very thin coating of oxide which form on the sufrace and block access for water. if this barrier is removed, aluminium can react with water violently  easy demonstration is eg. "amalgamated aluminium foil" experiment, where you soak rolled balls of aluminium foil in solution of Hg2+ ions, disrupting the crystal structure of the aluminium metal and ending in reaction of otherwise unreactive Al.


----------



## joekbit

FrugalRefiner said:


> *When In Doubt, Cement It Out*
> 
> This is advice I often give to new members who find they've created a bit of a mess, and they're wondering how to recover their values (gold, silver, PGMs, etc.).
> 
> Perhaps they've followed a process they've seen on YouTube that left out some important details. Perhaps they've used too much oxidizer. Perhaps they've dissolve a bunch of ewaste into a toxic mix of predominantly base metals with a small amount of values. Whatever the cause, "cementation" is a way to recover.
> 
> But cementation is not just for recovering from a mess. It is also the principle used in the stock pot. Solutions that have traces of values remaining in them are best treated in the stock pot to recover whatever may remain after the bulk of the values have been recovered through other methods.
> 
> It is also a good method for precipitating PGMs. PGM salts, particularly platinum(IV) salts, are very hazardous. While PGMs can be precipitated as relatively insoluble salts, they are still hazardous and must be further processed to recover them as metals, and some of the metal salts will still remain in solution. Cementing them out of solution recovers them as metals, and does so completely.
> 
> In simple terms, a solid piece of metal is put into a solution that already has a metal dissolved in it. The solid metal goes into solution and the dissolved metal precipitates, or "cements", out. This is also known as a "replacement reaction", as the solid metal replaces the metal that was in solution. The precipitate often looks like wet cement due to its color and texture as it settles to the bottom of the container. That simple reaction is the subject of this post.
> 
> *Testing*
> The first question to ask is whether there are values in the solution.
> 
> As an example, someone may have put a bunch of gold plated circuit boards into some acids, watched their gold disappear, and so they "know" they have gold in their solution. But, although their gold may have dissolved into the acids, it may have already "cemented" back out onto base metals in and on the circuit boards. Or it may never have dissolved, but been coated by other metals as the various, more reactive, metals went into and out of solution on metals that remained on the circuit boards.
> 
> The first thing to do is to test the solution. If you're pursuing gold or PGMs, stannous chloride is most often used. To test for palladium, use dimethylglyoxime (DMG). If your target is silver, salt or HCl can be used to detect its presence. All these tests are discussed in the book in my signature line below, as well as extensive posts on the forum that can be found using the search function.
> 
> *Cementation*
> Cementation is a process where a solid, elemental metal is used to replace a dissolved, ionic metal that is in a solution. The metals we pursue are usually known as noble metals. The name comes from the resistance of these metals to being oxidized and dissolved. This is all based on the number of electrons in their various orbits, and their locations in the various "shells", but that is far beyond the scope of this post. It is sufficient to understand that various metals are more or less resistant to oxidation, and we can use these properties to our advantage.
> 
> These varying resistances to oxidation are summarized in the reactivity series of metals. The list below is my own compilation of the many charts I've reviewed. For this post, it contains only the more common metals.
> 
> Aluminum
> Zinc
> Chromium
> Iron
> Cadmium
> Nickel
> Tin
> Lead
> Copper
> Silver
> Mercury
> Palladium
> Platinum
> Gold
> 
> You may see charts that vary slightly from the list above. Many metals can exist in more than one oxidation state, and those varying oxidation states can move a metal up or down the list. Mine is a "generalized" list that serves the purpose of this post.
> 
> When viewing a reactivity chart, the more reactive elements (primarily metals) are usually at the top of the chart, indicating they are more reactive (higher reactivity), and the less reactive metals are usually toward the bottom of the chart (lower reactivity). _In general_, a more reactive metal can be used to "replace" a metal that is lower on the chart (see notes below in "Things To Keep In Mind").
> 
> It can occur unintentionally during a process as described in the example above where a bunch of circuit boards have been put into acid and metals have dissolved, then cemented back out of solution in an uncontrolled manner. It can also be used intentionally to recover values that have been dissolved.
> 
> *A Cementation Tank*
> The simplest way to cement values out of a solution is to simply put a piece of solid metal into the solution. But the reaction will be slow and may not recover all the values. The solution needs to circulate so the dissolved values come into close proximity to the solid metal. Circulation also helps prevent the solid metal from just developing a plated surface that will stop further reaction, leaving values in solution.
> 
> 4metals was kind enough to share his design for a simple, but very effective cementation rig in a post in the Fuzz Button Interconnects, need some advice thread. I've reproduced his diagram below, but it's worth reading the complete, original thread.
> 
> View attachment 46977
> 
> 
> My setup is slightly different. I'm sure whatever 4metals used was many times larger than my little system. My modifications suit my much smaller needs.
> 
> My PVC pipe is the full height of my container, while 4metals' is shorter and the top sits below the liquid level. My pipe for this build is 2" diameter PVC. I drill large holes in both the bottom and the top of my pipe to allow the solution to flow in at the bottom and out at the top, where his solution simply flows out of the top of the pipe.
> 
> The holes at the bottom are a bit above the bottom of the pipe so it doesn't tend to draw in any cement as the solution flows in. The holes at the top are at various levels a little higher than where I put the copper. This allows the solution to flow out regardless of how full the container is, as long as it is at least as high as the lowest holes.
> 
> I put a small hole near the bottom of the pipe that I can put my air hose through. It's just big enough for the hose to make a snug fit that keeps it in place.
> 
> View attachment 46978
> 
> 
> I also put a piece of perforated plastic just above the lower set of holes. I use a short piece of the same 2" diameter PVC with a section cut out. I can squeeze it together and push it into the bottom of the main pipe, then push it up the pipe so it is just above the lower holes. The tension of this "retainer" holds it in place, but allows it to be removed for cleaning. The round disk of perforated plastic then sits on top of the PVC retainer. The perforated plastic is sold in craft stores as "plastic canvas". It is easily cut with a pair of scissors. This keeps me from having to drill holes in the chunks of copper to hang them inside the pipe. I can just drop a couple of chunks into the pipe and I'm ready to go. *Note:* I use these chunks of copper because I have many pounds of them. Using pieces of copper pipe that have been cut open and flattened will work faster due to the increased surface area.
> 
> View attachment 46979
> 
> View attachment 46980
> 
> 
> I use a lid on my small container to contain the spray. *Note:* While the lid is silver and might look like metal in the pictures, it is plastic. I glue a short piece of a smaller diameter, 1-1/2" PVC pipe to the center of the lid of my container. It fits inside my main pipe and helps keep the main pipe centered in the container. I put small, matching holes through both pieces of pipe so I can assemble the cap and pipe, and put a small strip of PVC through both of them to hold them together, so I can put it all together before screwing the cap on when I run the rig. I cut the strip along the length of a piece of pipe. I round the edges a bit and heat the ends a bit so I can bend them down a bit to make assembly easier. This is a little fancier than it needs to be, but I enjoy the build.
> 
> I drill a small hole in the lid for the air hose. I drill another larger hole and glue a short piece of small diameter CPVC pipe to it to act similar to a reflux condenser. Any spray that tries to escape the container settles onto the inside of the pipe and drips back into the container while allowing the air from the pump to escape.
> 
> View attachment 46981
> 
> 
> View attachment 46982
> 
> 
> Here are all the parts laid out before it's put together.
> 
> View attachment 46983
> 
> 
> And this is the full rig put together.
> 
> View attachment 46984
> 
> 
> That's it! To put it together, fit the retainer ring into the main pipe and push it up till it's just above the lower set of holes. Put the air hose through the lid and then through the bottom of the pipe. I cut a taper on the end of the hose so it will fit into the pipe a little easier. Drop in the perforated disk and add some copper, or hang it inside if you haven't built a perforated disk like mine. Align the main pipe with the smaller section of pipe glued to the lid and put the strip of PVC through the holes to hold them together. Lower the lid and PVC pipe into the jar, screw the lid on, and turn on the air pump.
> 
> 4metals was kind enough to provide a picture of a 50 gallon cementation tank used by one of his customers.
> 
> View attachment 46985
> 
> 
> For you video fans, here's a quick video showing me putting it all together.
> 
> 
> 
> You can watch a larger view of the video on YouTube by clicking on the title of the video above.
> 
> The air bubbles rise through the pipe, carrying a constant, fresh flow of solution and helping to dislodge the cemented values from the copper. Let it run. Test a sample of the solution from time to time. When the solution tests negative, turn off the pump and remove the lid, pipe, and any remaining copper. Allow the cement to settle and decant or syphon off the barren solution. You can wash the cement in the container, or pour it off to an appropriately sized container for washing.
> 
> *Why Copper?*
> Many people talk about using iron, zinc, aluminum, or other metals for cementing. While they will certainly work, and they have their place in certain situations, they will also cement everything below them on the reactivity series. The advantage of using copper is that it will only cement silver, gold, PGMs, and mercury if it happens to be in your solution. Any other metals can be cemented out with iron when you treat the solution for waste. This is discussed fully in the book in my signature line and on the forum. Search for "stock pot".
> 
> *Things To Keep In Mind*
> For cementation to work, the metal being used to cement out the values must be soluble in the solution. Looking at the reactivity list, it might be tempting to try to use silver to cement out gold or PGMs. But silver is not soluble in a chloride solution, so it won't work for gold. Copper will work in both nitrate and chloride solutions, so it can be used to recover all of our target metals from either type of solution.
> 
> There also needs to be a significant difference in the reactivities of the metals. Silver and the other precious metals are far less reactive than copper, so it works well. Tin is only slightly more reactive than lead, so it won't work well to cement lead out of a solution.
> 
> Keep all of the copper under the surface of the solution. If it extends above the solution, it can react with the oxygen in the air, and bits of copper oxides can flake off and join the cement, contaminating it. While cementation is generally considered a recovery process, so the cement will probably be refined further, it's better to keep out as much contamination as possible.
> 
> Circulation is necessary. As mentioned above, the solution must be kept in motion. It brings fresh solution into proximity with the copper, and the air bubbles help to dislodge the cement, preventing the copper from being plated/coated over stopping the reaction.
> 
> Some people report difficulties when their solutions are highly concentrated. They can be prone to forming an adherent coating on the copper, slowing or stopping the cementing process. In these cases, diluting the solution can help stop this problem, allowing the cemented metal to fall more easily from the copper.
> 
> Keep your air pump ABOVE the tank. Electricity can go out. The pump can fail. The hose can burst or come off the pump. If any of those happen, and the pump isn't above the container, the liquid can rush up the air hose and over the top creating a syphon that can cause your solution to flow out and possibly be lost.
> 
> I haven't been able to refine much since we moved, so I may have forgotten some important points. Please feel free to add to this thread as needed.
> 
> Dave



Well done, one of the best. I have a 3 gallon glass pickle jar. It has a bunch of pennies in it. I keep telling myself, JOE take out the pennies, put that thing in a milk crate for a cement tank and quit fighting with a 5 gallon bucket you cant see through. Just emptied the bucket the other day. Looks like about 1/2 oz of Au, but it would be so much easier with that glass jar


----------



## FrugalRefiner

Thanks. The jar, and everything else in the rig is plastic. The only metal is the copper used to cement the values.

If you're using pennies, be aware that they are not pure copper. Those minted before 1982 are 95% copper and 5% zinc. From 1983 on, they're 97.5% zinc with a copper plating. The zinc will cement out most metals, so pennies will cement out more than just gold.

Dave


----------



## joekbit

I'm not using the pennies. It's my penny jar full of pennies. I need to take them out and cash them in, then use the jar. Then I can actually see when the fluid has settled and what's sitting on the bottom without ever disturbing the jar. A bucket is just a plain old pain in the butt.


----------



## snail

Just remember plastic buckets don’t break, glass can break.


----------



## Inxed

Thanks alot @Frugal for this elaborate piece. Well like any begginer, I find my self in a mess already. I have some chalcopyrite obtained from an old copper mine in the Rwenzori mountains. This is the kilembe copper mine. 



I crushed the ore into a very fine dust, which i divided into half. One half for mercury extraction and the other for acid extraction.
I washed the sample then added nitric acid. I put to low heat for about an hour. I again washed with tap water till the water was clear. I then added aqua regia and put to heat for 30 mins. After I filtered solution but the color was a dark redisd brown color 

I added urea till all bubbling and fizzing stopped. I then mixed ironsulpate in warm water and stirred till it dissolved. On pouring it to my filtered solution nothing happened. The solution only turned the color t a pale bueish color. 
On doing a stannous test. It was all negative for gold. Be it the blue solution and the reddish brown solution

Now am stuck with this solution and hoped cementing will recover the gold. I know there is gold bed the second dust in mercury produced amalgam which contained gold dust. Is it still possible to cement gold from this solution.
Thanks


----------



## Martijn

If there is any gold in sution, Yes you can. 
Keep your questions about this subject in one thread please. 









Aqua regia and chalcopyrite


Hello all, forgive the newbie. Anyone with experience handling aqua regia with chalcopyrite ...? I would surely use your help. Thanks




goldrefiningforum.com





Your choice of recovery processes are not the best ones imo. Dangerous. 
Study a lot more before you proceed with a new sample.


----------



## Inxed

Martijn said:


> If there is any gold in sution, Yes you can.
> Keep your questions about this subject in one thread please.
> 
> 
> 
> 
> 
> 
> 
> 
> 
> Aqua regia and chalcopyrite
> 
> 
> Hello all, forgive the newbie. Anyone with experience handling aqua regia with chalcopyrite ...? I would surely use your help. Thanks
> 
> 
> 
> 
> goldrefiningforum.com
> 
> 
> 
> 
> 
> Your choice of recovery processes are not the best ones imo. Dangerous.
> Study a lot more before you proceed with a new sample.


Thanks, and point taken by about the threads,otherwise what method should I use to recover gold from this solution


----------



## Martijn

I mean making the solution in the first place or the mercury way are questionable. 
To get gold out, cement it out.


----------



## Yggdrasil

Martijn said:


> I mean making the solution in the first place or the mercury way are questionable.
> To get gold out, cement it out.


If he has Mercury in solution, it would be better to precipitate chemically, so the Mercury stay in solution. Then make this batch into a separate waste stream.


----------



## Martijn

I believe he is going to try to extract gold from ore in two ways: AR and the mercury amalgamation route... so he's reintroducing the old crazy miners revovery way. 

Not the best option imo. 

I see you tubers like Dan Hurd pan out a lot of mercury beads from beautiful natural places because of this polluting gold recovery method in the past. 
They didn't care back then. 
I hope we all do care now.


----------



## pwm97128

Martijn said:


> If there is any gold in sution, Yes you can.
> Keep your questions about this subject in one thread please.
> 
> 
> 
> 
> 
> 
> 
> 
> 
> Aqua regia and chalcopyrite
> 
> 
> Hello all, forgive the newbie. Anyone with experience handling aqua regia with chalcopyrite ...? I would surely use your help. Thanks
> 
> 
> 
> 
> goldrefiningforum.com
> 
> 
> 
> 
> 
> Your choice of recovery processes are not the best ones imo. Dangerous.
> Study a lot more before you proceed with a new sample.


Everyone who responds to questions: Thank you!

As a retired accountant and wannabe urban miner your comments and cliches are invaluable. The title to this thread is a great example.

I am recovering gold leaf from some form of "plastic" plate and I was at an impasse. I knew there was gold but not sure how much. Following Hoke I tried removing the plastic coating with lye, then Pyrolyzed the plates followed by poor man's nitic to disolve the metals. The current attempt is to leach the broken pieces with poor man's AR.

Important lessons learned: There is a reason that Hoke uses many simple examples to demonstrate refining. Working with unknow materials, e.g. plastic plates, adds significant complexity to the recovery and refining of metal. Read the Forum Regularly and Frequently. Something unimportant I read 3 months ago suddenly becomes the key to success today. Cliches like "When in Doubt ..." in reality condense years of experience into easy to remember quotes that focus the problem solving process.

For Example: 'When in Doubt, Cement it Out' was a thread I saw yesterday. Both my burned plates and AR leaching produced solutions that kind of looked like gold in solution. Both failed the Stannous test and would not precipitate using SMB. I applied "When in Doubt ..." and added zinc as a starter then switched to copper from my electrolytic cell to force any precious metals out of solution.

Success, yesterday I recovered a 12K gold/copper bead from the burnt plates. Today I am waiting on the AR leach to finish precipitating. I added a small amount of zinc to repeat the precipitation process from yesterday, but instead the pregnant SMB/AR solution flipped into the "normal" SMB drop.

Thank you so much for all your great advice.


----------



## campbellj46

@FrugalRefiner , awesome post and I find myself pulling out my tools for a build  this seems to be a lot cleaner than just sticking the copper in a beaker of nitrate solution. Only 1 question to the set up..... is the airline above or below the mesh cage that the copper goes in? I looked at the photos you posted but couldn't tell where the airline was in relation to the mesh.


----------



## FrugalRefiner

The airline sits below the plastic mesh. The bubbles go up through it, getting broken up a bit, and of course the copper sits above that.

Dave


----------



## Martijn

snail said:


> Just remember plastic buckets don’t break, glass can break.


----------



## FrugalRefiner

What type of plastic was it, and what did you have in it?

I would restate Snail's warning as "plastic containers are less prone to breakage than glass, but check them regularly as many of the solutions we use can cause them to become brittle over time". 

Nitric, in particular, will cause many plastics, including HDPE, to become brittle.

Dave

Edited to correct error as pointed out by orvi in the next post.


----------



## orvi

FrugalRefiner said:


> What type of plastic was it, and what did you have in it?
> 
> I would restate Snail's warning as "plastic containers are less prone to breakage than *plastic*, but check them regularly as many of the solutions we use can cause them to become brittle over time".
> 
> Nitric, in particular, will cause many plastics, including HDPE, to become brittle.
> 
> Dave


I think you mean glass 


Martijn said:


> View attachment 49532


Yes, it depends strongly on the type of plastic. Ordinary buckets are made of PP - problematic when cold, and also flexible just to some point. PP buckets are easy to break when smashed, or also it is easy to punch the hole through (eg when stirring with heavy rod) from the inside. Pick the buckets with thick wall, not these transparent thin ones. Good stuff is from old indoor wall paints or some pre-made plaster.

You can often found type of plastic on the bottom - either a number in that "recycling triangle" or stated in some other way.

PE buckets are much more durable and "bendable" - they do not break easily, even in the cold. They also withstand much more "chemistry", but nitric and even worse AR will slowly decay the plastic.

When dissolving and handling large volumes of eg waste solutions, I always stick to the classical PE canisters. From my experience, they are fine with nitric for quite a long time (50% nitric to be clear), but only at room temperature. Hot acids will make it brittle after few days.


----------



## FrugalRefiner

orvi said:


> Good stuff is from old indoor wall paints or some pre-made plaster.


Agreed. I use 1 gallon paint buckets, especially as secondary containers for a lot of acids. When we were rehabbing houses, I ended up with quite a few.

Here in the US, they are usually heavy polypropylene. I believe I have posted about them in the past.

Dave


----------



## orvi

I luckily acquired 3 heavy duty PE buckets for chemical shipping. Round, 25 L big and tall. If I was a refiner like folks in India, this type will be the best - for sedimentation of gold.


----------



## Martijn

They're actually pretty sturdy. I was waiting for the moment one bucket to fail or get brittle to make a picture of it, for this reply only.  It didn't

This one was the iron pot for quite a few years. But I wanted to replace it before it got brittle anyway and so I smashed it on the edge of my bench to make the picture. Tried to break by pushing on the side and it was flexible as if it was new. Darn things.


----------



## yellowfoil

Martijn said:


> They're actually pretty sturdy. I was waiting for the moment one bucket to fail or get brittle to make a picture of it, for this reply only.  It didn't
> 
> This one was the iron pot for quite a few years. But I wanted to replace it before it got brittle anyway and so I smashed it on the edge of my bench to make the picture. Tried to break by pushing on the side and it was flexible as if it was new. Darn things.


Depends what type of plastic it is made of. They make biodegradable plastics these days and used for buckets as well. Those will disintegrate very soon, specially outside, in the sun. Mostly made for food products, including new buckets supplied for hardware stores. I use buckets made for motor oils or some cleaning agent supplied for industry.


----------



## Daniel7878780

Hello everyone, what steps after cementation, what should I do with cement, how do I recover?

Thanks for the response


----------



## Yggdrasil

Daniel7878780 said:


> שלום לכולם, מה השלבים הבאים לאחר המלט, מה אני צריך לעשות עם המלט, איך אני מתאושש?
> תודה על המענה


There are a few Isreali's here, but if you want an answer to your question, the chances increase many fold if you translate it to English.


----------



## Yggdrasil

Well, that depends on what kind of cement you are talking about, and how pure you want it.
Is it Gold, Silver or PGM's?
Silver on copper can if done correctly get up to 97% or more in purity if done correctly.
Many are happy with that. If not, electrolytic recovery is usually the next step regarding Silver.

The slimes from Gold/PGM's do usually need additional refining, by AR or other suitable method.
Recover? 
As cement it is already recovered??


----------



## Yggdrasil

Daniel7878780 said:


> Hello everyone, what steps after cementation, what should I do with cement, how do I recover?
> 
> Thanks for the response


Please leave the original content alone if you edit like this, it's better to see the progress of the thread.
Thanks


----------



## CO-WYO-Peter

With regards to the need to agitate the solution with air to mix the solution to make contact with the copper; Will the addition of air cause the hcl to keep the precious metals in solution (AP leach ) and not cause cementation but actually just consume the copper ? I would like to understand this more.


----------



## NobleMetalsRecovery

FrugalRefiner said:


> . All these tests are discussed in the book in my signature line below, as well as extensive posts on the forum that can be found using the search function.


I did not see the "book" that you mentioned.


----------



## Shark

The agitation causes the solution to make contact with the copper which is needed to allow the pgm’s to trade places with the copper ion’s. The pgm’s then stick to the copper as the copper goes in to solution.


----------



## Yggdrasil

NobleMetalsRecovery said:


> I did not see the "book" that you mentioned.


If you are usung a phone to read, turn it sideways to read the signature lines.
The forum software does that


----------



## huggybear

FrugalRefiner said:


> *Why Copper?*
> Many people talk about using iron, zinc, aluminum, or other metals for cementing. While they will certainly work, and they have their place in certain situations, they will also cement everything below them on the reactivity series. The advantage of using copper is that it will only cement silver, gold, PGMs, and mercury if it happens to be in your solution. Any other metals can be cemented out with iron when you treat the solution for waste. This is discussed fully in the book in my signature line and on the forum. Search for "stock pot".


Thanks for your detailed explanation, but there is one thing I still don't understand.

From what I have found online, copper is not soluble in HCl alone so if you are dealing with aqua regia which you have deNOX'd, there will be no cementation reaction if using copper.


----------



## Yggdrasil

huggybear said:


> Thanks for your detailed explanation, but there is one thing I still don't understand.
> 
> From what I have found online, copper is not soluble in HCl alone so if you are dealing with aqua regia which you have deNOX'd, there will be no cementation reaction if using copper.


That is correct, Copper do not dissolve in HCl. 
But our goal by cementing is not to dissolve Copper.
What we do by cementing is to let the ions from precious metals change place with the Copper ions.
So the Chloride in the Gold Chloride happily grabs a Copper molecule from the Copper and forms Copper Chloride leaving the Gold behind as metal.
Or Palladium,Silver, Mercury and so on.


----------



## Shark

Ion exchange is what happens. A copper ion is traded for a PM ion. PM ion comes out of solution in exchange for an ion of copper going into solution. This is the simple explanation as I understand it. 

Copper will not dissolve into HCl, but on exposure to oxygen it will. Copper in HCl, left with no sealed lid is enough exposure to allow the copper to dissolve, but very slowly. By adding a larger amount of oxygen, for example an air pump, will speed up the process. This is often why an air source is used for agitation when cementing PM’s.

Yggdrasil beat me to it.


----------



## Lino1406

Shark said:


> Ion exchange is what happens. A copper ion is traded for a PM ion. PM ion comes out of solution in exchange for an ion of copper going into solution. This is the simple explanation as I understand it.
> 
> Copper will not dissolve into HCl, but on exposure to oxygen it will. Copper in HCl, left with no sealed lid is enough exposure to allow the copper to dissolve, but very slowly. By adding a larger amount of oxygen, for example an air pump, will speed up the process. This is often why an air source is used for agitation when cementing PM’s.
> 
> Yggdrasil beat me to it.


ו


----------



## Lino1406

Lino1406 said:


> ו


The reason for ion exchange with copper is AuCl4-, PdCl4=, are strong oxidizers. Air helps with stirring


----------



## huggybear

Thank you. It's good to understand the reason why things happen the way they do.


----------



## orvi

Lino1406 said:


> The reason for ion exchange with copper is AuCl4-, PdCl4=, are strong oxidizers. Air helps with stirring


I would just add that air is also quite beneficial from other point of view - it helps to dissolve the surface layer of copper in combination with HCL. This allow the cemented metals to more easily shed off the surface of copper, reviving fresh surface for further cementation to proceed. This is espetially crucial for PGM cementation, as the formed cement tend to adhere to the surface of copper, blocking the access of more PGM ions to the Cu.

Manual stirring function is also very helpful in removing the cement, and it is nice synergy working for you in terms to obtain cemented values quicker. Altough, in exchange for more copper dissolved.

Very similar to issue of cementing copper out on iron. If you leave bucket uncovered, copper chloride will synproportionate with copper metal cemented, creating CuCl in solution, which in turn gets oxidized back to CuCl2 - slowly ruining your effort to get the copper out of solution - because in the end, only iron is spent and copper will stay as "oxidation" carrier.


----------



## orvi

huggybear said:


> Thank you. It's good to understand the reason why things happen the way they do.


It is always very useful to understand theoretic principles. With deeper understanding, you can much more easily solve the problems which arise along the way, be prepared that some things may happen and how to solve the possible issues  

Scaled refining is quite complicated inorganic chemistry, and as you add more and more elements, you can get very strange reactions, shifted equilibriums, stalled cementations, strange complexes formation (mainly PGM chemistry) which refuse to react with anything (like cementing Pt with zinc going on for 4 days and still not complete...), delayed autocatalytic runaway reactions (like adding fresh nitric acid to hot nitric depleted AR, creating eruption of desorbed NOx gasses)... All sorts of "not so nice" things  With theory, you can predict quite a bit of them, making your life much easier. And with theory, you can use the observations and findings more easily, as you rationalize them much more efficiently.

It is time consuming to go into detailed chemistry, oxidation potentials, solubilities and stuff, but if you intend to refine for more than few weekends in your life, it is well worth your time.


----------



## snoman701

Why would I get a bunch of blue crystals when cementing silver from silver nitrate with copper busbar? 

Cu, Ni, Zn, Ag and likely some Pb and Co present. I let it bubble for a couple an extended period of time. Silver nitrate bearing liquor was diluted by 4x as much water as acid. 

The crystals are minimally soluble in water, but are soluble in HCl, and make a beautiful green solution.


----------



## Elemental

@snoman701

Are you rinsing your silver crystals with hot distilled water? This can take several rinses, until the rinse water is clear on a white background, a sheet of paper works well for this. If you have some test tubes, you can keep a bit of each rinse water to see the color change as well. Rinse will be light blue then fade to eventually a clear wash. This will remove any copper nitrate solution which may be on the crystals, causing it to cement out as copper nitrate when the crystals are dried. 

To further purify your silver crystal, you would want to run in through a silver cell.

Elemental


----------



## snoman701

Oh no...these crystals defeat the possibility of rinsing the silver from the outset. I've had to rinse the silver with HCl to get rid of the blue crystals, then essentially treat as if the whole lot is AgCl.


----------



## orvi

snoman701 said:


> Oh no...these crystals defeat the possibility of rinsing the silver from the outset. I've had to rinse the silver with HCl to get rid of the blue crystals, then essentially treat as if the whole lot is AgCl.


This is very strange since practically all nitrates are perfectly soluble in water.

One thing that comes to my mind is to check the pH to the end of the process. Some metal salts, bonded with anions from relatively weak acids (like nitric) could undergo partial or full hydrolysis, if pH isn´t kept below certain value. Maybe you accidentally created this enviroment and produced some hydroxy-nitrate copper salts (??), which maybe does not have good solubility in water, but dissolve nicely in HCL since you reacidify them and make soluble.


----------



## NobleMetalsRecovery

My earlier question should have been, Does FrugalRefiner have a "book" for sale?


----------



## Shark

The book in Frugal Refiner’s signature line is by C.M. Hoke known as Refining Precious Metal Wastes.


----------



## NobleMetalsRecovery

Thank you.


----------



## huggybear

Is a magnetic stirrer with a beaker a decent "substitute" for this set-up? I understand it may not be as effective but I am looking to cement out a one-off batch of PGMs in solution.

Thanks,
HuggyBear


----------



## Yggdrasil

huggybear said:


> Is a magnetic stirrer with a beaker a decent "substitute" for this set-up? I understand it may not be as effective but I am looking to cement out a one-off batch of PGMs in solution.
> 
> Thanks,
> HuggyBear


It’s hard to know what you mean with “this set-up” without rereading the whole thread, but I assume you mean cementing on copper.

For cementing PGMs the most important is vigorous stirring.
Air bubbling or stirring will do that.
The important part is that there is plenty turbulent flow around the copper bar, dislodging the cemented metal to expose fresh copper.


----------



## huggybear

Sorry, I should be more specific. I meant the copper cementing set-up described by FrugalRefiner in the original thread.

Thanks for your response. I will try cementing using my magnetic stirrer and copper powder.


----------



## Yggdrasil

huggybear said:


> Sorry, I should be more specific. I meant the copper cementing set-up described by FrugalRefiner in the original thread.
> 
> Thanks for your response. I will try cementing using my magnetic stirrer and copper powder.


I saw now. That is a very nice set up, but is not very good for copper powders. 
For powders a very strong stirring will be neccessary and adding air bubbling to the same will probably increase efficiency.
Turbulence is your friend when cementing PGMs


----------



## Rreyes097

I have a question or 2.
First thanks for the time you took on that post. It was beyond simple information on cementation. It was well put together to say the least and I thank you.
1. How long would say a half gallon or full gallon of solution take for cementation to be thoroughly finished? Approximately of course.
2. Actually only one question! I found the answer to the other.


----------



## orvi

huggybear said:


> Is a magnetic stirrer with a beaker a decent "substitute" for this set-up? I understand it may not be as effective but I am looking to cement out a one-off batch of PGMs in solution.
> 
> Thanks,
> HuggyBear


Cementation of PGMs on copper is better done with that bubbling. That´s because PGM cement form thick layer on the surface of copper which does not permeate new solution to the surface of the copper. Air helps to dissolve surface copper into the solution and allow the PGMs to flake off the copper bar.

If you have decent quantity of PGMs in solution, I would cement them on iron for the sake of time and efficiency. Use just a tiny bit - copper also come out of solution, but if you use just a little iron, little copper came out vith VAST SURFACE AREA - which will then exchange for PGMs and precipitate them from the solution  Now, the magnetic stirrer comes handy  not exactly scientific approach, but it works and saves time. If you are only using it to concentrate PGMs from larger quantity of liquid. Because the cement from Fe nor Cu won´t be nowhere nice and clean, there would be plenty of base metals present as copper and also iron flake off with PGM cement. Just to be prepared that this isn´t exactly rafination method, just a recovery method.


----------



## kurtak

huggybear said:


> Is a magnetic stirrer with a beaker a decent "substitute" for this set-up? I understand it may not be as effective but I am looking to cement out a one-off batch of PGMs in solution.


 Yes - if you only have a small amount of solution (couple liters) & stirrer hot plate & copper powder (& of course beaker) there is absolutely no reason why you can't do it this way instead of with hanging a copper bar & running a bubbler

You just need to make sure the solution is just "a bit" to the hot side of warm & that each time you add copper powder you let it stir for a while to insure the copper fully dissolves as the PGMs cement out

Leave plenty of room in the beaker for foaming up of the solution when you add the copper powder - when the foaming dies down let it stir for a couple/few minutes before adding more copper powder (to insure the copper is fully dissolved)

As you near the end (of doing copper powder addition) it starts taking longer for the copper powder to fully dissolve - so you want to let it stir longer between copper addition to insure the copper powder fully dissolves

The down side of this method is knowing when to stop with the copper powder additions (when all the PGMs are cemented out) so that you are not adding copper that does not dissolve any longer & you end up contaminating the cemented PGMs with copper

So stannous testing is important especially as you near the end

For small amounts of solution this is actually my preferred method over that of copper bar & bubbler

Please *ALL* of this tread ------









Fuzz Button Interconnects, need some advice


okay, back a while ago, I found a bunch of fuzz button interconnects... like the ones from this thread: http://goldrefiningforum.com/phpBB3/viewtopic.php?f=34&t=16018&hilit=fuzz+button&start=20 after doing some research on them, I was figuring on Be/Cu/Au wire was most likely what I was dealing...




goldrefiningforum.com





On page 2 you will see a post of the results of my first time using the copper powder method (& I have used it many times since then)

That said - it will serve you well to *read the whole thread *

Kurt


----------



## kurtak

Rreyes097 said:


> 1. How long would say a half gallon or full gallon of solution take for cementation to be thoroughly finished? Approximately of course.


That depends entirely on a few things ----

1) how diluted - or - how concentrated the solution is

2) how much free acid is in the solution - if there is a lot of free acid in the solution the acid need to work at dissolving copper before it actually starts cementing the precious metals

3) though not as much of a factor of the above - temp of the solution also plays "some" roll in the time

So depending on the above it could take anywhere from a few hours to 3 days

Example of 3 days = *VERY* dilute + *free* acid + plus *cold *

Kurt


----------



## kurtak

And for what it is worth (side note) --------

Stirring & copper powder works better on concentrated solutions

Copper bar & bubbling works better on diluted solutions

Kurt


----------



## Rreyes097

I constructed this today. Thanks so much for the blueprints to create this! The build was fairly easy. And I used 1.25" PVC. Any advice or critiques on how to improve it are welcome.


----------



## Rreyes097

Oh yeah. One more question. Are you using an air stone? Or just straight air coming out of the tube?


----------



## Rreyes097

Rreyes097 said:


> I constructed this today. Thanks so much for the blueprints to create this! The build was fairly easy. And I used 1.25" PVC. Any advice or critiques on how to improve it are welcome.


So I was thrift shopping at the goodwill looking for glassware because all my fancy lab glass has broke over time and I'm too poor to buy more fancy glass. So I look for pyrex and what not.... So I came across this! And although it's not glass it seems to suit my needs perfectly! It's a iced tea or flavored water, or whatever you want to call it pitcher thingy.  it is a bit smaller then my original build. But what I like about it is that it's clear! You can see what's going on while it bubbles away. In the middle of it there is a clear tube with holes all the way thru it. That screws on and off. Plus it being a pitcher, it's shaped to pour which the first container was NOT. Maybe there's too many holes but at least it looks like this bubbles will get all over the copper since I simply ran the air line down to the bottom of the tube containing the copper.


----------



## goldshark

You may want to put it in a containment vessel, in the event a heat reaction breaks it.


----------



## Rreyes097

goldshark said:


> You may want to put it in a containment vessel, in the event a heat reaction breaks it.


Oh like have it sitting in a container? Just in case it breaks or heats up and possibly melt? Well I do. It just was moved so people can see it.


----------



## madscientistatlarge

Rreyes097 said:


> So I was thrift shopping at the goodwill looking for glassware because all my fancy lab glass has broke over time and I'm too poor to buy more fancy glass. So I look for pyrex and what not.... So I came across this! And although it's not glass it seems to suit my needs perfectly! It's a iced tea or flavored water, or whatever you want to call it pitcher thingy.  it is a bit smaller then my original build. But what I like about it is that it's clear! You can see what's going on while it bubbles away. In the middle of it there is a clear tube with holes all the way thru it. That screws on and off. Plus it being a pitcher, it's shaped to pour which the first container was NOT. Maybe there's too many holes but at least it looks like this bubbles will get all over the copper since I simply ran the air line down to the bottom of the tube containing the copper.


You should check out the prices at aliexpress.us. It is buyer beware (thuogh you can usually get your' $$ back). I'd avoid the very cheapest sellers and personally don't use sellers that have been using it for less than 2 years, and I prefer longer term users. Also try to look for factories or vendors who specialize in what you are looking for, many sellers have a real hodge podge of items and don't know any of them. 

Look for sellers who have Borosillicate labware, the generic non trade mark name for "pyrex". And yes, always use some secondary containment in case a vessel cracks/shatters (all solutions used for this are very nasty at room temp and terrifyingly toxic/corrosive when heated). If you get anything hot enough to melt borosilicate you have other major problems, even if you melt ordinary sodalime glass your' at very high temps and your' solution has boiled dry (above 1300 Deg F!) and you may have already started a fire. Major down side is it will take a month or so to get your' package depending on what country you are in, in the US it's usually about a month. If you have any doubt ask the seller if it's borrosillicate. I also look for sellers with a high feedback score, ignore any less than 90%, above 95% is better.

I've had to have testubes reshipped as the first ones were plastic, styrene I think, despite the add saying "glass". Many resellers just copy other peoples listings, propagating errors widely. I always test the glass by applying a lighter flame to one edge for a bit (5-10 seconds). Borrosillicate handles this, sodalime cracks fairly quickly (do be careful as it might shatter, tough gloves would be a good idea, as well as doing it over the sink etc. in case it shatters, use eye protection as well). Courtesy when dealing with vendors is essential, Asians tend to disrespect those who don't show proper courtesy, when messaging always thank them etc. (good practice in any culture).


----------



## Rreyes097

So I'm in doubt so I'm attempting to cement it out. I had an AR solution which I put the ends of ribbons and some other stuff like small pieces of circuit board that have gold plating. But when testing with stannis nothing was coming up even though I seen that the gold was dissolved. Not knowing exactly what the problem was whether it was tin or something else that may be stopping my stannous test from showing that there was indeed gold in the solution like I seen it dissolve. What makes a stannis test not work? Like what I mean is what in the solution could block the stanous test from coming up positive? So I put some pieces of copper pipe into the solution hoping just to cement it out but the nitric acid keeps dissolving the copper and I put probably 20 g of copper in it? That's an approximation though. This should be more than enough copper to use up the nitric that was in there, which was not a lot. Cement out after the nitrate was spent.


----------



## Martijn

You've answered your own question: too much nitric. Keep adding copper. 
Next time dissolve it the right way.

Edited for spelling


----------



## Rreyes097

Martijn said:


> You've answered your own question: too much nitric. Keep adding copper.
> Next time dissolve it the right way.
> 
> Edited for spelling


Dissolve what exactly the right way? I'm not following you.


----------



## cejohnsonsr1

Rreyes097 said:


> Dissolve what exactly the right way? I'm not following you.


Only add enough nitric to dissolve the gold. Incremental dosing. But even before you get to AR, you need to recover the gold by separating it from whatever it’s bound to. Usually copper. For that you use AP.


----------



## Rreyes097

cejohnsonsr1 said:


> Only add enough nitric to dissolve the gold. Incremental dosing. But even before you get to AR, you need to recover the gold by separating it from whatever it’s bound to. Usually copper. For that you use AP.


I did add the nitric incrementaly. But maybe it didn't react right away and so I may have added too thinking it wasn't enough?


----------



## Yggdrasil

Rreyes097 said:


> So I'm in doubt so I'm attempting to cement it out. I had an AR solution which I put the ends of ribbons and some other stuff like small pieces of circuit board that have gold plating. But when testing with stannis nothing was coming up even though I seen that the gold was dissolved. Not knowing exactly what the problem was whether it was tin or something else that may be stopping my stannous test from showing that there was indeed gold in the solution like I seen it dissolve. What makes a stannis test not work? Like what I mean is what in the solution could block the stanous test from coming up positive? So I put some pieces of copper pipe into the solution hoping just to cement it out but the nitric acid keeps dissolving the copper and I put probably 20 g of copper in it? That's an approximation though. This should be more than enough copper to use up the nitric that was in there, which was not a lot. Cement out after the nitrate was spent.


As Martijn say, you have too much Nitric so before the Gold will stay out of solution, you need to overcome the Nitric.
(We know that there are too much Nitric because the Copper gets eaten away)
On the other hand there may not be Gold in there at all.

cejohnsonsr1 is also correct. Removing the golden color of the end of the ribbons do not necessarily dissolve the Gold permanently.
It may just relocate it to another piece of undissolved base metal, 
and that is why we take away the base metals completely or dissolve all the metals present.

Stannous sometimes react just in a flash if there are too much oxidizer, how did you test with Stannous?


----------



## Rreyes097

Yggdrasil said:


> As Martijn say, you have too much Nitric so before the Gold will stay out of solution, you need to overcome the Nitric.
> (We know that there are too much Nitric because the Copper gets eaten away)
> On the other hand there may not be Gold in there at all.
> 
> cejohnsonsr1 is also correct. Removing the golden color of the end of the ribbons do not necessarily dissolve the Gold permanently.
> It may just relocate it to another piece of undissolved base metal,
> and that is why we take away the base metals completely or dissolve all the metals present.
> 
> Stannous sometimes react just in a flash if there are too much oxidizer, how did you test with Stannous?


Qtip
And I'm not disagreeing that there is too much nitric. Because there obviously is. I was just saying that the method of delivery of said nitric was incremental.


----------



## Yggdrasil

Rreyes097 said:


> Qtip
> And I'm not disagreeing that there is too much nitric. Because there obviously is. I was just saying that the method of delivery of said nitric was incremental.


How much of said cables was used, and were they totally dissolved?
Have you tried a Stannous after the copper was dissolved in the solution?
Are there any trace of black mud in the bottom?


----------



## Martijn

With that much copper in solution, a stannous test will be too brown to show traces of purple. 
What was the amount of used nitric and cable ends and other material? 

For that 20 grams of copper that dissolved, you had at least about 80ml of free nitric in the AR. If you were dissolving only gold, that would would have been enough for 8o grams of gold.. 
With your beaker holding 600ml, you can add about as much cable ends to recover 5 grams of gold. And i think that's on the very optimistic side of things. 
So to have at least 80 ml of nitric too much in there is overshooting it a bit too fast, yes. 
What was the temperature of the first AR bath?


----------

