How to destroy sodium cyanide & hydrogen peroxide

[kurtak]

Please advise how to proceed? Recover gold first and then destroy cyanide or destroy cyanide first and then recover gold?
Thanks!

As I said yesterday & underlined in the above quote --- you want to FIRST recover the gold - & then destroy the cyanide (to make it safe for disposal)

To recover the gold you can run it through an electrolytic winning cell

Or you can run it though a carbon column using "activated" carbon

Or you can use zinc or aluminum - the zinc or aluminum should be "foil" cut into strips

This is no where near enough info to get you started :!: you need MUCH more info to get started - do NOTHING yet :!:

In your first post - you posted

We have a gold cyanide solution of 28 liters. We removed gold from gold plated connectors. We used 475 grams of commercial grade sodium cyanide and 5 liters of hydrogen peroxide of 36%.

I may be wrong about this - but - it sounds like you used to much H2O2 (oxidized) in you solution to dissolve your gold (& maybe WAY to much oxidizer)


To much oxidizer in a cyanide solution can cause a problem with recovery of the gold from the solution - which is why a say to do NOTHING yet

Also - though I have worked with cyanide - my experience is limited (in fact very limited - have only done it once)

Off the top of my head - some of the members here that I know & "trust" to help here are Nick - 4metals - GSP - Deano & Lino --- hopefully they will chime in here

once again - until this has been FULLY discussed - & you FULLY understand what to do --- do NOTHING

Kurt

 

[Goldextraction32]

Please advise how to proceed? Recover gold first and then destroy cyanide or destroy cyanide first and then recover gold?
Thanks!

As I said yesterday & underlined in the above quote --- you want to FIRST recover the gold - & then destroy the cyanide (to make it safe for disposal)

To recover the gold you can run it through an electrolytic winning cell

Or you can run it though a carbon column using "activated" carbon

Or you can use zinc or aluminum - the zinc or aluminum should be "foil" cut into strips

This is no where near enough info to get you started :!: you need MUCH more info to get started - do NOTHING yet :!:

In your first post - you posted

We have a gold cyanide solution of 28 liters. We removed gold from gold plated connectors. We used 475 grams of commercial grade sodium cyanide and 5 liters of hydrogen peroxide of 36%.

I may be wrong about this - but - it sounds like you used to much H2O2 (oxidized) in you solution to dissolve your gold (& maybe WAY to much oxidizer)


To much oxidizer in a cyanide solution can cause a problem with recovery of the gold from the solution - which is why a say to do NOTHING yet

Also - though I have worked with cyanide - my experience is limited (in fact very limited - have only done it once)

Off the top of my head - some of the members here that I know & "trust" to help here are Nick - 4metals - GSP - Deano & Lino --- hopefully they will chime in here

once again - until this has been FULLY discussed - & you FULLY understand what to do --- do NOTHING

Kurt

Thanks a lot !

 

[4metals]

Kurt is correct in assuming you added a lot of peroxide. I would aerate it with an aquarium bubbler outside in the sunshine for few days to drive off the excess peroxide, then follow this procedure and you will have your gold. Do not throw away any sludges or anything you filter out until you are sure you have all the gold you expect. We can walk you through any situations that come up if you have to find lost gold but we can't do that if you don't save everything.

This doesn't address the waste liquid, that is another story. come back with results and we can get you through the waste too.

These are procedures I have written up; you actually are starting at the point where the gold is dissolved in solution.

Recovering Gold from potassium or sodium gold cyanide

Required supplies and equipment

• Zinc dust 325 mesh is commonly available. Make sure the powder is pure zinc with no declumping chemicals added. (cab-o-sil)
• A slab of zinc metal with a hole drilled in the top edge so it can be tied and hung in a bucket of solution.
• Sodium hydroxide, either flake or as 50% caustic liquid
• Sodium or Potassium cyanide
• pH papers or a pH meter
• A strong propeller driven mixer

Process

• If the salts are in powder form they must be dissolved in warm water, if they are in the form of a solution and any salts have dropped out, heat the solution to assure all of the crytstallization has dissolved, if necessary add water.
• Allow the solution to cool to room temperature.
• Check the pH, if it is below 12, raise it with sodium hydroxide, try not to add too much sodium hydroxide, it shouldn’t take a lot to get the solution to pH 12.
• Add 5 grams per liter of solution of either sodium or potassium cyanide. This makes the dropping of the gold easier and more complete.
• While stirring, slowly add powdered zinc dust. If the zinc dust has clumped up due to humidity, sift it through a flour sifter before adding it. Clumped up zinc dust causes you to use too much and is just a waste. A rule of thumb is one gram of zinc dust for every gram of gold expected. When you first add the zinc dust, you will notice the dark gray zinc dust will appear brown in color. That is because the original addition immediately displaces gold which accounts for the color. Add until all of the precipitate brought up from stirring is gray in color.
• Hang a bar of zinc metal in the solution and allow it to settle overnight. The zinc will both drop any minute quantities that may still be in solution and prevent the re-dissolution of any precipitated gold.
• Decant the clear solution and filter the balance to collect the solids.
• Rinse the collected solids several times with hot water. This is to remove the cyanide from the solids. Collect the rinses and put them with the solution collected earlier.
• While a hood is not necessary for the first steps, it doesn’t hurt. The following steps however, MUST BE CARRIED OUT IN A FUME HOOD!
• Place the solids filtered in a beaker or bucket and add water to allow the leaching of the excess zinc with nitric acid. If your water supply is heavily chlorinated, distilled water would be better.
• Add a small amount of nitric acid, it will react quickly and aggressively dissolving any excess zinc. When the reaction dies down, stir the solution and add another small portion of nitric acid. Stir and repeat until there is no longer any reaction when nitric acid is added.
• Filter the solution and save the insoluble gold residue. This gold should be refined in aqua regia.


EPA regulations today make production processes using cyanide difficult. For refiners processing small lots of gold salts as outlined above, the cyanide solution can pose a problem if allowed to mix with your standard waste stream. Fortunately, cyanide breaks down completely with the heat of incineration. The best way to treat the liquid from which the gold was removed by cementation with zinc is to pour it into an absorbant lot of house sweeps just as it is going into incineration. The resultant incinerated solid will bear no traces of the cyanide after incineration temperatures are reached.

Housekeeping procedures for Cyanide use

• Wear gloves whenever handling cyanide salts or solutions. Wash your hands when done handling the material. If you feel a slippery feeling on your skin when you remove the gloves you likely got some cyanide on your skin. It won’t kill you but wash your hands well with soap. A little vinegar will neuralize the slippery feel if soap is not successful.
• Obtain a small quantity of either potassium or sodium cyanide powder. Store it in a plastic bag inside a tight sealing container. Label the container clearly.
• Do not store the cyanide near any acid. Generally the cyanide is used infrequently and is best stored away from the acid processing area.
• Weigh out the required quantity of the cyanide in a clean tared beaker without bringing the container into the acid processing area. Be careful to avoid spilling any powder and if it is spilled sweep it up dry and wipe up with a damp cloth with bleached water and dry the area.
• Clean out the hood of any standing acid when preparing to process cyanide gold salts.
• Maintain an alkaline pH in all solutions involving cyanide to prevent generating cyanide gas.
• Incinerate the waste liquid or any cloths used from cleaning up spills as detailed above.
• Cyanide is still widely used by electroplaters and refiners and it is perfectly safe if handled properly and with respect.

 

[Goldextraction32]

Kurt is correct in assuming you added a lot of peroxide. I would aerate it with an aquarium bubbler outside in the sunshine for few days to drive off the excess peroxide, then follow this procedure and you will have your gold. Do not throw away any sludges or anything you filter out until you are sure you have all the gold you expect. We can walk you through any situations that come up if you have to find lost gold but we can't do that if you don't save everything.

This doesn't address the waste liquid, that is another story. come back with results and we can get you through the waste too.

These are procedures I have written up; you actually are starting at the point where the gold is dissolved in solution.

Recovering Gold from potassium or sodium gold cyanide

Required supplies and equipment



• Zinc dust 325 mesh is commonly available. Make sure the powder is pure zinc with no declumping chemicals added. (cab-o-sil)
• A slab of zinc metal with a hole drilled in the top edge so it can be tied and hung in a bucket of solution.
• Sodium hydroxide, either flake or as 50% caustic liquid
• Sodium or Potassium cyanide
• pH papers or a pH meter
• A strong propeller driven mixer

Process

• If the salts are in powder form they must be dissolved in warm water, if they are in the form of a solution and any salts have dropped out, heat the solution to assure all of the crytstallization has dissolved, if necessary add water.
• Allow the solution to cool to room temperature.
• Check the pH, if it is below 12, raise it with sodium hydroxide, try not to add too much sodium hydroxide, it shouldn’t take a lot to get the solution to pH 12.
• Add 5 grams per liter of solution of either sodium or potassium cyanide. This makes the dropping of the gold easier and more complete.
• While stirring, slowly add powdered zinc dust. If the zinc dust has clumped up due to humidity, sift it through a flour sifter before adding it. Clumped up zinc dust causes you to use too much and is just a waste. A rule of thumb is one gram of zinc dust for every gram of gold expected. When you first add the zinc dust, you will notice the dark gray zinc dust will appear brown in color. That is because the original addition immediately displaces gold which accounts for the color. Add until all of the precipitate brought up from stirring is gray in color.
• Hang a bar of zinc metal in the solution and allow it to settle overnight. The zinc will both drop any minute quantities that may still be in solution and prevent the re-dissolution of any precipitated gold.
• Decant the clear solution and filter the balance to collect the solids.
• Rinse the collected solids several times with hot water. This is to remove the cyanide from the solids. Collect the rinses and put them with the solution collected earlier.
• While a hood is not necessary for the first steps, it doesn’t hurt. The following steps however, MUST BE CARRIED OUT IN A FUME HOOD!
• Place the solids filtered in a beaker or bucket and add water to allow the leaching of the excess zinc with nitric acid. If your water supply is heavily chlorinated, distilled water would be better.
• Add a small amount of nitric acid, it will react quickly and aggressively dissolving any excess zinc. When the reaction dies down, stir the solution and add another small portion of nitric acid. Stir and repeat until there is no longer any reaction when nitric acid is added.
• Filter the solution and save the insoluble gold residue. This gold should be refined in aqua regia.


EPA regulations today make production processes using cyanide difficult. For refiners processing small lots of gold salts as outlined above, the cyanide solution can pose a problem if allowed to mix with your standard waste stream. Fortunately, cyanide breaks down completely with the heat of incineration. The best way to treat the liquid from which the gold was removed by cementation with zinc is to pour it into an absorbant lot of house sweeps just as it is going into incineration. The resultant incinerated solid will bear no traces of the cyanide after incineration temperatures are reached.

Housekeeping procedures for Cyanide use

• Wear gloves whenever handling cyanide salts or solutions. Wash your hands when done handling the material. If you feel a slippery feeling on your skin when you remove the gloves you likely got some cyanide on your skin. It won’t kill you but wash your hands well with soap. A little vinegar will neuralize the slippery feel if soap is not successful.
• Obtain a small quantity of either potassium or sodium cyanide powder. Store it in a plastic bag inside a tight sealing container. Label the container clearly.
• Do not store the cyanide near any acid. Generally the cyanide is used infrequently and is best stored away from the acid processing area.
• Weigh out the required quantity of the cyanide in a clean tared beaker without bringing the container into the acid processing area. Be careful to avoid spilling any powder and if it is spilled sweep it up dry and wipe up with a damp cloth with bleached water and dry the area.
• Clean out the hood of any standing acid when preparing to process cyanide gold salts.
• Maintain an alkaline pH in all solutions involving cyanide to prevent generating cyanide gas.
• Incinerate the waste liquid or any cloths used from cleaning up spills as detailed above.
• Cyanide is still widely used by electroplaters and refiners and it is perfectly safe if handled properly and with respect.

Thanks for this help !
I will get back to you when I am done with what you have suggested.

 

[FrugalRefiner]

Goldextraction, you are being given a gift most could only hope to receive. Follow 4metals' directions to the letter. Do not substitute anything. Take this step by step as he guides you through the process and this thread can serve anyone who reads it in the future.

Hobbyists and Professionals Helping One Another!

Dave

 

[Goldextraction32]

Goldextraction, you are being given a gift most could only hope to receive. Follow 4metals' directions to the letter. Do not substitute anything. Take this step by step as he guides you through the process and this thread can serve anyone who reads it in the future.

Hobbyists and Professionals Helping One Another!

Dave

You are right Dave.
Thanks!