Presentation on theme: "The 14k gold chain must be inquarted (quartered) with pure silver. The gold and silver are melted together and this dilutes the gold so that the non-gold."— Presentation transcript:
The 14k gold chain must be inquarted (quartered) with pure silver. The gold and silver are melted together and this dilutes the gold so that the non-gold metals trapped in the 14K chain can be effectively dissolved with nitric acid. The molten inquarted gold is poured into cold water to cornflake the gold into small blobs that are easy to dissolve.
This is what the corn flakes look like. If you were to just splash this with some HCL (Hydrochloric Acid) they would become pretty but we dont care because the next step is to dissolve all of this in Nitric Acid Gold will not dissolve in Nitric Acid – but nearly every other metal will so in the next step we put all of the copper and silver into solution
Here are the corn flakes in a mix of 35% Nitric Acid and water. I am heating this mixture to speed things up. The disagreeable brown smoke is the result of the Nitric Acid working on the non-gold metals. This brown smoke is highly corrosive. This mixture will tend to turn green for copper and blue for silver. In this picture it looks to be on the green side but that is because it just started.
Pouring off the solution leaves semi-pure gold. This is probably 95% pure (total guess). Yes, it is an ugly black powder – but this is gold in a metal form. Melting this would get you pretty gold. There are still impurities in here since some silver gets trapped (surrounded by) gold. We will deal with that in a second
This is what the solution I poured off looks like. That is about 2.5oz of nearly pure silver. This solution is called Silver Nitrate Later we will drop the silver from this solution by adding copper. Long story short, if you add copper you precipitate pure silver.
Here is that gold again. On the right is Aqua Regia – or Royal Water. It is the only known acid that will desolve gold. It is a mix of 1 part Nitric Acid and 3 (or 4) parts Hydrochloric Acid. This will dissolve the gold and put it into solution – ironically it will not desolve the silver that is there. Any silver left in the gold will be converted to Silver Chloride – or silver in a salt form. This silver CAN NOT be melted down.
Adding the AR causes the gold to immediately start to dissolve. Notice that it makes a beautiful gold color in the solution.
Notice the smoke…. Do you see it? Near the stirring rod? This smoke is very similar to the nasty brown smoke that comes from the Nitric Acid but this time it has a golden color… Very cool. People have been doing this for thousands of years….
Once all the gold is dissolved (and boiled down a little) you end up with a thick deep golden liquid. I believe it is referred to as auric chloride – but dont quote me on that. In the background you see our silver in solution In the next slide you are going to see some of the last of the impurities that precipitated
The crap that is floating is Silver Chloride – this is the silver that was still in the black powder before we dissolved it in AR. This crap can be converted back to silver but it takes 2 steps – you cant just melt it down or you will lose it. We filter this off and save it for later
Here is a shot of all three… The gold in the middle is >99% pure by this point. The blue is our silver.
Here is that silver chloride that was floating around in our gold. Notice that it looks kinda blue
We now must get all of the residual Nitric Acid out of our gold solution. This can be done by boiling, by adding urea, or by adding additional gold. The idea is to bring the PH up to about 1.0. Any lower and you can not precipitate gold from the solution.
Changing gears for a second – here is a shot of the silver being precipitated out of the Silver solution using copper. Those are pure silver crystals growing on the copper tube…. We are trading copper for silver. We expect the solution to turn a dark green. Copper in solution is green, silver is blue We can test for all of these things
Now – the gold is filterd a few times We will dilute it in about 2x water
All ready to go
This is SMB…. Stump remover…. Sodium Meta Bisulfate Adding this will cause the gold to precipitate out as a black powder. Basically, we are getting it back to where we started from except it is much more pure.
I dissolve the SMB in water and slowly pour it in. You can instantly see the gold precipitate.
The gold is heavy so it sinks to the bottom. Once we precipitate all of the gold out the fluid will turn clear and we can decant the fluid off the top.
While we wait for the gold to drop this is the result of the copper bar we put into the silver solution. Notice how it is all green now… that is the copper. Our silver is sitting at the bottom. About 2.5oz pure
After we filter off the gold powder it is dried (on a heating element) and it turns a golden brown. This is pure gold. To make this look pretty we will melt it down.
This is my ghetto furnace… I have a better one that I use now built out of 2600 kiln bricks. Basically I just use a MAPP gas torch to melt the gold powder in a crucible Borax is used as the flux
The fun part….. Similar to the first step, once this is molten I am going to corn flake it by pouring it over cold water. This will cause the gold to turn into shot – or a bunch of small nuggets.
I take the shot and wash it in HCL – this is what it looks like after melting. This is >99.9% pure gold.
You can now use your teeth to test it This was the mile high overview. I also know all the testing procedures – how to test for PMs in solution, how to test the purity of silver, etc.