What's happening here?

[Barren Realms 007]

Postive test for AU inside (10) 186 chip's before foils are added.

 

[Barren Realms 007]

Update:

Don't trust your distilled water.

I washed some gold with nitric and distilled water and put it on a hot plate for coffee maker. Nothing else had been added to the beaker and the gold had been washed 3 times with distilled water before the nitric had been added. The old had been dried on the hot plate before this was done. NO HCL HAS COME CLOSE TO THIS. The nitric and distilled water dissolved a small amount of the gold and the solution tested positive for this. The solution was poured into another beaker and the gold powder was washed with distilled water into the 2nd beaker. This morning temperature was 9F outside. I added SMB and put the solution on the hot plate and percipitated the gold out. This is the 4th or 5th time I have done this. The other times I couldn't e sure contaminat of HCL could not be the culprit but this time I am 100% sure of this.

So for everyone that says you can not drop gold out of nitric with SMB I say BULL CRAP.

 

[Barren Realms 007]

Fun stuff. Gold can be found almost any where. This proves that gold can be found anywhere.

 

[eeTHr]

Barren---

Were you using home made nitric?

 

[Barren Realms 007]

Barren---

Were you using home made nitric?

Yep, but I haven't had this happen except with just nitric. Only when I have used a certain Mfg. distilled water. I'm either going to stop using thier water or start boiling it before I use thier's.

 

[eeTHr]

Barren---

You already know that you can end up with chlorides in home made nitric, right?

I would think that for there to be enough in water, to dissolve any Au, you would be able to smell it.

:?:

 

[Barren Realms 007]

Barren---

You already know that you can end up with chlorides in home made nitric, right?

I would think that for there to be enough in water, to dissolve any Au, you would be able to smell it.

:?:

Yea I know. That wasn't the jest of the post any way. I still want one of the experts to explain why I can drop the gold out of the nitric. I never can get an answer on that one. I guess I'm going to have to make a video of it and post it some day to get an answer. 8)

 

[4metals]

I still want one of the experts to explain why I can drop the gold out of the nitric. I never can get an answer on that one.

I think you mean can't drop the gold.

The reason you cannot drop the gold until the nitric is gone is because the nitric continues to regenerate Chlorine molecules from the HCl which will re-dissolve the gold. Actually the gold does drop and redissolve and cause the red fuming to continue. When all of the nitric is exhausted, the gold will drop. It's just using an excess of chemical to kill off the nitric by reacting with the gold that has just dropped from solution.

Often larger refiners will gas with SO2. The reaction often blows red fume while gold is being dropped and redissolved. A waste of SO2 but it is done often.

 

[Barren Realms 007]

I still want one of the experts to explain why I can drop the gold out of the nitric. I never can get an answer on that one.

I think you mean can't drop the gold.

The reason you cannot drop the gold until the nitric is gone is because the nitric continues to regenerate Chlorine molecules from the HCl which will re-dissolve the gold. Actually the gold does drop and redissolve and cause the red fuming to continue. When all of the nitric is exhausted, the gold will drop. It's just using an excess of chemical to kill off the nitric by reacting with the gold that has just dropped from solution.

Often larger refiners will gas with SO2. The reaction often blows red fume while gold is being dropped and redissolved. A waste of SO2 but it is done often.

NO HCL was used. The gold was dropped from nitric. I keep asking this and have never gotten an answer why this is possible. The only chlorine could have come from the distilled water.

 

[lazersteve]

The reason for removing nitric is not because the gold won't precipitate from nitric solutions, but because other metals can co-precipitate from nitric solutions when SO2 or SMB is used. Bottom line, SMB is not a selective reducing agent in the presence of nitric (or HCl for that matter).

In order to get the highest purity from your gold, you should avoid using nitric altogether or denox your solutions before precipitating the gold.

Here's a little chart I made to help you understand (remember you saw this here first!):



and a PDF of the chart (since the image is foggy):
PDF of Chart

The various types of solutions are listed across the top, mixtures will give mixed results. The reducing agents are listed down the left side. One important reagent to note is copper I chloride, it can be troublesome when SO2, Au, and Pd are in the same solution, also notice that SO2 will form CuCl in chloride solution containing dissolved copper.

The green boxes in the center area of the chart are the optimal combinations of solution and reducing agents. The red boxes are areas of concern where multiple, or alternate precipitates can form. Notice the nitrate column has lots of red. Acetylene is an explosive gas and should not be used as a reducing agent for Pd.

I have intentionally omitted other reducing agents. Some reducing agents not shown are merely salts of the ones listed (eg: ammonium oxalate, sodium meta-bisulfite).

Hopefully the chart will make things clearer for you, regardless of how you get your metals into solution.

It all comes down to how clean do you want your precipitated metals. Controlling the solution they are precipitated from will lead you to a purer product.

Here's a link to a brief descripition of how to read the chart:

Reading the Chart

Steve

 

[Barren Realms 007]

Thanks for the chart Steve.

Just a note it was not my intention to disslove the gold in the nitric I have. I was doing a wash procedure on some product I had.

It is a situation that needs to be addressed about the possaility of gold dissolving in nitric without HCL or other chlorines present so that other members can be aware that it is a possability and that if it does happen that there is a route for them to take to recover thier values.

It is something I have tried to have addressed in this thread more than once.

No where on the forum can I remember reading that you can recover gold in a nitrate solution with SMB or SO2. I felt this needed to be addressed so others would be aware of it. And have a plan of action for it. Other than just cementing all of it with copper and starting over.

But then again maybe I am just thick headed.

 

[lazersteve]

I've treated many ounces of gold with nitric using inquartation and have never found even a trace of gold dissolved in the resulting silver nitrate.

I avoid using nitric acid in my gold clean up process as it can react with chlorides trapped in the sponge structure of the gold and form AR dissolving some of the gold.

There are also other sources of stray chlorides such as dirty glassware, or improperly washed glassware, and stir rods or utensils. Chlorine can actually get trapped in the glass structure of beakers. A good rinse with distilled water before using can help alleviate this.

Steve

 

[Barren Realms 007]

On this perticular batch I am working with the glassware was cleaned and washed throughly but not with distilled water. It was some inquirted jewlery that I had been processing. I had run only nitric and distilled water in this batch no other solutions were used in this. The solution was not boiled it only on a coffee hot plate and had been washed with ammonia prior to this happening. I had put 3 runs of nitric thru this so now I will go back and check the other solutions.

Thanks Steve

 

[Irons]

On this perticular batch I am working with the glassware was cleaned and washed throughly but not with distilled water. It was some inquirted jewlery that I had been processing. I had run only nitric and distilled water in this batch no other solutions were used in this. The solution was not boiled it only on a coffee hot plate and had been washed with ammonia prior to this happening. I had put 3 runs of nitric thru this so now I will go back and check the other solutions.

Thanks Steve

Have you checked your water with Silver Nitrate to check for Chlorides? It wouldn't hurt to check your Nitric as well.

Never use Acetylene to precipitate metals. It will form highly sensitive and explosive acetylides. Some of these compounds have been used in detonator compositions.

Don't even think about it.

 

[Barren Realms 007]

On this perticular batch I am working with the glassware was cleaned and washed throughly but not with distilled water. It was some inquirted jewlery that I had been processing. I had run only nitric and distilled water in this batch no other solutions were used in this. The solution was not boiled it only on a coffee hot plate and had been washed with ammonia prior to this happening. I had put 3 runs of nitric thru this so now I will go back and check the other solutions.

Thanks Steve

Have you checked your water with Silver Nitrate to check for Chlorides? It wouldn't hurt to check your Nitric as well.

Never use Acetylene to precipitate metals. It will form highly sensitive and explosive acetylides. Some of these compounds have been used in detonator compositions.

Don't even think about it.

I didn't think about going that route, thanks Irons. I know I was working with some silver contacts with the same 2 solution's I was getting silver chloride back a couple of weeks ago but I didn't just take some silver nitrate and put it in the water to check I just made an assumption that it was the water.

 

[Barren Realms 007]

Making a new filter.

 

[Barren Realms 007]

Here is a video of the new vacume filter setup.

[youtube]http://www.youtube.com/watch?v=3ZaX4i7DWEY[/youtube]

 

[4metals]

Barren, a few suggestions.

The blue perforated disc you use as the bottom of the filter has holes all the way to the edge. On a Buchner funnel the holes stop about 3/8" from the edge. That provides a smooth surface for the paper to seal against the bottom and prevent liquid from leaking around and under the paper rather through the paper.

You could get by with less holes (which tend to blow through with a good vacuum) you can put a circle of fiberglass window screen which is smaller in diameter than your hole pattern which will raise the paper just a hair off the plastic and allow it to flow better. The smooth edge is still important to seal the paper to the filter at the edges.

Otherwise, nice job.

 

[Barren Realms 007]

Barren, a few suggestions.

The blue perforated disc you use as the bottom of the filter has holes all the way to the edge. On a Buchner funnel the holes stop about 3/8" from the edge. That provides a smooth surface for the paper to seal against the bottom and prevent liquid from leaking around and under the paper rather through the paper.

You could get by with less holes (which tend to blow through with a good vacuum) you can put a circle of fiberglass window screen which is smaller in diameter than your hole pattern which will raise the paper just a hair off the plastic and allow it to flow better. The smooth edge is still important to seal the paper to the filter at the edges.

Otherwise, nice job.

The filter papers are cut larger than the container and I have a ring that fits tightly inside the container and it presses the filter papers aginst the edge of the container to form a seal as it is all pressed down on the platic part with the holes. But I agree with you that when I build another one that is what I am going to do is keep the holes away from the edge at least 3/8 of an inch. I had already finished one run with this setup before I made the video and it filtered everything out. This was made with a new change of the filter paper. If you notice the sound on the the video, the picture I am pouring out of you can hear the ice in it and notice the frosting on the side of the container. The filter container I am pouring into also has ice in it to cool the solution.

Thank you for the advice. It is always appreciated from everyone.

 

[Barren Realms 007]

Another source for small silver contact point's, inside GFCI recepticals. A hammer does a good job of breaking them apart.