Oneal58 said:
Question 1-So you transfered the gold powder to the melting dish from the pan, what did you do, sweep it out with a little broom? Then melted into button and added it to your main run. What did you do with all the smut left on the pan, does this smut contain any gold? Or just wash it out with dawn detergent, and a scrub pad.
When I get to the stage of drying the gold, it is usually quite pure after many washings with distilled water. I have not seen "smut" in my drying pan in a long time. The smut in your drying pan is an indication that the gold powder was not pure. When pure gold powder dries, it leaves no residue - unless it is dirty from not being washed properly.
I have seen "smut" in my gold drying pan in the past though. It would bake onto the corningware casserole dish that I was using to dry the gold powder in. Its been a while, but I think I just washed it out.
When the gold powder is dry, it is very clean and I can loosen any that clings to the bottom of the corningware dish by simply giving the dish a light swirl. The loose particles of gold hit the stuck particles and loosen the clinging pieces. Some may be stuborn, and I use a stainless steel spoon to pull any that sticks away from the dish.
I use the same stainless steel spoon to transfer the gold powder to the melt dish. I use a single melt dish for several melts, then retire it to inquarting when it starts to get dirty looking.
I would not use any sort of metal dish to dry your gold powder in. It seems that this could cause contamination - use a corningware casserole dish with a handle.
Oneal58 said:
Question 2- I have a coule of ounces of silver nitrate from the silver drop with copper/urea
I'm not sure I understand this question. Do you have cemented silver metal that you recovered by putting copper in the solution and cementing the silver out?
If you have powdered silver metal from cementing the silver out of silver nitrate solution with copper, then you can wash the silver powder and melt into a nice button depending on how much you have.
It should be about 98% to 99% pure silver metal, depending on how careful you are about keeping small pieces of copper out of the silver during cementation with copper, and how thoroughly you wash the cemented silver powder.
Or you can wash it and put the silver powder in a jar and save it for later when you set up a silver cell. Then you can melt it into anode bars for your cell.
I melt all my cemented silver into anode bars for my silver cell.
Oneal58 said:
What process do you use, other than to put into filter, run suction and pour hot water over silver until solution runs clear.
In the past, I have put the silver into a large (1000 ml or 2000 ml) beaker and kept adding boiling distilled water and stirring then pouring off the wash water - usually through a filter to catch any powder that tries to escape with the wash water.
I did this over and over until all the color was gone. once the rinse water was clear, I then tested the wash water with some HCl. I take a small (10 or 20 ml) sample of the wash water and add a few drops of HCl to the sample. If there is still silver nitrate being washed out of the silver, then the sample will turn cloudy with silver chloride formation. When the sample of wash water stayed clear, I was confident that the silver powder was clean (of silver nitrate). Then I dry and melt or save the silver powder for later.
I still use a graphite mold I purchased of ebay. I have three identical molds. One is reserved for fine silver only, the next for fine gold only, and the third is for casting anode bars.
These molds have a slight taper to their sides, about 15 degrees if I remember correctly. This tapper allows the bars to slide right on out when you turn it over.
Oneal58 said:
It is light, small, very easy to move around and can be attached to the beaker with little effort. It was only $16.00 if I remember correctly. It was sold to deflate large matresses with, do you think this suction pump would work
I don't have any experience with one of these, but I am guessing it is pretty light duty and probably would not last long working with the acids.
I use an HVAC pump 2.5 cfm I purchased from Harbor Freight. It is a nice heavy duty pump. From what I have read on this forum, the oil has additives that neutralize acids, but the oil must be changed frequently.
I used one for about 15 months before it finally froze up. I confess that I never changed the oil during that entire 15 month period. I just bought a new one and the price had increased from $79 last year to $109 in November 2011.
I plan to change the oil at least every couple of months on this one to see if I can make it last a little longer.
the gage is from a diesel engine test kit also from Harbor freight. It cost $14.95 last year. It has a nice big dial that is easy to read. I have a small petcock type valve right after the gage connection. I can throttle the vacuum going to my flask if I need to.
The amount of suction I need varies from time to time. Sometimes I need just a little vacuum (like when I am washing cemented silver with boiling distilled water). I will turn the vacuum pump on and let it draw down to 10 or 15 inches Hg vacuum.
Other times I peg the gage at full vacuum (such as when filtering AuCl that has silver chloride in with it). Even then, with the vacuum gage pegged out, it can take hours to filter the AuCl.
Having to endure one of these marathon filtering sessions due to silver chloride formation in my AuCl is great incentive to make sure that all the silver bearing liquid is removed (through careful washing) before dissolving the gold.
I hope you can glean some helpful tips from this post.
kadriver