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Aqua Regia method with 12-13% Ag _inquart_
- Thread starter giahylxag
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Welcome to us.
You are adding a completely unrelated post to an existing thread.
Additionally it is a post regarding a Cyanide leach in a thread regarding AR.
Combine these two and you will most likely die.
I will delete this post in a few minutes and send you a PM in the mean time.
I looked at your video of the scrubber you built closely and realized that while your scrubber does provide visible fume extraction, it does not provide adequate exhaust for operating a refining operation.
On closer look what I do not see is the hood exhaust. When a refining hood is set up the preferred method is to have 2 actual forms of exhaust. The first is considered fugitive emissions by the EPA. What that means is any fumes that escape your scrubber. That can be the fumes when you filter a solution or when you open and pour your acids or any other refining task. These fumes are minimal and with an acceptable flow rate passing through your hood they never cause an issue. But without that constant exhaust of air, those fumes will build up as you noticed.
If left to linger in your workspace it will start to do things like peel paint off the wall, rust any steel, and many other slow to develop issues. The pH papers on your desk are an early indicator. When you are refining or treating waste or just have open containers of refining liquors in the hood it should be running.
The second form of exhaust is scrubbed emissions. That is air which passes through the fume scrubber after it is treated. You seem to have that issue taken care of for your small scale testing.
So I believe your issue is you only have 1 of the 2 necessary exhausts for your particular situation.
There are many threads on the forum about building exhaust hoods and you should find a method that works for your setup. But do not ignore this because it is a slow type of corrosion you are seeing. If you noticed it when processing small samples, it will be come very obvious (and dangerous) when you process large lots. Your health and the health of your workers should be a #1 priority.
giahylxag
Well-known member
I am processing a bigger lot today than the previous day. Around 1 oz of pure gold
I notice there a some "metallic" looking of piece that make it really hard for nitric to eat into
For example this piece
While every other pieces are settled and I see no reaction. This particular piece still reacts but wirh a much slower pace. I tried to split it by a glass rod but it appeared very hard.
I notice there a some "metallic" looking of piece that make it really hard for nitric to eat into
For example this piece
While every other pieces are settled and I see no reaction. This particular piece still reacts but wirh a much slower pace. I tried to split it by a glass rod but it appeared very hard.
You probably didn't manage to get the melt homogeneous enough.
So this part has too high Gold content for the Nitric to reach the Silver.
Take it out and put it into the next batch, or hammer it really flat and cut it to fine strips.
Then put it back after twisting them.
giahylxag
Well-known member
I used an induction furnance
Melted the gold with copper, to the point they became a button in the bottom of the crucible
Then pour it out to water
giahylxag
Well-known member
I can see some shiny gold nuggets
The result is dissapointed. Probably copper is still in there
giahylxag
Well-known member
Xrf result
One hopeful result is there is almost no gold lost after xrf
One hopeful result is there is almost no gold lost after xrf
Golddigger76
Well-known member
Did you refine your gold powder a second time ?
giahylxag
Well-known member
No
I am trying to make 999 gold by inquarting.
AR usually the next step, but I am focus just on inquarting
I can honestly say I have never inquarted gold with copper. I usually use either fine silver, cement silver, or sterling silver. Never straight copper.
Form your results I guess you can see that it kinda works with copper but it really works with Silver.
Probably as Ygg suggested, the copper didn't mix thoroughly because you poured it too soon? Or because you didn't shot it small enough.
Your silver reserves will build up soon enough so you can always use silver and get the results you experienced the first time.
giahylxag
Well-known member
I recall that I poured the shot too soon. Most of the inquarted gold became a big mass that I had to cut it into 3 smaller pieces. I noticed the big pieces are very hard to dissolve. And they have metallic suface that I believe is gold.
All of these little bumps in the road are teaching you to be a better refiner.
Overall you have done well.
Overall you have done well.
giahylxag
Well-known member
Today I proceed this piece using AR method.
There is not many problem since I began with a very low %Ag content.
As expected the liquid is light greenish yellow
I used sulfamic acid to denox and SMB to drop gold
I didn't know how much SMB to add so I added it till the liquid became clear
This is the result
Xrf read 99.99, machine is Vanta Gx SDD, brand is Olympus
Once you get enough experience with the process you can see a color shift in the green acid when all of the gold is dropped. The green goes from a bright green to a dull green. It’s subtle and in no way eliminates a need for stannous, but it is noticeable.
Congratulations, you have arrived! Now that you have proven to yourself you can make the gold you need, you have to scale up to start making better margins on your gold. And accumulating Silver.
Time to get a good hood exhaust going.
Time to get a good hood exhaust going.
giahylxag
Well-known member
Given the test was a success
I will stop my project for several months and redesign everything to scale up and steamline my business.
I am looking to buy a flask with a flask heater.
Is a 3 heads flask like this model sufficent for refining larger lot? size range from 5000ml to 12000ml.
the idea of a multi heads flask is that I can control where the acid will go and where the fume will escape. In short I will make it air tight
Or just buy a bigger becher?
This can be good for the aqua regia digestions but there are a few things to keep in mind. First is the small holes in the top. For solutions and reactions that dissolve well, they are fine but for reactions where there are insolubles that need to be removed from the vessel that is a problem.
Let's start by discussing volume, based on the acid used to digest gold and gold alloys, a 12 liter has an effective operating volume of 7 to 7.5 liters. This depth leaves enough room for the solution to rise without risk of shooting out the condenser. (Yes I have seen that happen with overfilled vessels!) So a 12 liter flask will digest 50 ounces of the powder you get from first inquarting and parting in nitric. The flask is light enough to lift and pour the contents into the funnel to filter it. since the yield is 99%+ fine gold to start, your yield should be close to 50 ounces per reaction. Another spherical reactor standard size is 22 liter which can refine 100 ounces per load. Also small enough to lift and pour by hand. Both are also available with 4" conical heads which allow you to put your hand into the vessel once it is rinsed free of the acid to collect any diamonds that were in the gold. both sizes are available with both hard heat mantles and soft heat mantles.
I know we are not talking about chemical stone removal but if your typical customer is a jeweler who sets stones, it is a valuable service to provide for your customers. But if you cannot get your hand in the vessel it will not work. This is all I'll say about stone removal now but if it were me, and the local market has the potential for that type of work, I would be having at least one vessel with a 4" conical head. You can always start another thread to discuss this further if you decide to try it once you are up and operating.
You also have to consider the nitric acid parting of the inquarted gold. This is the most cost effectively method done in a stainless steel pot. Usually 304 stainless. These are much more affordable and have a large capacity. This photo, which I have posted before is a simple setup used to dissolve Silver to make silver refining electrolyte.
For parting I would forego the heat band and place the pot on a large electric hot plate to get the heat from the bottom. My reason is 25% of the material you put in will not dissolve because it is gold, so heating from the bottom will likely penetrate the gold better during the process and result in higher purity. The funnel draws up into a fume scrubber and effectively exhausts the NOx. This setup was done without a hood because when the reaction stopped they let it cool and never handled hot acid. You will be decanting and rinsing and it will leak fumes. It should be done in a hood to keep the shop air much more liveable.
These pots come in many sizes typically 5 gallon but as high as 25 gallon. You need to consider 2 things. 1. how much you can easily lift. and 2. how much pure gold you want to refine in a single lot in a glass vessel. Matching the 2 volumes will make for efficient processing.
If you choose to start with a 12 liter vessel for aqua regia, a 5 gallon stainless pot should give you room to process 50 ounces of fine gold content inquarted 3:1 with silver. You should be able to inquart and part 2 lots a day and refine 2 lots a day in aqua regia. Maybe Mondays half that because you won't have a parted lot of powder to put up first thing in the morning. But I don't see a capacity of 450 fine ounces out of range per 5 day week for this system once you are comfortable with the process. I believe, without going back and looking, that is double of your weekly refining load which was 6 kg.
I think it would make an interesting informative thread to assist you in designing your refining operation. If you can provide the room dimensions where this will go and the locations of roof access for the required exhaust vents, we can optimize the available space and possibly come up with some unique layouts for processing and even future growth. If you want that input, please start another thread because this one is getting quite large.
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