Can I mix these?

[bswartzwelder]

I have several containers with processed gold in them. One container came from foils which I processed using Poorman"s AR. That powder is light brown in color and has been rinsed in distilled water to get rid of the acid. I also have some black sediment from my electrolytic cell which has been rinsed in distilled water.

I am getting close to the point where I want to melt this stuff down. I know that before melting it down, it needs to be as pure as possible. I plan on using HaroldV's method of boiling three times in HCl and then boiling three times in distilled water. My question: can I mix the gold powder from the Poorman's AR with the gold powder from the electrolytic cell and then process it all at one time?

I understand that each time I boil it,(in the HCl and the H2O) I need to boil for approximately 30 minutes. I'm really looking forward to that button.

 

[necromancer]

sure you can.

but why not wash and dry the 2 lots, weigh each then melt that way you will have a mental note of each yield

 

[Anonymous]

Modify Harold's process.

Wash in HCl then in water, then HCl again, and so on.

It works.

 

[Shark]

I have one container for powders. All from small batch's, but mixed in the final container, all twice refined before being mixed. Some looked better than others so when I am ready to melt I will run the entire lot once more. Then, final washes as per Harold's methods and then on to the melting. These are powders from my first attempts some months ago right up the small lot I will be dropping this evening (hoping for right at 1 gram from this evenings batch). Mix when they are as close to the same purity as reasonably possible, it makes no sense in adding contaminants to your higher purity materials.

 

[nickvc]

My advice is to re refine all the materials before melting, If the colour varies you haven't got very pure gold to start, do the rinses as recommended and then just re dissolve your powers and filter and precipitate again, follow the rinsing techniques and see if the colour is all the same, it should look like cinnamon powder when you finish, then melt your powders!

 

[jeneje]

When washing your gold powder, do not put a time frame on the washes. boil until you don't see a color change in the solution. 30minutes may be good and then again it may take a hour. Don't rush perfection :lol: . Be careful not to boil it dry. Also don't forget the ammonia wash it will remove a lot of contaminates. When you do your ammonia wash keep the solution separate and re-acidify the solution with HCL.

Ken

 

[Anonymous]

Ken my apologies but I cannot agree entirely with your post. I've never ever boiled for anything like 30 minutes. The major colour change usually occurs close to or at initial boiling point. It's weird because even heavily copper contaminated gold changes colour almost as you watch it.

It's never taken more than an hour to wash a batch of gold even if that includes 3 washes of HCl and 3 of water. That's my experience but I'm open to be corrected sir.

Jon

 

[butcher]

I normally do not time reactions, but I normally give them plenty of time, with some processes the more time you give them the better the results, example letting silver chloride settle over night will work to prcipitate most of the silver, but a week will work much better...

 

[jeneje]

Ken my apologies but I cannot agree entirely with your post. I've never ever boiled for anything like 30 minutes. The major colour change usually occurs close to or at initial boiling point. It's weird because even heavily copper contaminated gold changes colour almost as you watch it.

It's never taken more than an hour to wash a batch of gold even if that includes 3 washes of HCl and 3 of water. That's my experience but I'm open to be corrected sir.

Jon

Jon, if you are washing your gold in less than an hour from start to finish, please explain to me your technique sir. At the min it takes me two and half hours to do my, but i am in no hurry either.

What type of dish are you using? Do you use gas or electric to heat the washes with? Do you use Ammonia in your technique? Do you decant or siphon? Do you use a sandbath to heat your wash solutions on?

I cannot do a complete wash cycle in an hour from start to finish. I apologize sir but, i am at a loss here to see how you can complete a wash cycle in an hour and have high purity clean gold. :shock:

Ken

 

[Anonymous]

Ken

Absolutely no problem at all. Firstly I guess that one of the factors that may or may not differ from some people is that I tend to be washing quantities in excess of 15g per time so I do accept that for tiny quantities I could not use this process because of the potential losses.

I do use lab glass to do all this so please assume it's used throughout Ken.

First clean is a boil in pure 35% HCl in a 1 litre pyrex beaker. An inch of liquid over the powder as a max. I also use gas because it heats quicker than a electric heat source and the glass isn't as prone to heat shock in the way that larger beakers are. I've never cracked one but it still pays to be careful in the initial heating. The small quantity of acid also lets it heat through faster than using a large volume.

This first hard boil is for a max of 5 minutes, during which the acid discolours to a lesser or greater degree depending upon how dirty the drop was. The glass then goes onto a piece of wood (no thermal shock) for a minute and this allows it to cool pretty quickly. The first boil seems to take the majority of the copper out so that even dirty gold clumps together better rather than floating around in suspension or even on the surface. Then I decant it over into another beaker taking as much of the liquid off as possible before adding a similar amount of water to the original beaker and boiling up again.

After this it really is a case of "rinse and repeat" and the point at which I stop is when the acid or water is no longer changing colour. The beaker with the pour offs WILL contain some gold. Mostly from the initial acid wash where the gold is at its dirtiest. I allow this to settle overnight and then pour the liquid into a stock pot and add the residual gold to the next batch that I am going to clean.

As far as ammonia is concerned. I have only had to use ammonia once because the vast majority of any silver (of which frankly I've seen very little when doing ceramics or fingers) has already been precipitated out as AgCl during the AR digest. Proper filtering of the AR multiple times at this point has always left me with very little (if any) remaining.

I use Steve and Harold's process here and I'm certainly not going to even try to reinvent a darned good method of cleaning when their system is spot on. All I'm altering is the mechanics of applying said procedure. There are plenty of pictures of gold I've dropped, and buttons I've melted dotted around the forum and I hope you'd agree that it does all appear to be pretty clean.

Hope that helps but please feel free to improve what I'm doing here or to disagree widly - I certainly won't mind 8)

Jon

Edited for spelling mistakes.

 

[Anonymous]

Actually Ken I had best put this in context.

I have access to the facility to refine my gear for only 2 days at a time. When my house is built and I move in during August I can build the lab that I have designed with the help of many forum members but until then I have to literally take raw material and fully process it in 48 hours. Hence necessity has been the mother of invention.

I'm sure that when I have the luxury of being able to leave things in my own lab, I will probably take a more relaxed approach 8)

 

[bswartzwelder]

I want to thank everyone for their posts. Some of the gold I will be refining came from the time I first joined the forum several years ago. As you cab see, I am patient and not in any hurry as I do not want to lose any valuables.

I want to melt once my son comes for a visit. This is usually not too often, but he has a jeweler who is a close friend. I want him to take the finished ingot to his friend for an assay and to hear from him what it's worth.

I was also wondering if it makes any sense to do a final refining using Oxalic Acid and dropping with Copperas? Some time ago, I purchased both of these as well as 2.5 liters of Nitric Acid which I believe is 68%.

I hope to have more than 1 ounce, but less than 2 ounces when finished. I still have a lot of gold plated material to process and haven't even started processing the cell phone circuit boards (five or six 5 gallon buckets). I also haven't pyrolyzed any of the chips which I have accumulated.

Thanks again,
Bert

 

[Anonymous]

Bert

Good luck with it.

Jon

 

[FrugalRefiner]

I was also wondering if it makes any sense to do a final refining using Oxalic Acid and dropping with Copperas? Some time ago, I purchased both of these as well as 2.5 liters of Nitric Acid which I believe is 68%.

Bert,

By the way you've written this part, it's a little confusing. Both oxalic acid and copperas are used to drop (reduce) gold from acid solutions. The oxalic isn't used to dissolve gold, it's used to precipitate it.

The idea of using two different reducing agents is a sound one. One agent can cause coprecipitation or drag down of unwanted base metals that another may not. They each have advantages and disadvantages. I recall a thread a while back that discussed these.

Regardless of which reducing agent you use, the best way to ensure high quality is following the thorough washing routine recommended by Harold and others.

Dave

 

[bswartzwelder]

Sorry for the confusion. You are absolutely right that both of these can be used to precipitate the gold from the solution. When I do reprocess everything, I plan to use some of the Nitric Acid I have with HCl. I have learned my lesson about overusing nitric and will add approximately half of what I calculate I need, then add the remainder a few drops at a time until all the gold is dissolved. Nothing worse than having to kill an overabundance of Nitric.

Thanks to all.

 

[Anonymous]

If you have access to Sulfamic Acid then killing extra Nitric is incredibly simple, fast, and easy.

 

[necromancer]

If you have access to Sulfamic Acid then killing extra Nitric is incredibly simple, fast, and easy.

how much sulfamic acid to kill 5ml nitric acid ??

 

[4metals]

Just a hair over 1.5 grams per milliliter of 70% nitric acid

 

[Justincase]

If you want to impress your jeweler friend I would defiantly. put every thing back into A.R. and drop again.
Then wash.
every Jeweler is a gem in him self and will on his own make your effort's worth while.
Only one local jeweler has given me the time of day but already we have established two way traffic.
One good person makes up for all the rest go for impress.

 

[Shark]

Sulfamic will foam up in nitric. Add it in small increments, it does two things this way. One, you won't use more than you need as the nitric is used up in the refining process. Two, it will help it not to foam over if you have a large excess of nitric, just give it a good stir for each addition. I dissolve the sulfamic into distilled water until it is saturated, and drop the saturated sulfamic/H2O into the solution containing nitric a spoon full at a time, give it a good stir and then decide if it needs more. Having plenty of extra space in your container holding the nitric solution helps. I tend to be extra cautious with things that have a tendency to foam up since I have only worked in smaller sized containers. I have kept the saturated sulfamic/H2O in a container for a week and still had success using it on the next project but I don't know how long it can be stored this way.