Question about inquarting electrum gold

[oro-del-sur]

I want to inquart some doré which I produce from electrum. The doré is a remarkably pure natural alloy (99.9% gold/silver) having a silver content around 60%.

Does adding copper to reduce the gold content to 25% affect recovery of the silver by cementation with a copper bar?

Maybe a better option is to add more silver but it seems illogical to dissolve a bunch of silver just to turn around and get it back out of solution.

I have cemented out silver a couple of times from other solutions using a copper bar but it's a bit labor intensive, standing there for a couple hours. Is there a more practical way?

thanks in advance!

 

[kurtak]

Maybe a better option is to add more silver but it seems illogical to dissolve a bunch of silver just to turn around and get it back out of solution.

you can use ether silver or copper to inquart - but ----

It takes (about) 4 times more nitric acid (67 - 70 %) to dissolve a gram of copper compared to dissolving a gram of silver

It takes (about) 1 ml nitric to dissolve a gram of silver - so (about) 4 ml of nitric to dissolve a gram of copper

So your cost for the acid goes up 4 times for every gram of copper you add to do your inquarting

the alloy you are dealing with is already high in silver - so if you add copper - when you go to dissolve the silver & copper away from the gold - you will still have to cement the silver from the silver/copper solution - but you will need more acid to dissolve the silver/copper - compared to if you just add more silver

In other words you gain nothing by using copper instead of silver & in fact "add" cost to the process because you need more acid to dissolve the copper

Kurt

 

[nickvc]

The good thing you have on your side is that you will be self sufficient in silver fairly quickly and have an excess to sell fairly quickly and as Kurt pointed out you will save money on acids.

 

[oro-del-sur]

Those are good points although there is extra work involved in cementing out the additional silver that was added whereas the copper added is not. Which brings me to the next question...is there a more practical way to cement out the silver? I have done it only a couple of times but it took hours, holding (suspending) the copper bar in the solution then rinse and repeat. Something more automated? I'm considering doing it in batches of 500 grams (alloy weight).

 

[FrugalRefiner]

4metals described a simple solution. Cut a piece of PVC pipe a little longer than the height of your container. Drill some holes near the bottom and near the top right about at the top of the solution. Hang the copper inside the pipe. Secure an air hose at the bottom of the PVC pipe and attach it to an aquarium air pump. The air bubbling up through the pipe will constantly draw fresh solution in at the bottom that will exit at the top. The bubbles will help to knock the cemented silver loose from the copper.

Dave

 

[Shark]

Just thinking out loud here...

If the starting material was inquarted using silver, would it be easier to drop the relatively clean silver as a chloride then convert it to metal be viable? Also it would reduce the chance of copper contamination of the recovered silver, I would think, reducing the refining time required for the silver. It should also save some money on the nitric cost. The down side may well be in any extra time it would take to recover that much silver chloride. Any thoughts on that idea?

 

[oro-del-sur]

4metals described a simple solution. Cut a piece of PVC pipe a little longer than the height of your container. Drill some holes near the bottom and near the top right about at the top of the solution. Hang the copper inside the pipe. Secure an air hose at the bottom of the PVC pipe and attach it to an aquarium air pump. The air bubbling up through the pipe will constantly draw fresh solution in at the bottom that will exit at the top. The bubbles will help to knock the cemented silver loose from the copper.

Dave

Just now searching and could not find the post by 4metals although I get the basic idea...so the silver cementing out on the copper falls and collects at the bottom but doesn't redissolve? I have cemented out silver before but had to remove the bar after a few seconds and rinse off the silver in a bucket of water, or else the silver would drop to the bottom of the solution bucket and partially redissolve.

 

[oro-del-sur]

Just thinking out loud here...

If the starting material was inquarted using silver, would it be easier to drop the relatively clean silver as a chloride then convert it to metal be viable? Also it would reduce the chance of copper contamination of the recovered silver, I would think, reducing the refining time required for the silver. It should also save some money on the nitric cost. The down side may well be in any extra time it would take to recover that much silver chloride. Any thoughts on that idea?

I think cementing it out gets you closer to metal, just rinse well with hot water, dry and melt (smelt).

 

[FrugalRefiner]

Just now searching and could not find the post by 4metals although I get the basic idea...so the silver cementing out on the copper falls and collects at the bottom but doesn't redissolve? I have cemented out silver before but had to remove the bar after a few seconds and rinse off the silver in a bucket of water, or else the silver would drop to the bottom of the solution bucket and partially redissolve.

It will only redissolve as long as there is free nitric acid. Once the excess nitric is consumed, the silver will drop to the bottom and remain as solid silver cement.

Dave

 

[oro-del-sur]

I searched the library and also 4metals posts but didn't find the photos / description of the apparatus he uses. Does anyone have a link?

I used a pvc pipe and aquarium pump (airlift). The cemented silver comes off very fine and collects at the top of the tube and around the holes. Is it supposed to settle inside or outside the pvc tube? The hand method with a copper bar I used before the silver forms in clumps, like cottage cheese, easy to filer and rinse.

If I can get a working model I'll post pictures and explain.

Thanks

 

[FrugalRefiner]

Found it.

Fuzz Button Interconnects, need some advice.

Dave