itsmeadam95
Member
hope You are doing good !! What is the best tool for heating or evaporating chemical solutions?
I would have loved to have one, I have so far never found any Pyroceram vessels.Most members use corning ware to put the beaker in on an electric hot plate.
You can put a sand layer in to protect the glass beaker from the heat.
https://goldrefiningforum.com/threads/corning-ware-a-guide-of-whats-what.23620/#post-249217There are also electric heating mantels for round bottom flasks.
Except that as refiners we can not always plan on ending up with solutions that don't need evaporation & in fact can often find ourselves in situations where we have to plan for evaporation simply because we find ourselves in situations where we have to do A LOT of washing to get the values washed out of the materials we are leaching which results in VERY diluted solutions & as we know VERY diluted solutions can/will result in ULTRA fine precipitation of our target PM metals which in turn can result in settling &/or filtering problems &/or washing problems of the PM precipitate --- so we are better served to evaporate before dropping our PMs from solutionAnd not lastly, plan your operations in a way that you does not need to evaporate the solution, as it is apart from hassle with the very nature of this operation also extremely energy consuming.
I simply cannot use evaporation because I do not have time nor means how to do it in place where I work with PM recovery. This led me to develop techniques, which completely avoid evaporation. And where it cannot be eliminated, I need to be rather distilling off the liquid, otherwise I would wreck the fume hood and fan, which are not desined to deal with large quantity of corrosive wet HCL fumes etc.Except that as refiners we can not always plan on ending up with solutions that don't need evaporation & in fact can often find ourselves in situations where we have to plan for evaporation simply because we find ourselves in situations where we have to do A LOT of washing to get the values washed out of the materials we are leaching which results in VERY diluted solutions & as we know VERY diluted solutions can/will result in ULTRA fine precipitation of our target PM metals which in turn can result in settling &/or filtering problems &/or washing problems of the PM precipitate --- so we are better served to evaporate before dropping our PMs from solution
Examples -----------
1) washing the electrolyte out of the silver crystals from your silver cell - the electrolyte is quite dilute to start with & so should actually be evaporated before cementing the silver out of it or the silver cement will come down VERY fine (this is just the first decant of the electrolyte) then you still need to wash the electrolyte tied up in the crystals out - this takes multiple washings to insure all the silver nitrate is washed out before drying the crystals - (testing a sample of each wash with HCL until no AgCl cloud forms) this results in a VERY diluted silver nitrate solution that NEEDS evaporation before recovery of the silver from the electrolyte & wash
2) IC chip ash (even as concentrates) requires A LOT of washing to insure all the values are washed out so again ending up with a very diluted solution (stannous testing of each wash) that needs evaporation before recovery of the values from the solution
This is especially true if you are processing BGA chips where the green fiber part can't be separated from the black epoxy part of the chip - that is because of the fiberglass sheet in the green fiber part of the chip which turns to fine fiberglass hairs/fluff that will tie up & hold bond wires after milling & sifting & as well there is gold plating involved in these chips so you can't really do a proper concentration wash on these type chips (without losing gold) so if you are after all the gold in these type chips you really need to leach the whole of the ash/fiber after incineration & milling - meaning A LOT more washing to get the values out of the leached ash/fiber so VERY diluted solutions that needs evaporation --- for what it is worth that is why these type BGA should ALWAYS be processed completely separate from other type chips --- if you try to process them together with other chips the glass fiber/fluff will cause lost gold when running the milled ash on a concentrator table
3) Leaching MLCCs - I posted about that yesterday in the "Processing MLCCs" thread ----------
I said -----
IF (the BIG IF) you are going to leach MLCCs
The reason I posted that in bold print is that IMO (In My Opinion) leaching MLCCs - even in small batches is one of the worst ways to go about recovering the Ag & Pd from MLCCs for a number of reasons
1) during the leaching - the ceramic breaks down into an ULTRA fine mud - like clay which is impossible to filter --- so you have to let the ceramic mud settle then decant the leach - then wash with water - let settle & decant again AND you have to do that multiple times AND it is next to impossible to get all the Ag/Pd washed out - at the very best at least traces of Ag/Pd will stay tied up in the ceramic mud
2) So you will end up with a LOT of VERY diluted Ag/Pd solution which you will then want to evaporate back down - otherwise when you go to drop the Ag as AgCl - the AgCl will come down ULTRA fine - so fine it will likely cause washing/filtering problems when you go to wash the still dissolved Pd out of the AgCl
3) washing the Pd out of the AgCl presents the same problem as washing the Ag/Pd out of the ceramic mud - it takes a LOT of washing to get all the Pd washed out resulting in a VERY diluted solution again (if you are not set up to vacuum filter --- vacuum filtering does NOT work on the ceramic mud - but will on the AgCl)
Added note; - due to the amount of washing required - to get ALL the values out of leaching MLCCs - you will more then likely not only have to evaporate after washing the Ag/Pd out of the original leach - but evaporate again after washing the Pd out of the AgCl
So as much as I agree that avoiding the need for evaporation in the first place is good advice - there are situations where evaporation becomes necessary
Kurt
Per the bold print - I completely agree with you on this one Orvi - smelting of the above materials (& so much more) really is the way to go IMOSo for IC chips ashes, I never leach them, I smelt them down. Too much hassle with decantation and filtration, time consuming and for me not worth the spent time.
MLCCs - I smelt them directly, too. All hydrometallurgy treatment of MLCCs lead to culprits along the way, so I invested in time and equipment before I started facing these problems, and completely obviated this by using induction furnance and pyrometallurgy.
I only add to the "corrosive enviroment" issue.I would always advise you to buy a good quality secondhand Laboratory hotplate.
I know you can find low-quality cheap two and one-ring heaters meant for Hotel rooms and other domestic appliances.
But they will simply not hold up to the rigor involved with highly corrosive environments.
For just a few quid more you can invest in a unit that will serve you for years.
So anything less is a false economy.
Evaporation and reductions are an intrinsic part of our processes.
People always try and bend the real world to their needs. which is not always appropriate or prudent.
https://www.ebay.com/itm/3245955672...3g/1Fg=|tkp:Bk9SR4zilZmOYQ&LH_ItemCondition=4
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