The manufacture of the cupels is to me the most fascinating part.
Lou said:The manufacture of the cupels is to me the most fascinating part.
Topher_osAUrus said:You know a lot about their processes... Are you sure you're not the cool guy with sunglasses? 8)
I don't mean to sound like a jerk. I have actually been watching all of the goldrecovery65 video's, and have a couple of questions for the poster. Such as, in one video, he takes ceramic cpus and uses HNO3, HF, and H2SO4 on them.
What benefit comes from the HF? Does he experience any dissolving of the gold prematurely from that method?(as I have read that any halogens in sulfuric can and will dissolve gold, especially at elevated temperatures) why not just go straight to AR?
Are his vessels titanium ones? Surely he is losing some values when decanting through that metal strainer, its mesh size looks pretty large for fine gold wires.
I do have more questions than that, but, wasn't sure if you wanted them in this thread, or if you would like to make a new one that encompasses all of your videos.
Either way, it's very interesting to see how people across the world are recovering gold. Thank you very much for sharing. 8)
4metals said:The cupels are made from a 50:50 mix of "Ash and Calcium Hydroxide" would that be bone ash?
Lou said:Turns out there's tons of information to be had.
https://books.google.com/books?id=7TLnAAAAMAAJ&pg=PA649&lpg=PA649&dq=cupel+press+portland+cement&source=bl&ots=wJPMhlU3Dt&sig=wEmqWYkCRbSvl2_DLTLjzLP4QXo&hl=en&sa=X&ved=0ahUKEwjT2dKn3u3RAhVD1CYKHTJGCTwQ6AEIGjAA#v=onepage&q=cupel%20press%20portland%20cement&f=false
Alternative link https://archive.org/details/miningscien100unse
https://books.google.com/books?id=i_JMAAAAMAAJ&pg=PA177&lpg=PA177&dq=cupel+press+portland+cement&source=bl&ots=fKwsd93pni&sig=xjTTAMrq8YYf8ulKEYJ_3dxOj2g&hl=en&sa=X&ved=0ahUKEwjT2dKn3u3RAhVD1CYKHTJGCTwQ6AEIHDAB#v=onepage&q=cupel%20press%20portland%20cement&f=false
Alternative link https://archive.org/details/samplingandassa00smitgoog
https://books.google.com/books?id=DGXwAAAAMAAJ&pg=RA1-PA33&lpg=RA1-PA33&dq=portland+cement+cupel&source=bl&ots=jDTD-JwKMX&sig=YmjvUHvr27tpUyctvE2Vktnp9pw&hl=en&sa=X&ved=0ahUKEwjfgNaT3-3RAhXCOiYKHbAYDlAQ6AEIMTAD#v=onepage&q=portland%20cement%20cupel&f=false
Alternative link https://babel.hathitrust.org/cgi/pt?id=pst.000007232183;view=1up;seq=161 Search for cupel to get the good parts
https://books.google.com/books?id=3WgtAQAAMAAJ&pg=PA264&lpg=PA264&dq=cupel+press+portland+cement&source=bl&ots=4brlVwXmQv&sig=rtsPhaPinJLFhW_rADP4aW6Q-4w&hl=en&sa=X&ved=0ahUKEwjT2dKn3u3RAhVD1CYKHTJGCTwQ6AEIJTAD#v=onepage&q=cupel%20press%20portland%20cement&f=false
Alternative link Not found yet
I know magnesia and calcia are the best to melt platinum in. Lime you can even press into blocks and melt very large quantities of platinum in with O2/H2, al la Deville, who melted several hundred kilograms.
https://books.google.com/books?id=xriMAgAAQBAJ&pg=PA286&lpg=PA286&dq=melting+platinum+lime+block+deville&source=bl&ots=FKCJzg8azS&sig=V3A1bacUi_QSenn29BAMiLjNWtY&hl=en&sa=X&ved=0ahUKEwj6s4-z3-3RAhVMQyYKHUvvCs8Q6AEITDAN#v=onepage&q=melting%20platinum%20lime%20block%20deville&f=false
Alternative link http://www.technology.matthey.com/wp-content/uploads/ as 27 separate pdf (00-...26-)
The lime block furnace is in chapter 15.
I would like to make one such of those furnaces and do a couple kilograms (I don't even have a 100+ kg at a time to melt!)
4metals said:I was able to take 100 grams of powder ground and ball milled from this type material and using the identical flux ratio he used and end up after the fusion with a lead cone from a reasonably fluid flux, no noticeable beads were clinging to the crucible after the fusion. Which in an assay fusion are easy to see while the crucible is still red hot after the pour. I would expect a thinner flux from the addition of fluorspar which may increase the yield slightly because the flux did run thicker than I prefer but as I said I did not notice any bead left behind.
Cupellation in a standard 2" Mabor cupel yielded a 52 milligram doré bead.
I did not use lead recovered from previous fusions I just used granulated assay lead. The yield was as a doré bead which was white. It was in the range of result (actually a bit better than the video's yield) but I did not digest the bead and break it down into silver palladium and gold.
This proves the method is scalable.
patnor1011 said:Too bad that I cant locate any cupel sellers in EU. Shipping from USA is way too expensive. I would love to try some samples myself as I do have about 10 kilograms of good stuff so far and pile keeps growing. It would be nice to know what I do have there before I would have to send it somewhere to recover metals.
4metals said:The cupellation I did was at 1000 degrees C and it worked fine so at 1200ºC you should do fine. Remember the alloy is heavily influenced by the melting point of lead which is quite low.
I have drawn a sketch from memory of the furnace I used in South America to cupel large lots of mining doré. This was a no frills system which effectively cupelled the material.
removable bed cupellation.pdf
The stack rose quite high as there was no bag house or scrubber to eliminate the lead fume. I remember asking how they deal with the lead and they responded "very high" ! So I got the hint.
The tray was a cast iron tray and the bone ash mixture was pressed into the tray and shaped so there was a depression large enough to hold all of the lead alloy. They had a lot of trays and when a used one came out it was emptied and the tray was refilled with the mixture and shaped to hold the pool of molten lead. They lay out in the sun to dry for a good week before use.
When the new tray was added, the roof slab was lifted off and the furnace was charged. The tray was about 18" wide (45 cm) and 36" long (90 cm). I think it would be desirable to add a hole in the center which could be covered with a brick to facilitate looking into the muffle chamber to check progress or add more material.
This could be easily made to whatever size you need based on the size of the tray you are using for the bone ash. The trays slide in from the side and are not dropped in from the top. A stack of refractory brick seals in the burn chamber after the tray is inside.