Cupelling help

[goldshark]

A couple of things bother me about Jason's techniques. 1. he doesn't show any base line for wether the ore is basic , or acidic. Other then they are concentrates off his shaker table. Usually a quartz concentrate, since Gold is only associated with quartz. Not too bad showing on pyrite cons assay/smelting 2. he never explains, very well, the reason he uses lead, instead of PbO ( Litharge, assay grade ), wether he is producing a mono, bi, etc., silicate flux. Hire a chemist to explain the difference, in layman's terms A couple more minor grievances, but I will not nit pick too much. He's better then anyone else out there, but then again, I haven't seen any other youtube videos touting our industry. Maybe trade secrets keep is out of the main stream? A shout out to Jason, thanks, fun to learn from you. Also a huge shout out thanks to , is it sreetips, or streetips, seen it both ways. Nothing to complain about with your youtube videos, yet.

MBMMLLC has perfect videos about pyrometallurgy on youtube. Watch them out, you will visually learn a lot about cupelling and smelting.

If I were you, I will try to take like 10g of lead and do a "blank" cupellation - to elucidate wheather the feed is causing problems, or you just do not have equipment/temps/oxygen right.

A very good idea.

 

[SRM]

Here are some photos of an old school (100 years + ) commercial assay furnace, located in Leadville, Colorado. Note that the lower muffle lining is gone, but the upper cupeling liner is still intact. This was a coal fired furnace. The walls are over 1' thick. Red hard fired brick on the outside, then fire brick, then another layer of some kind of refractory insulating brick. These were used on a daily basis for firing 100's of assays per day. I bet not many still have one of these around. I wanted to build one, but DFC no longer stocks the muffle linings. Cheers to the old school.

Actually, I think most ran on charcoal from the nearby kilns. I spent a few decades there working in mines and even at the mining museum. There are, or were, some remnants of other furnaces scattered around the mining district.

 

[goldshark]

Good point. I wasn't there when they were in operation. Would have loved to see the Arkansas Valley Smelter in operation in it's hay days. Talk about contamination! I don't know if you ever knew W.H. Smith. He did assaying for me back in the 80's. His furnace and office has been preserved very nicely.

 

[goldshark]

Ben2363, download this book: "A Textbook of Fire Assaying" by Edward E. Bugbee. Everything you need to know is in there. https://ia800308.us.archive.org/35/items/textbookoffireas00bugbrich/textbookoffireas00bugbrich.pdf

Hey Peterm, can you put the book in the "Books" section of the forum, please. I searched the whole book collection, and only found a minor reference to assaying. Headline the thread with "Text book of Fire Assaying" so it is easy to find. Thanks in advance.

 

[Tomcat]

Have similar problem. Lead stays in a pool then cools to a the same size. Im using Portland cement. Do you have to make a cupel from paste or can you just use the Portland in a dish? They call it refractory cement sometimes. Pre-heating it helps? I dont have a temp gage but with a torch from a propane tank how long should it take? Or is it best to put it in the kiln and put the top on? They say the 02 flow is critical so i thought a lid would not be best.

 

[Yggdrasil]

Have similar problem. Lead stays in a pool then cools to a the same size. Im using Portland cement. Do you have to make a cupel from paste or can you just use the Portland in a dish? They call it refractory cement sometimes. Pre-heating it helps? I dont have a temp gage but with a torch from a propane tank how long should it take? Or is it best to put it in the kiln and put the top on? They say the 02 flow is critical so i thought a lid would not be best.

What post are you commenting?
There are 3 pages here.

 

[Shark]

If you mix water with cement you get a concrete like substance that won’t adsorb much of anything. Pack it to shape dry by force to use it as a cupel.

Make sure you use Portland cement. Not concrete or other types of cement. The formulas can be way different depending on the particular use it is intended for.

 

[Shark]

Have similar problem. Lead stays in a pool then cools to a the same size. Im using Portland cement. Do you have to make a cupel from paste or can you just use the Portland in a dish? They call it refractory cement sometimes. Pre-heating it helps? I dont have a temp gage but with a torch from a propane tank how long should it take? Or is it best to put it in the kiln and put the top on? They say the 02 flow is critical so i thought a lid would not be best.

Here is a very quick video on how to make a cupel from Portland Cement. He has several other videos with a better explanation if needed. Using a torch with an oxygen tank is needed, and operate it with a very oxygen rich flame.



Edited several times for grammar and spelling.