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- เผยแพร่เมื่อ 2 มิ.ย. 2024
- I fire assay two very different samples of gold ore, one mostly quartz and the other high in copper and sulfides. I show the process of crushing, smelting and cupelling, and then show a method of estimating the concentration of gold in the sample.
Keywords: Gold Ore, Gold Assay, Fire Assay, Crushing Ore, Smelting Ore, Cupelling, Gold Concentration
Terimah kasi master ilmunya salam indonesia
Greetings from Los Angeles! -- Dave
Thank you for your vedios! let me know the fire assay process.
Good job. Chapman flux is good for smelting mostly gold, the manganese in the flux can make the silver stay in the slag/mat
Yes, I like the results so far as long as I dilute the Chapman's flux with sufficient additional Borax and Soda to get a good flow and add iron rebar to reduce the lead. Thanks so much for the information! Dave
nice! You might want to add some fluorspar as a thinner. Electric furnaces barely get hot enough, smelting really requires 2200-2300 deg to get water like pours. chapman flux has some oxidizers in it that will reduce some of the lead in the smelting process, you might be better off with a hand made flux. minimum 2 to 1 flux to ore, some ores require 3 or 5 to 1 flux ratios. Nails work for reducing sulfides, as there is more surface area, or even thin sheet metal works very well. Copper in the lead will pull the gold into the cupel and throw off assay result drastically, best to oxidize the copper out if you are assaying for gold/silver. Love your content by the way, keep it up - smelting and assaying often requires a lengthy learning curve.
What a great comment! Thanks so much. I can already tell that this is going to take some time to figure out. I'm glad that I smelted two very different types of ore. It was a great experience to see such a huge difference in results. Yes, the copper is a pain in the butt. I have a professional assay of sample 108 coming back in a few days. I'll make a video about that. I'm reading "Fire Assaying" by Shepard and Dietrich. What little chemistry I had has all leaked out of the vessel long ago, so it's a bit of a struggle following it. Anyway, it sure is fun to try.
@@orophilia I use lawrence hittle from colorado for my assays, super fast and low price - he just provides results for gold and silver though. Charles Butler torch assay information might be a welcome addition to your gold assaying arsenal, basically a micro torch cupel process, it works well and is fast and cheap to do. Shepard and Dietrich is a great book. I'm in santa clarita if you want to connect sometime, i have lots of ore crushing and pulverizing equipment that would save you a ton of labor and time.
@@AUMINER1 It would be great to get together. I have a cabin in the Mojave desert if you're interested in joining me sometime. I would have used Lawrence this time but I wanted a more complete analysis. I'll look into Butler's torch assay. Thanks for the tip. Cheers, Dave
@@orophiliaI am a Chemical Lab Technician - Fire Assayer. I live in Canada but would love to run some samples when the family and I head down south for winters. We have a place in Cochise AZ. I can even do samples at my house if you'd want to ship it up here or wait till we're down there. I can only run like 5 samples per day at my house. I do 400-500/day at the lab with their equipment 😅
Not sure what I can legally say about recipes. But I will tell you 100% you can use an electric furnace for both smelt, and cupellation.
Btw, not sure what you get charged per assay. But our lab is like $95 CAD per sample, been around almost 100 years helping mining industry in Canada. Mostly diamond drill cores that is dealt with. But occassionally stuff for local prospectors.
@@ProspectiveProspector I used to vacation in Sunglow, AZ and I've been in Cochise. I love that part of the world. I'd love to take you up on your offer when you're at your AZ home. Thanks so much.
Beautiful 😅
To reduce more lead you need to add something to deal with the sulfides. Potassium or Sodium nitrate works well for that, or as AU Miner pointed out, iron from a nail/
Yes, I now add iron rebar at the start of the smelt. This reduces sufficient lead to produce a perfect button. Your comments are appreciated! Dave
Put an iron rod into the crucible it helps split the Fes2 the iron woll be attracted to the rod and sulfur will float and any gold caught up inbetween will drop out with the lead. Same thing with Galena
Hi Colin. Yes, that's what I do now. Thanks! -- Dave
You need iron to reduce sulphides, iron sulphide is soluble in the flux, this can be avoided by roasting low sulphur ores but high S ore eg pyrites won’t give up hidden lattice gold without reduction, the viscosity of the pour can be thinned by making the flux more basic, this also suppresses bb formation in the slag (lost lead) for best results use sodium or potassium hydroxide, the carbonates or bicarbonates won’t fuse with the silica before becoming salts of boric acid so avoid them, my pours with copper also did the same, unfortunately the lead and copper do not alloy well use silver or more copper as the collector for ore with high copper, the copper is best electrowinned away, cupelling cu will cost too high of losses of precious metals to get accurate assays, avoid cu ore unless it’s what’s available to you, don’t mix pb and cu intentionally, the dark red copper in the slag is a signal to add iron and copper to remelt for a cu prill and 2nd shot to capture the precious metals, your close 😊
Excellent info, thanks so much! -- Dave
Bacanisimo
Hello how are you my friend can I ask a question do you have knowledge about the manufacture of crucible through ammonia oxide and materials❤
Sorry, but I don't.
Hello how is my friend a question can I write the names of materials I can't find a translation I hope you explain to me materials in mixing zero, black and eggs
Flux = 1 part Sodium Carbonate (white), 1 part Manganese Dioxide (Black), 1 part Borax (white)
Charge = 100 grams Ore + 300 grams Flux + 40 grams Litharge (orange) + 12 grams Flour (white) + Iron rod
How the unit is obtained from formula it's going to be out Mt3 /g
I'm sorry but I don't understand the question. -- Dave
It didnt go
Your cone mold is too small and you poured too slow
Hi Darrell. I agree. I need a bigger cone, higher temperature and a faster pour. I'm working on it. Thanks. -- Dave