Fire Assaying

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I still haven't found any good recipes for tabled black sands. I know " black sands " can consist of various minerals, so it is hard to nail 1 specific recipe down. The gist I get, is to just dilute the black sand down with an extra amount of fluxes, to the ratio of about 2 times the flux, by weight, as concentrates, as you would if assaying a standard high pyrite by weight ore sample. Adjusted for the oxidizing magnetite. Anybody out there know of a good black sand flux ?
 
Chapman's Flux is very common. Premixes are available if you can't make your own from a valid formula. If your flux is to contain borax, be sure to use anhydrous borax. It will run faster and with less foaming and bumping. I use oxalic acid mixed with anhydrous borax and pulverized anhydrous silicon for highly metallic black sands. The ratio is adjustable in relation to the non-precious metal content of the sand. Be sure to roast, pulverize, and classify first. A Miller Table helps recover PM fines and separately recover the sulfides.
 
I don't want to buy Chapman's, I use too much of their product. Besides I want to know more specifically what I am doing, so want to start from scratch. Any base line formulation recommendations? I can figure it on my own with a couple of preliminary fires, but was wondering if I could use the forum to streamline a little more.
 
This document does provide a variety of fluxes including Hematite and Magnetite ores, hope it helps....
 

Attachments

  • A Manual on fire Assaying and Determination of Noble Metals.pdf
    9.7 MB · Views: 29
Here is what comes up when I open the attachment;

<</Linearized 1/L 10128851/0 574/E 37130/N 66/T 101117830/H [656 872]>>

One of about 15 similar lines, not relative to a manual on fire assaying. Tried it twice, still a no go.
 
Here is what comes up when I open the attachment;

<</Linearized 1/L 10128851/0 574/E 37130/N 66/T 101117830/H [656 872]>>

One of about 15 similar lines, not relative to a manual on fire assaying. Tried it twice, still a no go.
Try downloading the pdf file and open it locally on your device.

Edit for spelling
 
Last edited:
Sand, borax, and lime. That works well on black sands.

1:1:1 and add more silica as req'd.
I used this and stuck with it for many years - have tried other experiments, products and mixes - but always come back here just for one reason or another.
 
I didn't see a note for collector metal. Non used? I wasn't sure if you were using the elevated temperature method ( 2500 F.) using the converted Fe for collector metal, as suggested in the patent on using this process. Sorry, can't find the recent thread/post. Last couple of days.
 
I did, that is what comes up when I do it.
The file is a PDF, so it won't open correctly in a text editor.
1.) The file name should end in ".pdf".
2.) If double clicking doesn't open it correctly, try opening it in a web browser (browsers have file auto-detection).
Send me a private message if you still have trouble.
 
The file is a PDF, so it won't open correctly in a text editor.
1.) The file name should end in ".pdf".
2.) If double clicking doesn't open it correctly, try opening it in a web browser (browsers have file auto-detection).
Send me a private message if you still have trouble.
Stupid me :rolleyes:
I never asked what program he tried opening it with.
Thanks for pointing out the most likely error.
Personally whenever things do not open correctly, I run it through a Hex editor\wiever to see the file type it is.

Edit for better language.
 
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