Laboratory Testing & General Mineral Processing Engineering

Laboratory Testing & General Mineral Processing Engineering 2017-03-23T09:50:31+00:00
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Simple Gold Assay Method (7 replies)

Tarun Karakoti
1 year ago
Tarun Karakoti 1 year ago

Please I want to know the methods that were being used manually to determine the quantity of gold in solution before the invention of the AAS machine.

Subhash-Kumar-Roy
1 year ago

Refer to "A Textbook of Fire Assaying", Edward E Bugbee or "The Analytical Chemistry of the Noble Metals", F.E. Beamish should be available at your local library/University.

OberstGruppen
1 year ago
OberstGruppen 1 year ago

Here was a method developed at Dome mine early last century for gold in solution. It was used to determine the amount of gold in the barren solution. I suggest you purchase EM Hamilton Cyanidation handbook. It will have the procedure for you. Note this is not a fast procedure.

Subhash-Kumar-Roy
1 year ago

Note that a Chiddy assay used to be performed to confirm AAS results (both barren & pregnant solutions) this included adsorbing the PM's from solution with lead dust &cupelling the sponge w/Ag in quarts the dore would be dissolved in HNO3 & the annealed Au sponge weighed on a Cahn electro balance.

OberstGruppen
1 year ago
OberstGruppen 1 year ago

A good reference for analysis of gold in cyanide solutions is GOLD ANALYSIS IN ALKALINE CYANIDE SOLUTIONS by SOCIETY OF MINERAL ANALYSTS. The AAS should be used for plant monitoring. The Chiddey or copper sulfate method should be used for metallurgical balance.

The precipitation analysis can use a large volume of solution that will result in ppb sensitivity using a microbalance.

Subhash-Kumar-Roy
1 year ago

All said methods need a lab; there are field colorimetric methods to determine the presence of Au in solutions a test with Sn solution referred to as 'purple of Cassius' is an indicator on the amount of soluble Au; another classic 1950's text to refer to is A.I.Vogel's Qualitative Inorganic Analyses. See http://is.gd/uYcVc3

OberstGruppen
1 year ago
OberstGruppen 1 year ago

It is correct these methods are quick indications of qualitative analysis, not quantitative. The time to do a Chiddey or copper sulfate through gravimetric finish is about 3-4 hours.

Bob Mathias
1 year ago
Bob Mathias 1 year ago

You can make a dish out of assay lead foil evaporate a weighed amount of solution in it then cupel the foil. The resulting gold bead can then be weighed. All these methods require good lab technique to obtain accurate results.

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