chloroauric acid

[butcher]

teddy garcia,

If testing were showing negative results I would not try and spend time getting nothing.

Also you need to make sure your testing procedure works, did you use a Known standard to test your testing solution's.
Was there free oxidizer or some other cause in condition of your acid solution that would make the test method not work, or like other metals in solution masking the color of the reaction?

Is this the best or only way to test for values in this ore, or would a fire assay be a better choice?

Was the ore roasted and sulfide converted before leaching the ore?

Did your leach only leach out the Iron and leave the values if any behind, that is if the ore had values to begin with?

Before trying to precipitate any thing else from this solution, I would try a different test on it, take a small sample and (make sure the excess oxidizer is removed from the sample) use a spot plate or white plastic spoon, add a few drops of the solution, put a crystal of ferrous sulfate in it, see if there is a brown ring around crystal (gold), after this reacts, take an eye dropper and remove the liquid on the outside from this brown ring (more clear solution from this spot plate), put this drop of liquid on Q-tip or filter paper and retest this drop with stannous chloride, to see if you may by chance have some kind of PGM.

If negative, I would consider not wasting more time trying to get something from nothing.
Look into maybe a fire assay of the ore, or some other test to determine if it has value, if it does show positive for value you may also have to experiment to find a leach process that works to get the values out.

The color of the solution does look very interesting and looks like it may contain values, but looks can be very deceiving.

 

[teddy garcia]

thank you very much for the much needed advices butcher, fire assays cost much here maybe around $140 for the test, by following your advice i guess i will have more confirmation, i knew nothing about the content of the clay ore, but i had a preminilary washing of the sample by dilluting it with HCL and applying medium heat on a hot plate for 10 to 15 minutes i suppose and decanting the HCL before digesting it in a new AR solution.

usually experience refiners like you and a lot more in this forum had a reliable and trained eye by looking at a stannous test color and by looking at the solution. it might not be a hundred percent but i trust your personal opinions.

best regards

 

[butcher]

Teddy Garcia,
Sometimes tests can be hard to judge, or then other times there is no doubt, sometimes something may interfere with the tests.

You should be able to do your own fire assay, it takes just a little study, to make the flux, you can use a collector metal like lead, melt, pour into cone mold, break off slag glass, then cupel lead button, and use acids to part the metals, your home assay may not be as accurate as one done by a professional, but it can be good enough to tell you if this ore is worth working on.



A simple test in the field for gold in sulfide ore:
Any gold sulfide ore may be dissolved by fusion with a pinch of powdered mineral, in a surplus mix of one part ammonium chloride and 2.5 parts of ammonium nitrate,
The melted fusion is cooled, then dissolved in a few drops of HCl hydrochloric acid, putting a drop of this solution on filter paper, and a drop of stannous chloride added, a red to violet color indicates presence of gold
This will not tell you how much is present, but can be an indicator of the presence of gold.

 

[teddy garcia]

thank you very much for your words of advices butcher,........... can iron sulfite in an ore ( excessive ) hamper any detection from stannous testing? and can hamper dropping of the values? ...........i would like to know what is the color of an iron sulfite once digested in aqua regia as the case maybe,
is there a way to get rid of the sulfites before proceeding to aqua regia so the ore is free from hindrances to be check by stannous and precipitate?

best regards !

 

[butcher]

Iron sulfites do not break down in acids easily, sometimes there may be gold locked up in the structure of iron sulfides, leaching without converting the sulfides (by roasting) will not leach this bound up gold, but free gold in the ore can be leached.

Grinding to powder and roasting to red hot holding heat an hour or more will break down, the iron sulfide will drive off SO2 sulfur dioxide gas, caution some ore has arsenic and other deadly fumes.

Leaching ore with iron sulfide I really do not believe would interfere with the stannous test for gold.

A big problem with leaching gold from ore when using non selective leach is the ore can contain metals, that use up the leach, and cement or precipitate the values from the leach solution, so concentrating values is important, by some means, floatation, panning or other gravity mechanical means, and pre-leaching of base metals from values.

Ore can be very complex and its chemistry can work against the chemistry of the leach.

Before wasting time and acids, you should determine the value of the ore if any (assay, and knowing its chemistry or what it is composed of can also help in determining what methods may or may not work.

I only play with ore a little as a hobby, and really know very little about it, and I always want to learn more, but what I have learned is it can be very complicated to work with.