Merril Crowe Tailings

[odin66669]

Hi to everyone in the forum, this is my first question here in fireassays:

Me and my team are reading with AA (Perkin Elmer AAnalist 200) the Merril Crowe tailings (solutions), the point is that we are having a LOT of diference in some re-readings, for example this one:

Merril Crow tailing 8:00 PM Au=0.0821g/L Ag=0.0987g/L
Reanalisis (only Au) tailing 8:00 PM Au=0.0458g/L

So, is there a way to make the tailing readings more acurate, or to concentrate them in order to be read with higher absorbance values, because a concentration of 0.04 g/L has more or less 0.002 Absorbance value wich is in the lower AA capabilities and very easily confused with noise.

Thanks in advance to any who answer my question.
Apologies if my english isn't good enough, my languaje isn't english.

Best Regards

 

[fireguy]

Hi to everyone in the forum, this is my first question here in fireassays:

Me and my team are reading with AA (Perkin Elmer AAnalist 200) the Merril Crowe tailings (solutions), the point is that we are having a LOT of diference in some re-readings, for example this one:

Merril Crow tailing 8:00 PM Au=0.0821g/L Ag=0.0987g/L
Reanalisis (only Au) tailing 8:00 PM Au=0.0458g/L

So, is there a way to make the tailing readings more acurate, or to concentrate them in order to be read with higher absorbance values, because a concentration of 0.04 g/L has more or less 0.002 Absorbance value wich is in the lower AA capabilities and very easily confused with noise.

Thanks in advance to any who answer my question.
Apologies if my english isn't good enough, my languaje isn't english.

Best Regards

Hi Odin:
Are the second readings always LOWER? What kind of solutions are these? Are these the cyanide solutions after the zinc precipitation in the Merrill-Crowe plant?

I would suspect that the difference would be caused by one of the following:
1) fine particulate particles in the solution that may be settling out over time (not the more likely reason imho)
Or, more likely
2) a difference in temperature between the two readings. This can change the viscosity of the solutions- sometimes dramatically.

That is A LOT of variation. If there is a more sensitive line, or a nebulizer with greater sensitivity I would definitely try those. More absorbance will be better.

 

[odin66669]

Thanks

I've been very busy with my work, so that's why I haven't replied.
I will try those two, thanks a lot.

 

[odin66669]

Results

This is the way we used to solve the problem, just in case that someone runs in the same problems that we did:

Reading time is set at 3 seconds per replica, with 7 replicates and 3 seconds of delay (AAnalyst 200-400).

We are using a standar of 0.1 mg/Lt to calibrate for the lower values that's matrix matched with the samples.

Samples are kept in a room at 66°F since they arrive at the assay lab.

I hope it helps someone.