Does anyone stannus chloride test their heavies? If so, how reliable have your positive results been?
Reason for question is that I've been panning around a really interesting stream. Has all great indicators but I hadn't found more than a couple specs of gold. Really annoying, right?
Up to now, I haven't been a fan of stannus chloride testing of concentrates. Just too many unknowns. However, this area had me stumped, so I took a few grams of concentrates and tested them. Got a clear positive for gold.
Now, even if I smelt concentrates and extract gold, I still will not know how accurate concentrate stannus testing is. I have only one data point. If reliable, I might start testing concentrates more frequently. (Note, I'm only testing less than 10 grams of material and using a tiny amount of aqua regia per sample).
My sample preparation was as follows. Warm HCL wash followed by 2 filtered water rinses.
After preparing sample, I covered it in a bit of aqua regia. Solution was warmed to assist with dissolving sample (well, whatever happened to be dissolveable in sample). Dropped in spinner to help keep material agitated. Let test run for an hour. After an hour, I neutralized the nitric using formic acid.
I didn't dilute aqua regia or cool it before testing. Not sure if this was good, bad or indifferent.
Update: As a QC check, I decided to try dropping gold from test solution with SMB. Result was a tiny bit of gold along with some other dark precipitate that didn't readily melt under torch. Also, had a good amount (relative to sample size) of silver chloride fall out of solution. If silver prices rise dramatically, I'll be in good shape
.
Reason for question is that I've been panning around a really interesting stream. Has all great indicators but I hadn't found more than a couple specs of gold. Really annoying, right?
Up to now, I haven't been a fan of stannus chloride testing of concentrates. Just too many unknowns. However, this area had me stumped, so I took a few grams of concentrates and tested them. Got a clear positive for gold.
Now, even if I smelt concentrates and extract gold, I still will not know how accurate concentrate stannus testing is. I have only one data point. If reliable, I might start testing concentrates more frequently. (Note, I'm only testing less than 10 grams of material and using a tiny amount of aqua regia per sample).
My sample preparation was as follows. Warm HCL wash followed by 2 filtered water rinses.
After preparing sample, I covered it in a bit of aqua regia. Solution was warmed to assist with dissolving sample (well, whatever happened to be dissolveable in sample). Dropped in spinner to help keep material agitated. Let test run for an hour. After an hour, I neutralized the nitric using formic acid.
I didn't dilute aqua regia or cool it before testing. Not sure if this was good, bad or indifferent.
Update: As a QC check, I decided to try dropping gold from test solution with SMB. Result was a tiny bit of gold along with some other dark precipitate that didn't readily melt under torch. Also, had a good amount (relative to sample size) of silver chloride fall out of solution. If silver prices rise dramatically, I'll be in good shape
.
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