stannous chloride test

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Lighean

Member
Joined
Feb 4, 2014
Messages
6
I have a weird result on a stannous chloride test and i don't know what the precipitate is.
I am testing ores for PGM and on one sample I am getting a precipitate. The procedure is as follows:
I pan out the pyrites, heavies from the crushed ore and I warm it up to red to burn out the sulfur, after that I leach it with HCl + H2O2.
The result of the test for this sample was a orange spot on the q-tip (it is not uniform around the q-tip).
I repeated the test, this time I only boil the minerals in HCl and did the test on the solution and I get the same result. I put some of the solution in a evaporating dish added stannous chloride until the colour became white or pale green, I warm it up and it becomes black, I let it to settle and there is a very fine black/brown powder that in time, settles. I took a part and add some HCl, but it did not dissolve until I added few drops of H2O2. After that I tested it with stannous and it become white, even if I warm it up, no change. By the way, why all the solution without PGM that I test on q-tips with stannous becomes white few minutes after I test and on the spotting plate transparent or pale green , why the colour changes to transparent/white?
I think my stannous solution is good, I get instant result when I test on known solution.
I attach the picture with regular sample (no PGM) in the left side and this on the right. I know this sample is no PGM, because with my standards, if I do the same, the colour for PGM show up again, but what is it?
 

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If it's liquid, send 3-5 mL out for ICP. I have a lab that is good and reasonable if you want to PM me.
 
Thank you Lou.
I sent some crushed rock to Activation labs. The problem with this guys is that you have to wait at least 3 weeks to get the result after they received it.
I can imagine a scenario where Pt from pyrites promotes formation of SO3 when I burn it and when I add HCl forms a mixture of HCl and H2SO4. I am not familiar with stannous signals when H2SO4 is present in the mix.
 
hey guys. i dissolve some PGMs in aqua reigia, now i want check the solution for pgms. this is mathod i use to process honeycombs, these honeycombs are mixed ceramic and metalic. crush them. give 3 baths with aqua reigia and heat it. and combine the solution. now solution looks like as i upload a pic. later on i check with stannous. but it gives no color change, that may be mixed pgm solution can not be tested for every pgm with stannous. so how i can chek this solution for Au, Pt, Pd
 

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