# red solution



## arthur kierski (May 26, 2008)

dear friends,i might be boring you but i have to make the questions:friday i precipitated 5,9grams of a black powder from a. ar solution with iron powder .to eliminate base metals in this 5,9grams(specially lead) i left the pwder in a pure hcl solution(no water) and today to continue i filtated the hcl solution---the 5,9 grams became 2,56 grams and the solution was red----did the stanous chloride test and indicated palladium----to the red solution i put nh4oh and it become blue---and a lead ppt was formed---i filtrated the blue solution and added hcl and beautifull yellow palladium salt was formed which i made with hidrazine 1,39grams of pd---obviously that there is more pd and rh and pt in the 2,56grams which i will extract tomorow---my question is does pure hcl(dissolves pd??is the ppt from the red solution just lead or might have other pgm metals??? thanks in advance------------------------------
the problem is that i wanted to precipitate each metal individually and pd is coming out with hcl and will come out more tomorrow whem i put the powder in a hno3 solution


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## lazersteve (May 26, 2008)

Arthur,

HCl will slightly attack Pd. In the finely divided state this may occur more readily. I would venture to say you may have had some Pd oxide or the solution may have contained free chlorine or some other oxidizer that formed free chlorine with the HCl.

I'm more concerned with why you are rapidly losing mass. You started out with 5.9 grams and now you have 2.56 g after HCl treatment. It's hard for me to believe you had that many impurities in your PGM powder unless you used an extreme excess of iron to drop the PGMs.

Another thing that's odd is your Pd yield. 

5.9g - 2.56g = 3.34 g

Yet you only obtained 1.39 g of Pd? Where did all the mass (1.95g) go? What color is the solution now that you have filtered out the yellow Pd powder? Does it test positive to stannous chloride? The precipitate may be your missing weight. I can't imagine that you have that much lead in so little PGMs. You should do some more tests on the precipitate (dissolve in HCl and test with stannous).

If you added an extremely large amount of Fe (for precipitating the PGMs) that may explain the discrepancy in mass.

Steve


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## arthur kierski (May 26, 2008)

steve,thanks for the quick reply.i used a lot of iron powder to precipitate the pgms but as i always do ,i used a 20% h2so4 solution to dissolve the excees iron used and after drying the pgm which yealded 5,9grams i simply pulverized it and left for the weekend in 50cc hcl----the liquid from hcl leach(after the yellow powder ppt ) is str ongly green and i did not do the test with stanous yet.the precipitate from ammonia added to leave pd in solution will be tomorrow dissolved in hcl and make the test for pgm(hoping the missing mass is there)-----after doing this i will mantain you informed of the results ----funny it is the second time that i have pd directly---once the yellow powder and now the red solution


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