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Collecting isotopic thallium metal on Pt cathode from Tl2SO4 solution

2007

I would like to tap into the great wealth of knowledge and expertise here to find a way to quantitatively collect thallium metal from a saturated or near saturated aqueous thallous sulphate solution onto a platinum cathode that would be easy to remove the thallium metal. I work at a national lab and have several pounds of isotopic thallium 203 and 205 oxide. I can not obtain consistent quantitative results using zinc powder (or a shiny zinc plate) to get thallium metal to form. I can not start processing the isotopic material until I can work out a procedure with the much cheaper natural (non-isotopic) thallium. The isotopic material wasmagnetically enriched and is very costly. I have also tried aluminum as a reductant, also to no avail. I am aware that using hydrogen sulfide as a precipitator would yield quantitative results, but I have to avoid using this or any process that would generate hydrogen sulfide as a by product, so I thought electrolysis might be the answer, but have no experience nor can I find much information on thallium salt electrolysis. This thallium oxide material also contains trace amounts of copper and iron, but I am not concerned with this. What would be an optimum solution pH (of the thallium sulphate), voltage/current etc, to begin with? Thanks very much,
Sincerely,

Gary L. Lynch
Development Engineer - Powder Springs, Tennessee USA

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It's not something I actually know about, Gary, but a lit search shows "Electrodeposition of Thallium Powder from Sulphate Baths"( El-Halim A M A; Khalil R M; Surface Technology, 1984, vol. 23, p. 215-223) and "Electrodeposition of Thallium from Sulphamate Solution" (Surface & Coatings Technology, Johal C P S; Gabe D R; Eastham D R; 1988, vol. 35, p. 181-194 ).

If you can't get these online from a database service, hard copy might be available from http://finpubs-dwh.demonweb.co.uk/ as they have abstracted it. Otherwise, D R Gabe is a well known electrochemical researcher who you may be able to reach at www.lboro.ac.uk/departments/iptme/staff/academics/drg/index.html. Good luck.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
2007