Summary for rhodium analysis Discussion
Rhodium analysis is the focus of this thread, with Gerald A. Smith Jr. asking for a very accurate way to measure Rh in plating chemistries and precious-metal refining solutions. He recalls an older gravimetric method attributed to Dr. D.G. Foulke of Sel-Rex/OMI/Enthone, in which rhodium was reduced from sulfate solution with hydrazine sulfate or oxalic acid, then fired under hydrogen and weighed as metal. Brian Terry advises that AA can be improved by using matrix-matched standards because plating solutions can suppress or enhance readings. Terry Tomt says dissolved rhodium should be measurable by ICP if the concentration is suitable, and recommends the method of standard additions to address matrix-matching problems. A later question from Manikandan asks how to analyze rhodium in anode slime at 1–5 ppm, but no procedure is given in the excerpt. Overall, the discussion favors ICP or AA with careful matrix control over relying on inconsistent fire assay results.
2007
Hi
My company is a manufacture of Electroplating chemistries and a Precious Metal Refiner. We are a member of the AESF and subscribe to
Metal Finishing.
With the ever-increasing price of Rhodium we are looking for a very accurate method of Rhodium Analysis…Years ago before AA and ICP we used a method developed by Dr. D.G. Foulke who was a research chemist for Sel-Rex, OMI, (now Enthone).
The process was to reduce the Rhodium from a sulphate solution using hydrazine sulphate or oxalic acid..can’t remember which. and fire the percipate under hydrogen in a crucible and weigh the Rh as metal..Do you have any information on this analysis? or a method to do Rh by ICP or AA. We find all the instrumentation results to be high..Fire assy, even by the best umpires are not consistent..
Best Regards
Jerry Smith
Gerald A Smith Jr
– Seminole, Florida
Gerald,
Have you tried using matrix matched standards for AA? Many components of a treatment system can have an effect on the overall reading you obtain (either supression or enhancement) so if you are using a complex mixture (as many plating solutions are) then it is advisable to matrix match standards.
Brian Terry
Aerospace – Yeovil, Somerset, UK
2007
2007
Jerry –
You should be able to analyze dissolved Rhodium by ICP depending on how low you feel the concentration might be.
As far as accuracy is concerned – if you run the method of standard additions that should help you with matrix matching problems.
Terry
Terry Tomt
– Auburn, Washington
Q. dear sir,
How to analyse rhodium in anode slime samples? In anode slime its range should be 1-5 ppm (I don’t know but I guess).
Please tell me correct procedure to analyse Rh in slime samples.
Manikandan
– Tuticorin, Tamilnadu, India
August 30, 2012