Attack of refractory platiniferous materials by acid mixtures at elevated temperatures

Abstract

Iridium and other refractory metals and a ll oys of the platinum group can be easily prepared for analysis, or for small-scale refin ing, by solu tion with hydrochloric acid and suitable oxidants in sealed tubes at temperatures up to 300 0 C . The effects on the rate of solution of iri d ium caused by variations in temperature. in concentrations of hydrochloric acid and of the oxidant, and in the nature of the oxidant, a re reported . The rate increases rapidly with increa e in temperature. It also increases with increasing concentration of hydrochloric acid, up to nearly anhydrous hydrogen chloride. With variation in the concentration of chlorine or equivalent oxidants, the rate passes through a maximum at a relatively low concentration.

Low-blank digestion of geological samples for platinum-group element analysis using a modified Carius Tube design

“…Once closed, the Carius Tubes must be handled with extreme care since they pose the risk of explosion from the buildup of internal pressure. The reader is referred to previous publications for proper handling procedures [11,[14][15][16].…”

Inductively coupled plasma-atomic emission spectrometry (ICP-AES) in support of nuclear waste management. [HHDECMP (hexyl hexyl-N,N diethylcarbamolymethylphosphonate) and n-octyl(phenyl)-N,N diisobutylcarbamoylmethylphosphine oxide]

“…Standards for Pd, Rh, and Ru were prepared by the sealed tube dissolution [11] of spectrographically characterized high-purity metals and appropriate dilution into mixed working standards.…”

Determination of platinum, iridium, and rhodium in uranium alloys by atomic- absorption spectrophotometry

“…from the closed end. Proceed with the dissolution as described by Wichers 5 or by Metz and Waterbury. 6 4.…”