Platinum economic importance

The two metals platinum and palladium are of the greatest economic importance among the PGMs. The other four - rhodium, ruthenium, iridium and osmium - are obtained as by-products. 

In the case of the direct electrochemical approach, while the electrolysis conditions are less severe, the selection of the appropriate electrode material is still very important, and further reading on the use of stainless steel [93], platinum [94], graphite [95], doped Sn02 [92], doped Pb02 [86, 87, 96], and so on, is suggested. The economic viability of the electrochemical treatment approach is influenced in no small way by the cost and lifetime of the anode material this can easily make or break the field implementation of the process. Some authors have used high-surface area, porous anodes for cyanide treatment in order to combat the problems of mass-transport limitations so evident at cyanide concentrations below 100 ppm [88]. That system consists of a reticulated vitreous carbon porous anode that was activated for cyanide oxidation by the deposition of some copper oxide. The process looks very promising at the laboratory scale,... 

In analysis, glass or platinum vessels are used, but in less important operations those of other materials are more convenient and economical. 

For this reason it is of considerable importance to scrutinize the catalytic activity of platinum on the atomic scale, to learn what makes this metal so versatile as a catalyst and so selective for important catalytic transformations after suitable preparation. Once the elements of catalytic activity are revealed, it should be possible to use this metal more economically or perhaps to find ways to synthesize new catalyst systems to substitute for this excellent but rare catalyst. 

Among the second- and third-row transition metal halide complexes, those of platinum have received considerable study. Both the octahedral platinum(IV) complex PtCli and the square planar platinum(II) complex PtCl have been investigated. Both complexes are substitution inert under thermal conditions, and kinetic studies of their substitution chemistry have been important in the development of a general understanding of the mechanisms of substitution reactions in transition metal chemistry. The photochemistry of PtCli" was one of the earliest such studies to be made, and the early discoveries of the photosensitive nature of platinum halides led to these salts being used in photographic processes. The subsequent decision to use a silver-based process was based more on economical rather than on technical reasons. 

Spent honeycomb exhaust catalysts contain a relatively high concentration of the precious metal, and these can be recycled. It is certain that they will become an important and economic source of the metals as the use of automobiles continues to increase. About 15% platinum and 5% rhodium were recycled in 1990. The predicted demand for the metals to be used in autocatalysts, compared with the potentially available supplies, is shown in Table 11.12. ... 

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