Platinum, uses

South Africa is by far the largest producer of primary (newly mined) PGMs. It suppHed 76% of the platinum used in the West in 1993, and over 50% of all PGMs. South African PGMs are mined as primary product. Other metals such as nickel, copper, and cobalt are by-products. The principal PGM mining houses in South Africa are Anglo American Platinum Corporation (Amplats), Impala Platinum, Lonrho South Africa, and Northam Platinum. 

Platinum, palladium and the normal alloys of platinum used in industry are easily workable by the normal techniques of spinning, drawing, rolling, etc. To present a chemically clean surface of platinum and its alloys after fabrication, they may be pickled in hot concentrated hydrochloric acid to remove traces of iron and other contaminants —this is important for certain catalytic and high-temperature applications. In rolling or drawing thin sections of platinum, care must be taken to ensure that no dirt or other particles are worked into the metal, as these may later be chemically or elec-trolytically removed, leaving defects in the platinum. 

The strain-free coil of pure platinum used in the resistance thermometer must meet one of the following specifications 1 (302.9146 K) > 1.11807 or 1 (234.3156 K) < 0.844235. If the resistance thermometer is to be used over the entire range 13.8033 to 1234.93 K, it must also meet the requirement that 1 (1234.93 K) > 4.2844. Temperatures 790 are calculated from the equation... 

Among the various strategies [34] used for designing enantioselective heterogeneous catalysts, the modification of metal surfaces by chiral auxiliaries (modifiers) is an attractive concept. However, only two efficient and technically relevant enantioselective processes based on this principle have been reported so far the hydrogenation of functionalized p-ketoesters and 2-alkanons with nickel catalysts modified by tartaric acid [35], and the hydrogenation of a-ketoesters on platinum using cinchona alk oids [36] as chiral modifiers (scheme 1). 

Sherikar, A. V. Phalke, P. N. Dhadke, P. M. Solvent extraction and separation studies of platinum using bis(2-ethylhexyl) hydrogen phosphate. Bull. Chem. Soc. Jpn. 1997, 70, 805-808. 

The highest demands made on the purity of the produced hydrogen are for its use in fuel cells, since even the slightest trace of carbon monoxide impedes the functioning of the precious metal catalyst in the fuel cell.10 For the platinum used in hydrogen fuel... 

British scientist William Hyde Wollaston Anticorrosive, soft metal often found combined with platinum useful in dentistry, as a cancer-fighting agent easily absorbs hydrogen and used as a purifier of that gas. 

Swedish chemist Anders Gustav Ekeberg Hard anticorrosive metal sometimes substituted for platinum used in electrolytic capacitors to power cell phones and computers. 

The salt is most conveniently prepared by the addition of ammonia to dichloro-diammino-platinum, using the salts of cyanic acid, which evolve ammonia when hydrolysed. 

Many examples of ring closures by oxidation of hydrazone derivatives have been reported. Anodic oxidation of chalcone72 phenylhydrazone (17) performed in CH3CN—LiCI04 at platinum, using controlled potential electrolysis, gave 1,3,5-triphenylpyrazole (15-40% yield) (18), 1,3,5-triphenyl-A2-pyrazoline (19), l,3,5-triphenyl-A2-pyrazolinium perchlorate, 4,4-bis[3,5-diphenyl-A2-pyrazolinyl-(l)]-biphenyl (20), the diperchlorate of 20, and 4,4 -bis-[3,5-diphenylpyrazolyl-(l)]-biphenyl (21) [Eq. (30)]. 

Fig. 13. The structure of Pt spheres changes dramatically as a function of the gas composition and temperature. Micrographs of Pt spheres in reaction mixtures, (a) After exposure to 10% NH3 in air at I350°C, the Pt sphere appears pitted, (b) Irregular crystalline structures build up on Pt sphere exposed to 10% CO in air at 1000°C. (c) Deep wavy channels form on Pt sphere used in 2% C,H8 oxidation, (d) Carbon particles deposited on platinum used in 14% C3Hg in air mixtures at 727°C (27).

Platinum price doubling leads to an increase of 9% of capital investment of the chemical plant due to platinum use in S03/S02 conversion reactor and for electrolysers. 

A gas flow techique was successfully used by Hacker et al. [66] in 1961, who studied the recombination of O atoms on quartz and platinum using ESR spectroscopy and isothermal calorimetry with mutually consistent results. However, only in the last few years has the technique been developed for the study of recombination under conditions far removed from those associated with static side arm systems. 

When samples of unknown behavior are tested, investigators will often line the bottom of the casing (under the specimen) with alumina pellets or platinum foil. This will protect the casing against accidental specimen melting. Platinum foil can be used as an interface between pushrod/specimen and speci-men/casing back in order to protect against inadvertent reaction. The expansion of the known thickness of platinum used must then be corrected for in the specimen expansion data. 

Persulphuric acid or persulphates are produced by the oxidation of sulphuric acid or sulphates at an anO de of smooth pure platinum using a high current density. Only smooth platinum can be used for the anodes because no other material displays such a high oxygen overvoltage. 

The six platinum group metals, platinum, palladium, ruthenium, osmium, rhodium, and iridium, usually occur together in nature. These metals are not often found in artifacts. These metals are rare and have only been widely used in industry and for ornaments since the early twentieth century. Most platinum used today is as a catalyst in the systems used to control car exhaust emissions, in dentistry, and to make surgical tools, jewelry, and electrical equipment. 

The steamed sample (HPst) was treated with a O.IM hydrochloric acid solution at reflux for two hours in order to remove most of the EFAL generated (sample HPs ac). All the samples were then impregnated with 0.3 wt% platinum, using a solution of hexachloroplatinic acid in a 0.2M hydrochloric acid, by complete evaporation in a rotatory evaporator, and calcined at 773 K for three hours. 

Finally, a simple empirical rule (49) was discovered to connect the resistance curve of my platinum with that of the samples of platinum used by Kamerlingh-Onnes and Clay. For if the resistances of two samples of platinum are denoted by Wj, and W2, and the resistance at o° C. is taken as i ooo as usual, then the equation,... 

The purpose of these experiments was to determine the binding mode of 6-mercaptopurineriboside to platinum using EXAFS spectroscopy. The Pt-EXAFS data presented here establish the presence of two nitrogen and two sulfur atoms at normal bonding distances from the platinum in Pt(6—mercaptopurineriboside) 2 and Pt(2-amino—6—mercaptopurine—riboside)2. For Pt(6—MPR>2 and... 

Determination on the Pt LO sample for platinum using various techniques are given in Table VI for INAA, the figure for the dried plant sample was unusually high 44 ppm Pt), and no agreement was obtained between the 158 keV peak and 208 keV peak. 

The same methodology could be applied to platinum using Pt2(dba)3 and various room-temperature ionic liquids, and led to metallic Pt nanoparticles with a mean size near 2.0-2.5 nm (Scheme 6). " The isolated Pt(0) nanoparticles could be redispersed in the ionic liquid or in acetone or else used in solventless conditions for liquid-liquid biphasic,... 

The lifetime of TPCs is much longer than pyrolytically coated or normal graphite tubes. Figure 60 shows peak shapes for vanadium and platinum using totally pyrographite cuvettes, pyrolytically coated cuvettes, and electrographite cuvettes. The TPC peak is narrower and appears earlier than the peaks of the other cuvette types. 

---