Platinum world reserves

Other than monetary costs, one must also take into account the availability of raw materials needed for fuel-cell production. Assuming a total platinum content in both electrodes of 0.8 mg/cm and an optimistic value of 1 W/cm for the specific power, then one will need 0.8 g platinum/kW. With a price of platinum of 30 /g, this gives 24 /kW. Therefore, an electric car with a power of 50 kW would have a price tag of 1200 for only the platinum in the fuel cells. It must of course be taken into account here that with a production volume of 1 million electric cars per year, 40 tons of platinum metal were needed, representing about 20% of current world production. An even more difficult situation would arise in the mass production of fuel cells with mixed platinum-ruthenium catalysts. World reserves of ruthenium are very limited and would not admit mass production on such a scale. For this reason, it will be one of the prime tasks in further fuel-cell development to broadly search for ways to lower the platinum metal content of the catalytic layer and to find new nonplatinum catalysts. 

Total known world resources of platinum-group metals have been variously estimated as between 68,000 (7) and 96,000 metric tons (8). Assuming the former estimate and 1979 levels of demand, these reserves should be sufficient to supply the Western world weU into the twenty-fourth century. Reserves and relative proportions of the PGMs in the larger deposits are given in Tables 5 and 6. Relative amounts of the PGMs vary from deposit to deposit. 

More than 200 ores are known to contain cobalt but only a few are of commercial value. The more important are arsenides and sulfides such as smaltite, C0AS2, cobaltite (or cobalt glance), CoAsS, and linnaeite, C03S4. These are invariably associated with nickel, and often also with copper and lead, and it is usually obtained as a byproduct or coproduct in the recovery of these metals. The world s major sources of cobalt are the African continent and Canada with smaller reserves in Australia and the former USSR. All the platinum metals are generally associated with each other and rhodium and iridium therefore occur wherever the other platinum metals are found. However, the relative proportions of the individual metals are by no means constant and the more important sources of rhodium are the nickel-copper-sulfide ores found in South Africa and in Sudbury, Canada, which contain about 0.1% Rh. Iridium is usually obtained from native osmiridium (Ir 50%) or iridiosmium (Ir 70%) found chiefiy in Alaska as well as South Africa. 

Ninety-eight per cent of the world s supply of platinum metals comes from three countries — the former Soviet Union (49%), the Republic of South Africa (43%), and Canada (6%). Because of the different proportions of Pt and Pd in their deposits, the Republic of South Africa is the major source of Pt and the former USSR of Pd. Only in the RSA (where the Bushveld complex contains over 70% of the world s reserves of the platinum metals at concentrations of 8-9 grams per tonne) are the... 

Palladium occurs in combination with platinum and is the second most abundant platinum group metal (pgm), accounting for 38% of pgm reserves. The USSR produces over 50% of the world s palladium, which is more than double that produced in South Africa. Two major sources of the metal are braggite, a mixed sulfide of platinum, palladium and nickel, which contains 16-20% palladium, and michenerite (PdBi3). 

The platinum-group metals (Ru, Os, Rh, Ir, Pd and Pt) are rare (Figure 23.1) and expensive, and occur together either native or in sulfide ores of Cu and Ni. Three sites of mineral deposits in the former Soviet Union, Canada and South Africa hold the world s reserves. The main source of ruthenium is from wastes from Ni refining, e.g. from pentlandite, (Fe,Ni)S. Osmium and iridium occur in osmiridium, a native alloy with variable composition 15-40% osmium and 80-50% iridium. Rhodium occurs in native platinum and in pyrrhotite ores (Fei S, n = 0-0.2, often with <5% Ni). Native platinum is of variable composition but may contain as much as 86% Pt, other... 

In the early stages of platinum s discovery South America and especially today s Colombia and Equador had the world s largest known platinum reserves, but this is not the situation today. Active prospecting has revealed new deposits that have deprived South America of its leading position. This has now been taken over by South Africa, where platinum was discovered in 1924 and which nowadays controls more than 85% of the world s platinum reserves. An estimate of the reserves in different countries is given in Table 32.2. 

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