Platinum ores

Gr. rhodon, rose) Wollaston discovered rhodium in 1803-4 in crude platinum ore he presumably obtained from South America. 

L. Rhenus, Rhine) Discovery of rhenium is generally attributed to Noddack, Tacke, and Berg, who announced in 1925 they had detected the element in platinum ore and columbite. They also found the element in gadolinite and molybdenite. By working up 660 kg of molybdenite in 1928 they were able to extract 1 g of rhenium. 

At the start of the nineteenth century, platinum was refined in a scientific manner by William Hyde WoUaston, resulting in the successful production of malleable platinum on a commercial scale. During the course of the analytical work, WoUaston discovered paUadium, rhodium, indium, and osmium. Ruthenium was not discovered until 1844, when work was conducted on the composition of platinum ores from the Ural Mountains. 

Palladium and platinum are the longest known and most studied of the six platinum metals [1-11], a reflection of their abundance and consequent availability. Platinum occurs naturally as the element, generally with small amounts of the other platinum metals. It was used as a silver substitute by Colombian Indians and first observed there by Ulloa (1736), who called it platina del Pinto ( little silver of the Pinto river ) but the first sample was actually brought to Europe in 1741 by Charles Wood, Assay Master of Jamaica. Palladium was isolated in 1803 by W.H. Wollaston, who was studying the aqua regia-soluble portion of platinum ores (he announced his discovery by an anonymous leaflet advertising its sale through a shop in Soho) and named it after the newly discovered asteroid Pallas [12],... 

Iridium - the atomic number is 77 and the chemical symbol is Ir. The name derives from the Latin Iris, the greek goddess of rainbows because of the variety of colors in the element s salt solutions . Iridium and osmium were both discovered in a crude platinum ore in 1803 by the English chemist Smithson Tennant. Iridium was discovered independently by the French chemist H. V. Collet-Descotils also in 1803. Descotils actually published one month before Tennant but Tennent is given credit for the discovery, perhaps because he alone also found osmium in the ore. 

Osmium - the atomic number is 76 and the chemical symbol is Os. The name derives from the Greek osme for smell because of the sharp odor of the volatile oxide. Both osmium and iridium were discovered simultaneously in a crude platinum ore by the English chemist Smithson Tennant in 1803. 

Ruthenium - the atomic number is 44 and the chemcial symbol is Ru. The name derives from the Latin ruthenia for the old name of Russia . It was discovered in a crude platinum ore by the Russian chemist Gottfried Wilhelm Osann in 1828. Osann thought that he had found three new metals in the sample, pluranium, ruthenium and polinium.He later withdrew his claim of discovery. In 1844 the Russian chemist Karl Karlovich Klaus was able to show that Osann s mistake was due to the impurity of the sample but Klaus was able to isolate the ruthenium metal and he retained Osann s original name of ruthenium. 

Ruthenium is a rare element that makes up about 0.01 ppm in the Earth s crust. Even so, it is considered the 74th most abundant element found on Earth. It is usually found in amounts up to 2% in platinum ores and is recovered when the ore is refined. It is difficult to separate from the leftover residue of refined platinum ore. 

In 1827 or 1828 Gottfried Wilhelm Osann (1796—1866), a well-known German scientist, found in the Ural mountains of Russia what he claimed were several new elements in platinum ores, including ruthenium. However, after his announcement, nothing more happened and he did not withdraw his claim, as did Sniadecki. Some sources now give Osann credit for discovering ruthenium. 

Rhodium is a hard shiny-white metal that resists corrosion from oxygen, moisture, and acids at room temperatures. As a member of group 8 (VIII), Rh shares many chemical and physical properties with cobalt (j Co) just above it and iridium ( ylr) below it in the vertical group. Therefore, it is considered one of the elements that are transitory between metals and nonmetals. It is rare and only found in combination with platinum ores. 

Rhodium is rare, but not as rare as ruthenium. It makes up only 1 part in 20 milhon of the elements found in the Earths crust. Even so, it is considered the 79th most abundant element and is found mixed with platinum ore, and to a lesser extent, it is found with copper and nickel ores. It is found in Siberia, South Africa, and Ontario, Canada. 

ORIGIN OF NAME Its name is derived from the Greek word osme, meaning "odor" or "smell," because of the element s objectionable smell when it is first isolated from platinum ores using aqua regia. 

Iridium and its parmer osmium were discovered in 1803 by the Enghsh chemist Smithson Tennant (1761-1815). In essence, he employed the same technique to separate these elements from platinum ores that is used today to pmify iridium. He dissolved the minerals with aqua regia, which left a black residue that looked much like graphite. After analyzing this shiny black residue, he identified two new elements—Ir and Os. Tennant was responsible for naming iridium after the Latin word iris because of the element s rainbow of colors. 

Platinum is the main metal in the platinum group, which consists of metals in both period 5 and period 6. They are ruthenium (Ru), rhodium (Ro), and palladium (Pd) in period 5 and osmium (Os), iridium (Ir), and platinum (Pt) in period 6. All six of these metals share some of the same physical and chemical properties. Also, the other metals in the group are usually found in platinum ore deposits. 

Acceptability of food is dependent on a knowledge of its ingredients e.g. how pure is the drinking water or is there acrylamide in french fries or other fried food preparations, how much vitamin C, or li-carotene, or proline is there in juices, what preservatives are there in bread, sausages or other food preparations Alloys have to meet certain specifications to be used in tools, machinery or instraments. The price of platinum ores or used catalytic converters from cars depends on the platinum content. There are many more examples. This shows the importance of correct analytical results. 

The element was discovered in 1925 by Walter Noddack, Ida Tacke Noddack, and 0. Berg. They detected it by x-ray examination of platinum ores. X-ray studies also showed its occurrence in columbite and other minerals. It was named after the German river Rhine, called Rhenus in Latin. In 1929, Walter and Ida Noddack produced Ig of rhenium metal from 660 kg of Norwegian molybdenite. 

Rhenium does not occur alone in nature in elemental form. It is found in trace quantities in a number of minerals such as columbite, gadolinite, molybdenite, tantalite, wolfranite, and many platinum ores. Its average concentration in earth s crust is 0.0007mg/kg. 

W. H. Wollaston discovered rhodium in 1803-04 in crude platinum ore. Although he did not definitely state the source of this ore, it must have come from South America the Russian platinum ores had not yet been discovered. Since the platina to be procured in this country, said Wollaston, generally contains small scales of gold intermixed, as well as a portion of the mercury which the Spaniards employ for the separation of the gold, the platina used for my experiments, after being by mechanical means freed, as far as possible, from all visible impurities, was exposed to a red heat for the purpose of expelling the mercury (9). 

Rhodium occurs associated with platinum ores, and also in the mineral rhodite in die gold-bearing sands of Brazil and Colombia. 

This report, which was entitled "Chemical investigation of the residues of Ural platinum ore and of the metal ruthenium, occupied one hundred and eighty-eight pages in the Scientific Annals of Kazan University for 1844. In the following year it was published in book form. For patriotic reasons and also in recognition of the earlier work of Professor Osann, Klaus retained the name ruthenium, which means Russia. The white substance which Osann had taken for the oxide of this new metal consisted chiefly of silicic and titanic acids, iron peroxide, and zirconia (37). Klaus also found ruthenium in the osmiridium from American ores (36, 128). It constituted only from 1 to l1/o per cent of these residues and did not occur in the portion which is soluble in aqua regia (126). 

Probably Klaus s experiments on the residues from platinum ores and on the new metal ruthenium have already been described in the German journals. He sent me his paper in manuscript. You see thereby that he has also prepared colorless salts of iridium with sulfurous acid. The early severe winter in November interrupted the postal communication between Ystad and Stralsund, so that I have not received the German journals for three months (28). 

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