Rare earths consumption

Rare earth consumption could, however, be affected by a change in host lattice system, with Eu3+ still being retained as activator. Either cost or luminescence efficiency could drive such a change. Costs could be decreased either by eliminating rare earth host lattice cations or by a decrease in the required concentration of Eu. However, in spite of considerable research effort, new host systems that accomplish these objectives have not been found. 

Factors Affecting Rare Earth Consumption in TV Phosphors... 

The consumption of rare earths in color TV is dictated in the first instance by the choice to use rare earth phosphors and the number of picture tubes produced. Within these constraints, several other factors tend to exert a downward influence on rare earth consumption. Reclaim, that is, reuse of phosphor coated on but not retained by the picture tube screen, is now universally practiced in the U.S, TV industry. Reclaim was not practiced at the time of the introduction of Eu-based reds. The high cost and uncertain availability of rare earth phosphors... 

Rare earth consumption in various industries in the world is given in Table 1.8. 

The rare earths consumption pattern as a function of time (years) in tons is depicted in Fig. 1.2. 

FIGURE 1 Worldwide rare-earth consumption by market sector in 2008. Data taken from Goonan (2011). 

Lanthanide luminescence apphcations have already reached industrial levels of consumption. Additionally, the strongly specific nature of the rare-earths energy emissions has also led to extensive work in several areas such as photostimulable phosphors, lasers (qv), dosimetry, and fluorescent immunoassay (qv) (33). 

In 1990 world consumption of lanthanides was approximately 35,000 metric tons (45). The most important markets were the United States /Canada (32.8%), China (18.6%), Europe (15.8%), Japan (14.5%), Eastern Europe (9.5%), the rest of Asia (7.3%), and the rest of the world (1.4%). The principal rare-earth manufacturers in 1993 were Molycorp Inc. and RhcJ)ne-Poulenc in the United States RhcJ)ne-Poulenc and Treibacher Chemische WAG in Europe Shinetsu Chemical, Nippon Yttrium, Mitsubishi Chemical Inc., and Santoku Metal Inc. in Japan Indian Rare Earths in India and several additional companies located in the CIS and in the Baotou, Gansu, Yue Long, and Jiangxi provinces in China. 

An alternative commercial form of a metallic mixed lanthanide-containing material is rare-earth siUcide [68476-89-1/, produced in a submerged electric-arc furnace by the direct reduction of ore concentrate, bastnasite, iron ore, and quart2. The resulting alloy is approximately 1/3 mischmetal, 1/3 sihcon, and 1/3 iron. In addition there are some ferro-alloys, such as magnesium—ferrosilicons, derived from cerium concentrate, that contain a few percent of cerium. The consumption of metallic cerium is overwhelmingly in the mixed lanthanide form in ferrous metallurgy. 

The raw materials needed to supply about ten million new automobiles a year do not impose a difficult problem except in the case of the noble metals. Present technology indicates that each car may need up to ten pounds of pellets, two pounds of monoliths, or two pounds of metal alloys. The refractory oxide support materials are usually a mixture of silica, alumina, magnesia, lithium oxide, and zirconium oxide. Fifty thousand tons of such materials a year do not raise serious problems (47). The base metal oxides requirement per car may be 0.1 to 1 lb per car, or up to five thousand tons a year. The current U.S. annual consumption of copper, manganese, and chromium is above a million tons per year, and the consumption of nickel and tungsten above a hundred thousand tons per year. The only important metals used at the low rate of five thousand tons per year are cobalt, vanadium, and the rare earths. 

In the 22 years between 1908 and 1930 about 1 100 - 1 400 tons of flints were produced as the most inportant rare earth product. This required the consumption of about 1 300 - 1 800 tons of rare earth oxides in the form of rare earth chloride. 

Scarce Resource Depletion. For any new technology, the longterm and worldwide effects on scarce-resource consumption should be assessed over its entire lifecycle. For instance, even minute amounts of rare earth metals per... 

The rare earths (RE) are actually far from rare.6 The known reserves are more than 84 x 106 tons, a 2300 year supply at the present rates of consumption. Even the scarcest one, thulium, is more common than Bi, As, Cd, Hg, or Se. The largest reserves (51%) are in mainland China other major deposits are in the USA (15%), Australia (6%), and India (3%). 

DRS measurements support the TPR results. The impregnated catalysts and steam treated (IMPV) did not show the presence of V after the reduction. Probably, the hydrogen consumption in the TPR profile is due to the reduction of cerium. The band in the d-d transition can be attributed to the formation of alloys like cerium vanadate, according to the literature [14]. Baugis et al. [15] reported that the presence of vanadate with rare earth decreases the diffusion of vanadium in the zeolite structure [14]. The existence of these compounds may affect the oxidation state, the dispersion, morphology and location of cerium species in the catalyst. 

From this table it is evident that all monazite contains much more ceria than thoria and since the mantle is mainly thoria a very large part of the ceria is not needed for mantle manufacture. The residue which remains after removal of the thoria contains about 45 per cent Ce02,25 per cent La203, and 15 per cent didymia, the remainder being yttrium earths, samaria, etc. The residue represents 60-65 per cent of the original monazite. Since the total world s consumption of monazite has been estimated as being about 88,000 tons up to 1918, it is evident that the supply of cerium material has been very large. Some firms have stored enormous quantities of these rare earth salts, and others have thrown them away. The residues are transformed to the chlorides, which are carefully dehydrated to prevent the formation of basic salts. The purity of the chlorides is not important, but the phosphorus and sulfur content must be low, and iron and aluminium should not be present in more than small amounts. A mixture of the... 

Non-noble metal catalysts A and B were developed in view of the rich resources of transition metal oxide and rare earth oxides as well as low cost in China. The catalysts were characterized by high effectiveness for the conversion of CO and HC, high crush strength and high stability to prevent poisoning by S02 and Pb. The catalytic converter can also be used in place of exhaust muffler while the consumption of fuel does not increase. 

The demand for the rare earth metals increased over the last two decades of the 20th century, and the demand for cerium oxides in motor vehicle catalytic converters (see equations 26.39 and 26.40) has been a major contributing factor. In 2001, the major use (34% of the total consumption) for rare earth metals in the US was in glass polishing and ceramics. Petroleum catalysts and catalytic converters... 

Owing to peculiar physical and chemical properties, rare-earth elements are used in various materials and consumer products, and thus, have become indispensable for our modem life. The world-wide rare-earth oxide consumption by the market sector in 2008 (Goonan, 2011) shown in Fig. 1 indicates that rare earths are used in glass industry, catalysts, neodymium magnets, battery alloys and other metallurgical additives, phosphors, ceramics, and other. According to the world mine production of rare earth in 2009 (Cordier, 2011),... 

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