Tungsten price

This last loss category is not likely to be altered. Only extremely high tungsten prices could affect the situation. 

FIGURE 13.3. Tungsten price (LBM quotation) versus time (1960-1996), including closure dates of MEC mines [13.7]. 

Eig. 2. Mean l ondon Metal bulletin price of tungsten concentrate by year. 

Bismuth is referred to as a minor metal. It is not generally mined for its own intrinsic value, rather it is mined primarily as a by-product of lead or copper ores. In China, however, bismuth can be found ia tungsten ores. In BoHvia the metal has been mined for its own value, but this has not happened on a consistent basis over the years because fluctuations ia the bismuth price have at times made it uneconomical to recover. 

Cheapest of all are the particulate composites. Aggregate plus cement gives concrete, and the composite is cheaper (per unit volume) than the cement itself. Polymers can be filled with sand, silica flour, or glass particles, increasing the stiffness and wear-resistance, and often reducing the price. And one particulate composite, tungsten-carbide particles in cobalt (known as "cemented carbide" or "hard metal"), is the basis of the heavy-duty cutting tool industry. 

Boron itself has been used for over two decades in filament form in various composites BO3/H2 is reacted at 1300° on the surface of a continuously moving tungsten fibre 12/tm in diameter. US production capacity is about 20 tonnes pa and the price in about 80(. The primary use so far has been in military aircraft and space shuttles, but boron fibre composites are also being studied as reinforcement materials for commercial aircraft. At the domestic level they are finding increasing application in golf shafts, tennis rackets and bicycle frames. 

Similarly, neither zirconium, tantalum, molybdenum, nor tungsten carbene complexes have been applied extensively by organic chemists for carbonyl olefination [609,727-729], probably because of the difficulty of their preparation and the high price of some of these compounds. These reagents can, however, have appealing chemo- and stereo-selectivity (Table 3.11). 

There are many types of mechanical grinding equipment available ball mills, ball and mortar sets, planetary mortars, impact mills, etc. These are available in a variety of materials steels, porcelain, agate, mullite, silicon carbide, tungsten carbide and others. Prices range from 200 to about 2,000. Unfortunately, the cost increases rather markedly as one goes to the harder materials, especially the carbides. 

When the performance and price of CVD tools compare favorably with those of PCD tools, CVD tools may displace PCD tools in some applications. Woodworking tools represent another major market segment for diamond coatings. Tungsten carbide blades already comprise a large part of the woodworking tool market. CVD-diamond-coated tools have yet to be used in woodworking and, thus, they offer an excellent business opportunity. 

From time to time, summaries about the tungsten ore reserves are published in the current literature. In principle, it must be taken into account that all those figures are based on estimates. Moreover, they are influenced by the demand of tungsten, the market situation, and consequently by the world market price for tungsten. 

Multitube furnaces (14 to 18 tubes arranged in two rows) are frequently in use today. A photograph of an industrial aggregate is shown in Fig. 5.26. The boat material, in most cases, is an iron alloy high in Ni and Cr (Inconel). More seldom, because of the high price, boats are made of TZM (molybdenum alloy with Ti, Zr, and C) or pure tungsten. 

Economic importance. About 23,000 tons/year of hardmetal are currently used in the western world, which correspond to more than 60% of tungsten demand [9.1]. The world market volume for hardmetal cutting tools in 1995 was estimated to be roughly 9 billion DM [9.10]. The price ofhardmetals, on average, equals that of silver. For special tools, like coated indexable inserts, the price is about double that of silver [9.11]. 

Last but not least, the pricing policy of virgin W products and the price stability of the recycled products influences tungsten recycling in general. 

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