Occurrence and production

Bismuth is a relatively rare element and ranks 64th in abundance in the earth s crust, which is estimated to contain 0.17-0.2 ppm of bismuth. This is comparable in abundance to silver and cadmium. Bismuth content increases from ultrabasic (1 X 10 %) to acid magmatic rock (1 X 10 %) and is not concentrated in the magmatic phase. Native bismuth is rarely found in nature in cobalt and silver veins, but usually occurs as the compounds, mostly sulfide (bismuthinite or bismuth glance, Bi2S3) together with complex minerals asso- 

Fusible alloys Metallurgical additives Chemicals Others Total 400 230 855 35 1520 32 431 77 189 729 

Flake graphite is found disseminated in metamorphosed silica-rich quartzites, gneisses, and marbles. Crystalline (vein) graphite occurs in transverse, igneous, or metamorphic rocks, where it was formed by the transformation of oil precursors. Amorphous graphite is the result of the metamorphosis of coal exposed to high pressure. Graphite is also present in the universe as evidenced by near-perfect crystals frequently found in meteorites. 

Besides the U.S., the major producers of graphite are Brazil (flake), Canada (flake), China (flake and amorphous), Korea (amorphous), Madagascar (flake), Mexico (amorphous), Sri Lanka (flake), and the former Soviet Union (flake and amorphous). The total world production was estimated at over 650,000 tons in 1991 at an average price of 1400Aon for fiake and 165/ton for amorphous.Pl 

The mining and refining of copper takes place on all six continents. Mines in Chile, USA, and Canada account for over 50% of the annual worldwide production of 11 x 10 tons of refined copper metal (ICSG 

The unique combination of properties of copper, including durability, ductility, malleability, and electrical and thermal conductivity, provide for the wide use of this metal in numerous applications. 

Worldwide, the largest use of copper (-9.75x10 tons) is in electrical wire and cable and other electronic applications (MARCO, 1989). Metal copper is also used in water piping, stills, roofing material, and kitchenware for chemicals and pharmaceutical equipment as a pigment and as a precipitant of selenium (Fabian 1986). Copper metal has contraceptive properties, and an intrauterine copper device (lUD) was developed for humans (Zipper et al. 1968) a typical lUD may add 80 p,Cu per day to the woman s body (Kjaer et al. 1993). 

Alloys of copper include those with zinc (brass), tin (bronze), nickel (money metal), aluminum, gold, lead, cadmium, chromium, beryllium, silicon, or phosphoms (Scheinberg 1971). Copper is a major constituent of many metallic amalgams, for 

Some of copper compounds ultimately end up as waste products and are incinerated. As copper compounds have catalytic properties in many chemical reactions, they also activate the formation of poisonous gasses during incineration (i.e., chlorinated dioxin and dibenzofurans Carson and Mumford 1988). Copper contents in wastes should therefore be reduced. 

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Describe the occurrence and production of sulfur, selenium, and tellurium... 

Describe the occurrence and production of nitrogen and phosphorus Describe some important reactions of nitrogen and phosphorus Describe the occurrence and importance of silicon Describe a few important compounds of silicon... 

Occurrence and Production The Earths crust contains about 13 mg kg thorium (Vietzke 1983), as a constituent of more than 100 minerals. Abundance is comparable to that of beryllium and cobalt, and three times above that of uranium. Typical concentrations range from 1 to 10 mg kg in sandstone, shale or limestone, while granite contains up to 80 mg kg thorium (Kathren 1984). Monazite, an orthophos-... 

Occurrence and Production The Earths crust contains about 2.4 mgkg uranium (Saager 1984), and seawater contains about l-3pgkg (Kathren 1984). Typical concentrations of uranium range... 

PRODUCTION OF GLYCOSYL GLYCEROLS 24.3.1 Occurrence and Production Methods... 

The treatment of metals. Chapter 23 of the eleventh edition, has been reorganized and augmented. Structure and bonding in metals and alloys are now covered in Chapter 12 (Solids and Modem Materials), and other parts of Chapter 23 have been combined with material from Chapter 24 of the eleventh edition to form a new chapter, Tran.sition Metals and Coordination Chemistry. Material covering occurrences and production of metals that was not widely used by instructors has been eliminated. 

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