Tellurium
Atomic no.
Relative Atomic Mass
Melting Point
Boiling Point
Density
Electrical Resistivity
Young's Modulus
Heat Capacity
Abundance
Thermal Conductivity
52
127.60
449.5 °C
988 °C
6240 kg/m3
50 mΩ⋅m
43 GPa
25.73 J/K⋅mol
5 ppb
2.35 W/m⋅K
Tellurium, like Selenium, is generally recovered from the anode slimes resulting from Copper refining.
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Sometimes the Te is refined all the way through to Tellurium Metal sticks (99.9% min) in country of origin (e.g. Peru) or, like Selenium, traded in a crude 96/97% form which will include high Lead, Copper, Selenium and Iron.
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Most Tellurium is used as an addition within Copper alloys and Stainless Steel to increase machinability. Lipmann Walton works closely with Alloy Masters Ltd who produce Copper Tellurium Master Alloy at their plant in mid-Wales.
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One unfortunate and unusual side effect of working with Tellurium is that, if inhaled, the dust will cause a bad breath and body odour akin to the smell of garlic.
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Tellurium was discovered in 1783 by the Baron Franz Joseph Müller von Reichenstein at Sibiu, in Romania and was named by Martin Heinrich Klaproth who isolated it in 1798.
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Tellurium is silvery-white, metallic-looking in bulk, but is usually obtained as a dark grey powder. It is a semi-metal. Tellurium burns in air or oxygen and is unaffected by water or HCl. However, it does dissolve in HNO3.
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Tellurium is sometimes found in its native form, but is more often found as the telluride of gold (calaverite), or combined with other metals. The principal source of tellurium is from anode sludges produced during the electrolytic refining of blister copper. However, it is also found as a component of dusts from blast furnace refining of lead.
Commercial-grade tellurium, which is not toxic, is usually marketed as minus 200-mesh powder but is also available as slabs, ingots, sticks, or lumps.
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Half of the tellurium consumed each year is used to improve the machinability of special iron and steel products. It is alloyed with copper to make copper more ductile, and with lead to prevent corrosion. These, and other nonferrous tellurium alloys, account for approximately 10% of tellurium use. Tellurium is also used to make catalysts and chemicals. Some of these chemicals are used in the petroleum industry and in making rubber. Tellurium is added to selenium-based photoreceptors to broaden the spectral range of copiers. Tellurium is also used in other electronic applications, and in the production of blasting caps for explosives.
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Nations producing tellurium and tellurium dioxide are the United States, Canada, Japan, Peru, and a number of other countries where copper is produced, such as Kazakhstan.
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Cadmium and its growing use in CdTe photovoltaics
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