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Division 2.2 Toxic gases – Gases which: are known to be so toxic or corrosive to humans as to pose a hazard to health; or; are presumed to be toxic or corrosive to humans because they have an LC 50 value equal to or less than 5000 ml/m 3 (ppm). e.g. hydrogen cyanide. Division 2.3
There are 2 parts per million of tantalum in the Earth's crust, making it the 51st most abundant element there. Soil contains on average 1 to 2 parts per billion of tantalum, and seawater contains 2 parts per trillion of tantalum. A typical human contains 2.9 parts per billion of tantalum. Tantalum is found in the minerals tantalite and ...
Tantalum was extensively used in the production of ultra high frequency electron tubes for radio transmitters. Tantalum is capable of capturing oxygen and nitrogen by forming nitrides and oxides and therefore helped to sustain the high vacuum needed for the tubes when used for internal parts such as grids and plates. [41] [70]
Natural tantalum (73 Ta) consists of two stable isotopes: 181 Ta (99.988%) and 180m Ta (0.012%). There are also 35 known artificial radioisotopes, the longest-lived of which are 179 Ta with a half-life of 1.82 years, 182 Ta with a half-life of 114.43 days, 183 Ta with a half-life of 5.1 days, and 177 Ta with a half-life of 56.56 hours.
Tantalum ores often contain significant amounts of niobium, which is itself a valuable metal.As such, both metals are extracted so that they may be sold. The overall process is one of hydrometallurgy and begins with a leaching step; in which the ore is treated with hydrofluoric acid and sulfuric acid to produce water-soluble hydrogen fluorides, such as the heptafluorotantalate.
The mineral group tantalite [(Fe, Mn)Ta 2 O 6] is the primary source of the chemical element tantalum, a corrosion (heat and acid) resistant metal.It is chemically similar to columbite, and the two are often grouped together as a semi-singular mineral called coltan or "columbite-tantalite" in many mineral guides.
The river water was contaminated with toxic metals including arsenic, copper, barium, cadmium, chromium, lead, mercury, nickel, and thallium. [2] Cleanup costs may exceed $1.2 billion. [3] A toxic heavy metal is a common but misleading term for a metal-like element noted for its potential toxicity. [4]
Many oxides of tantalum are called tantalates. They are viewed as derivatives of "tantalic acid", hypothetic compounds with the formulas Ta 2 O 5 ·nH 2 O [1] or HTaO 3 [2]). Examples of such tantalates are lithium tantalate (LiTaO 3), lutetium tantalate (LuTaO 4), neodymium tantalate (NdTaO 4) and lead scandium tantalate (PST or Pb(Sc x Ta 1-x ...