Thallium manufacture

Uses. Tballium compounds have limited use in industrial appHcations. The use of thaHous sulfate in rodenticides and insecticides has been replaced by other compounds less harmful to animals (see Insect control technology Pesticides). Tb allium sulfide has been used in photoelectric cells (see Photovoltaic cells). A thallium bromide—thallium iodide mixture is used to transmit infrared radiation for signal systems. ThaHous oxide is used in the manufacture of glass (qv) that has a high coefficient of refraction. Tb allium formate—malonate aqueous solutions (Cletici s solution) have been used in mineral separations. Many thallium compounds have been used as reagents in organic synthesis in researchlaboratoti.es. 

Thallium is likewise recovered from flue dusts emitted during sulfide roasting for H2SO4 manufacture, and from the smelting of Zn/Pb ores. Extraction procedures are complicated because of the need to recover Cd at the same time. There are no major commercial uses for T1 metal world production in 1983 was estimated to be 5-15 tonnes p.a. and the price ranged from 60 to 80 per kg depending on purity and amount purchased. 

Thallium oxide is used in manufacturing high coefficient of refraction optical glass (thallium flint glass). Also, the oxide is used to make synthetic gems. 

In 1865 Lamy became a professor of chemistry at the Central School of Arts and Manufactures at Paris. He published papers on magnetism, the progress of physics, the toxic effect of thallium, and the solubility of lime in water. He died at Paris on March 20, 1878 (16). 

Finally, herbal products imported from China may be contaminated with pesticides or with heavy metals added during the manufacturing process. Contaminated Chinese herbals have led to cases of arsenic, lead, mercury, thallium, and cadmium poisoning. Similarly, investigations of traditional Indian Ayurvedic remedies have shown them to sometimes contain dangerous levels of lead, zinc, mercury, arsenic, aluminum, and tin. 

Thallium is manufactured commercially as a by-product from the roasting of pyrite ores, from sulfuric acid plants, and from the smelting of lead, zinc, and copper. The global... 

A considerable number of organometallic species have been detected in the natural environment in recent years. A number of these are nonmethyl compounds which have entered the environment after manufacture and use (e.g. butyltin and phenyltin compounds in antifouling paints for boats). Only a few methyl compounds are now manufactured and used (e.g. methyltin compounds for oxide film precursors on glass and methylarsenic for compounds used as desiccants or defoliants). It is now well established that certain organometallic compounds are formed in the environment, unequivocally so for those of mercury, arsenic, selenium, tellurium and tin, and deduced on the basis of analytical evidence for lead, germanium, antimony and thallium . 

Uses. — Thallium compounds possess unusually high refracting power, so they are used in the manufacture of certain kinds of optical glass in which a high refractive index is desired. 

Gas discharge lamps. They are manufactured for the determination of sodium, potassium, mercury, cadmium and thallium atoms. They emit specific mono or polychromatic radiation for these elements. 

Thallium is obtained from the dust deposited in the flues of the pyrites burners used in the manufacture of sulphuric acid. The separation of thallium from other metals depends on the fact that it is the only metal with a soluble carbonate and an insoluble chloride. It is a bluish-white metal, easily deformed and softer than lead, being present at concentrations of 0.6-0.7 ppm in the earth s crust, and although it can be found in pure metallic form it is more commonly associated in mineral combination. 

Ternary systems of thallium, arsenic, and selenium are used in the manufacture of low-melting point glasses with a high refractive index. 

For simple gamma counting, thallium-activated sodium iodide [Nal(TI)] scintillation detectors, which became commercially available in the early 1950s, continue to render excellent sen/ices. In spite of the introduction of many other scintillation materials, they remained preeminent. Nal(TI) detectors can be manufactured in various sizes and shapes... 

Besides accidential or suicidal ingestion, there is occupational exposure of some groups of employees in the production and processing of heavy metal ores, manufacturing and use of thallium, its alloys and compounds, and in certain cement factories from roasting pyrites and ingestion of dust from the electric filter (Schaller et al., 1980). Whereas the excretion level in urine from persons without known occupational contact with thallium was found to be lower than 1.1 mg Tl/kg creatinine, it significantly increases upon exposure. No influence of the age of the person examined and the duration of employment, as well as no influence of alcohol and nicotine consumption was noted. 

Thallium is used mostly in manufacturing electronic devices, switches, and closures, primarily for the semiconductor industry. It also has limited use in the manufacture of special glass and for certain medical procedures. 

People SHOULD NOT take Prussian blue artist s dye in an attempt to treat themselves. This type of Prussian blue is not designed to treat radioactive contamination and is not manufactured in a germ-free area. People who are concerned about the possibility of being contaminated with radioactive cesium or thallium should go to their doctors for advice and treatment. 

Thallium is a soft metal that quickly oxidizes upon exposure to air. It Is a minor constituent in a variety of ores. Thallium salts are used In the manufacture of jewelry, semiconductors, and optical devices. Thallium is no longer used In the United States as a depilatory or a rodenticide because of its high human toxicity. 

Fig. 17. Isotopic abundances of thallium recorded electrically by FDMS and signal accumulation in a multichannel analyzer. For each measurement SO cyclic magnetic scans are performed, a natural abundance of thallium, theor. m/z 203 = 29.5%, m/z 205 = 70.5% > found m/z 203 = 29.2%, m/z 205 = 70.S%, standard deviation 0.18, mean error = 0.08 b stable isotope-enriched internal standard, measurement certificate of the Russian manufacturer (supplied by RohstofTEinfuhr GmbH, Diisseldorf, FRG.) isotope T1 = 87.0%, isotope T1 = 13.0%, found m/z 203 = 87.7%, m/z 205 = 12.3%, standard deviation 0.46, mean error = 0.20 c quantitative determination of thallium traces in brain tissues. Found m/z 203 = 43.01 %, m/z 205 = 56.99%, standard deviation 1.28, mean error = 0.57...

Many other metal compounds exist including the following often toxic examples barium compounds, eg., barium bromide beryllium compounds, eg., beryllium hydroxide cadmium compounds, e.g., cadmium iodide copper compounds like copper hydroxide, used as a pigment, in paper manufacturing, and as a pesticide lead compounds, like the soluble lead fluorosilicate thallium compounds, e.g., thallium sulphide and vanadium compounds, e.g., vanadium dichloride. 

Many types of cells are available from manufacturers for use with liquids. Various window materials are available (NaCl, KBr, CsBr, AgCl, CaFz, BaFz, IRTRAN-2, thallium bromoiodide, etc.) m both the demountable and the sealed cells. For these cells there are available spacers of various thicknesses of lead. Teflon, polyethylene, etc. Since the fixed-thickness sealed cells often contain lead spacers cemented to the windows by a mercury amalgam (and these metals are biological poisons) it is wise to consider whether the use of such cells is advisable in a particular instance (e.g., an aqueous enzymic system in one such cell). Cells are available for semimicro, micro, and ultramicro work. Variable path cells of the micrometer or wedge type are available, and these are particularly useful for solvent compensation. 

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