Tellurium 14 water content

Production and Economic Aspects. Thallium is obtained commercially as a by-product in the roasting of zinc, copper, and lead ores. The thallium is collected in the flue dust in the form of oxide or sulfate with other by-product metals, eg, cadmium, indium, germanium, selenium, and tellurium. The thallium content of the flue dust is low and further enrichment steps are required. If the thallium compounds present are soluble, ie, as oxides or sulfates, direct leaching with water or dilute acid separates them from the other insoluble metals. Otherwise, the thallium compound is solubilized with oxidizing roasts, by sulfatization, or by treatment with alkaU. The thallium precipitates from these solutions as thaUium(I) chloride [7791 -12-0]. Electrolysis of the thaUium(I) sulfate [7446-18-6] solution affords thallium metal in high purity (5,6). The sulfate solution must be acidified with sulfuric acid to avoid cathodic separation of zinc and anodic deposition of thaUium(III) oxide [1314-32-5]. The metal deposited on the cathode is removed, kneaded into lumps, and dried. It is then compressed into blocks, melted under hydrogen, and cast into sticks. 

Tellurium metal, its alloys, minerals or the teUurides may be dissolved in warm concentrated sulfuric acid or cold fuming sulfuric acid to form a red color, the intensity of which is proportional to the tellurium content in the substance. When this red solution is poured into water, black elemental tellurium metal precipitates out of solution. Oxidized tellurium does not respond to this test. 

Add tin dichloride and sulphurous acid solutions respectively to two test tubes containing solutions of tellurium(IV) oxide in hydrochloric acid diluted with water. Heat the contents of the test tubes. Comment on your observatioss. WriteJjie equations of the reactions. What property do the salts of tetravalent tellurium exhibit in the given reactions ... 

This is isolated in the usual manner from di-p-anisyl telluride. It sinters at 180° C. and melts at 183° to 184° C. The crystals consist of four-sided columns, easily soluble in warm benzene, toluene, xylene or chloroform, less soluble in alcohols, carbon disulphide or carbon tetrachloride, insoluble in petroleum ether. Boiling with water for a prolonged period yields a product of which the tellurium content lies between that of the dichloride and that of the oxide. 

Triphenyl Tellurium Cyanide1 20 g of a Baker CHA-541 resin are treated with aqueous sodium cyanide solution, the column is washed with ethanol/water mixtures with increasing ethanol content, and, finally, the column is covered with 95% ethanol. A solution of 0.1 g (2.5 mmol) of triphenyl telluronium chloride in 60 ml of 95% ethanol is slowly passed through the column. The column is eluted with 200 ml of ethanol, the cluate is evaporated, the oily residue is triturated with ethyl acetate, and the crystals are collected, washed with ethyl acetate, and dried under vacuum yield 0.82 g (85%) m.p. 184° (dec.). 

Selenium forms a volatile derivative, piazselenol, which can be subjected to GC analysis (Scheme 5.39). Young and Christian [612] treated selenium with 2,3-diaminonaph-thalene at pH 2.0 and extracted the resulting piazselenol into -hexane. With the use of an ECD, down to 5 10-I° g of selenium could be detected. The procedure, applied to the analysis of selenium in human blood, urine and river water, led to results equivalent to those obtained by neutron activation analysis. Similarly, Nakashima and Toei [613] performed the reaction of selenium (as selenious acid) with 4-chloro-o-phenylenediamine at pH 1 and extracted the derivative into toluene. They reported a detection limit of 0.04 jug. Shimoishi [614] analysed the content of selenium in metallic tellurium by this method. The sample was dissolved in aqua regia, followed by reaction with 4-nitro-o-phenylenediamine and extraction into toluene. Down to 10 ng of selenium could be determined using only a few milligrams of sample. Common ions did not interfere even when present in a large excess. Selenium in marine water was determined after the same derivatization step [615],... 

It may also be obtained by heating an intimate mixture of finely divided tellurium (100 parts) and platinum (150 parts) in a glass tube until combination takes place. The tube and its molten contents are now melted together and dropped into cold water. The telluride then yields quite good crystals. 

A hair sample (1 g) is washed with water, acetone, ether, and detergents followed by a successive rinse with water, acetone, and ether. After washing and drying the hair sample, it is digested with nitric, perchloric, and sulfuric acids. After digestion, the hydrochloric acid concentration of the sample solution is adjusted to 4 M, and it is boiled for 5 min. The tellurium content in the sample solution is determined by the hydride generation atomic absorption spectrometry described above. The lower detection limit is 1 ng/g and the levels of unexposed subjects are below the detection limit [13]. 

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