Strontium, deposition

Strontium in the maternal skeleton can be transferred to the fetus during pregnancy. Studies of residents of the Techa River who were exposed to strontium as result of releases from a plutonium production plant provide evidence for fetal transfer of strontium. The fetakmatemal strontium concentration ratio in four subjects who were exposed prior to pregnancy varied from 0.012 to 0.24, with the higher values associated with maternal exposures that occurred during adulthood and lower values associated with maternal exposures during childhood or adolescence (Tolstykh et al. 1998). The difference was not related to the maternal strontium burden at pregnancy and may reflect a lower availability of strontium deposited in bone... 

Soluble radioactive strontium can be detected in urine, blood or feces by liquid scintillation counting. Whole body counters (or chest counters for inhalation exposures) can measure internal radioactive strontium deposited in bone following high level exposures (see Section 7.1.1). Children tend to incorporate strontium more homogenously throughout bone than is the case for adults. 

Herring LC, Keefer DH. 1971a. II. Comparison of stable and radioactive strontium deposition in urinary calculi and human diet. Arch Environ Health 22 251-258. 

Deposits of celestite in Gloucestershire, the United Kingdom, represented the main source of the world supply from 1884 to 1941 and provided up to 90% of the world strontium supply (4). During World War II, shipments to the United States and Western Europe from the United Kingdom were dismpted, and celestite deposits in Mexico and Spain were developed. 

Strontianite is the naturally occurring form of strontium carbonate. It has a theoretical strontium oxide content of 70.2%, but no economically workable deposits are known. There are some naturally occurring strontium—barium and strontium—calcium isomorphs, but none has economic importance. 

Production. MetaUic strontium was first successfully produced by the electrolysis of fused strontium chloride. Although many attempts were made to develop this process, the deposited metal has a tendency to migrate into the fused electrolyte and the method was not satisfactory. A more effective early method was that described in Reference r5. Strontium oxide is reduced thermally with aluminum according to the following reaction ... 

Strontium Carbonate. Strontium carbonate, SrCO, occurs naturally as strontianite in orthorhombic crystals and as isomorphs with aragonite, CaCO, and witherite, BaCO. There are deposits in the United States in Schoharie County, New York in WestphaUa, Germany and smaller deposits in many other areas. None is economically workable. Strontianite has a specific gravity of 3.7, a Mohs hardness of 3.5, and it is colorless, gray, or reddish in color. 

Strontium Sulfate. Strontium sulfate, SrSO, occurs as celestite deposits in beds or veins in sediments or sedimentary rocks. Celestite has a specific gravity of ca 3.97, a Mohs hardness of 3.0—3.5, and is colodess-to-yeUow and often pale blue. Strontium sulfate forms colorless or white rhombic crystals with a specific gravity of 3.96 and an index of refraction of 1.622—1.631. It decomposes at 1580°C and has a solubiUty of 0.0113 g per 100 mL of water at 0°C. 

Barium titanate thin films can be deposited on various substances by treating with an aqueous solution containing barium salts and an alkanolamine-modifted titanate such as TYZOR TE (151). In a similar fashion, reaction of a tetraalkyl titanate with an alkah metal hydroxide, such as potassium hydroxide, gives oxyalkoxide derivatives (KTi O(OR) ), which can be further processed to give alkali metal titanate powders, films, and fibers (152—155). The fibers can be used as adsorbents for radioactive metals such as cesium, strontium, and uranium (156). 

Barium and strontium salts of polystyrene with two active end-groups per chain were prepared by Francois et al.82). Direct electron transfer from tiny metal particles deposited on a filter through which a THF solution of the monomer was percolated yields the required polymers 82). The A.max of the resulting solution depends on the DPn of the formed oligomers, being identical with that of the salt of polymers with one active end-group per chain for DPn > 10, but is red-shifted at lower DPn. Moreover, for low DPn, (<5), the absorption peak splits due to chromophor-chromophor interaction caused by the vicinity of the reactive benzyl type anions. 

Also increasingly common, as CVD precursors, are many halogen-acetylacetonate complexes, such as trifluoro-acetylacetonate thorium, Th(C5H4F302)4, used in the deposition of thoriated tungsten for thermionic emitters, the trifluoro-acetylacetonates of hafnium and zirconium and the hexafluoro-acetylacetonates of calcium, copper, magnesium, palladium, strontium, and yttrium. 

Strontium titanate (SrTi03) has a large dielectric constant of 12, and a high refractive index with potential opto-electronic applications. It is deposited by MOCVD from titanium isopropoxide and a strontium beta-diketonate complex at 600-850°C and 5 Torr.t" " ... 

Fell, W. A., Wessels, B., Tonge, L., and Marks, T., Chemically Vapor Deposited Strontium Titanate Thin Films and Their Properties, Proc. 11th. Int. Conf. on CVD, (K. Spear and G. Cullens, eds.), pp. 148-154, Electrochem. Soc., Pennington, NJ 08534(1990)... 

Odum, H.T. 1957 Biogeochemical Deposition of Strontium. Institute of Marine Science Publications No. 4, University of Texas, Austin 39-106. 

Figure 1.19. Strontium contents of anhydrites from the Matsumine, Shakanai, and Fukazawa deposits (Shika-zono et al., 1983).

Strontium isotopes. Strontium isotopic compositions ( Sr/ Sr) of anhydrite, gypsum and barite from Kuroko deposits are summarized in Fig. 1.45 (Farrell et al., 1978 Honma and Shuto, 1979 Farrell and Holland, 1983 Yoneda et al., 1993 Yoneda and Shirahata, 1995). Sr/ Sr values of anhydrite and gypsum are slightly lower than that of seawater, suggesting that most of the strontium was derived from seawater, but a small amount of... 

Figure 1.49. Change of the strontium content and Sr/ Sr ratio of Kuroko anhydrite during the deposition and dissolution due to the mixing of hot ascending solution and cold solution (normal seawater) (Shikazono et al., 1983). R mixing ratio (in weight) = S.W./(S.W.+H.S.) in which S.W. and H.S. are seawater and hydrothermal solution, respectively. Open triangle Fukazawa deposits. Solid triangle Hanawa deposits. Open square Wanibuchi deposits. Solid square Shakanai deposits. Concentration of Ca, Sr " " and SO of H.S. are assumed to be 1,(XX) ppm, 1 ppm, and 10 mol/kg H2O, respectively. Concentrations of Ca, Sr " and SO of S.W. are taken to be 412 ppm, 8 ppm, and 2,712 ppm. Temperatures of H.S. and S.W. are assumed to be 350°C and 5°C (Shikazono et al., 1983).

Farrell, C.W., Holland, H.D. and Petersen, U. (1978) The isotopic composition of strontium in barites and anhydrites from Kuroko deposits. Mining Geology, 28, 281-291. 

Farrell, C.W. and Holland, H.D. (1983) Strontium isotope geochemistry of the Kuroko deposits. Econ. Geol. Mon., 5, 302-319. 

Honma, H. and Shuto, K. (1979) On strontium isotope ratio of barite from Kuroko-type deposits, Japan. 

Yoneda, T., Yin, S. and Shirahata, H. (1993) Strontium isotopic composition in barite from the Minamishiraoi Kuroko-type deposit. Southwestern Hokkaido, Japan. Resource Geology, 43, 427-434. 

The scale may consist of calcium carbonate, barium sulfate, gypsum, strontium sulfate, iron carbonate, iron oxides, iron sulfides, and magnesium salts [943]. There are monographs (e.g.. Corrosion and Scale Handbook [159]) and reviews [414] on scale depositions available in the literature. 

Lehn, J.-M., Sauvage, J.-R, Ziessel, R., and Hilaire, L., Water photolysis by UV irradiation of rhodium loaded strontium titanate catalysts. Relation between catalytic activity and nature of the deposit from combined photolysis and ESCA studies, Isreal ]. Chem., 22,168,1982. 

Bodine, M. W., H. D. Holland, and M. Borcsik (1965), "Coprecipitation of Manganese and Strontium with Calcite. Symposium Problems of Postmagmatic Ore Deposition", Prague2, 401-406. 

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