Thorium distribution

Boecker BB. 1963. Thorium distribution and excretion studies. Am Ind Hyg Assoc J 24 155-163. 

Boecker BB, Thomas RG, Scott JK. 1963. Thorium distribution and excretion studies. II. General patterns following inhalation and the effect of the size of the inhaled dose. Health Phys 9 165-176. 

Hurst, A. Milodowski, A. (1996) Thorium distribution in some North Sea sandstones implications fw petrophysical evaluation. Petrol. Geosci., 2, 59-68. 

Because of the high acidity and high sulfate and phosphate content of sulfuric acid monazite leach solutions, distribution coefficients with primary and secondary amines are lower than in Table 6.18. In monazite sulfate solutions, thorium distribution coefficients with the primary amines of Table 6.18 are still greater than 500, however. The coefficient with di(tridecyl)amine is 4.6. These are still high enough for practical processes [C5]. 

Each of the elements has a number of isotopes (2,4), all radioactive and some of which can be obtained in isotopicaHy pure form. More than 200 in number and mosdy synthetic in origin, they are produced by neutron or charged-particle induced transmutations (2,4). The known radioactive isotopes are distributed among the 15 elements approximately as follows actinium and thorium, 25 each protactinium, 20 uranium, neptunium, plutonium, americium, curium, californium, einsteinium, and fermium, 15 each herkelium, mendelevium, nobehum, and lawrencium, 10 each. There is frequently a need for values to be assigned for the atomic weights of the actinide elements. Any precise experimental work would require a value for the isotope or isotopic mixture being used, but where there is a purely formal demand for atomic weights, mass numbers that are chosen on the basis of half-life and availabiUty have customarily been used. A Hst of these is provided in Table 1. 

Fig. 1. Global distribution of seabed mineral deposits, where x represents chromite + barite titanium, zirconium, hafnium, and thorium tin I gold, platinum, and silver 3 sand and gravel shell, calcium carbonate gems marine polymetaUic sulfides phosphorites Cl cobalt cmsts S sulfur and B...

Thorium has a wide distribution in nature and is present as a tetravalent oxide in a large number of minerals in minor or trace amounts. Thorium is significantly more common in nature than uranium, having an average content in the earth s cmst of approximately 10 ppm. By comparison, Pb is approximately 16 ppm. Thorium has a seawater concentration of <0.5 x 10 . Thorium refined from ores free of uranium would be almost... 

Surface water enrichment is the result of aeolian and fluvial inputs, which are thought to be the most important sources of Th to the ocean. Thorinm-232 has been proposed as a link between the radiogenic thorium isotopes and trace metals and anthropogenic pollutants. " While the pathways are very different for the radiogenic thorium isotopes, Th is delivered to the ocean in a fashion similar to many pollutants and trace metals. For example, Guo et found Th distributions in the Gulf of Mexico and off Cape Hatteras in the North Atlantic Ocean agreed well with the general distribution pattern of aluminum. 

Thorium is widely but rather sparsely distributed and its only commercial sources are monazite sands (see p. 1229) and the mineral conglomerates of Ontario. The former are found in India, South Africa, Brazil, Australia and Malaysia, and in exceptional cases may contain up to 20% Th02 but more usually contain less than 10%. In the Canadian ores the thorium is present as uranothorite, a mixed Th,U silicate, which is accompanied by pitchblende. Even though present as only 0.4% Th02, the recovery of Th, as a co-product of the recovery of uranium, is viable. 

Thorium(IV), distribution coefficients between aluminum, silicon, and... 

Bacon MP, Anderson RF (1982) Distribution of thorium isotopes between dissolved and particulate forms in the deep sea. J Geophys Res 87 2045-2056... 

Min GR, Edwards RL, Taylor FW, Recy J, Gallup CD, Beck JW (1995) Annual cycles of U/Ca in corals and U/Ca thermometry. Geochim Cosmochim Acta. 59 2025-2042 Moore WS (1981) The thorium isotope content of ocean water. Earth Planet Sci Lett 53 419-426 Moran SB, Hoff JA, Edwards RL, Landing WM (1997) Distribution of Th-230 in the Laborador Sea and its relation to ventilation. Earth Planet Sci Lett 150 151-160 Muhs DR, Simmons KR, Steinke B (2002) Timing and warmth of the Last Interglacial period new U-series evidence from Hawaii and Bermuda and a new fossil compilation for North America. Qrrat Sci Rev 21 1355-1383... 

Bacon MP, Spencer DW, Brewer PG (1976) Pb-210/Ra-226 and Po-210/Pb-210 disequilibria in seawater and snspended particulate matter. Earth Planet Sci Lett 32 277-296 Bacon MP, Anderson RF (1982) Distribution of thorium isotopes between dissolved and particulate forms in the deep sea. J Geophys Res 87 2045-2056... 

Cochran JK, Bacon MP, Krishnaswami S, Turekian KK (1983) °Po and °Pb distributions in the central and eastern Indian Ocean. Earth Planet Sci Lett 65 433-445 Cochran JK, Livingston HD, Hirschberg DJ, Surprenant LD (1987) Natural and anthropogenic radionuclide distributions in the northwest Atlantic-ocean. Earth Planet Sci Lett 84 135-152 Cochran JK (1992) The oceanic chemistiy of the uranium and thorium-series nuclides In Uranium-series disequihbrium applications to earth, marine, and environmental sciences. Ivanovich M, Harmon RS (eds) Oxford University Press, New York, p 334-395... 

Miller RJ, Smith CR, DeMaster DJ, Pomes WL (2000) Feeding selectivity and rapid particle processing by deep-sea megafaunal deposit feeders A " Th tracer approach. J Mar Res 58 653-573 Moore RM, Hunter KA (1985) Thorium adsorption in the ocean - reversibility and distribution amongst particle sizes. Geochim Cosmochim Acta 49 2253-2257 Moore RM, Millward GE (1988) The kinetics of reversible Th reactions with marine particles. Geochim Cosmochim Acta 52 113-118... 

Nozaki Y, Horibe Y, Tsubota H (1981) The water column distributions of thorium isotopes in the western North Pacific. Earth Planet Sci Lett 54 (2) 203-216... 

Neff U, Bollhofer A, Frank N, Mangini A (1999) Explaining discrepant depth profiles of " U/ U and °Thexc in Mn-crasts. Geochim Cosmochim Acta 63(15) 2211-2218 Nozaki Y, Cochran JK, Turekian KK, Keller G (1977) Radiocarbon and °Pb distribution in submersible-taken deep-sea cores from Project Famous. Earth Planet Sci Lett 34 167-173 Nozaki Y, Horibe Y, Tsubota H (1981) The water coluirm distributions of thorium isotopes in the western North Pacific. EarthPlanet Sci Lett 54 203-216... 

Martin JM, Nijampurkar V, Salvation F (1978b) Uranium anti Thorium isotope behavior in estuarine systems. In Biogeochemistry of estuarine sediments. UNESCO, p 111-127 Mathieu D, Bemat M, Nahon D (1995) Short-lived U and Th isotope distribution in a tropical laterite derived from Granite (Pitinga river basin, Amazoitia, Brazil) application to assessment of weathering rate. Earth Planet Sci Lett 136 703-714... 

Plater AJ, Ivanovich M, Dugdale RE (1995) Ra contents and Ra/ Ra activity ratios of the Fenland rivers and the Wash, eastern England spatial and seasonal trends. Chem Geol 119 275-292 Pliler R, Adams JAS (1962) The distribution of thorium and uranium in a Pennsylvanian weathering profile. Geochim Cosmochim Acta 26 1137-1146... 

Vigier N, Bourdon B, Turner S, Allegre CJ (2001) Erosion timescales derived from U-decay series measurements in rivers. Earth Planet Sci Lett 193 549-563 von Gunten HR, Roessler E, Lowson RT, Reid PD, Short SA (1999) Distribution of uranium- and thorium series radionuclides in mineral phases of a weathered lateritic transect of a uranium ore body. Chem Geol 160 225-240... 

The four isotopes, as those of any element, have the same chemical properties. The four are not, however, uniformly distributed in the earth s crust the occurrence of three of them, in minerals and rocks, is associated with the radioactive decay of isotopes of thorium and uranium. In most minerals and rocks the relative amounts (or the isotopic ratios) of the isotopes of lead (often expressed relative to the amount of stable lead-204) are generally within well-known ranges, which are independent of the composition of the mineral or rock they are, however, directly related to the amounts of radioactive thorium and uranium isotope impurities in them. 

Briggs, G.H., Distribution of the Active Deposits of Radium, Thorium and Actinium in Electric Fields, Phil. Mag. 41, 357, 1921. 

---