"Low toxicity alpha emitters" means natural uranium, depleted uranium, natural thorium; uranium-235, uranium-238, thorium-232, thorium-228 or thorium-230 when contained in ores or physical or chemical concentrates; or alpha emitters with a half-life of less than 10 days. "Natural thorium" means thorium isotopes with a naturally occurring ...

Chemical Compounds Containing Uranium and Thorium. By Otu Inyang 713-743-5858. June 10, 2021. Certain uranium and thorium containing compounds, e.g. …

The organic phase containing uranium and thorium is washed by small amount of pure water to remove small amount of rare earths, Fe, and other impurities in the organic phase. 60–80°C of hot water is used to strip uranium and thorium; the stripping conditions are that phase ratio O/A = 1:0.9 and the number of stages is 3–4.

A process for recovering tantalum and/or niobium metal compounds from an ore containing one or more compounds of said metal or metals and further containing uranium, thorium, radium, titanium, and rare earth metals, wherein in a first step (I) the crushed ore is decomposed with a 0.5 to 6-fold amount of 70 to 96 percent sulfuric acid at ...

(containing several wt% Th) in the Witwatersrand-type quartz-pebble conglomerates deposited in a highly anoxic fluvial environment. Abiotic alteration of uraninite and coffinite, including radiolysis ... The near-surface mineralogy of uranium and thorium provide a measure of a planet's geotectonic and geobiological history. In the absence of ...

The measurement of potassium, uranium and thorium concentrations is therefore a valuable geochemical and mineralogical information (Klaja & Dudek 2016). Potassium can be found in K-feldspars ...

Thorium is a naturally occurring, slightly radioactive element. It is widely distributed in nature with an average concentration of 10.5 ppm Th in the upper earth's crust. In general, thorium occurs in …

Thorium (chemical symbol Th) is a naturally occurring radioactive metal found at trace levels in soil, rocks, water, plants and animals. Thorium is solid under …

Such uranium-containing glass is often referred to as canary or vaseline glass. In part, collectors like uranium glass for the attractive glow that is produced when the glass is exposed to a black light. Even ordinary glass can contain high-enough levels of potassium-40 or thorium-232 to be detectable with a survey instrument.

According to estimates, the Earth's upper crust contains an average of 10.5 parts per million (ppm) of thorium, compared with about 3 ppm of uranium. "Because of …

not bioconcentrate in plants from soil. However, plants grown at the edge of impoundments of uranium tailings containing elevated levels of thorium had a plant/soil concentration ratio of about 3 (Ibrahim and Whicker 1988). The atmospheric mass concentration of thorium ranged from 0.2 to 1.0 ng/m 3, with a mean value of

Samples Containing Thorium or Uranium by Paul Gaines, Ph.D. Overview. Uranium (U) and Thorium (Th) are considered "Rare Earth" (RE) elements. More specifically, Th and U are members of the actinide …

A process for recovering one or more nonradioactive transition metal compounds from an ore containing one or more compounds of said transition metal or metals and further containing at least one complex of a member selected from the group consisting of uranium, thorium, radium, titanium, and rare earth metals, comprises decomposing said …

Unirradiated thorium means thorium containing not more than 10 −7 grams uranium-233 per gram of thorium-232. Unirradiated uranium means uranium containing not more than 2 × 10 3 Bq of plutonium per gram of uranium-235, not more than 9 × 10 6 Bq of fission products per gram of uranium-235 and not more than 5 × 10 −3 g of uranium-236 per ...

In 1959, Crouse and Brown reported the recovery of thorium, uranium, and rare earths from monazite sulfate liquors by an amine extractant (Crouse and Brown, 1959). ... More then 150 minerals containing uranium are known. Typically, however, uranium ores contain only about 0.1% uranium. In the commercial production of uranium metal, the …

(i) Uranium and thorium ores, concentrates of uranium and thorium ores, and other ores containing naturally occurring radionuclides that are intended to be processed for the use of these radionuclides; (ii) Natural uranium, depleted uranium, natural thorium or their compounds or mixtures, provided they are unirradiated and in solid or liquid form;

The DOE Office of Environmental Management now considers the disposal of this uranium-233 to be 'an unfunded mandate'. Thorium reactors also produce uranium-232, which decays to an extremely potent high-energy gamma emitter that can penetrate through one metre of concrete, making the handling of this spent nuclear fuel …

reactors fueled with natural or low-enriched uranium and containing thorium mixed with the uranium or in separate target channels. U-232 decays with a 69-year half-life through 1.9-year half-life Th-228 to Tl-208, which emits a 2.6 MeV gamma ray upon decay. We find that pressurized light-water-reactors fueled with LEU-thorium fuel at

In any event, there is ample uranium and thorium in the igneous rocks of the earth's crust to power a highly industrialized civilization for an extremely long time, certainly for thousands of centuries. ... Today the Atomic Energy Commission is buying small amounts paying about $4 per pound for a product containing at least 30% thorium oxide ...

Thorium is much more abundant than uranium in rocks from the Earth's crust; it is found in small amounts in most rocks and soils. Uranium can form compounds with many of …

Uranium-233 can be recovered and purified from neutron-irradiated thorium reactor fuels through the thorium extraction, or Thorex, process, which employs tributyl phosphate extraction chemistry. Irradiated fuel, containing either thorium metal or oxide, is dissolved in nitric acid containing a small amount of fluoride ion.

In 1897-8 Rutherford studied the radioactivity of uranium and thorium using an apparatus comprising zinc plates (A and B) 4 cm apart and charged to 50 V (see Fig 1). He placed aluminium foils of differing thicknesses above the uranium sample on A and measured the 'rate of leak' (current flowing through the ionised air) using a Thomson …

A method for determining the activity of the 230 Th isotope in uranium-containing minerals, including the isolation and isolation of chemical fractions of uranium and thorium by anion exchange chromatography, the production of alpha sources of uranium and thorium by electrodeposition, the measurement of the alpha activity of 238 U and 230 Th ...

Thorium is much more abundant in nature than uranium. Thorium can be used as a nuclear fuel through breeding to uranium-233 (U-233). ... lantern mantles, arc-light lamps, welding electrodes and heat-resistant ceramics. Glass containing thorium oxide has both a high refractive index and wavelength dispersion, and is used in high quality lenses ...

thorium (Th), radioactive chemical element of the actinoid series of the periodic table, atomic number 90; it is a useful nuclear reactor fuel. Thorium was discovered (1828) by Swedish chemist Jöns Jacob …

In general terms, "source material" means material containing either the element thorium or the element uranium; provided that the uranium is not enriched in …

The thorium daughter nuclide has a half-life of 24.1 days and decays into the protactinium nuclide 234 91Pa, which has a half-life of 6.75 hours and decays into 234 90U, whose half-life is 245 thousand years. In a sample of uranium-containing rock, of the four nuclides the most abundant will be _____. 3.

Long-lived radioactive elements such as uranium, thorium and potassium and any of their decay products, such as radium and radon are examples of NORM. ... The NORM aspect is due to monazite – a rare earth phosphate containing a variety of rare earth minerals (particularly cerium and lanthanum) and 5-12% (typically about 7%) thorium, and ...

natural uranium and thorium from place to place (including use as backfill) and still be exempt from the requirements of 10 CFR Part 40. As a result, this exemption could result in exposures above the unrestricted use criterion in 10 CFR 20.1402 for any high concentrations of uranium and thorium that may sometimes be found in nature. 3.2.4 10 ...

thorium are ingestion of food and water containing thorium and inhalation of thorium-contaminated dust. Ingestion is generally the main exposure concern, unless there is a nearby source of airborne dust containing thorium such as uranium mill tailings.