THORIUM OXIDE (ThO2)

Uranium thorium recovery: Working up of uranium-thorium wastes in Kernel casting process: ... evaporating a soln of uranium thorium oxide waste dissolved in a nitric acid hydrofluoric acid mixture up to the appearance of nitrous gases, the residue diluted in the hot condition with water and this soln brought to a pH between 2.5 and 3.5 with ammonia at a temp below 40 °C. The soln recovered by the process can be adjusted to any heavy metal (ie, uranium thorium) concn up to about 300 g/l at a pH of 3 to 3.5, is stable for over 1 month and is miscible with ... polyvinyl alcohol. This soln can be adjusted through further addition of uranium or thorium to the desired uranium ratio for the casting soln. ... According to the process, all wastes can be returned without loss during the production process.

SRP: At the time of review, criteria for land treatment or burial (sanitary landfill) disposal practices are subject to significant revision. Prior to implementing land disposal of waste residue (including waste sludge), consult with environmental regulatory agencies for guidance on acceptable disposal practices.

Disposal of ... wastes /containing uranium/ should follow guidelines set forth by the Nuclear Regulatory Commission & the EPA. /Uranium & cmpd/

If material not involved in fire: Contact the local, state, or Department of Energy Radiological Response Team. Keep sparks, flames, & other sources of ignition away. Keep material out of water sources & sewers.

Personnel protection: Keep upwind. Avoid breathing fumes from burning material. ... Do not handle broken packages unless wearing appropriate personal protective equipment. Wash away any material which may have contacted the body with copious amounts of water or soap & water.

SRP: Contaminated protective clothing should be segregated in such a manner so that there is no direct personal contact by personnel who handle, dispose, or clean the clothing. Quality assurance to ascertain the completeness of the cleaning procedures should be implemented before the decontaminated protective clothing is returned for reuse by the workers. Contaminated clothing should not be taken home at end of shift, but should remain at employee's place of work for cleaning.

30 [mg/m3]

330 [mg/m3]

2000 [mg/m3]

Retention of thorium from inhalation of thorium dioxide dust for 1 yr ... left 98% of the body burden of thorium in the lung and pulmonary lymph nodes, 2% in bone, and less than 0.1% in the rest of the body. The relative immobility of tissue deposited thorium is shown by the finding in the femur, and fractions of the latter amount in the kidney, spleen, and liver 6 to 7 yr after inhalation exposure had been terminated.

Thorium dioxide is a constituent of many minerals, and those of industrial importance incl monazite, thorite, and thorianite.

Monazite may contain 2.5-2.8% thorium oxide mixed with rare earth elements, zirconium, titanium, cadmium, niobium, and uranium. It is almost always found mixed with products of its disintegration ... .

The vein deposits of thorite (ThSiO4), such as occur in the area of Lemhi Pass, Idaho, are the highest grade thorium mineral, containing about 25 to 63 percent thorium oxide (ThO2).

Of 1107 patients given thorium dioxide between 1930 and 1952 primarily for the radiological visualization of blood vessels, 699 had died and 408 were alive up to the end of 1963. The long term sequelae were shown, statistically, to incl local granulomas in 81, cirrhosis of the liver in 42, fatal blood disorders in 16, and hemangioendotheliomas occurring in 22 and virtually thorium dioxide specific.

Brief case histories of 6 patients seen between 1967 and 1975, who had received thorium dioxide many yr earlier. Complications incl leukemia, aplastic anemia, tumors, and ... hyposplenism.

Tumors of the hepatic vasculature have been induced by thorium dioxide ... .

... After iv admin of thorium dioxide, most cancers were tumors of the reticuloendothelial system esp involving the liver with an equal distribution of sarcomas and carcinomas. Injection of thorium dioxide into the sinus cavities results in carcinomas. The latent period for tumor development is long (approx 15 yr), and tumorigenesis arises from alpha radiation.

For more Human Toxicity Excerpts (Complete) data for THORIUM DIOXIDE (31 total), please visit the HSDB record page.

Dogs, rabbits, guinea pigs, and mice exposed to inhalation of the oxide ... of thorium at 10-80 mg of metal/cu m for 60-270 days, showed no mortality, but leukocyte levels incr, and abnormal bone marrow and lung lesions of uncertain etiology were noticed.

Short term inhalation exposures of dogs for 2 to 10 weeks to the nitrate, oxide, fluoride, & oxalate separately, at mean exposure concentrations of 76, 51, 11, & 26 mg/cu m of cmpd, respectively, & mean particle diameters around 1 um showed abnormal leukocytes as the only evidence of toxicity.

Progressive cirrhosis of the lungs was found in a subchronic inhalation study in rats. Rats were exposed intermittently for 6-9 months to an inert aerosol (control), to the inert aerosol enriched with 1OX or 49% insoluble thorium dioxide, or to thorium dioxide (100%) alone. The severity of the lung cirrhosis was directly related to the radiation dose and the amount of thorium dioxide. Cirrhosis of the lungs became evident in 3-6 months in the 100% thorium dioxide group, in 9-12 months in the 49% thorium dioxide group, in 12-15 months in the 10% thorium dioxide group, and in 18-24 months in the inert aerosol control group. At lung exposures of up to 150 rad, reticulosarcoma was found, while at lung exposures of 100-2,700 rad, glandular cancerous tumors were found.

Rats were exposed to various concentrations of thorium dioxide for 6-9 months, and the frequency and histological type of lung tumors were determined following observation for up to 21 months. /It was/ concluded that the incidence and histological type of lung tumors that developed were dependent on the radiation dose to the lungs. At lung doses of up to 150 rad (3000 rems), primarily reticulosarcoma was found (in 16% of the animals), while at total doses of 1000-2700 rads (20,000-54,000 rems), glandular cancerous tumors (adenomatosis and squamous cell carcinoma) were found in all of the exposed animals, and the reticulosarcoma was no longer observed.

For more Non-Human Toxicity Excerpts (Complete) data for THORIUM DIOXIDE (7 total), please visit the HSDB record page.

Potential exposure to thorium dioxide may occur through inhalation of dust or gas, intravenous injection, ingestion of liquid thorium dioxide, and skin absorption. ...

Workers in plants where thorium oxide is refined ... .

Occupations at greatest risk of possible exposure were ceramic makers, incandescent lamp makers, magnesium alloy makers, metal refiners, nuclear reactor workers, chemists, and vacuum tube makers. OSHA estimated that 128,500 workers were possibly exposed to the compound during its production and use. A number of patients were exposed to Thorotrast when it was administered for x-ray procedures.

Basic Treatment: Establish a patent airway. Suction if necessary. Watch for signs of respiratory insufficiency and assist ventilations if needed. Administer oxygen by nonrebreather mask at 10 to 15 L/min. Monitor for pulmonary edema and treat if necessary ... . Monitor for shock and treat if necessary ... . Anticipate seizures and treat if necessary ... . For eye contamination, flush eyes immediately with water. Irrigate each eye continuously with normal saline during transport ... . Do not use emetics. For ingestion, rinse mouth and administer 5 ml/kg up to 200 ml of water for dilution if the patient can swallow, has a strong gag reflex, and does not drool ... . Cover skin burns with dry sterile dressings after decontamination ... . /Poison A and B/

Advanced Treatment: Consider orotracheal or nasotracheal intubation for airway control in the patient who is unconscious. has severe pulmonary edema, or is in respiratory arrest. Positive-pressure ventilation techniques with a bag valve mask device may be beneficial. Monitor cardiac rhythm and treat arrhythmias as necessary ... . Start an IV with D5W /SRP: "To keep open", minimal flow rate/. Use lactated Ringer's if signs of hypovolemia are present. Watch for signs of fluid overload. Consider drug therapy for pulmonary edema ... . For hypotension with signs of hypovolemia, administer fluid cautiously. Watch for signs Of fluid overload ... . Treat seizures with diazepam (Valium) ... . Use proparacaine hydrochloride to assist eye irrigation ... . /Poison A and B/

Persons in charge of vessels or facilities are required to notify the National Response Center (NRC) immediately, when there is a release of this designated hazardous substance, in an amount equal to or greater than its reportable quantity of 100 curie or 3.7x10+12 becquerel. The toll free number of the NRC is (800) 424-8802; In the Washington D.C. metropolitan area (202) 426-2675. The rule for determining when notification is required is stated in 40 CFR 302.4 (section IV. D.3.b). /(226)Thorium/

Persons in charge of vessels or facilities are required to notify the National Response Center (NRC) immediately, when there is a release of this designated hazardous substance, in an amount equal to or greater than its reportable quantity of 1 curie or 3.7x10+10 becquerel. The toll free number of the NRC is (800) 424-8802; In the Washington D.C. metropolitan area (202) 426-2675. The rule for determining when notification is required is stated in 40 CFR 302.4 (section IV. D.3.b). /(227)Thorium/

Persons in charge of vessels or facilities are required to notify the National Response Center (NRC) immediately, when there is a release of this designated hazardous substance, in an amount equal to or greater than its reportable quantity of 0.01 curie or 3.7x10+8 becquerel. The toll free number of the NRC is (800) 424-8802; In the Washington D.C. metropolitan area (202) 426-2675. The rule for determining when notification is required is stated in 40 CFR 302.4 (section IV. D.3.b). /(228)Thorium/

Persons in charge of vessels or facilities are required to notify the National Response Center (NRC) immediately, when there is a release of this designated hazardous substance, in an amount equal to or greater than its reportable quantity of 0.001 curie or 3.7x10+7 becquerel. The toll free number of the NRC is (800) 424-8802; In the Washington D.C. metropolitan area (202) 426-2675. The rule for determining when notification is required is stated in 40 CFR 302.4 (section IV. D.3.b). /(229)Thorium/

For more CERCLA Reportable Quantities (Complete) data for THORIUM DIOXIDE (8 total), please visit the HSDB record page.

Used in high-temperature ceramics, gas mantles, nuclear fuel, flame spraying, crucibles, non-silica optical glass, catalysis, filaments in incandescent lamps, cathodes in electron tubes and arc-melting electrodes. [CAMEO] Has been used as a radiopaque material in diagnostic radiology; [Merck Index]

Glass Manufacturing [Category: Industry]

Ceramics (high temp), gas mantles, nuclear fuel, flame spraying, crucibles, medicine, nonsilica optical glass, catalyst, thoriated tungsten filaments

In electrodes for arc welding

In incandescent mantles; glass with thorium oxide has a high refractive index and a low dispersion which is useful in high-quality camera lenses and scientific equipment; as a catalyst in sulfuric acid manufacture, petroleum cracking, and in the manufacture of nitric acid from ammonia.

Commercial mantles are made up of a mesh hood of /thorium/ oxide surrounding a flame and are used in decorative exterior lighting, gasoline lanterns for camping

(1986) 15,617 lb

(1985) 8.3X10+9 g

The 1979 TSCA Inventory lists five producers and importers of thorium dioxide with imports of 6,000 pounds.

Reduction of thorium nitrate

Monazite + sodium hydroxide (salt formation/separation; coproduced with rare earth oxide, hydrate)

Suspension containing 20-25% Thorium dioxide, Thorotrast

3-12 mm, sintered; -30, +200 mesh; -150, +325 mesh; -325 mesh, +10 microns, 99.5, 99.9 and 99.99% purity grades.

Technical and purities to 99.8% thorium dioxide; granular particles, crystals

Sterile contrast medium made up of 24-26% stabilized colloidal thorium dioxide in 25% aq dextrin and 0.15% methyl parasept as preservative

Umbrathor /is/ a soln of thorium dioxide.

Thorium oxide (ThO2): ACTIVE

The most important thorium compound ... owing to its high chemical and thermal stability.

The U.S. Department of Energy's inventory at year's end was 535,000 kg.