Thorium

232.038

232.03800

231-139-7

60YU5MIG9W

0337

2912|2975

DTXSID6049800

Soft gray-white metal; cubic|Grayish-white, lustrous, radioactive, metal; somewhat ductile and malleable

0

0.00000

Solid

11.7 g/cm³

1750 °C

4788 °C

Solubility in water at none°C: none

Dry finely divided tantalum, thorium, titanium, zirconium metals, or titanium-nickel, zirconium-copper alloys are not normally shock-sensitive. However, if they are enclosed in glass bottles which break on impact, ignition will occur. Storage of these materials moist & in metal containers is recommended.

1 Pa at 2360 deg C; 10 Pa at 2634 deg C; 100 Pa at 2975 deg C; 1 kPa at 3410 deg C; 10 kPa at 3986 deg C; 100 kPa at 4782 deg C

Explosive in powder form.

Valance 4; no stable nuclides; heat capacity: 27.32 J/mol K at 25 °C; darkens on prolonged exposure to air; finely divided metal is pyrophoric in air; HCl attacks metal vigorously, leaving up to 25% as an undissolved residue; nitric acid passivates (protects by forming an oxide layer) metal; dilute hydrofluoric acid and sulfuric acid, and concentrated phosphoric acid and perchloric acid attack thorium slowly, with evolution of hydrogen; metal is not attacked by alkali hydroxides|Thorium-232 found in nature undergoes natural decay by the emission of alpha- and beta-particles, and gamma-rays, eventually forming lead-208 (stable)|Pure thorium is soft, very ductile and can be cold-rolled, swaged, and drawn|Thorium is slowly attacked by water, but does not dissolve readily in most common acids, except hydrochloric|The physical properties of thorium are greatly influenced by the degree of contamination with the oxide

270 °C

Dust explosion possible if in powder or granular form, mixed with air. If dry, it can be charged electrostatically by swirling, pneumatic transport, pouring, etc.

approx. 586 kJ/mol

7

UN 3264 8/PG 3

23/24/25-34

S27;S45;S36/S37/S39;S26

XO6400000

T

Fireproof. Separated from strong oxidants. Cool. Well closed. Keep in a well-ventilated room.

When pure it is air-stable.

P210, P220, P221, P260, P261, P264, P270, P271, P280, P301+P312, P302+P352, P304+P340, P305+P351+P338, P312, P314, P321, P330, P332+P313, P337+P313, P362, P370+P378, P403+P233, P405, P501

H272

Tantalum, thorium, titanium, and zirconium (powdered & dry) ignited when a glass container of the powder was thrown at a wall with force sufficient to break the container.|Thorium incandesces in chlorine, bromine or iodine, & would be expected to ignite readily in fluorine. ... The massive metal ignites on heating in oxygen.|Thorium when heated with sulfur, reacts vigorously with incandescence.|Thorium, when heated with chlorine, reacts vigorously with incandescenece.|For more Hazardous Reactivities and Incompatibilities (Complete) data for THORIUM, ELEMENTAL (7 total), please visit the HSDB record page.

Qiu R; Youkuangye 4 (4): 62-6 (1985). Uranium, radium and thorium biosorption review. Wastewater treatment, for radium and thorium and uranium removal. Adsorption: Wastewater treatment adsorption by microorganisms. ...|DHHS/ATSDR; Toxicological Profile for Thorium (1990) ATSDR/TP-90/25

Highly flammable if powdered. Finely dispersed particles form explosive mixtures in air.|Flammable - 3rd degree, Reactive - 3rd degree

|Warning|H272 (100%): May intensify fire; oxidizer [Danger Oxidizing liquids; Oxidizing solids]|P210, P220, P221, P260, P261, P264, P270, P271, P280, P301+P312, P302+P352, P304+P340, P305+P351+P338, P312, P314, P321, P330, P332+P313, P337+P313, P362, P370+P378, P403+P233, P405, and P501|Aggregated GHS information provided by 4 companies from 2 notifications to the ECHA C&L Inventory. Each notification may be associated with multiple companies.

Powdered thorium metal is often pyrophoric and should be carefully handled. When heated in air, thorium turnings ignite and burn brilliantly with white light.|... Some alloys may ignite spontaneously. The metal in massive form is not flammable. ... Dusts of thorium have very low ignition points and may ignite at room temperature.|The powdered metal ignites at 270 °C. ... There is no limiting oxygen pressure that will prevent thorium ignition, for ignition will occur in pure carbon dioxide.|... Powdered metal ignites when rubbed or crushed, or on pouring as a stream in air, owing to intergranular friction.|Fire hazard /is/ moderate in the form of dust, when exposed to heat or flame ...

The minimal explosive concentration for thorium is 75 oz/1000 cu ft.|... Explosive in powder form.

Contact the local, state or Department of Energy radiological response team. Do not use water. Use graphite, soda ash, powdered sodium chloride, or suitable dry powder. /Thorium metal pyrophoric/

If material not on fire & not involved in fire: Contact the local, state, or Department Of Energy Radiological Response Team. Do not use water. Keep sparks, flames, & other sources of igintion away. Keep material out of water sources & sewers. Keep material dry. Do not attempt to sweep up dry material. /Thorium metal, pyrophoric/|Personnel protection: Keep upwind. Avoid breathing dusts, & 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. /Thorium metal, pyrophoric/|Evacuation: Keep unnecessary people out of incident area until area declared safe by Radiological Response Team. /Thorium metal, pyrophoric/|To avoid risk of dust explosions in plants where thorium powder is mfr by pulverizing or grinding process, operations should be conducted in atmosphere of nitrogen or helium.|Thorium disintegrates with production of thoron ((220)radon), which is alpha emitter and presents radiation hazard. Good ventilation of areas where thorium is stored or handled is therefore essential.

/GUIDE 162: RADIOACTIVE MATERIALS (LOW TO MODERATE LEVEL RADIATION)/ Health: Radiation presents minimal risk to transport workers, emergency response personnel and the public during transportation accidents. Packaging durability increases as potential hazard of radioactive content increases. Undamaged packages are safe. Contents of damaged packages may cause higher external radiation exposure, or both external and internal radiation exposure if contents are released. Low radiation hazard when material is inside container. If material is released from package or bulk container, hazard will vary from low to moderate. Level of hazard will depend on the type and amount of radioactivity, the kind of material it is in, and/or the surfaces it is on. Some material may be released from packages during accidents of moderate severity but risks to people are not great. Released radioactive materials or contaminated objects usually will be visible if packaging fails. Some exclusive use shipments of bulk and packaged materials will not have "RADIOACTIVE" labels. Placards, markings and shipping papers provide identification. Some packages may have a "RADIOACTIVE" label and a second hazard label. The second hazard is usually greater than the radiation hazard; so follow this GUIDE as well as the response GUIDE for the second hazard class label. Some radioactive materials cannot be detected by commonly available instruments. Runoff from control of cargo fire may cause low-level pollution. /Thorium metal, pyrophoric/|/GUIDE 162: RADIOACTIVE MATERIALS (LOW TO MODERATE LEVEL RADIATION)/ Fire or Explosion: Some of these materials may burn, but most do not ignite readily. Uranium and Thorium metal cuttings may ignite spontaneously if exposed to air ... . Nitrates are oxidizers and may ignite other combustibles ... . /Thorium metal, pyrophoric/|/GUIDE 162: RADIOACTIVE MATERIALS (LOW TO MODERATE LEVEL RADIATION)/ Public Safety: CALL Emergency Response Telephone Number ... . Priorities for rescue, life-saving, first aid, fire control and other hazards are higher than the priority for measuring radiation levels. Radiation Authority must be notified of accident conditions. Radiation Authority is usually responsible for decisions about radiological consequences and closure of emergencies. As an immediate precautionary measure, isolate spill or leak area for at least 25 meters (75 feet) in all directions. Stay upwind. Keep unauthorized personnel away. Detain or isolate uninjured persons or equipment suspected to be contaminated; delay decontamination and cleanup until instructions are received from Radiation Authority. /Thorium metal, pyrophoric/|/GUIDE 162: RADIOACTIVE MATERIALS (LOW TO MODERATE LEVEL RADIATION)/ Protective Clothing: Positive pressure self-contained breathing apparatus (SCBA) and structural firefighters' protective clothing will provide adequate protection. /Thorium metal, pyrophoric/|For more DOT Emergency Guidelines (Complete) data for THORIUM, ELEMENTAL (8 total), please visit the HSDB record page.

No person may /transport,/ offer or accept a hazardous material for transportation in commerce unless that person is registered in conformance ... and the hazardous material is properly classed, described, packaged, marked, labeled, and in condition for shipment as required or authorized by ... /the hazardous materials regulations (49 CFR 171-177)./|The International Air Transport Association (IATA) Dangerous Goods Regulations are published by the IATA Dangerous Goods Board pursuant to IATA Resolutions 618 and 619 and constitute a manual of industry carrier regulations to be followed by all IATA Member airlines when transporting hazardous materials.|The International Maritime Dangerous Goods Code lays down basic principles for transporting hazardous chemicals. Detailed recommendations for individual substances and a number of recommendations for good practice are included in the classes dealing with such substances. A general index of technical names has also been compiled. This index should always be consulted when attempting to locate the appropriate procedures to be used when shipping any substance or article.

Evacuate danger area! Consult an expert! Personal protection: complete protective clothing including self-contained breathing apparatus. Sweep spilled substance into covered containers. Carefully collect remainder. Then store and dispose of according to local regulations.

Fireproof. Separated from strong oxidants. Cool. Well closed. Keep in a well-ventilated room.

A nuisance-causing concentration of airborne particles can be reached quickly when dispersed.

May cause mechanical irritation to the eyes. Inhalation of the aerosol may cause damage to the lungs.

Repeated or prolonged inhalation of the aerosol may cause effects on the lungs. This substance is carcinogenic to humans.

NO open flames, NO sparks and NO smoking. NO contact with hot surfaces. Do NOT expose to friction or shock. Closed system, dust explosion-proof electrical equipment and lighting. Prevent deposition of dust.

PREVENT DISPERSION OF DUST! AVOID ALL CONTACT! IN ALL CASES CONSULT A DOCTOR!

Use closed system and ventilation.

Protective gloves. Protective clothing.

Wear face shield or eye protection in combination with breathing protection.

Radionuclides have been designated as a hazardous air pollutant under section 112 of the Clean Air Act. /Radionuclides/

Thorium is a naturally occurring, radioactive substance. In the environment, thorium exists in combination with other minerals, such as silica. Small amounts of thorium are present in all rocks, soil, water, plants, and animals. Soil contains an average of about 6 parts of thorium per million parts of soil (6 ppm). More than 99% of natural thorium exists in the form of thorium-232. It breaks down into two parts-a small part called "alpha" radiation and a large part called the decay product. The decay product is also not stable and continues to break down through a series of decay products until a stable product is formed. During these decay processes, radioactive substances are produced. These include radium and radon. These substances give off radiation, including alpha and beta particles, and gamma radiation. Some rocks in underground mines contain thorium in a more concentrated form. After these rocks are mined, thorium is usually concentrated and changed into thorium dioxide or other chemical forms. After most of the thorium is removed, the rocks are called "depleted" ore or tailings. Thorium is used to make ceramics, gas lantern mantles, and metals used in the aerospace industry and in nuclear reactions. Thorium can also be used as a fuel for generating nuclear energy.

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. The rule for determining when notification is required is stated in 40 CFR 302.4 (section IV. D.3.b). /Thorium-226/|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. The rule for determining when notification is required is stated in 40 CFR 302.4 (section IV. D.3.b). /Thorium-227/|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. The rule for determining when notification is required is stated in 40 CFR 302.4 (section IV. D.3.b). /Thorium-228/|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. The rule for determining when notification is required is stated in 40 CFR 302.4 (section IV. D.3.b). /Thorium-229/|For more CERCLA Reportable Quantities (Complete) data for THORIUM, ELEMENTAL (8 total), please visit the HSDB record page.

Industrial exposures to thorium occur during the refining of monazite sand, the handling of various thorium salts, the fabrication of thorium ingots, the handling thorium salts in various industrial uses, the casting and machining of thorium alloy parts, and the production of glazed tiles. In addition, there is potential for exposure through fumes from welding with thoriated-tungsten electrodes and from fires and explosions caused by thorium metal powder. ... Measurement of the radioactive gas, thoron (220Rn), a daughter product of Th, in exhaled air provides another measure of past thorium exposure|PRINCIPAL HAZARDS FROM THORIUM IN INDUSTRY ARE INHALATION OF THORIUM DUST & OF THORON GAS & ITS DECAY PRODUCTS, & EXPOSURE TO EXTERNAL BETA & GAMMA RADIATION. INHALATION HAZARD IS GREATEST IN DUSTY OPERATIONS SUCH AS GRINDING OF METALS, CERAMICS, HANDLING OF THORIUM POWDER, & CONTAMINATION FROM THORIUM FIRES.

273 men exposed to thorium and other rare earths between 1940 and 1973 at a monazite sand refinery were studied at Argonne National Laboratory from 1976 to 1980. In vivo measurements of body burden were made by counting gamma rays emitted by daughter products of retained thorium and by measuring exhaled thoron. Health status was ascertained through questionnaire, physical exam, and clinical lab tests. Measured body burden was found to be higher in those with a history of longer exposure. All parameters of the complete blood count were examined for evidence of an effect due to thorium. Comparisons of high and low body burden groups showed that only age and cigarette smoking had an effect on complete blood count parameters.

After inhalation exposure, the primary route of excretion is in the feces following ciliary clearance from the lungs to the gastrointestinal tract. /Thorium/

The purest specimens often contain several tenths of a percent of the oxide.|The crude alloy contains 4.1-7.0% Zn.

Fresh air, rest.

Remove contaminated clothes. Rinse and then wash skin with water and soap. Use radiation detector to ensure no remaining contamination.

Rinse with plenty of water for several minutes (remove contact lenses if easily possible).

EDTA (ethylenediaminetetraacetic acid) is believed to merit consideration in helping rid the body of thorium from accidental overexposure. Used in four patients whose exposure was complicated by burns and exposure to uranium, EDTA aided removal of thorium as a soluble undissociated complex, although bioassay was rendered more difficult by the complex.|Advanced Treatment. Consider orotracheal or nasotracheal intubation for airway control in the patient who is unconscious or is in severe respiratory distress. Monitor cardiac rhythm and treat arrhythmias as necessary. Start IV administration of 0.9% saline (NS) or lactated Ringer's (LR) TKO. For hypotension with signs of hypovolemia, administer fluid cautiously. Watch for signs of fluid overload. Treat seizures with diazepam or lorazepam. Perform routine advanced life support care as needed. Use proparacaine hydrochloride to assist eye irrigation. /Radioactives I, II, and III/|Special Considerations. Most symptoms from radioactive product exposure are delayed; treat other medical or trauma problems according to normal protocols. An accurate history of the exposure is essential to determine risk and proper treatment modalities. The dose of radiation determines the type and clinical course of exposure: 100 rads: GI symptoms (nausea, vomiting, abdominal cramps, diarrhea). Symptom onset within a few hours. 600 rads: Several GI symptoms (necrotic gastroenteritis) may result in dehydration and death within a few days. Several thousand rads: neurological/cardiovascular symptoms (confusion, lethargy, ataxia, seizures, coma, cardiovascular collapse) within minutes to hours. Bone marrow depression, leukopenia, and infections usually follow severe exposures./Radioactives I, II, and III/|Radiation (Ionizing) Emergency and Supportive Measures. Treatment of serious medical problems takes precedence over radiologic concerns. Maintain an open airway and assist ventilation if necessary. Treat coma and seizures if they occur. Replace fluid losses from gastroenteritis with intravenous crystalloid solutions. Treat leukopenia and resulting infections as needed. Immunosuppressed patients require reverse isolation and appropriate broad-spectrum antibiotic therapy. Bone marrow stimulants may help selected patients. Specific drugs and antidotes. Chelating agents or pharmacologic blocking drugs may be useful in some cases of ingestion or inhalation of certain biologically active radioactive materials, if they are given before or shortly after exposure. /Radiation (Ionizing)/|Decontamination. 1. Exposure to particle-emitting solids or liquids. The victim is potentially highly contaminating to rescuers, transport vehicles, and attending health personnel. 1. Remove victims from exposure, and if their conditions permit, remove all contaminated clothing and wash the victims with soap and water. b. All clothing and cleansing water must be saved, evaluated for radioactivity, and properly disposed of. c. Rescuers should wear protective clothing and respiratory gear to avoid contamination. At the hospital, measures must be taken to prevent contamination of facilities and personnel. d. Induce vomiting or perform gastric lavage if radioactive material has been ingested. Administer activated charcoal, although its effectiveness is unknown. Certain other adsorbent materials may also be effective. e. Contact Radiation Emergency Assistance Center & Training Site (REAC/TS/: telephone (865) 576-3131 or (865) 481-1000)/ and the state radiologic health department for further advice. In some exposures, unusually aggressive steps may be needed (eg, lung lavage for significant inhalation of plutonium). 2. Electromagnetic radiation exposure. The patient is not radioactive and does not pose a contamination threat. There is no need for decontamination once the patient has been removed from the source of exposure, unless electromagnetic radiation emitter fragments are embedded in body tissues. /Radiation (Ionizing)/

232Th radioisotope

The substance can be absorbed into the body by inhalation.

Cough.

Redness.

Cancer, Hematological (Blood Forming), Hepatic (Liver), Respiratory (From the Nose to the Lungs)

Over a ton of thorium is produced annually, approximately half of which is devoted to the production of gas mantles.|Principal nonenergy applications were in Welsbach incandescent gaslight mantles, as a hardener in thorium-magnesium alloys in thoriated tungsten electrodes, and in dispersion hardening, refractories, electronics, and chemical catalytic uses.

Powder, unsintered bars, sintered bars, sheets.|-200 mesh, 99.8% pure grade in airtight glass under argon.

Thorium: ACTIVE|The principal production stages are the concentration of thorium minerals, extraction of thorium from them, purification, and conversion to the metal or desired compounds, usually ThO2.|Monazite is the most common and commercially important thorium bearing mineral. ... Monazite sand is separated from other sands by physical or mechanical means following dredging operations. ... The metallurgical extraction of monazite sand concentrates for producing lighting mantle-grade thorium consists of digestion with hot, fuming sulfuric acid for several hours. The resulting mass is diluted with water which dissolves thorium, ... . Neutralization of liquor precipitates thorium phosphate ... . Instead of selective precipitation, the impure concentrate may be further treated by a liq-liq extraction process to yield reactor grade thorium.|(1985) Thorium product used and produced by the domestic industry came from imports, industry and government stocks|Source: Monazite, thorite. It is about as abundant as lead.|Domestic mine production of thorium-bearing monazite ceased at the end of 1994 as world demand for ores containing naturally occurring radioactive thorium declined.

AOAC Method 993.14. Trace Elements in Waters and Wastewaters by Inductively Coupled Plasma/Mass Spectrometric Method.|EMSLC Method 200.8. Determination of Trace Elements in Waters by Inductively Coupled Plasma and Mass Spectrometry Revision 5.4, May 1994. Detection limit= 0.1 ug/l.|AOB Method I-001-1. Metals in Soils and Sediments by X-Ray Fluorescence. Quantitation limit= 15.0 ppm.

Determination of thorium in bone ash by the use of the dye Arsenazo III ... can measure as little as 1 ug under suitable conditions. Because of gross amt of calcium & phosphate, preliminary separation is necessary. Di(2-ethylhexyl) phosphoric acid is used as thorium extractant from the ash. Ashing is done at 750 °C followed by soln in nitric acid, the Di(2-ethylhexyl) phosphoric acid stripped with ammonium carbonate, acidified Arsenazo III added, and absorbance measured at 660 mu. Beer's law is obeyed up to 4 ug thorium. The procedure should be adaptable to soft tissues. ... /Total thorium/

Chemical Classes -> Inorganic substances, Radionuclides (radioactive materials)|Fire Hazards -> Flammable - 3rd degree, Reactive - 3rd degree