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Metals -> Elements, Metallic

Flammable agents - 3rd degree

13.31 (NIOSH, 2024) - Denser than water; will sink

13.31

Zirconium and hafnium chemistries are almost identical ... the density of zirconium is about half that of hafnium.

Relative density (water = 1): 13.31

13.31

13.3 @25 °C

Gray crystals

Highly lustrous metal of hexagonal crystal structure

Hard, shiny, ductile metal with a color very similar to that of stainless steel ... hafnium sponge metal is a dull powder gray

Highly lustrous, ductile, grayish solid.

Crystallizes in a...cubic system which transforms to a hexagonal close-packed system below 2033 K.

Insoluble (NIOSH, 2024)

Hafnium is slowly attacked by concentrated sulfuric acid. Hafnium is unaffected by nitric acid in all concentrations. It is resistant to dilute solutions of hydrochloric acid and sulfuric acid. Hafnium is attacked by all mineral acids if traces of fluorides are present. Hafnium is very resistant to attack by alkalies.

Soluble in hydrogen fluoride

Solubility in water: none

Insoluble

8316 °F at 760 mmHg (NIOSH, 2024)

4603 °C

4602 °C

8316 °F

4603 °C @760 [mm Hg]

8316 °F

4041 °F (NIOSH, 2024)

2233 °C

2222 °C

4041 °F

2233 °C

4041 °F

0 mmHg (approx) (NIOSH, 2024)

1X10-05 Pa at 1767 °C; 1X10-04 Pa at 2007 °C

0 mmHg (approx)

0 mmHg (approx)

Hafnium powder, dry, is a grayish metallic colored powder. Dust from dry powder may be ignited by static electricity. The dry powder reacts with moisture to produce hydrogen, a flammable gas. The heat from this reaction may be sufficient to ignite the hydrogen. It does not appreciably react with large quantities of water.

Grayish powdery solid wetted with water.

Other Solid

Highly lustrous, ductile, grayish solid; [NIOSH]

Solid

GREY POWDER.

20 °C for dust cloud

20 °C

This chemical does not meet GHS hazard criteria for 34.4% (124 of 360) of reports.

Danger

H250 (50.6%): Catches fire spontaneously if exposed to air [Danger Pyrophoric liquids]

P210, P222, P231, P233, P280, P302+P335+P334, and P370+P378 (click each P-code to see the statement)

Aggregated GHS information provided per 360 reports by companies from 10 notifications to the ECHA C&L Inventory.

Not Classified

Hafnium is listed on the EPA's Chemical Data Reporting (CDR) system. Manufacturers and importers of Hafnium are required to report information about their production and use of this chemical to the EPA under the Toxic Substances Control Act (TSCA). (40 eCFR Part 711)

Status: Active Update: 16-07-2021 https://echa.europa.eu/registration-dossier/-/registered-dossier/11969

The New Jersey Worker and Community Right to Know Act requires public and private employers to provide information about hazardous substances at their workplaces. (N.J.S.A. 34:5A-1 et. seq.)

Spontaneously Combustible

Flammable Solid

Excerpt from ERG Guide 135 [Substances - Spontaneously Combustible]:

Excerpt from ERG Guide 170 [Metals (Powders, Dusts, Shavings, Borings, Turnings, or Cuttings, etc.)]:

· Flammable/combustible material.

· May react violently or explosively on contact with water.

Flammable. Finely dispersed particles form explosive mixtures in air. Risk of fire and explosion. See Chemical Dangers.

The substance may spontaneously ignite on contact with air and at higher temperatures with nitrogen, phosphorous and sulphur. /Hafnium powder, wet or dry/

Flammability: Both dry and wet may ignite in powders.

Excerpt from ERG Guide 135 [Substances - Spontaneously Combustible]:

Excerpt from ERG Guide 170 [Metals (Powders, Dusts, Shavings, Borings, Turnings, or Cuttings, etc.)]:

· Fire will produce irritating, corrosive and/or toxic gases.

· Oxides from metallic fires are a severe health hazard.

2545 135

1326 170

1326 170(powder, wet)

2545 135(powder, dry)

Metals, Elemental and Powder, Active

Metals, Elemental and Powder, Active

USEPA; Development Document for Effluent Limitations, Guidelines, & Standards for the Nonferrous Metals Manufacturing Point Source Category. Vol 9 Primary & Secondary Titanium, Primary Zirconium & Hafnium; GRA & I Issue 11 (1990) EPA 440/1-89/019.9

Strong Reducing Agent

Highly Flammable

Excerpt from ERG Guide 135 [Substances - Spontaneously Combustible]:

Excerpt from ERG Guide 170 [Metals (Powders, Dusts, Shavings, Borings, Turnings, or Cuttings, etc.)]:

Use special powder, dry sand, water in large amounts.

Fresh air, rest.

Rinse contaminated clothes (fire hazard) with plenty of water. Remove contaminated clothes. Rinse and then wash skin with water and soap.

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

Rinse mouth.

· CALL 911. Then call emergency response telephone number on shipping paper. If shipping paper not available or no answer, refer to appropriate telephone number listed on the inside back cover.

· ELIMINATE all ignition sources (no smoking, flares, sparks or flames) from immediate area.

· CALL 911. Then call emergency response telephone number on shipping paper. If shipping paper not available or no answer, refer to appropriate telephone number listed on the inside back cover.

· ELIMINATE all ignition sources (no smoking, flares, sparks or flames) from immediate area.

Excerpt from NIOSH Pocket Guide for Hafnium:

Excerpt from ERG Guide 170 [Metals (Powders, Dusts, Shavings, Borings, Turnings, or Cuttings, etc.)]:

General First Aid:

General First Aid:

(General first aid procedures)

· Wear positive pressure self-contained breathing apparatus (SCBA).

· Wear positive pressure self-contained breathing apparatus (SCBA).

If material on fire or involved in fire: Use suitable dry powder. ... Use dry chemical or carbon dioxide. ... Use water only if flooding quantities are available. /Hafnium powder, dry/

If material on fire or involved in fire: Use suitable dry powder. ... Use dry chemical or carbon dioxide. ... Use water only if flooding quantities are available. /Hafnium powder, wetted/

Persons not wearing protective equipment and clothing should be restricted from areas of spills until cleanup has been completed. 1. Ventilate area of spill. 2. Collect spilled material in most convenient and safe manner and deposit in sealed containers for reclamation, or for disposal in secured sanitary landfill. Liq containing hafnium...should be absorbed in vermiculite, dry sand, earth, or similar material.

Any spilled powder should be cleaned up immediately with water so that it has no chance to dry in place.

Spillage disposal: Evacuate danger area. Eliminate all sources of ignition. Do not wash away into sewer because it is flammable. Do not absorb in sawdust or other combustible absorbents. Wet the powder to prevent formation of dust or ignition; carefully collect the powder into sealable containers, and remove it to a safe place. During this procedure, use extra personal protection, e.g., a P2 filter respirator for harmful particles.

Environmental considerations: land spill: Dig a pit, pond, lagoon, holding area to contain liquid or solid material. ... Apply appropriate foam to diminish vapor and fire hazard. ... /SRP: If time permits, pits, ponds, lagoons, soak holes, or holding areas should be sealed with an impermeable flexible membrane liner./ /Hafnium powder, wetted/

Environmental considerations: water spill: Use natural barriers or oil spill control booms to limit spill travel. /Hafnium powder, wetted/

Excerpt from ERG Guide 135 [Substances - Spontaneously Combustible]:

Excerpt from ERG Guide 170 [Metals (Powders, Dusts, Shavings, Borings, Turnings, or Cuttings, etc.)]:

SRP: The most favorable course of action is to use an alternative chemical product with less inherent propensity for occupational exposure or environmental contamination. Recycle any unused portion of the material for its approved use or return it to the manufacturer or supplier. Ultimate disposal of the chemical must consider: the material's impact on air quality; potential migration in soil or water; effects on animal, aquatic, and plant life; and conformance with environmental and public health regulations.

If the quantity justifies recovery, get in touch with the supplier for special instructions.

Used papers and cloths which have become contaminated with powders should be kept wet in covered Containers until they are /disposed/.

Remove all ignition sources. Evacuate danger area! Consult an expert! Personal protection: particulate filter respirator adapted to the airborne concentration of the substance. Wet powder to prevent dusting and ignition. Sweep spilled substance into covered water-filled containers. Then store and dispose of according to local regulations. Do NOT wash away into sewer. Do NOT absorb in saw-dust or other combustible absorbents.

Redness.

In Animals: irritation eyes, skin, mucous membrane; liver damage

Routine medical examinations should be provided to each employee who is exposed to hafnium and compounds at potentially hazardous levels. The employer should screen employees for history of liver disease. ... The importance of this organ in the biotransformation and detoxification of foreign substances should be considered before exposing persons with impaired liver function. Only those giving a positive history of these conditions should be referred for further medical examinations.

/SIGNS AND SYMPTOMS/ Lungs may be affected by repeated or prolonged exposure. The substance may have effects on the liver.

/SIGNS AND SYMPTOMS/ Overexposure to hafnium and its compounds may cause mild irritation of the eyes, skin, and mucous membranes.

/LABORATORY ANIMALS: Subchronic or Prechronic Exposure/ To evaluate the biocompatibility of refractory metals, titanium, hafnium, niobium, tantalum and rhenium were implanted in rats, and histological observation and elemental mapping were performed by X-ray scanning analytical microscope (XSAM) and electron probe microanalyzer (EPMA). The titanium, hafnium, niobium, tantalum and rhenium wires were implanted in the subcutaneous tissue of the abdominal region and in femoral bone marrow of rats for either 2 or 4 weeks. No inflammatory response was observed around the implants, and all the implants were encapsulated with thin fibrous connective tissue. No dissolution of these metals was detected by XSAM in the soft tissue. Histological examination of the hard tissue showed that the amount of new bone formation decreased slightly from the second to the fourth week after implantation, and that the percentage of bone in contact with the implant increased markedly over the same period. No dissolution of these metals was detected by EPMA in the hard tissue. The Ca and P intensities in the mapping images of newly formed bone were higher after 4 weeks than those after 2 weeks, which suggests that the newly formed bone continued to mature from 2 to 4 weeks after implantation. These results indicate that titanium, hafnium, niobium, tantalum and rhenium have good biocompatibility and osteoconductivity.

/LABORATORY ANIMALS: Subchronic or Prechronic Exposure/ The aim of the present experimental study was to evaluate the tissue response to hafnium (Hf) a reactive metal closely related to titanium (Ti) and zirconium (Zr). Hf has not been previously evaluated as implant material in a biologic environment. In a first experiment, 21 machined Hf non-threaded implants (test) and 21 similar Ti implants (control) were inserted in the abdominal wall of 21 rats. Animals were sacrificed after 8 days (6 rats), 6 (7 rats) and 12 weeks (8 rats). In a second experiment, 18 rabbits received 18 Hf and 18 Ti threaded implants in their tibiae, one implant in each tibia. The rabbits were sacrificed after 6, 12 and 24 weeks (6 animals/time interval). The bulk metal of the abdominal wall implants, embedded together with the surrounding tissue, was electrolytically dissolved and semithin (1 microm) sections of the intact tissue-implant interface were evaluated by light microscopy (morphometry). Bone-implant contact and bone area within threads were evaluated in ground sections. In soft tissues, a fluid space containing predominantly monocytes/macrophages surrounded the abdominal implants at 8 days. At 6 and 12 weeks, a fibrous capsule, consisting of layers of macrophages and fibroblasts, surrounded the implants. Macrophages, including multinuclear giant cells, always formed the innermost layer in contact with the implant surface. No quantitative or qualitative difference in the tissue organization was detected between Ti and Hf implants. In rabbits, 6 weeks after insertion, the proximal two threads located within the cortical bone were filled with bone in contact with Hf and Ti. The distal threads contained bone marrow. After 12 and 24 weeks, mature bone was present in the proximal 3-4 implant threads. No statistically significant difference was found between Hf and Ti implants at any time periods. It is concluded that Hf is an interesting metal for biomedical applications in bone and soft tissue.

/OTHER TOXICITY INFORMATION/ There have been no published studies on the toxicity of metallic hafnium.

Hafnium can be absorbed into the body by inhalation of its aerosol.

The whole body retention of 181Hf was studied in marmosets (Callithrex jacchus) and found to be closely similar to that in rats and Chinese hamsters. Limited tissue distribution studies suggest a higher uptake in liver and much lower deposition in skin and muscle in the marmoset as compared to the rat or Chinese hamster. Studies in Chinese hamsters showed that treatment with the chelating agent diethylenetriaminepentaacetic acid resulted in only a small reduction in the whole body retention of 181Hf. The absorption of orally administered 181Hf, in various chemical forms, was found to be between 0.04 and 0.13% of the ingested dose and was unaffected by age between 5 and 21 months but was increased by fasting. The measured absorption of 181Hf in Chinese hamsters and in rats was similar to that of plutonium suggesting that radiohafnium could be used as a surrogate for plutonium for selected studies in human volunteers. /Radiohafnium/

Used to make high-temperature alloys, control rods for nuclear reactors, light bulb filaments, capacitors, cemented carbide tools, coatings for rocket engine parts, TV tubes, and x-ray tubes; [Reference #1]

Metal Preparation and Pouring [Category: Foundry]

Use in control rods in water-cooled nuclear reactors; in gas-filled tubes and incandescent lamps as a scavenger for oxygen and nitrogen; in the manufacture of photographic flash bulbs, light bulb filaments, and in electronic equipment as cathodes and capacitors.

Use as a substitute for tantalum in cemented carbide tool bits, as a coating on rocket engine parts, and in radio and television tubes, and in X-ray tubes

Cemented carbide cutting tools

The major uses of hafnium involve the metal. The largest use is as an alloying additive (1 - 2%) in nickel-based superalloys. These alloys are used in turbine vanes in the combustion zone of jet aircraft engines.

2 metric tons (1992; hafnium, unwrought and waste and scrap)

(2000) 11 metric tons /Hafnium, unwrought, waste and scrap/

(2001) 5 metric tons /Hafnium, unwrought, waste and scrap/

(2002) 5 metric tons /Hafnium, unwrought, waste and scrap/

For more U.S. Imports (Complete) data for HAFNIUM, ELEMENTAL (6 total), please visit the HSDB record page.

The largest use is as an alloy additive in nickel-based superalloys ... second major use is as a control-rod material in nuclear reactors

YEARLY DEMAND FOR HAFNIUM IN US IS NOW IN EXCESS OF 60,000 LB.

The yearly demand for hafnium in the US is now /1990/ in excess of 100,000 lb

Yearly demand for hafnium in US is now /2002/ in excess of 50,000 kg.

Extraction from the mineral cryolite.

Prepared by thermal decomposition of its iodide; by reduction of tetrachloride or of hydrofluohafniate with metallic sodium; by reduction of oxide with a mixture of calcium and sodium.

Extremely difficult to separate from zirconium. Most important methods are: 1) solvent extraction of thiocyanates by hexone; 2) solvent extraction of nitrates by tributyl phosphate; 3) fractional crystallization of double fluorides.

It was originally separated from zirconium by repeated recrystallization of the double ammonium or potassium fluorides by von Hevesey and Jantezen. Metallic hafnium was first prepared by van Arkel and deBoer by passing the vapor of the tetraiodide over heated a tungsten filament. Almost all hafnium metal now produced is made by reducing the tetrachloride with magnesium or with sodium (Kroll Process).

US 2741628

Forms available: powder; rods; single crystals

Available in sponge, iodide crystal bar, ingot, wrought products from bar to foil, and wire

Sold in chunk or particulate form /for alloying purposes/

Transportation Equipment Manufacturing

Hafnium: ACTIVE

Price of the metal is about $2/g.

...Extensively used as shielding material & as control rods in thermal nuclear reactors, because its thermal neutron cross section, 105 barns, is nearly 1000 times that of Zr; Hf can absorb & give up heat twice as fast as Zr & Ti. It is used as construction material in space technology & in jet engines...

Although hafnium /ore/ reserves are significant, demand is low and easily met as a byproduct of the production of reactor-grade zirconium

Six naturally occurring isotopes: 180 (35.22%); 178 (27.1%); 177 (18.56%); 179 (13.75%); 176 (5.21%); 174 (0.163%; alpha-emitter...); artificial isotopes: 157; 158; 168-173; 175; 181-183.