Ames process

Last updated

The Ames process is a process by which pure uranium metal is obtained. [1] It can be achieved by mixing any of the uranium halides (commonly uranium tetrafluoride) with magnesium metal powder or aluminium metal powder.

Contents

History

The Ames process was used on August 3, 1942, by a group of chemists led by Frank Spedding and Harley Wilhelm at the Ames Laboratory as part of the Manhattan Project. [2] It is a type of thermite-based purification, which was patented in 1895 by German chemist Hans Goldschmidt. [3] Development of the Ames process came at a time of increased research into mass uranium-metal production. The desire for increased production was motivated by a fear of Nazi Germany's developing nuclear weapons before the Allies. The process originally involved mixing powdered uranium tetrafluoride and powdered magnesium together. This mixture was placed inside an iron pipe that was welded shut on one side and capped shut on another side. This container, called a "bomb" by Spedding, was placed into a furnace. [Note 1] When heated to a temperature of 1,500 °C (2,730 °F), the contents of the container reacted violently, leaving a 35-gram ingot of pure uranium metal. The process was quickly scaled up; by October 1942 the "Ames Project" was producing metal at a rate of 100 pounds (45 kg) per week. The uranium tetrafluoride and magnesium were sealed in a refractory-lined reactor vessel, still referred to as a "bomb". The thermite reaction was initiated by furnace heating the assembly to 600 °C (1,112 °F); the large difference in density between slag and metal allowed complete separation in the liquid state, yielding slag-free metal. [4] By July 1943, the production rate exceeded 130,000 pounds (59,000 kg) of uranium metal per month. Approximately 1000 tons of uranium ingots were produced at Ames before the process was transferred to industry. [5]

The Ames project received the Army-Navy "E" Award for Excellence in Production on October 12, 1945, signifying 2.5 years of excellence in industrial production of metallic uranium as a vital war material. Iowa State University is unique among educational institutions to have received this award for outstanding service, an honor normally given to industry.[ citation needed ]

Ames process for rare-earth metals

The metallothermic reduction of anhydrous rare-earth fluorides to rare-earth metals is also referred to as the Ames process. [6]

The study of rare earths was also advanced during World War II: Synthetic plutonium was believed to be rare-earth-like, it was assumed that knowledge of rare earths would assist in planning for and the study of transuranic elements; ion-exchange methods developed for actinide processing were forerunners to processing methods for rare-earth oxides; methods used for uranium were modified for plutonium, which were subsequently the basis for rare-earth metal preparation. [7] [8]

Related Research Articles

The actinide or actinoid series encompasses the 14 metallic chemical elements with atomic numbers from 89 to 103, actinium through Lawrencium. The actinide series derives its name from the first element in the series, actinium. The informal chemical symbol An is used in general discussions of actinide chemistry to refer to any actinide.

<span class="mw-page-title-main">Thorium</span> Chemical element, symbol Th and atomic number 90

Thorium is a chemical element; it has symbol Th and atomic number 90. Thorium is a weakly radioactive light silver metal which tarnishes olive gray when it is exposed to air, forming thorium dioxide; it is moderately soft and malleable and has a high melting point. Thorium is an electropositive actinide whose chemistry is dominated by the +4 oxidation state; it is quite reactive and can ignite in air when finely divided.

<span class="mw-page-title-main">Uranium</span> Chemical element, symbol U and atomic number 92

Uranium is a chemical element; it has symbol U and atomic number 92. It is a silvery-grey metal in the actinide series of the periodic table. A uranium atom has 92 protons and 92 electrons, of which 6 are valence electrons. Uranium radioactively decays by emitting an alpha particle. The half-life of this decay varies between 159,200 and 4.5 billion years for different isotopes, making them useful for dating the age of the Earth. The most common isotopes in natural uranium are uranium-238 and uranium-235. Uranium has the highest atomic weight of the primordially occurring elements. Its density is about 70% higher than that of lead and slightly lower than that of gold or tungsten. It occurs naturally in low concentrations of a few parts per million in soil, rock and water, and is commercially extracted from uranium-bearing minerals such as uraninite.

<span class="mw-page-title-main">Thermite</span> Pyrotechnic composition of metal powder, which serves as fuel, and metal oxide

Thermite is a pyrotechnic composition of metal powder and metal oxide. When ignited by heat or chemical reaction, thermite undergoes an exothermic reduction-oxidation (redox) reaction. Most varieties are not explosive, but can create brief bursts of heat and high temperature in a small area. Its form of action is similar to that of other fuel-oxidizer mixtures, such as black powder.

<span class="mw-page-title-main">Mischmetal</span> Pyrophoric rare-earth metal alloy

Mischmetal (from German: Mischmetall – "mixed metal") is an alloy of rare-earth elements. It is also called cerium mischmetal, or rare-earth mischmetal. A typical composition includes approximately 55% cerium, 25% lanthanum, and 15~18% neodymium, with traces of other rare earth metals; it contains 95% lanthanides and 5% iron. Its most common use is in the pyrophoric ferrocerium "flint" ignition device of many lighters and torches, although an alloy of only rare-earth elements would be too soft to give good sparks. For this purpose, it is blended with iron oxide and magnesium oxide to form a harder material known as ferrocerium. In chemical formulae it is commonly abbreviated as Mm, e.g. MmNi5.

<span class="mw-page-title-main">Frank Spedding</span> Canadian American chemist (1902–1984)

Frank Harold Spedding was a Canadian American chemist. He was a renowned expert on rare earth elements, and on extraction of metals from minerals. The uranium extraction process helped make it possible for the Manhattan Project to build the first atomic bombs.

Ames National Laboratory, formerly Ames Laboratory, is a United States Department of Energy national laboratory located in Ames, Iowa, and affiliated with Iowa State University. It is a top-level national laboratory for research on national security, energy, and the environment. The laboratory conducts research into areas of national concern, including the synthesis and study of new materials, energy resources, high-speed computer design, and environmental cleanup and restoration. It is located on the campus of Iowa State University.

<span class="mw-page-title-main">Hans Goldschmidt</span> German chemist (1861–1923)

Johannes Wilhelm "Hans" Goldschmidt was a German chemist notable as the discoverer of the Thermite reaction. He was also co-owner of the Chemische Fabrik Th. Goldschmidt, as of 1911 Th. Goldschmidt AG and its most important chemist. The reaction, also called the Goldschmidt process, is used for thermite welding, often used to join railway tracks. Thermites have also been used in metal refining, disabling munitions, and in incendiary weapons. Some thermite-like mixtures are used as pyrotechnic initiators in fireworks.

<span class="mw-page-title-main">Ion exchange</span> Exchange of ions between an electrolyte solution and a solid

Ion exchange is a reversible interchange of one kind of ion present in an insoluble solid with another of like charge present in a solution surrounding the solid with the reaction being used especially for softening or making water demineralised, the purification of chemicals and separation of substances.

Uranium-233 is a fissile isotope of uranium that is bred from thorium-232 as part of the thorium fuel cycle. Uranium-233 was investigated for use in nuclear weapons and as a reactor fuel. It has been used successfully in experimental nuclear reactors and has been proposed for much wider use as a nuclear fuel. It has a half-life of 160,000 years.

<span class="mw-page-title-main">Aluminothermic reaction</span> Heat-producing chemical reactions with aluminum

Aluminothermic reactions are exothermic chemical reactions using aluminium as the reducing agent at high temperature. The process is industrially useful for production of alloys of iron. The most prominent example is the thermite reaction between iron oxides and aluminium to produce iron itself:

<span class="mw-page-title-main">Fernald Feed Materials Production Center</span> Uranium fuel factory in the United States

The Fernald Feed Materials Production Center is a Superfund site located within Crosby Township in Hamilton County, Ohio, as well as Ross Township in Butler County, Ohio, in the United States. It was a uranium processing facility located near the rural town of New Baltimore, about 20 miles (32 km) northwest of Cincinnati, which fabricated uranium fuel cores for the U.S. nuclear weapons production complex from 1951 to 1989. During that time, the plant produced 170,000 metric tons uranium (MTU) of metal products and 35,000 MTU of intermediate compounds, such as uranium trioxide and uranium tetrafluoride.

<span class="mw-page-title-main">Liquid fluoride thorium reactor</span> Type of nuclear reactor that uses molten material as fuel

The liquid fluoride thorium reactor is a type of molten salt reactor. LFTRs use the thorium fuel cycle with a fluoride-based molten (liquid) salt for fuel. In a typical design, the liquid is pumped between a critical core and an external heat exchanger where the heat is transferred to a nonradioactive secondary salt. The secondary salt then transfers its heat to a steam turbine or closed-cycle gas turbine.

<span class="mw-page-title-main">Bismuth phosphate process</span>

The bismuth-phosphate process was used to extract plutonium from irradiated uranium taken from nuclear reactors. It was developed during World War II by Stanley G. Thompson, a chemist working for the Manhattan Project at the University of California, Berkeley. This process was used to produce plutonium at the Hanford Site. Plutonium was used in the atomic bomb that was used in the atomic bombing of Nagasaki in August 1945. The process was superseded in the 1950s by the REDOX and PUREX processes.

<span class="mw-page-title-main">Nuclear transmutation</span> Conversion of an atom from one element to another

Nuclear transmutation is the conversion of one chemical element or an isotope into another chemical element. Nuclear transmutation occurs in any process where the number of protons or neutrons in the nucleus of an atom is changed.

<span class="mw-page-title-main">Neptunium(VI) fluoride</span> Chemical compound

Neptunium(VI) fluoride (NpF6) is the highest fluoride of neptunium, it is also one of seventeen known binary hexafluorides. It is an orange volatile crystalline solid. It is relatively hard to handle, being very corrosive, volatile and radioactive. Neptunium hexafluoride is stable in dry air but reacts vigorously with water.

<span class="mw-page-title-main">Harley A. Wilhelm</span> American chemist (1900–1995)

Harley A. Wilhelm was an American chemist who helped to establish the United States Department of Energy's Ames Laboratory at Iowa State University. His uranium extraction process helped make it possible for the Manhattan Project to build the first atomic bombs.

The Ames Project was a research and development project that was part of the larger Manhattan Project to build the first atomic bombs during World War II. It was founded by Frank Spedding from Iowa State College in Ames, Iowa as an offshoot of the Metallurgical Laboratory at the University of Chicago devoted to chemistry and metallurgy, but became a separate project in its own right. The Ames Project developed the Ames Process, a method for preparing pure uranium metal that the Manhattan Project needed for its atomic bombs and nuclear reactors. Between 1942 and 1945, it produced over 1,000 short tons (910 t) of uranium metal. It also developed methods of preparing and casting thorium, cerium and beryllium. In October 1945 Iowa State College received the Army-Navy "E" Award for Excellence in Production, an award usually only given to industrial organizations. In 1947 it became the Ames Laboratory, a national laboratory under the Atomic Energy Commission.

<span class="mw-page-title-main">Thorium compounds</span> Any chemical compound having at least one atom of thorium

Many compounds of thorium are known: this is because thorium and uranium are the most stable and accessible actinides and are the only actinides that can be studied safely and legally in bulk in a normal laboratory. As such, they have the best-known chemistry of the actinides, along with that of plutonium, as the self-heating and radiation from them is not enough to cause radiolysis of chemical bonds as it is for the other actinides. While the later actinides from americium onwards are predominantly trivalent and behave more similarly to the corresponding lanthanides, as one would expect from periodic trends, the early actinides up to plutonium have relativistically destabilised and hence delocalised 5f and 6d electrons that participate in chemistry in a similar way to the early transition metals of group 3 through 8: thus, all their valence electrons can participate in chemical reactions, although this is not common for neptunium and plutonium.

Zinaida Vasilyevna Yershova was a Soviet and Russian chemist, physicist and engineer. She spent her entire career working with radioactive elements and headed laboratories producing radioactive materials used mostly in the Soviet atomic bomb project and the Soviet space program.

References

  1. "Ames Laboratory and Uranium Production in World War II". American Chemical Society. Retrieved 2023-02-08.
  2. Frank H. Spedding, Harley A. Wilhelm, and Wayne H. Keller, "Production of uranium", U.S. Patent no. 2,830,894 (filed: 7 Nov. 1947; issued: 15 April 1958).
  3. H. Goldschmidt, "Verfahren zur Herstellung von Metallen oder Metalloiden oder Legierungen derselben" (Process for the production of metals or metalloids or alloys of the same), Deutsche Reichs Patent no. 96317 (13 March 1895).
  4. The Metal Thorium, Proceedings of the Conference on Thorium, Oct 11, 1956, American Society for Metals & US Atomic Energy Commission, H. Wilhem, Editor, 1958.
  5. 1972–1973 Ames Laboratory Highlights, Ames Laboratory, Iowa State University, Ames, IA, ERDA 0575.
  6. Huffine, C.; Williams, J. (1959-11-01). Refining and purification of rare-earth metals (Report). pp. AECU––4426, 4213369. doi:10.2172/4213369 . Retrieved 2022-01-06.
  7. A. H. Danne, Chapter 8: Metallothermic Preparation of Rare Earth Metals, The Rare Earths, F. H. Spedding & A. H. Daane (ed), John Wiley & Sons, Inc. 1961.
  8. "DOE Pulse". web.ornl.gov. Retrieved 2023-02-08.

Notes

  1. In laboratory jargon, pressure vessels, such as steel autoclaves and gas cylinders, are commonly called "bombs".