Ames process
Encyclopedia
The Ames process is a process by which pure uranium
metal is obtained. It can be achieved by mixing any of the uranium halide
s (commonly uranium tetrafluoride
) with magnesium metal
powder or aluminium metal
powder.
at the Ames Laboratory
as part of the Manhattan Project
. It is a type of thermite
-based purification, which was patented in 1895 by German chemist Hans Goldschmidt
. 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
discovering nuclear fission
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. When heated to a temperature of 1500°C, 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 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 (1110°F); the large difference in density between slag and metal allowed for complete separation in the liquid state, yielding slag-free metal. By July 1943, the production rate exceeded 130,000 pounds of uranium metal per month. Approximately 1000 tons of uranium ingots were produced at Ames before the process was transferred to industry.
The Ames project received the Army-Navy ‘E’ Award
for Excellence in Production on October 12, 1945, signifying two-and-a-half 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.
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.
Uranium
Uranium is a silvery-white metallic chemical element in the actinide series of the periodic table, with atomic number 92. It is assigned the chemical symbol U. A uranium atom has 92 protons and 92 electrons, of which 6 are valence electrons...
metal is obtained. It can be achieved by mixing any of the uranium halide
Halide
A halide is a binary compound, of which one part is a halogen atom and the other part is an element or radical that is less electronegative than the halogen, to make a fluoride, chloride, bromide, iodide, or astatide compound. Many salts are halides...
s (commonly uranium tetrafluoride
Uranium tetrafluoride
Uranium tetrafluoride is a green crystalline solid compound of uranium with an insignificant vapor pressure and very slight solubility in water. Uranium in its tetravalent state is very important in different technological processes...
) with magnesium metal
Magnesium
Magnesium is a chemical element with the symbol Mg, atomic number 12, and common oxidation number +2. It is an alkaline earth metal and the eighth most abundant element in the Earth's crust and ninth in the known universe as a whole...
powder or aluminium metal
Aluminium
Aluminium or aluminum is a silvery white member of the boron group of chemical elements. It has the symbol Al, and its atomic number is 13. It is not soluble in water under normal circumstances....
powder.
History
The Ames process was used on August 3, 1942 by a group of chemists led by Frank SpeddingFrank Spedding
Frank Harold Spedding was a Canadian chemist who led a group of chemists at Ames Laboratory which developed an efficient process for obtaining high purity uranium from uranium halides. The general technique is known as the Thermite process, or more specifically, the Ames process...
at the Ames Laboratory
Ames Laboratory
Ames Laboratory is a United States Department of Energy national laboratory located in Ames, Iowa. The Laboratory conducts research into various areas of national concern, including the synthesis and study of new materials, energy resources, high-speed computer design, and environmental cleanup...
as part of the Manhattan Project
Manhattan Project
The Manhattan Project was a research and development program, led by the United States with participation from the United Kingdom and Canada, that produced the first atomic bomb during World War II. From 1942 to 1946, the project was under the direction of Major General Leslie Groves of the US Army...
. It is a type of thermite
Thermite
Thermite is a pyrotechnic composition of a metal powder and a metal oxide that produces an exothermic oxidation-reduction reaction known as a thermite reaction. If aluminium is the reducing agent it is called an aluminothermic reaction...
-based purification, which was patented in 1895 by German chemist Hans Goldschmidt
Hans Goldschmidt
Johannes Wilhelm "Hans" Goldschmidt was a German chemist.Born in Berlin, he was a student of Robert Bunsen. His father, Theodor Goldschmidt, was the founder of the chemical company Chemische Fabrik Th...
. 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
Nazi Germany
Nazi Germany , also known as the Third Reich , but officially called German Reich from 1933 to 1943 and Greater German Reich from 26 June 1943 onward, is the name commonly used to refer to the state of Germany from 1933 to 1945, when it was a totalitarian dictatorship ruled by...
discovering nuclear fission
Nuclear fission
In nuclear physics and nuclear chemistry, nuclear fission is a nuclear reaction in which the nucleus of an atom splits into smaller parts , often producing free neutrons and photons , and releasing a tremendous amount of energy...
before the Allies
Allies of World War II
The Allies of World War II were the countries that opposed the Axis powers during the Second World War . Former Axis states contributing to the Allied victory are not considered Allied states...
. 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. When heated to a temperature of 1500°C, the contents of the container reacted violently, leaving a 35-gram ingot
Ingot
An ingot is a material, usually metal, that is cast into a shape suitable for further processing. Non-metallic and semiconductor materials prepared in bulk form may also be referred to as ingots, particularly when cast by mold based methods.-Uses:...
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 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 (1110°F); the large difference in density between slag and metal allowed for complete separation in the liquid state, yielding slag-free metal. By July 1943, the production rate exceeded 130,000 pounds of uranium metal per month. Approximately 1000 tons of uranium ingots were produced at Ames before the process was transferred to industry.
The Ames project received the Army-Navy ‘E’ Award
Army-Navy ‘E’ Award
The Army-Navy "E" Award was an honor presented to a company during World War II for excellence in production of war equipment. The award was also known as the Army-Navy Production Award. The award would consist of a pennant for the plant and emblems for all employees in the plant at the time the...
for Excellence in Production on October 12, 1945, signifying two-and-a-half years of excellence in industrial production of metallic uranium as a vital war material. Iowa State University
Iowa State University
Iowa State University of Science and Technology, more commonly known as Iowa State University , is a public land-grant and space-grant research university located in Ames, Iowa, United States. Iowa State has produced astronauts, scientists, and Nobel and Pulitzer Prize winners, along with a host of...
is unique among educational institutions to have received this award for outstanding service, an honor normally given to industry.
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.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
Ion exchange
Ion exchange is an exchange of ions between two electrolytes or between an electrolyte solution and a complex. In most cases the term is used to denote the processes of purification, separation, and decontamination of aqueous and other ion-containing solutions with solid polymeric or mineralic 'ion...
methods developed for actinide processing were forerunners to processing methods for rare earth oxides; methods used for uranium
Uranium
Uranium is a silvery-white metallic chemical element in the actinide series of the periodic table, with atomic number 92. It is assigned the chemical symbol U. A uranium atom has 92 protons and 92 electrons, of which 6 are valence electrons...
were modified for plutonium
Plutonium
Plutonium is a transuranic radioactive chemical element with the chemical symbol Pu and atomic number 94. It is an actinide metal of silvery-gray appearance that tarnishes when exposed to air, forming a dull coating when oxidized. The element normally exhibits six allotropes and four oxidation...
which were subsequently the basis for rare-earth metal preparation.