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Before the war, the only uranium metal available commercially was produced by the [[Westinghouse Electric and Manufacturing Company]], using a photochemical process. Brown oxide was reacted with [[potassium fluoride]] in large vats on the roof of Westinghouse's plant in [[Bloomfield, New Jersey]].{{sfn|Hewlett|Anderson|1962|pp=65–66}} This produced ingots the size of a [[Quarter (United States coin)|quarter]] that were sold for around $20 per gram. [[Edward Creutz]], the head of the Metallurgical Laboratory's group responsible for fabricating the uranium, wanted a metal sphere the size of an orange for his experiments. With Westinghouse's process, this would have cost $200,000 ({{Inflation|US|200,000|1942|fmt=eq}}) and taken a year to produce.{{sfn|Compton|1956|pp=90–91}}
The hydride or "hydramet" process was developed by Peter P. Alexander, at Metal Hydrides, which used [[calcium hydride]] ({{chem2|CaH2}}) as the [[reducing agent]].{{sfn|Alexander|1943|p=3}}{{sfn|Wilhelm|1960|p=59}}<ref>{{Cite journal |last=Adams |first=David L. |date=March 1996 |title=Metal Hydrides and the Dawn of the Atomic Age |url=https://pubs.acs.org/doi/abs/10.1021/ed073p205 |journal=Journal of Chemical Education |language=en |volume=73 |issue=3 |pages=205 |doi=10.1021/ed073p205 |issn=0021-9584}}</ref> By this means the Metal Hydrides plant in Beverly, Massachusetts, managed to produce a few pounds of uranium metal. Unfortunately, the calcium hydride used contained unacceptable amounts of [[boron]], a neutron poison, making the metal unsuitable for use in a reactor. Some months would pass before Clement J. Rodden from the National Bureau of Standards and Union Carbide found a means to produce sufficiently pure calcium hydride.{{sfn|Hewlett|Anderson|1962|pp=65–66}}{{sfn|Manhattan District|1947e|pp=12.9–12.10}} Meal Hydrides managed to produce {{convert|41|ST|t|order=flip}} of metal by the time operations were suspended on 31 August 1943. It then started reprocessing scrap uranium metal, and produced {{convert|1,090|ST|t|order=flip}} at a cost of $0.33 per pound.{{sfn|Manhattan District|1947a|pp=10.7–10.7}}
At the [[Ames Project]] at [[Iowa State College]], Frank Spedding and [[Harley Wilhelm]] began looking for ways to create the uranium metal. At the time, it was produced in the form of a powder, and was highly [[pyrophoric]]. It could be pressed and [[sintered]] and stored in cans, but to be useful, it needed to be melted and cast. Casting presented difficulty because uranium corroded [[crucible]]s of beryllium, magnesia and graphite. To produce uranium metal, they tried reducing uranium oxide with hydrogen, but this did not work. While most of the neighboring elements on the [[periodic table]] can be reduced to form pure metal and [[slag]], uranium did not behave this way.{{sfn|Payne|1992|pp=66–67}} (At the time it was mistakenly believed that uranium belonged under [[chromium]], [[molybdenum]] and [[tungsten]] in the periodic table.{{sfn|Wilhelm|1960|p=60}}) In June 1942 they tried reducing the uranium with carbon in a hydrogen atmosphere, with only moderate success. They then tried aluminium, magnesium and calcium, all of which were unsuccessful. The following month the Ames team found that molten uranium could be cast in a graphite container.{{sfn|Payne|1992|pp=66–67}} Although graphite was known to react with uranium, this could be managed because the carbide formed only where the two touched.{{sfn|Corbett|2001|pp=15–16}}
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