Manhattan Project feed materials program: Difference between revisions

Revision as of 19:44, 21 April 2025

Revision as of 20:41, 21 April 2025

Line 266:

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}} 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 aluminiumaluminum, 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}}

{{Gallery

Line 414:

[[Polonium]] was chosen for use as a strong [[alpha particle]] emitter for the [[modulated neutron initiator]]s developed for the first atomic bombs. Production was carried out by the [[Dayton Project]] in [[Dayton, Ohio]].{{sfn|Jones|1985|p=592}}{{sfn|Hoddeson|Henriksen|Meade|Westfall|1993|pp=119–125}}<ref>{{cite news|url=http://www.atomicheritage.org/index.php/component/content/83.html?task=view|title=The Dayton Project|first=Jim|last=DeBrosse|newspaper=[[Dayton Daily News]]|date=25 December 2004|page=A1|access-date=25 May 2013|archive-date=14 August 2013|archive-url=https://web.archive.org/web/20130814002324/http://www.atomicheritage.org/index.php/component/content/83.html?task=view|url-status=dead}}</ref> Polonium occurs naturally in various ores, and the [[lead dioxide]] residues from the refinery in Port Hope, left over after the removal of [[uranium]] and radium, were estimated to contain {{convert|0.2|to|0.3|mg|lk=on|sp=us}} of polonium per metric ton.{{sfn|Manhattan District|1947g|pp=5.1–5.2}}{{sfn|Moyer|1956|p=2}} (A [[Curie (unit)|curie]] of polonium weighs about {{convert|0.2|mg|sp=us}}.{{sfn|Moyer|1956|p=3}}) About {{convert|35|ST|t|order=flip|sp=us}} of lead dioxide was treated with nitric acid, and about {{convert|40|Ci|TBq}} (8 mg) of polonium was produced.{{sfn|Moyer|1956|pp=5–6}} The lead dioxide was not purchased by the Manhattan Project, as it had been acquired by the Canadian government. In June 1945, the lead was precipitated as a [[lead carbonate]] slurry, and shipped to the Madison Square area to be dried and returned to Canada.{{sfn|Manhattan District|1947g|p=5.6}}

Polonium could also be produced by neutron irradiation of [[bismuth]] in a nuclear reactor.{{sfn|Moyer|1956|pp=5–6}} Bismuth was purchased from the [[American Smelting and Refining Company]] of the highest purity it could produce. It was sent to the Hanford Engineer Works, where it was canned, and placed inside a reactor for 100 days. The irradiated slugs were shipped to Dayton, where they were bathed in hydrochloric acid to dissolve the aluminiumaluminum canning. This formed an aluminiumaluminum chloride solution that was disposed of, as it was highly radioactive due to the iron impurities in the aluminiumaluminum. The bismuth slugs were then repeatedly dissolved in [[aqua regia]] to achieve a 1000–1 concentration, and the polonium was electroplated on [[platinum]] foils. The main problem with the process was that it required glass-lined containers due to the aqua regia, and mechanisms for safe handling of the radioactive material. By the end of 1946, Hanford was shipping material that contained up to {{convert|13,200|Ci|TBq}} (2.6 g) of polonium per metric ton of bismuth.{{sfn|Manhattan District|1947g|p=5.7–5.11}}

=== Thorium ===