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    "label": "Proof, no date",
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    "id": "75730948",
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    "contentType": "document",
    "title": "Proof, no date",
    "citationUrl": "https://catalog.archives.gov/id/75730948",
    "collections": [
        "Safety Light Collection",
        "Records Related to Radium Dial Painters"
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    "seq": 4,
    "pageIndex": 0,
    "type": "photo",
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    "ocrText": "4.\nThe Uranium ore is treated with sulphuric acid which dissolves the Uranium.\nThe radium and barium in the form of insoluble sulphate salts are separated\nfrom the solution containing the Uranium; the insoluble radium and barium\nsulphate salts are treated to remove certain impurities; the sulphate salts are\nconverted to an acid soluble form and additional impurities are removed; the\nacid soluble salts are converted to the water soluble radium and barium chloride\nor bromide salts; the radium and barium are separated by a process of fractional\ncrystallization, the end product being a. radium bromide salt of approximately\n90% - 98% purity.\nThe radium salt has now reached a stage where subdivision prior to\nfinal processing can be made. To determine the quantity of material present, a\nmeasurement of the intensity of the emitted radiations is required and the radium\nsalt must, therefore, be enclosed in a sealed tube or container to retain the\ndisintegration products of the radium. The unsealed radium preparation emits\nessentially only alpha radiation since the first disintegration product is\nradon, a gas, which is dissipated in the air. Determination of quantity by\nmeasurement of alpha radiation intensity is difficult and very inaccurate due to\nthe very slight penetrating power of this radiation. Alpha radiation will not\npenetrate a material even as thin as a cigarette paper and most of this radiation\nwould, therefore, be absorbed in the body of the radium salt itself and be\nunavailable for measurement. The salt is, therefore, enclosed in sealed tubes,\nthe radon retained and, after a lapse of time of approximately thirty days, to\npermit growth of disintegration products, quantity of radium present is determined\nby measurement of the intensity of gamma radiation emitted by Radium C.\nRadium salts (radium bromide, radium chloride, radium sulphate) have\nno industrial or therapeutic use. Quantities available are very small and the\ncost prohibitive. The value of radium is not in the radium or radium salt itself"
}