{
  "patent_number": "US 400664",
  "country": "US",
  "title": "How Charles Hall Invented Modern Aluminum Production",
  "original_title": "Process of reducing aluminium from its fluoride salts by electrolysis",
  "summary": "This 1889 patent describes the Hall-Héroult process, which uses electricity to extract pure aluminum from its ore, making the metal affordable for everyone.",
  "what_it_does": "The patent details a method for isolating aluminum by dissolving aluminum oxide in a bath of molten cryolite. An electric current is then passed through this mixture, causing the aluminum to separate and collect at the bottom of the vessel. This process effectively lowers the melting point of the aluminum ore, allowing it to be processed at temperatures that are commercially practical.",
  "what_it_does_not_cover": [
    "Does not cover chemical reduction methods that rely on heat alone without electrolysis",
    "Does not cover the refining of aluminum from non-fluoride salts",
    "Does not cover the specific design of the industrial smelting pots used in modern plants"
  ],
  "filed": "1886-07-09",
  "granted": "1889-04-02",
  "expires": "1906-07-09",
  "status": "expired",
  "holder": "Individual",
  "holder_url": "https://patentbrief.org/company/individual",
  "inventors": [
    {
      "name": "M Hall Charles",
      "url": "https://patentbrief.org/inventor/m-hall-charles"
    }
  ],
  "times_cited": 18,
  "tags": [
    "mechanical",
    "energy",
    "materials"
  ],
  "abstract": null,
  "url": "https://patentbrief.org/patent/us/400664/hall-process-aluminum-smelting",
  "markdown_url": "https://patentbrief.org/patent/us/400664/hall-process-aluminum-smelting/md",
  "google_patents_url": "https://patents.google.com/patent/US400664",
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}