Patents by Inventor Anthony S. W. De Freitas

Anthony S. W. De Freitas has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Recovery and purification of silica
    Patent number: 4885149
    Abstract: A process for preparing silica comprising:(a) acidifying a basic aqueous solution containing silicate ions and molybdate ions to produce silicomolybodic acid;(b) adding to the acidified solution an organic base to precipitate a silicomolybdate; and,(c) heating the resulting precipitate to drive off volatile components and leave a purified form of silica is disclosed. The process is particularly useful for producing purified silica from dilute aqueous media.
    Type: Grant
    Filed: December 9, 1987
    Date of Patent: December 5, 1989
    Assignee: Canadian Patents and Development Limited
    Inventors: Anthony S. W. De Freitas, Archibald W. McCulloch, Alister G. McInnes