Process for the preparation of precipitated silicas having morphology similar to pyrogenic silicas
Patent 4127641 Issued on November 28, 1978. Estimated Expiration Date: 
June 22, 1997. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
June 22, 1997. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent References 3235331 3325249 3787561 3859420 Amorphous precipitated siliceous pigments and improved process for producing such pigments Patent #: 3977893 InventorsAssigneeApplicationNo. 05/808736 filed on 06/22/1977US Classes:423/339, By precipitating106/482Inorganic silicon compound, e.g., diatomaceous earth, soil, glass, sand, etc., or material derived therefromExaminersPrimary: Cooper, JackAttorney, Agent or FirmInternational ClassesC08K 3/36 (20060101)C09C 1/30 (20060101) C09C 1/28 (20060101) C01B 33/00 (20060101) C01B 33/193 (20060101) C08K 3/00 (20060101) AbstractA multistage precipitation and flocculation production process is disclosed in which primary silica particles are prepared and flocculated useing an alkali metal salt solution and further silica precipitated in the presence of the salt, the pH of the mixture reduced and the silica isolated, purified carefully dried and optionally milled. |
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