Process for improving the brightness of fine-grained kaolin clays
Patent 5810998 Issued on September 22, 1998. Estimated Expiration Date: 
June 5, 2017. 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 5, 2017. 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 3343973 3450257 3528769 3536264 3615806 3635662 3661515 3701417 3879283 Opacifying pigments and methods for making same InventorsAssigneeApplicationNo. 869409 filed on 06/05/1997US Classes:209/166, With modifying agents106/486, Clay or material derived therefrom containing209/10, TREATMENT SUBSEQUENT209/12.1, PLURAL, DIVERSE SEPARATING OPERATIONS209/17, Aqueous suspension and sifting209/39, Magnetic and fluid suspension501/148, Using organic substance as treating agent501/149Water pretreatmentExaminersPrimary: Lithgow, Thomas M.Attorney, Agent or FirmInternational ClassesB03B 007/00B03D 001/02 C09C 001/24 AbstractFine-grained kaolin clays having improved brightness can be produced by (a) using centrifugation to fractionate the clay starting material into finer and coarser fractions, (b) subjecting the coarser fraction to flotation to remove discoloring impurities and (c) combining the finer and floated coarser fractions to produce fine-grained kaolin clays having improved brightness. | |
