The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 24, 1997
Filed:
Jul. 17, 1995
Albena Blagev, Woodbury, MN (US);
Gerald G Endres, Hastings, MN (US);
Minnesota Mining and Manufacturing Company, St. Paul, MN (US);
Abstract
This invention provides a method of producing goethite particles comprising the steps of a) reacting, in aqueous solution, less than a stoichiometric amount of an alkali compound with an iron (II) salt to form a precipitated complex intermediate, b) oxidizing iron (II) in the complex intermediate to iron (III) at an average rate less than 10 g iron(III)/l/hr to form goethite seed particles until 20 to 70% of iron (II) in the precipitated complex intermediate has been converted to iron (III), and c) after 20 to 70% of iron (II) in the precipitated complex intermediate has been convened to iron (III), increasing the average oxidation rate to greater than 10 g iron(III)/l/hr.