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:
Oct. 18, 1977
Filed:
Feb. 24, 1975
Angelo Garberi, Cilavegna (Pavia), IT;
Agostino Geddo, Trecate (Novara), IT;
Gian Lorenzo Marziano, Novara, IT;
Montedison S.p.A., Milan, IT;
Abstract
A process is disclosed for preparing magnetite having an equiaxial morphology and a narrow particle size dispersion by precipitation from a ferrous sulphate solution, characterized in that: A. during a first step, at a temperature between 15.degree. and 40.degree. C, alkali is added to the ferrous sulphate solution, in a stoichiometric amount adapted to precipitate, in the form of ferrous hydroxide, 2/3 of the Fe.sup.+.sup.+ ion, and then, at the conclusion of said precipitation, air is blown thereinto thus oxidizing ferrous hydroxide to goethite .alpha.FeO(OH); and B. during a second step, alkali is added to the slurry obtained in the first step, the remaining Fe.sup.+.sup.+ is precipitated in the form of ferrous hydroxide, and the slurry is heated to a temperature between 70.degree. and 100.degree. C, thus causing the formation of magnetite which is then separated from the solution.