Hard magnetic compositions from iron oxide fines and methods for making same

Patent metadata

Field	Value
Publication number	US-2016343485-A1
Application number	US-201515112749-A
Country	US
Kind code	A1
Filing date	Jan 29, 2015
Priority date	Jan 31, 2014
Publication date	Nov 24, 2016
Grant date	—

Abstract

Disclosed herein are compositions and methods of making a hard magnetic material from iron oxide fines, the hard magnetic material having a general formula MFe x O y . In one aspect, the method comprises a) providing an iron oxide fine; b) providing a metal carbonate of a general formula M x (CO 3 ) y ; c) mixing the iron oxide fine and the metal carbonate to form a mixture; d) calcining the mixture of the iron oxide fine and the metal carbonate; wherein M is a divalent metal ion.

First claim

1 . A method for making a hard magnetic material of a general formula MFe x O y , the method comprising:
a) providing an iron oxide fine; b) providing a metal carbonate of a general formula M x (CO 3 ) y ; c) mixing the iron oxide fine and the metal carbonate to form a mixture; d) calcining the mixture of the iron oxide fine and the metal carbonate; wherein M is a divalent metal ion.

2 . The method of claim 1 , wherein the iron oxide fine is provided as a by-product of an iron processing or iron making process.

3 . The method of claim 1 , wherein the iron oxide fine comprises at least about 93 wt % Fe 2 O 3 .

4 . The method of claim 1 , wherein M is strontium.

5 . The method of claim 1 , wherein M x (CO 3 ) y is SrCO 3 .

6 . The method of claim 1 , wherein the mixture is calcined at a temperature of at least about 1000° C.

7 . The method of claim 1 , wherein the mixture is calcined for about 4 to 12 hours.

8 . The method of claim 1 , wherein M is strontium; and Fe x O y is Fe 12 O 19 .

9 . The method of claim 1 , wherein the hard magnetic material is a hard ferrite.

10 . The method of claim 9 , wherein the hard ferrite is a hexagonal ferrite.

11 . The method of claim 1 , wherein the hard magnetic material is hexagonal ferrites; M is strontium; and Fe x O y is Fe 12 O 19 .

12 . The method of claim 1 , wherein the hard magnetic material comprises from greater than 0 to about 15 wt % SrO and from greater than 85 to about 95 wt % Fe 2 O 3 .

13 . The method of claim 1 , wherein the hard magnetic material comprises from greater than 0 to about 10 wt % SrO and from greater than 83 to about 90 wt % Fe2O3.

14 . The method of claim 1 , wherein the metal carbonate is provided in at least a stoichiometric amount relative to an amount of the iron oxide fine.

15 . The method of claim 1 , wherein the hard magnetic material has an intrinsic coercivity ( i H c ) of at least 100 kA/m.

16 . The method of claim 1 , wherein the hard magnetic material has an intrinsic coercivity ( i H c ) in the range of from 100 to 550 kA/m.

17 . The method of claim 1 , wherein the hard magnetic material has a saturation magnetization (Ms) of at least about 50 Am 2 /kg.

18 . The method of claim 1 , wherein the hard magnetic material has a saturation magnetization (Ms) in the range of about 50 to100 Am 2 /kg.

19 . The method of claim 1 , wherein no crushing step is required for the iron oxide fine.

20 . The method of claim 1 , wherein no preheating step is required for the iron oxide fine.

21 . A method for making a hard magnetic material of a general formula SrFe x O y , the method comprising:
a) providing an iron oxide fine; b) providing a metal carbonate comprising SrCO 3 ; c) mixing the iron oxide fine and the metal carbonate to form a mixture; d) calcining the mixture of the iron oxide fine and the metal carbonate.

21 - 60 . (canceled)

Assignees

• Saudi Basic Ind Corp

Inventors

• Saddik Mohamed Bahgat
• Awan Fazal-Ur-Rehman

Classifications

• C04B2235/3217

  Aluminum oxide or oxide forming salts thereof, e.g. bauxite, alpha-alumina · CPC title

• C01P2006/42

  Magnetic properties · CPC title

• C04B35/2633 Primary

  containing barium, strontium or calcium · CPC title

• C01G49/0036

  containing one alkaline earth metal, magnesium or lead · CPC title

• C04B2235/3232

  Titanium oxides or titanates, e.g. rutile or anatase · CPC title