Process for preparing a magnetic talcous composition, and magnetic talcous composition

Patent metadata

Field	Value
Publication number	US-9570217-B2
Application number	US-201214367690-A
Country	US
Kind code	B2
Filing date	Dec 21, 2012
Priority date	Dec 22, 2011
Publication date	Feb 14, 2017
Grant date	Feb 14, 2017

Abstract

A process for preparing a magnetic talcous composition including mineral particles, referred to as magnetic talcous particles, having a non-zero magnetic susceptibility, in which, during an oxidative contacting step, talcous particles chosen from the group formed from 2:1 lamellar silicates having a zero electric charge are brought into contact with particles including at least one magnetic iron oxide chosen from the group formed from magnetite and maghemite, the magnetic particles having a mean equivalent diameter of between 1 nm and 50 nm. A magnetic talcous composition including mineral particles, referred to as magnetic talcous particles, having a non-zero magnetic susceptibility, at least 20% by weight of talcous particles and at least 0.5% by weight of magnetic particles is also described.

First claim

The invention claimed is:

1. A process for preparing a composition, called a magnetic talcous composition, comprising mineral particles, called magnetic talcous particles, having a non-zero magnetic susceptibility, wherein, during a contacting step:
talcous particles chosen from the group formed of the 2:1 sheet silicates having a zero electric charge and a mean equivalent diameter of from 10 nm to 300 nm are contacted with
particles, called magnetic particles, comprising at least one magnetic iron oxide chosen from the group formed of magnetite and maghemite, said magnetic particles having a mean equivalent diameter of from 1 nm to 50 nm.

2. The process as claimed in claim 1 , wherein the talcous particles and the magnetic particles are contacted in a liquid medium.

3. The process as claimed in claim 1 , wherein, during the contacting step:
an aqueous solution is prepared,
talcous particles and magnetic particles are added to the aqueous solution, and
the aqueous solution is removed.

4. The process as claimed in claim 1 , wherein, during the contacting step:
at least one precursor element of said magnetic particles is introduced into an aqueous suspension comprising talcous particles,
a precipitation reaction of said magnetic particles is carried out.

5. The process as claimed in claim 2 , wherein, after contacting the talcous particles and the magnetic particles in a liquid medium the talcous particles and the magnetic particles are dried, the magnetic particles and the talcous particles being in contact in a dry state.

6. The process as claimed in claim 1 , wherein, during the contacting step, co-grinding of the talcous particles and of the magnetic particles in the dry state is carried out.

7. The process as claimed in claim 1 , wherein the 2:1 sheet silicates having a zero electric charge are devoid of interfoliar cations and of interfoliar water molecules.

8. The process as claimed in claim 1 , wherein the talcous particles have the chemical formula (Si x Ge 1−x ) 4 M 3 O 10 (OH) 2 wherein:
x is a number in the range of 0 to 1, and
M denotes at least one divalent metal having the formula Mg y(1) CO y(2) Zn y(3) Cu y(4) Mn y(5) Fe y(6) Ni y(7) Cr y(8) ; each y(i) representing a number in the range of 0 to 1, and such that

∑

i
=
1

8

⁢

y
⁡

(
i
)

=
1.

9. The process as claimed in claim 1 , wherein the talcous particles are formed of talc Si 4 Mg 3 O 10 (OH) 2 .

10. The process as claimed in claim 1 , wherein said magnetic particles have a mean equivalent diameter of from 1 nm to 30 nm.

11. The process as claimed in claim 1 , wherein said talcous particles have a mean equivalent diameter of from 10 nm to 200 nm.

12. The process as claimed in claim 1 , wherein, during the contacting step, the talcous particles are contacted with the magnetic particles in such a manner that the ratio by mass between the magnetic particles and the talcous particles is from 0.005 to 4.

13. A composition, called a magnetic talcous composition, comprising mineral particles, called magnetic talcous particles, having a non-zero magnetic susceptibility, said magnetic talcous particles comprising:
from 20 wt % to 99.5 wt % talcous particles relative to the total weight of said magnetic talcous composition, said talcous particles being chosen from the group formed of the 2:1 sheet silicates having a zero electric charge and a mean equivalent diameter of from 10 nm to 300 nm, and
from 0.5 wt % to 80 wt % magnetic particles, comprising at least one magnetic iron oxide chosen from the group formed of magnetite and maghemite, relative to the total weight of said magnetic talcous composition, said magnetic particles having a mean equivalent diameter of from 1 nm to 50 nm,
The ratio by mass between the magnetic particles and the talcous particles being from 0.005 to 4.

14. The composition as claimed in claim 13 , wherein said magnetic talcous particles have a positive magnetic susceptibility.

15. The composition as claimed in claim 13 , wherein it comprises at least 0.5 wt. % maghemite particles.

16. The composition as claimed in claim 14 , wherein it comprises at least 0.5 wt. % maghemite particles.

Assignees

• Centre Nat De La Rech Scient (C N R S )
• Université Paul Sabatier Toulouse Iii
• Univ Toulouse 3 Paul Sabatier

Inventors

• Martin Francois
• Micoud Pierre
• Dumas Angela
• Le Roux Christophe
• Gardes Emmanuel

Classifications

• Y10T428/2982

  Particulate matter [e.g., sphere, flake, etc.] · CPC title

• C09C1/28

  Compounds of silicon {(C09C1/0009, C09C1/0015, C09C1/0078 take precedence)} · CPC title

• C01G49/08

  Ferroso-ferric oxide [Fe3O4] · CPC title

• C01B33/20 Primary

  Silicates (persilicates C01B15/14 {; containing aluminium C01B33/26}) · CPC title

• H01F1/01 Primary

  of inorganic materials (H01F1/44 takes precedence) · CPC title