Sintered product with high iron oxide content

Patent metadata

Field	Value
Publication number	US-11390786-B2
Application number	US-201716094039-A
Country	US
Kind code	B2
Filing date	Apr 19, 2017
Priority date	Apr 19, 2016
Publication date	Jul 19, 2022
Grant date	Jul 19, 2022

Abstract

A sintered material exhibiting the following chemical composition, as percentages by weight: iron oxide(s), expressed in the Fe2O3 form, ≥85%, CaO: 0.1%-6%, SiO2: 0.1%-6%, 0.05% ≤TiO2, 0≤Al2O3, TiO2+Al2O3≤3%, and constituents other than iron oxides, CaO, SiO2, TiO2 and Al2O3: ≤5%. The CaO/SiO2 ratio by weight is between 0.2 and 7. The TiO2/CaO ratio by weight is between 0.2 and 1.5.

First claim

The invention claimed is:

1. A sintered material having the following chemical composition, as percentages by weight:
iron oxide(s), expressed in the Fe 2 O 3 form, >92%,
CaO: 0.1%-6%, and
SiO 2 : 0.1%-6%, and
0.05%≤TiO 2 , and
0≤Al 2 O 3 , and
TiO 2 +Al 2 O 3 ≤3%, and
constituents other than iron oxides, CaO, SiO 2 , TiO 2 and Al 2 O 3 : ≤5%, the CaO/SiO 2 ratio by weight being between 0.2 and 7, the TiO 2 /CaO ratio by weight being between 0.2 and 1.5.

2. The sintered material as claimed in claim 1 , having a relative density of greater than or equal to 90%.

3. The sintered material as claimed claim 1 , exhibiting a mean grain size of less than 100 μm and greater than 0.5 μm.

4. The sintered material as claimed in claim 1 , comprising, as percentages by weight:
a content of CaO of greater than 0.2% and less than 4%; and/or
a content of SiO 2 of greater than 0.2% and less than 6%; and/or
a content of TiO2 of greater than 0.1% and less than 3%; and/or
a content of Al 2 O 3 of greater than 0.1% and less than 2.5%; and/or
a total content of TiO 2 +Al 2 O 3 of greater than 0.2% and less than 2.5%; and/or
a CaO/SiO 2 ratio by weight of greater than 0.4 and less than 6.5; and/or
a TiO 2 /CaO ratio by weight of greater than 0.3 and less than 1.4; and/or
a content of constituents other than iron oxides, CaO, SiO 2 , TiO 2 and Al 2 O 3 of less than 4%; and/or
a content of manganese oxide, expressed in the MnO form, of greater than 0.1% and less than 3%.

5. The sintered material as claimed in claim 4 , comprising, as percentages by weight:
a content of CaO of greater than 0.3% and less than 2%; and/or
a content of SiO 2 of greater than 0.4% and less than 3%; and/or
a content of TiO 2 of greater than 0.3% and less than 2.5%; and/or
a content of Al 2 O 3 of greater than 0.1% and less than 1.5%; and/or
a total content of TiO 2 +Al 2 O 3 of greater than 0.3% and less than 2%; and/or
a CaO/SiO 2 ratio by weight of greater than 0.4 and less than 5; and/or
a TiO 2 /CaO ratio by weight of greater than 0.5 and less than 1.3; and/or
a content of constituents other than iron oxides, CaO, SiO 2 , TiO 2 and Al 2 O 3 of
less than 2%; and/or
a content of manganese oxide, expressed in the MnO form, of greater than 0.2%
and less than 2%.

6. The sintered material as claimed in claim 5 , comprising, as percentages by weight:
a content of iron oxide, expressed in the Fe 2 O 3 form, of greater than 95%; and/or
a content of CaO of greater than 0.3% and less than 1%; and/or
a content of SiO 2 of greater than 0.7% and less than 2%; and/or
a content of TiO 2 of greater than 0.5% and less than 2%; and/or
a content of Al 2 O 3 of greater than 0.1% and less than 1%; and/or
a total content of TiO 2 +Al 2 O 3 of greater than 0.4%; and less than 2%; and/or
a CaO/SiO 2 ratio by weight of greater than 0.4 and less than 3; and/or
a TiO 2 /CaO ratio by weight of greater than 0.7 and less than 1.2; and/or
a content of constituents other than iron oxides, CaO, SiO 2 , TiO 2 and Al 2 O 3 of less than 1%; and/or
a content of manganese oxide, expressed in the MnO form, of greater than 0.4% and less than 1%.

7. A particulate mixture, comprising, as percentages by weight:
(a) more than 60%, by weight, of aggregate particles having a size of greater than or equal to 50 μm, more than 90% by weight of said aggregate particles being particles made of the sintered material as claimed in claim 1 ;
(b) more than 15%, by weight, of matrix particles having a size of less than 50 μm;

the particulate mixture comprising more than 5% by weight of the aggregate particles having a size of greater than 1 mm.

8. The particulate mixture as claimed in claim 7 , more than 60% of the particulate mixture, as percentage by weight, being made of the sintered material.

9. The particulate mixture as claimed in claim 8 , more than 90% of the particulate mixture, as percentage by weight, being made of the sintered material.

10. The particulate mixture as claimed in claim 7 , in which a matrix fraction, formed of the matrix particles, has the following chemical analysis, as percentages by weight based on the following oxides:
iron oxide(s), expressed in the Fe 2 O 3 form, ≥85%,
CaO≤6%, and
SiO 2 : 0.1%-6%, and
TiO 2 : 0.1%-6%, and
Al 2 O 3 ≤2%, and
other oxides: ≤5%,
the CaO/SiO 2 ratio by weight being less than 1, and
the CaO/TiO 2 ratio by weight being less than 1.

11. The particulate mixture as claimed in claim 7 , in which a matrix fraction, formed of the matrix particles, has the following chemical analysis, as percentages by weight based on the following oxides:
iron oxide(s), expressed in the Fe 2 O 3 form, ≥85%,
CaO: 0.1%-6%, and
SiO 2 : 0.1%-6%, and
0.05%<TiO 2 , and
0≤Al 2 O 3 , and
TiO 2 +Al 2 O 3 ≤3%, and
other oxides ≤5%,
the CaO/SiO 2 ratio by weight being between 0.2 and 7, and
the TiO 2 /CaO ratio by weight being between 0.2 and 1.

12. A sintered product obtained by sintering the particulate mixture as claimed in claim 7 , wherein the sintering results in conversion of the matrix particles into a binding phase which bind together the aggregate particles and the aggregate particles are substantially unaffected by the sintering.

13. A thermal storage unit comprising heat energy storage elements, said heat energy storage elements being made of the sintered product as claimed in claim 12 .

14. The thermal storage unit as claimed in claim 13 , in which the heat energy storage elements are shaped and arranged so that said thermal storage unit comprises a void volume fraction of less than or equal to 60%.

15. An assembly comprising:
a thermal storage unit as claimed in claim 13 , and
a device for circulation of a heat-exchange fluid through said thermal storage unit.

Assignees

• Saint Gobain Ct Recherches

Inventors

• His Christian
• Villermaux Franceline

Classifications

• F28D17/02

  using rigid bodies, e.g. of porous material · CPC title

• F28D20/0056

  using solid heat storage material (F28D20/0052 takes precedence) · CPC title

• C04B2235/3272

  Iron oxides or oxide forming salts thereof, e.g. hematite, magnetite · CPC title

• C04B2235/782

  Grain size distributions · CPC title

• C04B2235/3208

  Calcium oxide or oxide-forming salts thereof, e.g. lime · CPC title