Sintered zirconia mullite refractory composite, methods for its production and use thereof

Patent metadata

Field	Value
Publication number	US-11208354-B2
Application number	US-201615773580-A
Country	US
Kind code	B2
Filing date	Nov 3, 2016
Priority date	Nov 5, 2015
Publication date	Dec 28, 2021
Grant date	Dec 28, 2021

Abstract

The present invention relates to a zirconia mullite refractory composite comprising 55 wt.-% to 65 wt.-% Al 2 O 3 , 15 wt.-% to 25 wt.-% SiO 2 , 15 wt.-% to 25 wt.-% ZrO 2 and less than 3 wt.-% raw material based impurities, whereby the mineralogical composition of the composite comprises 65 wt.-% to 85 wt.-% mullite and 15 wt.-% to 35 wt.-% zirconia.

First claim

The invention claimed is:

1. A sintered zirconia mullite refractory composite based on aluminosilicate, alumina, and zircon sand, wherein
the zirconia mullite refractory composite has a chemical composition comprising, in weight-percent:
55% to 65% Al 2 O 3 ;
15% to 25% SiO 2 ;
15% to 25% ZrO 2 ; and
less than 3% raw material-based impurities,

the zirconia mullite refractory composite has a mineralogical composition comprising 65 wt.-% to 85 wt.-% mullite and 15 wt.-%-35 wt.-% zirconia, and
the zirconia mullite refractory composite comprises zirconia particles essentially homogeneously distributed in a mullite matrix, wherein the average particle diameter of the zirconia particles is less than 2 μm.

2. A composite according to claim 1 , wherein the aluminosilicate comprises andalusite, kyanite, and/or sillimanite.

3. A composite according to claim 2 , wherein the raw material basis of the composite comprises
25 wt.-% to 35 wt.-% andalusite;
35 wt.-% to 45 wt.-% alumina; and
25 wt.-% to 35 wt.-% zircon sand.

4. A refractory castable for producing refractory bricks or cast pieces, comprising a refractory composite according to claim 1 , wherein when sintered at a temperature between 1000° C. and 1700° C.,
the castable has
a Cold Module of Rupture (CMOR), measured according to EN 1402-5, of more than 80 MPa, and
a Cold Crushing Strength (CCS), measured according to EN 1402-6, of more than 500 MPa.

5. A refractory castable according to claim 4 , wherein the castable is a low cement castable (LCC) having a cement content of about 5 wt.-% or an ultra-low cement castable (ULCC) having a cement content of less than 2 wt.-%.

6. A method for manufacturing a sintered zirconia mullite refractory composite according to claim 1 , the method comprising the steps:
homogeneously mixing of finely ground raw material powders;
forming a shaped body from the homogeneous mixture of the raw material powders;
sintering the shaped body at a temperature range between 1400° C. and 1700° C.;
crushing the sintered body to obtain a desired particle size distribution.

7. A method according to claim 6 , wherein the forming of the shaped body comprises the steps:
adding 15 wt.-% to 50 wt.-% water and 0.1 wt.-% to 1.0 wt.-% of a dispersant, each based of the total weight of the raw material mixture;
homogenising the mixture to obtain a homogeneous dispersion of finely ground raw material powders;
casting the homogeneous dispersion into a mold; and
drying and subsequently sintering the cast material.

8. A method according to claim 6 , wherein the forming of the shaped body comprises the steps:
compacting the powder mixture at pressures up to 300 MPa to obtain compacts, whereby optionally small amounts of water are added;
optionally drying of the compacts; and
sintering the compacts.

9. A method according to claim 6 , wherein the finely ground raw material powders comprise 25 wt.-% to 35 wt.-% andalusite, 35 wt.-% to 45 wt.-% alumina, and 25 wt.-% to 35 wt.-% zircon sand, each having a particle size of less than 5 μm.

10. A refractory castable for producing refractory bricks or cast pieces, comprising a refractory composite according to claim 2 , wherein when sintered at a temperature between 1000° C. and 1700° C., the castable has:
a Cold Module of Rupture (CMOR), measured according to EN 1402 5, of more than 80 MPa, and
a Cold Crushing Strength (CCS), measured according to EN 1402 6, of more than 500 MPa.

11. A refractory castable according to claim 10 , wherein the castable is a low cement castable (LCC) having a cement content of about 5 wt.-% or an ultra-low cement castable (ULCC) having a cement content of less than 2 wt.-%.

12. A refractory castable for producing refractory bricks or cast pieces, comprising a refractory composite according to claim 3 , wherein when sintered at a temperature between 1000° C. and 1700° C., the castable has:
a Cold Module of Rupture (CMOR), measured according to EN 1402 5, of more than 80 MPa, and
a Cold Crushing Strength (CCS), measured according to EN 1402 6, of more than 500 MPa.

13. A refractory castable according to claim 12 , wherein the castable is a low cement castable (LCC) having a cement content of about 5 wt.-% or an ultra-low cement castable (ULCC) having a cement content of less than 2 wt.-%.

Assignees

• Imertech Sas

Inventors

• Bouchetou Marie-Laure
• Joubert Olivier
• Poirier Jacques
• Weissenbacher Michael

Classifications

• C04B2235/6562

  Heating rate · CPC title

• C04B35/106 Primary

  containing zirconium oxide or zircon (ZrSiO4) · CPC title

• C04B2235/606

  Drying · CPC title

• C04B2235/96

  Properties of ceramic products, e.g. mechanical properties such as strength, toughness, wear resistance · CPC title

• C04B2235/6565

  Cooling rate · CPC title