Refractory product having improved flow

Patent metadata

Field	Value
Publication number	US-10233107-B2
Application number	US-201415109215-A
Country	US
Kind code	B2
Filing date	Dec 18, 2014
Priority date	Dec 30, 2013
Publication date	Mar 19, 2019
Grant date	Mar 19, 2019

Abstract

An unshaped product including a particulate mixture containing: a coarse fraction, representing >50%<91% of particulate mixture, in mass percentage, and containing particles size ≥50 μm, “coarse particles”, and matrix fraction, forming remainder up to 100% of particulate mixture, and containing particles sizes <50 μm, product having chemical analysis, in mass percentage based on oxides of product, such: −45%<Al 2 O 3 , −7.5%<SiO 2 <35%, −0%≤ZrO 2 <33%, providing 10%<SiO 2 +ZrO 2 <54%, −0.15%<B 2 O 3 <8%, other oxides: <6%, Al 2 O 3 forming remainder up to 100%, coarse fraction including more than 15% coarse particles having size >1 mm, in mass percentage based on particulate mixture, matrix fraction having a chemical analysis, in mass percentage based on oxides of matrix fraction, such: Al 2 O 3 +SiO 2 +ZrO 2 >86%, providing 35%<Al 2 O 3 .

First claim

The invention claimed is:

1. An unshaped product comprising a particulate mixture consisting of:
a coarse fraction, representing more than 50% and less than 91% of the particulate mixture, as weight percentage, and consisting of the particles having a size greater than or equal to 50 μm, referred to as “coarse particles”, and
a matrix fraction, forming the remainder up to 100% of the particulate mixture, and consisting of the particles having a size less than 50 μm, referred to as “matrix particles”,
the product having a chemical analysis, as weight percentage on the basis of the oxides of the product, such that:
45%<Al 2 O 3 ,
7.5%<SiO 2 <35% and 0%≤ZrO 2 <33%, provided that 10%<SiO 2 +ZrO 2 <54%,
0.15%<B 2 O 3 <8%,
other oxides: <6%,
Al 2 O 3 constituting the remainder up to 100%,
said coarse fraction comprising more than 15% of coarse particles having a size greater than 1 mm, as weight percentage on the basis of the particulate mixture,
said matrix fraction having a chemical analysis, as weight percentage on the basis of the oxides of the matrix fraction, such that:
Al 2 O 3 +SiO 2 +ZrO 2 >86%, provided that 35%<Al 2 O 3 ,
said unshaped product comprising particles comprising boron.

2. The unshaped product as claimed in claim 1 , wherein 0.2%<B 2 O 3 <6.5% and/or the content of other oxides is less than 5%.

3. The unshaped product as claimed in claim 2 , wherein 0.75%<B 2 O 3 <4.5% and/or the content of other oxides is less than 2%.

4. The unshaped product as claimed in claim 3 , wherein B 2 O 3 <2.6%.

5. The unshaped product as claimed in claim 1 , wherein the particles comprising boron are selected from the group consisting of boron carbide, boron oxides, boric acid, colemanite, sodium borate, compounds comprising silica and boron oxide, SiB 6 , alumina borates, AlB 3 and mixtures thereof.

6. The unshaped product as claimed in claim 1 , wherein the matrix fraction, other than the particles comprising boron, consists, for more than 80% of its weight, of alumina particles and/or silica particles and/or mullite particles and/or mullite-zirconia particles and/or particles of a silicoaluminous material having an alumina content greater than 50%.

7. The unshaped product as claimed in claim 1 , wherein more than 50% of the particles comprising boron are matrix particles, as weight percentage on the basis of the oxides.

8. The unshaped product as claimed in claim 1 , wherein
Al 2 O 3 +SiO 2 >83% or Al 2 O 3 +SiO 2 +ZrO 2 >92% or 15%<SiO 2 +ZrO 2 <50% or SiO 2 >10%.

9. The unshaped product as claimed in claim 8 , wherein
Al 2 O 3 +SiO 2 >90% or 20%<SiO 2 +ZrO 2 <40% or SiO 2 >13%.

10. The unshaped product as claimed in claim 1 , wherein, if the silica content in the matrix fraction is greater than 10%, as weight percentage on the basis of the oxide phases of the matrix fraction, said matrix fraction has an alumina/silica ratio greater than 2 and less than 10.

11. The unshaped product as claimed in claim 10 , wherein said ratio is less than 5.

12. The unshaped product as claimed in claim 1 , wherein more than 80% by weight of the coarse particles have a size greater than 200 μm and less than 25 mm.

13. The unshaped product as claimed in claim 1 , wherein the coarse fraction consists, for more than 80% of its weight, of alumina particles and/or mullite particles and/or mullite-zirconia particles and/or particles of a silicoaluminous material having an alumina content greater than 50%.

14. The unshaped product as claimed in claim 1 , having
a chemical analysis such that:
Al 2 O 3 : remainder up to 100%,
(21%≤SiO 2 ≤25% and ZrO 2 <1%) or (14%<SiO 2 <17% and 26%<ZrO 2 <32%),
0.2%<B 2 O 3 <2.6%,
other oxides: <3%, and

a matrix fraction having a chemical analysis such that Al 2 O 3 +SiO 2 +ZrO 2 +B 2 O 3 >90%, and
an amount of matrix particles between 20% and 35% of the weight of the particulate mixture, and
more than 15% of coarse particles having a size greater than 1 mm,
the contents of the chemical analysis being expressed as weight percentages on the basis of the oxides.

15. A process for manufacturing a sintered part, comprising the following steps:
A) preparing of a starting charge from an unshaped product according to claim 1 ;
B) forming of said starting charge so as to form a preform;
C) sintering of said preform so as to obtain a sintered product having a microstructure consisting of grains bonded by a matrix, and having a chemical analysis such that, as weight percentages on the basis of the oxides and for a total of 100%:
45%<Al 2 O 3 ,
7.5%<SiO 2 <37% and 0%≤ZrO 2 <35%, provided that 10%<SiO 2 +ZrO 2 <54.3%,
0.1%<B 2 O 3 <2.5%,
other oxides: <6.4%,

Al 2 O 3 constituting the remainder up to 100%,
the boron being distributed in the body of said sintered product, and
more than 15% of grains having an equivalent diameter greater than 1 mm.

16. A process according to claim 15 , wherein 0.25%<B 2 O 3 <1% in the sintered product.

17. A process according to claim 15 , wherein the boron is distributed in the matrix substantially homogeneously.

18. A process according to claim 15 , wherein the aggregate consists, for more than 80% by number, of alumina grains and/or mullite grains and/or mullite-zirconia grains.

19. A process according to claim 15 , wherein 20%<SiO 2 +ZrO 2 <40% in the sintered product.

20. A process according to claim 15 , wherein Al 2 O 3 <85% in the sintered product.

21. A process according to claim 15 , wherein said sintered product has
a chemical analysis such that:
Al 2 O 3 : remainder up to 100%,
(21%≤SiO 2 ≤25% and ZrO 2 <1%) or (14%<SiO 2 <17% and 26%<ZrO 2 <32%),
0.25%<B 2 O 3 <1%,
other oxides: <3%, and

more than 15% of grains having an equivalent diameter greater than 1 mm,
the contents of the chemical analysis being expressed as weight percentages on the basis of the oxides.

22. A process for manufacturing a glass furnace, wherein a sintered product is manufactured according to claim 15 , and used to make said glass furnace.

23. A process as claimed in claim 22 , wherein said sintered product is included in a region which is not capable of coming into contact with molten glass.

24. A process as claimed in claimed in claim 23 , wherein said sintered product is included in a superstructure of said furnace.

25. A process as claimed in claimed in claim 24 wherein said sintered product is included in a crown of said furnace.

Assignees

• Saint Gobain Ct Recherches

Inventors

• Champion Thibault
• Citti Olivier
• Bobo Michel

Classifications

• C04B2235/3217

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

• C04B2235/6562

  Heating rate · CPC title

• F27D1/02

  Crowns; Roofs · CPC title

• C04B2235/3821

  Boron carbides · CPC title

• C04B35/185

  Mullite {3Al2O3-2SiO2} · CPC title