Uncalcined geopolymer-based refractory material and method for its preparation

Patent metadata

Field	Value
Publication number	US-11873247-B2
Application number	US-202318129441-A
Country	US
Kind code	B2
Filing date	Mar 31, 2023
Priority date	Sep 14, 2020
Publication date	Jan 16, 2024
Grant date	Jan 16, 2024

Abstract

Disclosed is a method for preparing an uncalcined geopolymer-based refractory material. The method includes the steps of mixing a mineral powder, a fly ash, a metakaolin, and silicon carbide whiskers by ball milling to form a milled material; mixing the milled material with a sodium water glass solution and water to form a slurry; and curing the slurry to obtain the uncalcined geopolymer-based refractory material. The uncalcined geopolymer-based refractory material thus prepared contains a geopolymer matrix formed of the mineral powder, the fly ash, and the metakaolin and the silicon carbide whiskers embedded in the geopolymer matrix.

First claim

What is claimed is:

1. A method for preparing an uncalcined geopolymer-based refractory material, the method comprising the steps of:
(a) mixing a mineral powder, a fly ash, a metakaolin, and silicon carbide whiskers by ball milling to form a milled material;
(b) mixing the milled material with a sodium water glass solution and water to form a slurry; and
(c) curing the slurry to obtain the uncalcined geopolymer-based refractory material,
wherein the uncalcined geopolymer-based refractory material comprises (i) a geopolymer matrix formed by polymerization of a mixture consisting of the mineral powder, the fly ash, and the metakaolin, and (ii) the silicon carbide whiskers embedded in the geopolymer matrix.

2. The method of claim 1 , further comprising, before step (a), subjecting the silicon carbide whiskers to a dispersion treatment by mixing the silicon carbide whiskers with a dispersant solution by ultrasonic vibration, followed by drying, wherein the dispersant solution is a 95 wt. % aqueous solution of 2-amino-2-methyl-1-propanol.

3. The method of claim 1 , wherein, in step (a), the mineral powder, the fly ash, the metakaolin, and the silicon carbide whiskers are ball milled together with zirconium oxide beads having a diameter of 5 mm at a rotation speed of 150 rpm for 25 min.

4. The method of claim 1 , wherein the sodium water glass used in step (b) has a SiO 2 /Na 2 O modulus in the range from 1.5 to 3.5, the ratio of the mass of sodium silicate in the sodium water glass solution to the total mass of the mineral powder, the fly ash, and the metakaolin is 0.15:1, and the ratio of the total mass of the water used in step (b) and the water in the sodium water glass solution to the total mass of the mineral powder, the fly ash, and the metakaolin is 0.4:1.

5. The method of claim 1 , wherein, in step (c), the slurry obtained in step (b) is cured by placing it in a mold inside a curing chamber for 24 h at 95±5% relative humidity and 23±0.5° C. and then maintaining it inside the curing chamber after removal from the mold for 7 days under the same temperature and humidity conditions.

6. The method of claim 1 , wherein the silicon carbide whiskers are present in the geopolymer matrix in an amount of 0.8 to 1.2 wt. %.

7. The method of claim 6 , wherein the silicon carbide whiskers, consisting of pure silicon carbide only or boron nitride coated silicon carbide, have a diameter of 0.1 to 2.5 μm and a length of 2 to 50 μm.

8. The method of claim 7 , wherein the boron nitride coated silicon carbide whiskers have a 50 to 250 nm thick boron nitride coating.

9. The method of claim 6 , further comprising, before step (a), subjecting the silicon carbide whiskers to a dispersion treatment by mixing the silicon carbide whiskers with a dispersant solution by ultrasonic vibration, followed by drying, wherein the dispersant solution is a 95 wt % aqueous solution of 2-amino-2-methyl-1-propanol.

10. The method of claim 1 , wherein the silicon carbide whiskers, consisting of pure silicon carbide or boron nitride coated silicon carbide, have a diameter of 0.1 to 2.5 μm and a length of 2 to 50 μm.

11. The method of claim 10 , wherein the boron nitride coated silicon carbide whiskers have a 50 to 250 nm thick boron nitride coating.

12. The method of claim 10 , further comprising, before step (a), subjecting the silicon carbide whiskers to a dispersion treatment by mixing the silicon carbide whiskers with a dispersant solution by ultrasonic vibration, followed by drying, wherein the dispersant solution is a 95 wt % aqueous solution of 2-amino-2-methyl-1-propanol.

13. The method of claim 1 , wherein the mineral powder is a high-calcium mineral powder, the fly ash is a Class F fly ash, and the mass ratio of mineral powder:fly ash:metakaolin is (35-45):(25-35):(25-35).

Assignees

• Univ Shenzhen

Inventors

• Fang Yuan
• Xing Feng
• Wang Aoxuan

Classifications

• C04B28/006 Primary

  containing mineral polymers, e.g. geopolymers of the Davidovits type · CPC title

• C04B14/324

  Silicon carbide · CPC title

• C04B14/383

  Whiskers · CPC title

• C04B35/66 Primary

  Monolithic refractories or refractory mortars, including those whether or not containing clay {(making or repairing of linings F27D1/16)} · CPC title

• C04B2235/349

  Clays, e.g. bentonites, smectites such as montmorillonite, vermiculites or kaolines, e.g. illite, talc or sepiolite · CPC title