Non-fired monoliths

Patent metadata

Field	Value
Publication number	US-11111179-B2
Application number	US-201816754290-A
Country	US
Kind code	B2
Filing date	Oct 11, 2018
Priority date	Oct 11, 2017
Publication date	Sep 7, 2021
Grant date	Sep 7, 2021

Abstract

The invention relates to methods for manufacturing an inorganic polymer object from a precursor wherein the precursor consists of one or more or comprises one or more selected from the group consisting of gibbsite-containing bauxite, gibbsite containing residue of the Bayer process, thermally processed gibbsite-containing bauxite, and thermally processed gibbsite-containing residue of the Bayer process, the method comprising the steps of alkaline-activating said precursor, mixing the precursor, shaping the mixed precursor and hydrothermally curing the shaped precursor at a temperature between 70° C. and 350° C.

First claim

The invention claimed is:

1. A method for manufacturing an inorganic polymer object from a precursor that comprises a gibbsite-containing residue or a thermally processed gibbsite-containing residue of the Bayer process, the precursor comprising less than 0.01 wt % silica fume, the method comprising:
alkaline-activating the precursor;
mixing the precursor;
shaping the precursor after the mixing; and
hydrothermally curing the precursor, after the shaping, at a temperature from 70° C. to 350° C. and under a pressure greater than 1 bar and less than 500 bar.

2. The method according to claim 1 , wherein the gibbsite containing residue comprises gibbsite in an amount greater than 2 wt %.

3. The method according to claim 1 , wherein the precursor further comprises a gibbsite containing bauxite or a thermally processed gibbsite containing bauxite.

4. The method according to claim 1 , wherein said precursor comprises up to 40 wt % one or more of a component selected from the group consisting of quartz sand, precipitated silica, natural clay, calcareous sand, thermally-activated clay, chemically-activated clay, mechanically-activated clay, fly ash from bituminous coal, subbituminous coal or lignite, gibbsite-containing electrostatic precipitation dust (ESP dust), aluminium salt cake, processed aluminium dross, CaCO 3 , CaO, Ca(OH) 2 , monocalcium silicate, dicalcium silicate, tricalcium silicate, metallurgical slag, EN 197-1 blended cement, cement kiln dust, soda-lime-silica glass or other glass compositions, thermally processed bauxite residue, and vitreous slag.

5. The method according to claim 1 , wherein the hydrothermal curing is performed under a pressure from 1 bar to 90 bar.

6. The method according to claim 1 , wherein the precursor consists of a naturally occurring mineral, of a rock, or of a residue from an ore subjected to the Bayer process.

7. The method according to claim 1 , wherein the precursor contains less than 15 wt % diaspore [(α-AlO(OH)] and less than 15 wt % boehmite [γ-AlO(OH)].

8. The method according to claim 1 , wherein the precursor has a normalized chemical composition, as deduced by X-Ray fluorescence analysis, comprising the following elements, expressed as oxides:
from 1 wt % to 60 wt % Fe 2 O 3 ;
from 5 wt % to 80 wt % Al 2 O 3 ;
from 0 wt % to 50 wt % SiO 2 ;
from 0 wt % to 25 wt % TiO 2 ;
from 0 wt % to 20 wt % Na 2 O; and
from 0 wt % to 20 wt % CaO.

9. The method according to claim 1 , wherein the precursor has, as determined by a thermogravimetric analysis carried out at a temperature between 25° C. to 1000° C., a loss on ignition or volatile substances from 1 wt % to 40 wt %.

10. The method according to claim 1 , wherein the alkaline-activating the precursor comprises contacting the precursor with an alkaline solution selected from one or more of the group consisting of hydroxides, silicates, sulfates, sulfides, sulfites, carbonates of Na- and/or K- and/or Ca, spent Bayer liquor, Na-aluminate solution, and a liquid component of bauxite residue slurry.

11. The method according to claim 1 , wherein the alkaline-activating the precursor comprises contacting the precursor with an alkaline solution having a 0.5 mol/L to 28 mol/L equivalent concentration for NaOH and a 0.5 mol/L to 22 mol/L equivalent concentration for KOH.

12. The method according to claim 1 , wherein the alkaline-activating the precursor comprises contacting the precursor with a solution that has a total molar ratio of SiO 2 /(Na 2 O+K 2 O) from 0 to 4 and a total molar ratio of H 2 O/(Na 2 O+K 2 O) from 5 to 200.

13. The method according to claim 1 , wherein shaping the precursor comprises casting the precursor into a mold, optionally followed by vibration, with a shaping pressure not exceeding 5 MPa.

14. The method according to claim 1 , wherein shaping the precursor comprises press-shaping the precursor at a pressure from 5 MPa to 80 MPa.

15. The method according to claim 1 , wherein the shaping of the precursor is performed for a time from 1 sec to 10 min.

16. The method according to claim 1 , wherein the hydrothermal curing is performed at a temperature from 90° C. to 350° C.

17. The method according to claim 1 , wherein the precursor comprises from 0 wt % to less than 0.01 wt % water-soluble silicate in the form of sodium silicate or potassium silicate.

18. The method according to claim 1 , wherein the precursor comprises from 0 wt % to less than 0.1 wt % fluoride.

19. The method according to claim 1 , wherein the precursor comprises a total from 0 wt % to less than 0.01 wt %, based on the total weight of the precursor, of ground granulated blast furnace slag, basic oxygen furnace slag, kaolin tailings, and coal gangue.

20. The method according to claim 1 , wherein the precursor further comprises from 0.05 wt % to 0.3 wt % fibers, based on the total weight of the precursor.

Assignees

• Univ Leuven Kath

Inventors

• Hertel Tobias
• Pontikes Yiannis

Classifications

• C04B28/008 Primary

  Mineral polymers other than those of the Davidovits type, e.g. from a reaction mixture containing waterglass · CPC title

• C04B28/005 Primary

  containing gelatineous or gel forming binders, e.g. gelatineous Al(OH)3, sol-gel binders · CPC title

• C04B14/10

  Clay {(sepiolite C04B14/042; grog C04B18/025)} · CPC title

• C04B40/024

  Steam hardening, e.g. in an autoclave · CPC title

• C04B20/0048

  Fibrous materials · CPC title