Non-fired monoliths

Patent metadata

Field	Value
Publication number	US-2021198144-A1
Application number	US-201816754290-A
Country	US
Kind code	A1
Filing date	Oct 11, 2018
Priority date	Oct 11, 2017
Publication date	Jul 1, 2021
Grant date	—

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

1 - 20 . (canceled)

21 . 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.

22 . The method according to claim 21 , wherein the gibbsite containing residue comprises gibbsite in an amount greater than 2 wt %.

23 . The method according to claim 21 , wherein the precursor further comprises a gibbsite containing bauxite or a thermally processed gibbsite containing bauxite.

24 . The method according to claim 21 , 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.

25 . The method according to claim 21 , wherein the hydrothermal curing is performed under a pressure from 1 bar to 90 bar.

26 . The method according to claim 21 , wherein the precursor consists of a naturally occurring mineral, of a rock, or of a residue from an ore subjected to the Bayer process.

27 . The method according to claim 21 , wherein the precursor contains less than 15 wt % diaspore [(α-AlO(OH)] and less than 15 wt % boehmite [γ-AlO(OH)].

28 . The method according to claim 21 , 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.

29 . The method according to claim 21 , 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 %.

30 . The method according to claim 21 , 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 liqour, Na-aluminate solution, and a liquid component of bauxite residue slurry.

31 . The method according to claim 21 , 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.

32 . The method according to claim 21 , 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.

33 . The method according to claim 21 , wherein shaping the precursor comprises casting the precursor into a mold, optionally followed by vibration, with a shaping pressure not exceeding 5 MPa.

34 . The method according to claim 21 , wherein shaping the precursor comprises press-shaping the precursor at a pressure from 5 MPa to 80 MPa.

35 . The method according to claim 21 , wherein the shaping of the precursor is performed for a time from 1 sec to 10 min.

36 . The method according to claim 21 , wherein the hydrothermal curing is performed at a temperature from 90° C. to 350° C.

37 . The method according to claim 21 , 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.

38 . The method according to claim 21 , wherein the precursor comprises from 0 wt % to less than 0.1 wt % fluoride.

39 . The method according to claim 21 , 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.

40 . The method according to claim 21 , 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

• C04B18/0409

  Waste from the purification of bauxite, e.g. red mud · CPC title

• C04B40/024

  Steam hardening, e.g. in an autoclave · 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

• C04B20/0048

  Fibrous materials · CPC title