Method for manufacturing cement from an aluminosilicate raw material

Patent metadata

Field	Value
Publication number	US-11919808-B2
Application number	US-202117456249-A
Country	US
Kind code	B2
Filing date	Nov 23, 2021
Priority date	Nov 26, 2020
Publication date	Mar 5, 2024
Grant date	Mar 5, 2024

Abstract

A method for manufacturing cement may include: supplying at least one etching effluent of a substrate based on silicon including a silicate of an alkali metal, M, having formula SiO 2 :M 2 O, and having a molar ratio SiO 2 /M 2 O greater than or equal to 0.8; supplying an aluminosilicate raw material, and mixing the aluminosilicate raw material with the etching effluent having a molar ratio SiO 2 /M 2 O greater than or equal to 0.8. The silicate solution of alkali metal may be recovered with an existing silicon industrial process, implementing a silicon etching. The environmental impact of the method of manufacturing cement may therefore be reduced.

First claim

The invention claimed is:

1. A method for manufacturing cement, the method comprising:
mixing an aluminosilicate raw material with at least one etching effluent of a substrate comprising silicon comprising a silicate of a dissolved alkali metal M, and having a formula SiO 2 :M 2 O, with an SiO 2 /M 2 O molar ratio greater than or equal to 0.8.

2. The method of claim 1 , further comprising, prior to the mixing:
verifying that the SiO 2 /M 2 O molar ratio of the at least one etching effluent is greater than or equal to 0.8.

3. The method of claim 2 , wherein the verifying comprises measuring the SiO 2 /M 2 O molar ratio in the at least one etching effluent, and optionally modifying the at least one etching effluent in such a way that the SiO 2 /M 2 O molar ratio reaches a determined value.

4. The method of claim 3 , wherein the modifying of the at least one etching effluent comprises adjusting relative molar concentrations between the silicate and the alkali metal M, and/or a combination of a plurality of separate etching effluents.

5. The method of claim 1 , further comprising, prior to mixing with the at least one etching effluent:
measuring the SiO 2 /M 2 O molar ratio in the at least one etching effluent, and optionally modifying the at least one etching effluent in such a way that the SiO 2 /M 2 O molar ratio reaches a determined value.

6. The method of claim 5 , wherein measuring the SiO 2 /M 2 O molar ratio is taken in an etching bath, during an etching of the substrate, by an equipment suitable for regulating the etching bath.

7. The method of claim 6 , wherein the etching of the silicon comprises a plurality of successive etchings of substrates based on silicon in the etching bath,
wherein several measurements of the SiO 2 /M 2 O molar ratio are taken during the plurality of successive etching.

8. The method of claim 1 , wherein the at least one etching effluent has a pH greater than 9.

9. The method of claim 1 , wherein the SiO 2 /M 2 O molar ratio is greater than or equal to 0.8 and less than or equal to 3.

10. The method of claim 1 , wherein the aluminosilicate raw material is a natural mineral, metallurgical slag, fly ash, silica fume, volcanic tuff, tailings, or a mixture of two or more of any of these.

11. The method of claim 1 , wherein the substrate is based on silicon suitable for forming a photovoltaic cell.

12. The method of claim 1 , wherein the substrate is based B on silicon suitable for forming a microelectronic component.

13. The method of claim 1 , wherein the SiO 2 /M 2 O molar ratio greater than or equal to 1.40.

14. The method of claim 13 , further comprising, prior to the mixing:
verifying that the SiO 2 /M 2 O molar ratio the at least one etching effluent is greater than or equal to 1.40.

15. The method of claim 1 , wherein the aluminosilicate raw material comprises kaolinite and/or clay.

16. A method of manufacturing cement, the method comprising: combining a geopolymer cement raw material and an etching effluent of a substrate comprising silicon, formed from a silicate solution of a monovalent metal, having a formula SiO 2 :M 2 O, and having an SiO 2 /M 2 O molar ratio greater than or equal to 0.8.

17. The method of claim 16 , wherein the substrate is based on silicon suitable for forming a photovoltaic cell or a microelectronic component.

Assignees

• Commissariat Energie Atomique

Inventors

• Vandenbossche Martin

Classifications

• C04B12/005 Primary

  Geopolymer cements, e.g. reaction products of aluminosilicates with alkali metal hydroxides or silicates · CPC title

• C04B7/24 Primary

  Cements from oil shales, residues or waste other than slag · CPC title

• C04B28/006

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

• Y02P40/10

  Production of cement, e.g. improving or optimising the production methods; Cement grinding · CPC title

• C04B14/10

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