Insulating mineral foam
A process for producing a mineral foam includes (i) separately preparing one or more slurries of cement, and an aqueous foam for which a D50 of bubbles is less than or equal to 400 μm; (ii) homogenizing the one or more slurries of cement with the aqueous foam to obtain a slurry of foamed cement; (iii) casting the slurry of foamed cement and leaving the cast slurry of foamed cement to set.
1. A process for production of a mineral foam continuously comprising:
(i) separately preparing one or more slurries of cement, and an aqueous foam for which a D50 of bubbles is less than or equal to 400 μm;
(ii) homogenizing the one or more slurries of cement with the aqueous foam to obtain a slurry of foamed cement;
(iii) casting the slurry of foamed cement without interruption and leaving the cast slurry of foamed cement to set,
wherein said slurry of foamed cement comprises at least, in % by mass relative to the mass of the slurry of foamed cement:
from 20 to 70% of cement;
from 1 to 5% of calcium sulfate;
from 0.5 to 10% of calcium aluminate cement;
from 0.05 to 3% of a water reducer, a plasticizer or a superplasticizer;
from 0.001 to 0.5% of a retarder;
from 0.1 to 5% of a foaming agent;
from 15 to 40% of water;
the calcium aluminate cement/calcium sulphate ratio being from 0.5 to 2.5, wherein said calcium aluminate cement and said calcium sulphate are expressed in mass percentage;
the calcium sulphate/cement ratio being from 0.03 to 0.09; wherein said calcium sulphate and said cement are expressed in mass percentage.
2. The process for production of a mineral foam according to claim 1 , wherein step (i) comprises the preparation of two slurries of cement, one of which is a slurry of calcium aluminate cement.
3. The process for production of a mineral foam according to claim 1 , wherein step (ii) comprises the introduction of the slurry or slurries of cement and the aqueous foam into a static mixer to obtain a slurry of foamed cement.
4. The process for production of a mineral foam according to claim 1 , wherein the aqueous foam is generated continuously.
5. The process for production of a mineral foam according to claim 1 , wherein the one or more slurries of cement is/are generated continuously.
6. The process for production of a mineral foam according to claim 3 , wherein the static mixer includes elements in the form of a propeller to ensure complete radial mixing and successive divisions of flow for each combination of liquids and gas.
7. The process for production of a mineral foam according to claim 3 , wherein the static mixer includes helical elements which transmit a radial speed to fluid, which is directed alternatively towards a side of the mixer, then towards a centre of the mixer.
8. The process for production of a mineral foam according to claim 1 , wherein the slurry of foamed cement comprises a foaming agent that is a protein.
9. The process for production of a mineral foam according to claim 8 , wherein the foaming agent is keratin.
10. A process for production of a mineral foam continuously comprising:
(i) separately preparing one or more slurries of cement, and an aqueous foam for which the D50 of the bubbles is less than or equal to 400 μm;
(ii) homogenizing the one or more slurries of cement with the aqueous foam to obtain a slurry of foamed cement;
(iii) casting the slurry of foamed cement without interruption and leave it to set;
wherein said slurry of foamed cement comprises at least, in % by mass relative to the mass of the slurry of foamed cement:
from 30 to 75% of cement described according to the European NF EN 197-1 Standard of February 2001 or mixtures thereof;
from 10 to 70% of fine mineral particles with a D50 less than or equal to 5 μm;
from 0 to 15% of ultrafine mineral particles with a D50 less than or equal to 1 μm;
from 0.05 to 3% of a water reducer, a plasticizer or a superplasticizer;
from 0.0001 to 1% of a retarder;
from 0 to 0.1% of a thickening agent;
from 0.01 to 5% of a foaming agent;
from 0 to 0.5% of alkaline sulphates;
from 0 to 1% of an accelerator;
from 10 to 70% of water;
the fine mineral particles/cement ratio being comprised from 0.27 to 0.6, wherein said fine mineral particles and said cement are expressed in mass percentage;
the ultrafine mineral particles/fine particles ratio being comprised from 0 to 0.5, wherein said ultrafine mineral particles and said fine mineral particles are expressed in mass percentage.
11. The process for production of a mineral foam according to claim 10 , wherein step (ii) comprises the introduction of the slurry or slurries of cement and the aqueous foam into a static mixer to obtain a slurry of foamed cement.
12. The process for production of a mineral foam according to claim 10 , wherein the aqueous foam is generated continuously.
13. The process for production of a mineral foam according to claim 10 , wherein the one or more slurries of cement is/are generated continuously.
14. The process for production of a mineral foam according to claim 11 , wherein the static mixer have elements in the form of a propeller to ensure complete radial mixing and successive divisions of flow for each combination of liquids and gas.
15. The process for production of a mineral foam according to claim 11 , wherein the static mixer have helical elements which transmit a radial speed to fluid, which is directed alternatively towards a side of the mixer, then towards a centre of the mixer.
16. The process for production of a mineral foam according to claim 10 , wherein the slurry of foamed cement comprises a foaming agent that is a protein.
17. The process for production of a mineral foam according to claim 16 , wherein the foaming agent is keratin.