Method for the continuous production of a low-density mineral foam
A method for the continuous production of a mineral foam of which the density in the dry state (d) is from 40 to 600 kg/m 3 , includes (i) mixing cement; a water reducing agent; 0.5 to 10%, % by weight with respect to the total weight of cement, of ultrafine particles having a liquid-solid contact angle comprised from 30° to 140°, and of which the D50 is from 10 to 600 nm; water, with a water/cement weight ratio from 0.3 to 2.5; (ii) adding to the mixture from 0.5 to 10% of a pore-forming agent, % by weight with respect to the weight of cement; (iii) applying the mixture obtained at step (ii) on a support; (iv) leaving the mixture to expand on the support.
1. A method for the continuous production of a mineral foam of which the density in the dry state (d) is comprised from 40 to 600 kg/m 3 , comprising the following steps:
(i) mixing
cement;
a water reducing agent;
0.5 to 10%, % by weight with respect to the total weight of cement, of ultrafine particles having a liquid-solid contact angle comprised from 30° to 140°, and of which the D50 is comprised from 10 to 600 nm;
water, with a water/cement weight ratio comprised from 0.3 to 2.5;
(ii) adding to the mixture from 0.5 to 10% of a pore-forming agent, % by weight with respect to the weight of cement;
(iii) applying the mixture obtained at step (ii) on a support;
(iv) leaving the mixture to expand on the support.
2. The method according to claim 1 , wherein the cement of the mixture of step (i) is a cement of which the Blaine specific surface area is comprised from 5000 to 9000 cm 2 /g.
3. The method according to claim 1 , wherein there is no foaming agent in the mixture of step (i) or (ii).
4. The method according to claim 1 , wherein the mixture of step (i) or step (ii) further comprises a transition metal salt.
5. The method according to claim 4 , wherein the transition metal salt is a manganese salt or an iron salt.
6. The method according to claim 1 , wherein the mixture of step (i) further comprises a mineral addition of which the particles have a D50 comprised from 0.1 to 4 mm.
7. The method according to claim 6 , wherein the mineral addition is selected from the group consisting of a pozzolan, a slag, calcium carbonate, a fly ash, a sand and mixtures thereof.
8. The method according to claim 1 , wherein the pore-forming agent added at step (ii) is a solution of hydrogen peroxide, a solution of peroxomonosulphuric acid, a solution of peroxodisulfphuric acid, a solution of alkaline peroxides, a solution of alkaline earth peroxides, a solution of organic peroxide, a suspension of particles of aluminium or mixtures thereof.
9. The method according to claim 8 , wherein the organic peroxide is peroxoacetic acid or peroxobenzoic acid.
10. The method according to claim 1 , wherein the mixture of step (i) further comprises a hydration accelerator of the cement.
11. The method according to claim 10 , wherein the hydration accelerator is calcium chloride.
12. The method according to claim 1 , wherein the mixture obtained at step (ii) is not fractionated.
13. The method according to claim 1 , wherein at step (iii), the mixture is applied without using a spray nozzle.
14. The method according to claim 1 wherein step (iii) is carried out without a spray.
15. The method according to claim 1 , wherein the support used at step (iii) is treated prior to the application of the mixture obtained at step (ii).
16. A mineral foam capable of being obtained according to the method of claim 1 .
17. A method comprising utilizing the mineral foam according to claim 16 as insulation material.
18. The method according to claim 17 , wherein the insulation material is a thermal or phonic insulation material.