PROCESS FOR THE PRODUCTION OF AN ULTRA-LIGHT MINERAL FOAM
A process for the production of a mineral foam includes (i) separately preparing a slurry of cement and an aqueous foam, wherein the cement slurry includes water (W) and Portland cement (C); (ii) contacting the slurry of cement with the aqueous foam to obtain a slurry of foamed cement; (iii) adding a transition metal salt before, during or after procedure (ii); (iv) casting the slurry of foamed cement and leaving it to set.
1 . A method for the production of a mineral foam comprising the following steps:
(i) separately preparing a cement slurry and an aqueous foam, wherein the cement slurry comprises water (W) and Portland cement (C);
(ii) contacting the cement slurry with the aqueous foam to obtain a slurry of foamed cement;
(iii) adding a transition metal salt before, during or after step (ii);
(iv) casting the slurry of foamed cement and leaving it to set.
2 . The method according to claim 1 , wherein the transition metal salt is a manganese salt.
3 . The method according to claim 1 , wherein the transition metal salt is added to the Portland cement before the addition of water in the preparation of the cement slurry in step (i).
4 . The method according to claim 1 , wherein the transition metal salt is added to the cement slurry before contacting the cement slurry with the aqueous foam in step (ii).
5 . The method according to claim 1 , wherein the transition metal salt is added in an amount comprised between 0.8% and 1.2% in weight of dry transition metal salt relative to the weight of cement.
6 . The method according to claim 1 , wherein the water/cement (W/C) ratio (weight/weight ratio) of the cement slurry prepared in step (i) is comprised between 0.30 and 0.40.
7 . The method according to claim 1 , wherein the cement slurry comprises at least one supplementary mineral component selected from calcium carbonate, silica, ground glass, solid or hollow glass beads, glass granules, expanded glass powders, silica aerogels, silica fume, slags, ground sedimentary siliceous sands, fly ash, pozzolanic materials or mixtures thereof.
8 . A method comprising utilizing a transition metal salt for enhancing the mechanical stability and/or reducing the collapse of a slurry of foamed cement, said slurry of foamed cement being obtained by:
(i) separately preparing a cement slurry and an aqueous foam, wherein the cement slurry comprises water (W) and Portland cement (C);
(ii) contacting the cement slurry with the aqueous foam to obtain a slurry of foamed cement;
(iii) adding the transition metal salt before, during or after step (ii).
9 . The method according to claim 8 , wherein the transition metal salt is added in an amount comprised between 0.8% and 1.2% in weight of dry transition metal salt relative to the weight of cement.
10 . The mineral foam obtained or obtainable according to claim 1 having a density of 20 to 300 kg/m 3 .
11 . The mineral foam according to claim 10 having a thermal conductivity of 0.030-0.150 W/(m·K).
12 . A method comprising utilizing the mineral foam according to claim 10 as construction material or as insulating material.
13 . An element of construction comprising a mineral foam according to claim 10 .
14 . The process according to claim 2 , wherein the manganese metal salt is manganese chloride or manganese sulfate.
15 . The process according to claim 6 , wherein the water/cement (W/C) ratio (weight/weight ratio) of the cement slurry prepared in step (i) is comprised between 0.32 and 0.38.
16 . The process according to claim 15 , wherein the water/cement (W/C) ratio (weight/weight ratio) of the cement slurry prepared in step (i) is 0.37.
17 . The method according to claim 8 , wherein the transition metal salt is a manganese salt.
18 . The method according to claim 17 , wherein the manganese salt is manganese chloride or manganese sulfate.
19 . The method according to claim 18 , comprising utilizing a manganese chloride solution or a manganese sulfate solution.